Dissertations / Theses: 'Rotari'

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Giannotti, Filomena. "Ombre solenni. Personaggi tardoantichi nella letteratura contemporanea." Doctoral thesis, Università di Siena, 2006. http://hdl.handle.net/11365/1207783.

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L'elaborato tratta la presenza di importanti personaggi dell'età imperiale nella cultura contemporanea, in particolare nella narrativa e nel cinema: PARTE PRIMA - FILOSOFI AL POTERE. Capitolo I - Marco Aurelio. Capitolo II - Giuliano l'Apostata. PARTE SECONDA - IMPERATORI 'MINORI'. Capitolo I - Eliogabalo. Capitolo II - Romolo Augustolo. PARTE TERZA - RE BARBARI. Capitolo I - Attila. Capitolo II - Rotari. PARTE QUARTA - PADRI DELLA CHIESA. Capitolo I - Ambrogio. Capitolo II - Girolamo. Capitolo III - Agostino. PARTE QUINTA - SCRITTORI FRA LETTERATURA E IMPEGNO POLITICO. Capitolo I - Claudiano. Capitolo II - Sinesio di Cirene. Capitolo III - Paolo Diacono. PARTE SESTA - FIGURE FEMMINILI. Capitolo I - Ipazia. Capitolo II - Galla Placidia.

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Walsh, Brendan Walsh Patrick. "Rotary." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-12052008-145205/.

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Matos, Catherine Anne Moseley. "Download reduction on a wing-rotor configuation." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/12058.

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Xie, Lihan. "Suivi numérique des bifurcations pour l'analyse paramétrique de la dynamique non-linéaire des rotors." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI018/document.

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Au cœur des moyens de transport, de transformation d'énergie, et de biens d'équipements, les machines tournantes peuvent avoir des comportements dynamiques complexes dus à de multiples sources de non linéarités liées aux paliers hydrodynamiques, à la présence de fissures, aux touches rotor-stator, ... Des phénomènes comme les décalages fréquentiels et donc de vitesses critiques, les cycles d'hystérésis avec sauts d'amplitudes, le changement brutal du contenu fréquentiel des réponses, sont des expressions de ces comportements. Résoudre les équations du mouvement induites par des modélisations avec des éléments finis de type poutre ou volumique, pour calculer les réponses à des sollicitations diverses (comme le balourd ou le poids propre), est réalisable avec des méthodes d'intégration pas à pas dans le temps mais au prix de temps de calcul prohibitifs. Cela devient particulièrement préjudiciable au stade du pré-dimensionnement où il est nécessaire de réaliser rapidement des études paramétriques. Aussi une alternative intéressante est de mettre en {\oe}uvre une méthode numérique, à la fois générale et efficace pour analyser la réponse non linéaire des rotors en régime stationnaire. La démarche proposée combine, dans un premier temps, la méthode de la balance harmonique (HBM) et la technique de bascule Temps-Fréquence (AFT) afin d'obtenir rapidement dans le domaine fréquentiel les réponses périodiques des rotors à grand nombre de degrés de liberté apportés par les éléments finis volumiques. Puis, l'association à la méthode de continuation par pseudo-longueur d'arc aboutit à établir continûment l'ensemble des solutions d'équilibre dynamique sur la plage de vitesse de rotation. Enfin la stabilité dynamique locale de la solution périodique est analysée grâce à des indicateurs de bifurcation basés sur l'évolution des exposants de Floquet. Ainsi sont détectées les bifurcations de branches de solutions périodiques de type point limite, point de branchement et notamment Neimark-Sacker. Leur localisation est déterminée précisément en résolvant un système augmenté constitué de l'équation du mouvement et d'une équation supplémentaire caractérisant le type de bifurcation considéré. En déclarant un paramètre du système (coefficient de frottement, jeu rotor/stator, amplitude de l'excitation,...) comme nouvelle variable, l'utilisation de la technique de continuation conjointement avec le système augmenté détermine directement le cheminement des bifurcations en fonction de ce paramètre sur la nappe des réponses non linéaires. Les suivis de bifurcations délimitent les zones de fonctionnement spécifiques, extraient efficacement l'essentiel du comportement dynamique et offrent ainsi une nouvelle approche pour dimensionner de façon efficace les systèmes notamment en rotation. Nombre des développements réalisés sont implantés dans le code de calcul Cast3M
Generally speaking, the rotating systems utilized in the energy production have a small rotor-stator gap, are able to run during long periods, and are mounted on hydrodynamic bearings. Rotor-stator interactions in case of blade loss, crack propagation due to fatigue, and a variable stiffness due to the nonlinear restoring forces of the bearings can make the rotordynamics nonlinear and the responses complicated: significant amplitude and frequency shifts are introduced, sub- and super-harmonics appear, and hysteresis occurs. It is of great importance to understand, predict and control this complicated dynamics. Due to the large number of DOFs and the broad range of study frequency, the computation time for solving the equations of motion by a temporal integration method can be quite prohibitive. It becomes particularly disadvantageous at the design stage where a parametrical study need to be quickly performed. An alternative numerical method, which is general and effective at the same time, is proposed in order to analyse the nonlinear response of the rotors at steady state. Firstly, the periodic responses of nonlinear rotors are calculated in the frequency domain by combining harmonic balance method (HBM) and alternating frequency-time (AFT). With the help of continuation method, all dynamic equilibrium solutions of nonlinear systems are determined for the range of study frequency. Then, Floquet exponents which are the eigenvalues of Jacobian are sought for stability analysis of periodic solutions. Then the local stability of the periodic solution is analysed through the bifurcation indicators which are based on the evolution of Floquet exponents. The bifurcations of periodic solution branch, such as limit point, branch point, and Neimark-Sacker bifurcation, are thus detected. By declaring a system parameter (friction coefficient, rotor / stator gap, excitation amplitude, ...) as a new variable, applying once again the continuation method to the augmented system determines directly the bifurcation's evolution as a function of this parameter. Thus, parametric analysis of the nonlinear dynamic behaviour is achieved, the stability boundary or the regime change boundary is directly determined. Numerous developments are implemented in the calculation code Cast3M

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Huo, Chao. "Analyse numérique et expérimentale d’un doublet de rotors contrarotatifs caréné au point fixe." Thesis, Toulouse, ISAE, 2012. http://www.theses.fr/2012ESAE0010/document.

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Cette étude se propose d’analyser le comportement du double rotor contra-rotatif caréné dans lecadre des échelles réduites des microdrones, pour exploiter le potentiel d’amélioration desperformances stationnaires des rotors libres. La demande d’une performance propulsive de hautniveau, alors que les échelles sont très réduites constitue un véritable défi scientifique. De façongénérale, par rapport au rotor libre, l’ajout de la carène permet de piloter la contraction del’écoulement et offre un potentiel de poussée de carène. La tuyère par sa condition d’adaptationpilote le débit entrant à puissance donnée. L’augmentation du débit massique, par comparaison ausystème de rotor libre, amplifie la poussée à travers la dépression distribuée sur toute la surface decaptation. Pour comprendre les lois de fonctionnement d’un système propulsif caréné, il a d’abord été proposé un modèle théorique simplifié basé sur une extension de la théorie de Froude pour les rotors libres: le système rotor est assimilé à un disque actuateur, générateur de débit dans une conduite à section variable. Une simulation Navier Stokes 2D axisymétrique a permis d’optimiser les paramètres de forme du carénage. Les simulations ont confirmé l’influence déterminante des sections d’entrée et de sortie, et relativisé l’impact des formes possibles, pourvu que les variations de sections limitent le décollement de la couche limite. Après conception d’un banc d’essai utilisant un doublet de rotor coaxial placé dans cette carène optimisée, l’étude expérimentale complète et confirme les performances globales du système et qualifie l’écoulement méridien. Enfin, une simulation 3D instationnaire a été entreprise pour compléter l’analyse de l’écoulement autour des rotors
This study aims to analyze the behavior of shrouded, contrarotating coaxial rotor in the reducedMAVs’ scale in order to exploit its potential to improve the free rotor steady performance. The highhover ability under low operational Reynolds number is therefore, a scientific challenge. Generally,comparing with free rotor, the addition of the shroud decreases the flow contraction and gives thepotential to generate an extra thrust. A suitable nozzle can control the mass flow for a given power.The increased mass flow, comparing with free rotor, amplifies the thrust offered by the lowpressure formed at the air entrance. To understand the principals of shrouded propulsion system, a simplified theory model was first proposed through the extension of Froude theory for free rotors: the double rotor is initially treated as an actuator disk, generating the flow at varied sections through the shroud passage. A 2D simulation which accounts for an axial flow of viscous effects within the actual shroud profile, confirmed effects of all defined geometrical parameters. It further demonstrated that within the non-stalling region of the different crosssections, shroud shape and inlet shape do not have asignificant impact on performance. The experimental study, carried out with coaxial rotor, contributed to the confirmation of the overall performance and the approximation of the flow field through the shroud. Meanwhile, the 3D simulation, developed to better model the actual coaxial rotor in counter rotation, was validated to well solve the steady performance. It was applied to complement the analysis of the flow around the coaxial rotor

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Alnakar, Raran, and Danilo Catovic. "Rotary parking system." Thesis, KTH, Mekatronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295808.

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Automatic parking systems are intended to save a lot ofspace and create a more favourable parking experience. In this thesis the main goal was to create a functional and user-friendly rotary parking system. The system consistsof a framework, DC-motor, driveline, ultrasonic distance sensor and platforms. Most of the construction consists of plastic, the remaining parts are made of metal. The system was evaluated using two experiments, one that measured the speed of the system and the other one measuring the level of accuracy. After the first experiment, it was concluded that the system works well for the corresponding speed. The second experiment showed that improvements of the accuracy can be made.
Automatiska parkeringssystem är avsedda att spara utrymme och skapa en bättre parkeringsupplevelse. I denna avhandling var huvudmålet att skapa ett funktionellt och användarvänligt roterande parkeringssystem. Systemet består av ett ramverk, likströmsmotor, drivlina, ultraljudssensor och plattformar. Majoriteten av konstruktionen består av plast, de återstående delarna är gjorda av metall. Systemet utvärderades med hjälp av två experiment, ett som mätte systemets hastighet och ett annat som mätte noggrannheten. Efter det första experimentet drogs slutsatsen att systemet fungerar bra för motsvarande hastighet. Det andra experimentet visade att förbättringar av noggrannheten kan göras.

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Alnakar, Rayan, and Danilo Catovic. "Rotary parking system." Thesis, KTH, Mekatronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295808.

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Automatic parking systems are intended to save a lot ofspace and create a more favourable parking experience. In this thesis the main goal was to create a functional and user-friendly rotary parking system. The system consistsof a framework, DC-motor, driveline, ultrasonic distance sensor and platforms. Most of the construction consists of plastic, the remaining parts are made of metal. The system was evaluated using two experiments, one that measured the speed of the system and the other one measuring the level of accuracy. After the first experiment, it was concluded that the system works well for the corresponding speed. The second experiment showed that improvements of the accuracy can be made.
Automatiska parkeringssystem är avsedda att spara utrymme och skapa en bättre parkeringsupplevelse. I denna avhandling var huvudmålet att skapa ett funktionellt och användarvänligt roterande parkeringssystem. Systemet består av ett ramverk, likströmsmotor, drivlina, ultraljudssensor och plattformar. Majoriteten av konstruktionen består av plast, de återstående delarna är gjorda av metall. Systemet utvärderades med hjälp av två experiment, ett som mätte systemets hastighet och ett annat som mätte noggrannheten. Efter det första experimentet drogs slutsatsen att systemet fungerar bra för motsvarande hastighet. Det andra experimentet visade att förbättringar av noggrannheten kan göras.

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Nováková, Naděžda. "Dynamické radiální síly působící na oběžné kolo odstředivého čerpadla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230329.

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This thesis deals with the radial forces acting on the impeller of a centrifugal pump. It focuses on the centrifugal pump type BETA 26. It addresses forces acting on the pump shaft. These forces are converted into the impeller. The most extensive part of this thesis is devoted to the experimental measurement and evaluation. The results are summarized and processed graphically.

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Soykasap, Omer. "Aeroelastic optimization of a composite tilt rotor." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11823.

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Montesanti, Richard Clement. "High bandwidth rotary fast tool servos and a hybrid rotary/linear electromagnetic actuator." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34987.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 541-555).
This thesis describes the development of two high bandwidth short-stroke rotary fast tool servos and the hybrid rotary/linear electromagnetic actuator developed for one of them. Design insights, trade-off methodologies, and analytical tools are developed for precision mechanical systems, power and signal electronic systems, control systems, normal-stress electromagnetic actuators, and the dynamics of the combined systems. A fast tool servo (FTS) is a high-speed auxiliary servo axis that is added to a diamond turning machine (ultra-precision lathe) to allow generating free-form non-axisymmetric or textured surfaces on a workpiece. A rotary fast tool servo produces an in-and-out motion of the tool relative to a workpiece by swinging the tool along an arc having a fixed radius. The rotary fast tool servos developed in this project were designed for diamond turning prescription textured surfaces on small spherical workpieces (diameters in the range of 10 mm or less), and are suitable for generating free-form non-axisymmetric surfaces on similar-sized workpieces. Straightforward modifications would allow them to be used on larger workpieces. These rotary fast tool servos set new benchmarks for demonstrated closed-loop bandwidth (2 kHz and 10 kHz) and tool tip acceleration (400 g).
(cont.) The first machine, referred to as the 2 kHz rotary fast tool servo, uses a commercially available moving-magnet galvanometer as the actuator (Lorentz force), and provides proof-of-principles for a flexure bearing, small diamond tool and mounting method, circuit topology for a high bandwidth current-mode amplifier, and control system design. The following closed-loop performance is demonstrated for the 2 kHz rotary fast tool servo: -3dB bandwidth of 2 kHz, 20 g tool tip acceleration at 2 kHz, maximum tool travel of 50 [mu]m PP, and tool position noise level of 10 nm PP. The 2 kHz FTS is integrated with a diamond turning machine and used to produce optical quality textured surfaces on the face and outside diameter of aluminum workpieces while operating at 2 kHz. The machining tests validate that a rotary-type fast tool servo can be used to produce optical quality surfaces on a spherical workpiece from its pole to its equator. The second machine, referred to as the 10 kHz rotary fast tool servo, incorporates the proof-of-principles from the first machine and is the vehicle for developing the hybrid rotary/linear electromagnetic actuator used in it.
(cont.) The actuator is a normal-stress variable reluctance machine with a demonstrated order of magnitude increase in the peak torque and in the ratio of peak torque divided by the electrical power at its terminals, when compared to the actuator used in the 2 kHz FTS. By integrating the tool holder directly to the moving mass of the actuator to form a single rigid body, the overall torque-to-inertia ratio for the system and the frequency of the first uncoupled-mass resonance are both increased. The following closed-loop performance is demonstrated for the 10 kHz rotary fast tool servo: -3dB bandwidth of 10 kHz, 400 g tool tip acceleration at 5 kHz, 870 g tool tip acceleration at 10 kHz (aided by a stable mechanical resonance), maximum tool travel of 70 [mu]m PP, and tool position noise level of 1.4 to 2.5 nm rms (depending on the magnitude of the bias flux used). The hybrid rotary/linear electromagnetic actuator utilizes a constant bias magnetic flux, which linearizes the torque versus drive-current relationship for the actuator and provides up to half of the torque-producing magnetic flux in the rotor/stator air gaps. The actuator is similar to the rotary actuators used to drive and sustain a resonance in a mechanical oscillator in certain electric engraving heads.
(cont.) This research is distinguished from the prior art by the ability to generate closed-loop arbitrary trajectories for the tool tip. Using a separate current-mode amplifier for each stator half allows demonstrating closed-loop control of the rotary and linear degrees of freedom that are inherent in this class of actuators. This research is further distinguished from the prior art by a magnetic circuit that substantially decouples certain magnetic flux paths when a coil is used instead of a permanent magnet to provide the bias magnetic flux. This reduces the complexity of the actuator electrical dynamics from a MIMO system to a SISO system, and allows using loop-shaping techniques with classical control theory to design the control systems. Torque control for the hybrid rotary/linear actuator in the 10 kHz FTS is independent of force control, but force control requires a torque-generating current to act as an operating point. Alternate magnetic circuit topologies that fully decouple torque and force control are described and compared. Future work that utilizes the linear mode as an active suspension for improving the performance of a predominantly rotary system is considered. Using the experience gained by designing, building, and testing the 10 kHz FTS and hybrid rotary/linear actuator, future work involving alternate concepts for the actuator is suggested for a follow-on rotary fast tool servo, and a high bandwidth steering mirror.
by Richard Clement Montesanti.
Ph.D.

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Azzam, Tarik. "Aérodynamique et contrôle de l'écoulement de jeu dans un ventilateur axial obtenu par rotomoulage." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0080/document.

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Aujourd’hui, la fabrication des turbomachines est conditionnée par des normes de plus en plus restrictives. L'enjeu industriel pour les chercheurs est d'envisager des solutions optimales visant à réduire les sources de perte d'énergie, d'instabilité et du bruit, en particulier l'écoulement de jeu (débit de fuite). Des actions préliminaires ont été élaborées à Arts & Métiers ParisTech sur le rotomoulage du ventilateur axial de refroidissement d'automobile. L'idée de ce travail est d'utiliser la forme creuse induite par le rotomoulage afin de l'exploiter dans le controle de l'écoulement de jeu radial par soufflage rotatif. Pour cela, la virole comporte des trous d'injection orientés de façon à réduire simultanément le débit de fuite et le couple. Dans ce travail, trois parties ont été traité. La première concerne la réalisation du ventilateur par rotomoulage. La deuxième concerne l'étude expérimentale menée dans le banc d'essai ISO 5801. Cette étude comporte la réalisation d'un montage dédié au contrôle par soufflage rotatif, la métrologie menée pour la détermination des performances globales et la caractérisation de la vitesse axiale du sillage proche. La troisième partie traite la modélisation numérique des conditions expérimentales rentables ensuite l'extrapolation du travail vers des taux d'injection importants. Pour ce dernier, on arrive à annuler le débit de fuite avec un gain considérable du couple mettant ainsi le ventilateur en autorotation
Nowadays, the manufacture of turbomachinery is conditioned by more and more restrictive rules. The industrial challenge for researchers has to consider optimal solutions to reduce sources of energy loss, instability and noise, particularly the tip clearance flow (leakage flow rate). Preliminary actions have been developed at Arts & ParisTech on rotational molding process used for the automobile cooling axial fan. The idea of this work is to use the hollow shape induced by rotational molding process in order to exploit it in the control of tip clearance flow through rotary steady air injection. For this, the shroud ring is composed of injection holes oriented in such away to reduce both of leakage flow rate and the torque. In this work, the thesis focuses on three parts. The first concerns the build of the fan by rotational molding process. The second concerns the experimental study carried out in the ISO 5801 test bench. This study involves the realization of drive system dedicated to rotary steady air injection, metrology for performance determination and the characterization of the near wake axial velocity. The third part deals with the numerical modeling of efficient experimental conditions, then the extrapolation of work towards high injection rates. For this latter, it is possible to cancel leakage flow rate with a considerable gain of the torque thus putting the fan in autorotation

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Blažo, Marek. "Hnací ústrojí závodního Wankelova rotačního motoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229075.

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The main aim of master’s thesis was to handle the computing proposal and the construction design of the powertrain of racing Wankel rotary engine with 300 kW power output and in the case of 9000 speed per minute. On the basic of these values was made the primary design of the rotary engine, design of the eccentric shaft and rotor housing. Mechanical stress and torsional vibrations of the eccentric shaft were analyzed by using the course of indicator diagram.

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Маренич, М. М. "Розробка та дослідження конструкції ротаційного компресора з ротором що котиться. Моделювання коливань ротора." Master's thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/72120.

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У дослідній частині поставлені задачі виконати дослідження та проектування резонансних частот коливань ротаційного компресора з ротором що котиться. У конструкторській частині виконано міцнісний розрахунок вала компресора, конструктивні розрахунки підшипників, муфти, ущільнень, клапанів. Визначення основних геометричних розмірів проектованого компресора. Конструктивний розрахунок конденсатора повітряного охолодження. В розділі охорони праці проведено аналіз небезпечних та шкідливих виробничих факторів при роботі ротаційного компресора з ротором що котиться, виконано розрахунок занулення електрообладнання.
В исследовательской части поставленные задачи выполнить исследования и проектирования резонансных частот колебаний ротационного компрессора с ротором что катится. В конструкторской части выполнен прочностной расчет вала компрессора, конструктивные расчеты подшипников, муфты, уплотнений, клапанов. Определение основных геометрических размеров проектируемого компрессора. Конструктивный расчет конденсатора воздушного охлаждения. В разделе охраны труда проведен анализ опасных и вредных производственных факторов при работе ротационного компрессора с ротором что катится, произведен расчет зануления электрооборудования.
In the research part of the task to perform research and design of the resonant frequencies of a rotary compressor with a rotor that rolls. In the design part, the strength calculation of the compressor shaft, structural calculations of bearings, couplings, seals, valves are performed. Determination of the main geometric dimensions of the designed compressor. Constructive calculation of the air-cooled condenser. In the section of labor protection, an analysis of hazardous and harmful production factors has been carried out during the operation of a rotary compressor with a rotor that rolls, the calculation of electrical vanishing has been performed.

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Qi, Fei. "Light-driven molecular rotary motors." HKBU Institutional Repository, 2017. https://repository.hkbu.edu.hk/etd_oa/434.

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In the past two decades, a number of artificial molecular motors have been constructed using organic molecules as components which can perform unidirectional motion. Among the best-known examples are the light-activated molecular rotary motors synthesized and analyzed in B. L. Feringa's lab. Yet there is limited understanding of the photoisomerization and thermal isomerization processes that control the speed and energy conversion efficiency of these molecular devices. The present thesis work aims at: 1) developing a computational methodology to provide the atomic and electronic details that allow for quantitative descriptions of light-activated molecular motion, 2) improving the understanding of the physical principles governing photo- and thermal-isomerization processes in specific molecular systems, and 3) proposing a new strategy of molecule design to assist experimental investigations. A key component in our methodology is the calculation of the potential energy surface (PES) spanned by collective atomic coordinates using ab initio quantum mechanical methods. This is done both for the electronic ground state, which is relatively straightforward, and for the photo-excited state, which is more involved. Once the PES is known, classical statistical mechanical methods can be used to analyze the dynamics of the slow variables from which information about the rotational motion can be extracted. Calculation of the PES is computationally expensive if one were to sample the very high dimensional space of the atomic coordinates. A new method, based on the torque experienced by individual atoms, is developed to capture key aspects of the intramolecular relaxation in terms of angular variables associated with the rotational degrees of freedom. The effectiveness of the approach is tested on specific light-driven molecular rotary motors that were successfully synthesized and analyzed in previous experiments. Finally, based on the experience accumulated in this study, a new molecular rotary motor driven by visible light is proposed to reach MHz rotational frequency.

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Roy, Matthew J. "Rotary forming of cast aluminum." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44789.

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The application of rotary forming to A356 offers a potential improvement in material use, simplified castings and ameliorated fatigue resistance. To investigate the utility of adopting this process industrially, an extensive characterization and modelling effort was undertaken. The constitutive behaviour of A356 in the as-cast condition was assessed with compression tests performed over a range of deformation temperatures (30-500°C) and strain rates (~0.1-10/s). The flow stress as a function of temperature and strain rate was quantified via an extended Ludwik-Hollomon and Kocks-Mecking framework. The through-process microstructural effects on A356 subjected to rotary forming at elevated temperatures was also investigated. This was conducted on material at 350°C with an industrially-scaled, purpose-built apparatus, inducing varying levels of spinning deformation. This was also conducted on commercially flow formed material with high levels of deformation at the same temperature. Macro and micro-hardness testing was used to track the changes from the as-cast and as-formed states, as well as following a T6 heat treatment. Further EDX analysis indicate that precipitation aspects of heat treatment is not appreciably affected by forming. Forming was found to principally affect the eutectic-Si particle size, resulting in a finer particle post heat treatment. An explicit finite element rotary forming model reciprocating experimental forming conditions was developed incorporating the Ludwik-Hollomon description. This forming model was found to be computationally expensive; however, demonstrated reasonable agreement with experimental geometry and phenomena. In evaluating the effect of forming on fatigue, multiaxial testing of A356-T6 was conducted to apprehend the basic fatigue mechanisms. Endurance limits are found to be generally governed by porosity and maximum principal stress for high cycle fatigue. Uniaxial fatigue tests of both experimentally and commercially formed material showed a 30% increase in endurance limits over unformed material, principally through mitigating porosity.

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Grieve, David G. "Computer simulation of rotary forging." Thesis, University of Nottingham, 1991. http://eprints.nottingham.ac.uk/14392/.

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This thesis presents two computer packages to simulate the rotary forging process, by means of a mathematical model. The results are displayed in a graphical and numerical manner, showing the tool movement and the tool / workpiece interaction. The first package, PATH, is shown to be capable of simulating the motions of all known rotary forging systems. Its results show the rotary forging tool path throughout a chosen process. The motions of any rotary forging system can be programed by a simple set of instructions displayed on the screen, and the results displayed quickly and graphically. The widely used motions of rocking - die rotary forging machines were investigated. From these investigations, formulae were put forward, which were shown to be capable of predicting the tool motion of any rocking - die rotary forging situation. The second package, PROFS, presents a meshed representation of the tools and workpieces used in rotary forging systems. The rotary forging tool is represented as a conic wire frame mesh, on which no forces or loads are considered to act. The workpiece is represented as a cylinder constructed from a number of hexahedral elements. The elements are treated in either a non - constant volume or a constant volume manner. The non - constant volume model workpiece is one which is simply cut away by the action of the tool on it. This model is similar to a process of 'rotary cutting'. Using the model, a technique of investigation into the progression of the contact geometries created during a real rotary forging, was developed. It enabled the progression and size of the contact geometry to be followed from start to finish of the forging cycle. No consideration of the loads or forces occurring during the process was taken into account. The constant model workpiece requires that its volume remains fixed during the simulation. This is achieved by a radial expansion of the elements of the workpiece as it is being 'deformed' by the tool. Again no consideration of the loads or forces occurring in rotary forging was taken into account. Investigations, using the model, enabled the instantaneous contact geometries, contact areas, and displaced volumes of material to be predicted during two real rotary forging processes. Results revealed the potential of PROFS, to determine areas of workpiece instability in the early stages of forging, and reveal ares of insufficient die fill. The potential of data from the simulations, to control a rotary forging machine, is discussed, and is seen as the first step towards the design and manufacture of rotary forging parts and dies by a C.A.D. - C.A.M. route. Contact areas produced during the rotary forging process are essential for any calculations of the forces and stresses occurring in the die and workpiece. The possibility of PROFS to be used as a die / design tool and in pre production trials for new parts is discussed. A physical simulation of a non - constant volume model workpiece was carried out using a 'short lead milling' technique to cut away a solid workpiece. This revealed the instantaneous contact geometries and areas of the workpiece, which were shown to be accurately predicted by PROFS using the non - constant volume. The results confirmed the accuracy and validity of the simulated instantaneous geometries, allowing a large degree of confidence to be assumed in the accuracy of the package. A data base of radial, circumferential, and custom die profiles has been built up and incorporated into PROFS. From the data base a chosen profile can be used to generate a conic meshed representation of a rotary forging die. Investigations, using a die generated from a custom profile, revealed areas of possible workpiece instability. The two packages put forward in this thesis have been shown to be capable of simulating the motions and contact geometries of the rotary forging process, and confirmed using physical and real rotary forging comparisons.

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Urs, Shravan B. R. "SCHEDULING ROTARY INJECTION MOLDING MACHINE." Ohio University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1132529304.

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Heydenrych, Michael David. "Modelling of rotary kilns : proefschrift ... /." [Enschede?] : University of Twente, 2001. http://www.ub.utwente.nl/webdocs/ct/1/t00000628.pdf.

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19

Jarroux, Clément. "Nonlinear transient dynamics of on-board rotors supported by Active Magnetic Bearings." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI069/document.

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De manière générale, les turbomachines sont des machines tournantes permettant la conversion des différents types d’énergie. Ces dernières sont composées d’une partie mécanique en rotation, appelée rotor, interagissant avec un fluide. La rotation a donc un rôle clé pour ces machines et la liaison entre les parties fixes et les parties tournantes, appelée palier, est primordiale pour un fonctionnement fiable et optimal. Les turbomachines supportées par des paliers magnétiques actifs (PMAs) sont de plus en plus utilisées par les industriels notamment grâce à l’absence de contact direct entre parties fixes et parties tournantes, permettant un gain d’énergie et une réduction des émissions de CO2. La plupart du temps, ces machines sont « embarquées » et reposent sur des supports mobiles. Les mouvements générés par ces supports doivent être considérés dans la prévision du comportement dynamique des turbomachines afin d’améliorer les designs en conséquence. Cette thèse est une contribution à l’étude des turbomachines supportées par des PMAs sujettes à de fortes sollicitations extérieures. L’approche est numérique et expérimentale. L’utilisation d’un banc d’essais académique composé d’un système rotor-PMA, aux propriétés d’une turbomachine industrielle, a permis de tester les modèles développés pour des cas de sollicitations extérieures de type séisme et choc, générées grâce à l'excitateur 6-axes de l'equipex PHARE. Il est montré que le modèle permet la bonne prévision du comportement réel de la machine. Cet outil pourra donc être utilisé pour des designs de type industriel
Turbomachines are rotating machines enabling the conversion of the different types of energy. The latter are composed of a rotating mechanical part, called rotor, interacting with a fluid. Therefore, rotation play a key role in these machines and the mechanical link between the fixed and the rotating parts, called bearing, is essential for reliable and optimal operations. Turbomachines supported by active magnetic bearings (AMBs) are increasingly used by industrial companies, especially thanks to the absence of direct contact between fixed and rotating parts, enabling energy savings and reduction of CO2 emissions. Most of the time, these machines are "on-board" and are fixed on mobile supports. The motions generated by these supports must be considered in the prediction of the dynamic behaviour of turbomachinery in order to improve the designs accordingly. This PhD is a contribution to the study of turbomachines supported by AMBs subjected to strong external base motions. The approach is numerical and experimental. The use of an academic scale test rig comprising a rotor-AMB system, with the properties of an industrial turbomachine, allowed to test the developed models for cases of external solicitations such as earthquake and shock, thanks to the 6-axis shaker of the equipex PHARE. It is shown that the model provides good predictions of the behaviour of the machine for the tested cases. This tool can therefore be used for industrial designs

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Ozbay, Serkan. "Extension-Twist Coupling Optimization in Composite Rotor Blades." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/10422.

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For optimal rotor performance in a tiltrotor aircraft the difference in the inflow and the rotor speeds between the hover and cruise flight modes suggests different blade twist and chord distributions. The blade twist rates in current tiltrotor applications are defined based upon a compromise between the figure of merit in hover and propeller efficiency in airplane mode. However, when each operation mode is considered separately the optimum blade distributions are found to be considerably different. Passive blade twist control, which uses the inherent variation in centrifugal forces on a rotor blade to achieve optimum blade twist distributions in each flight mode through the use of extension-twist coupled composite rotor blades, has been considered for performance improvement of tiltrotor aircraft over the last two decades. The challenge for this concept is to achieve the desired twisting deformations in the rotor blade without altering the aeroelastic characteristics of the vehicle. A concept referred to as the sliding mass concept is proposed in this work in order to increase the twist change with rotor speed for a closed-cell composite rotor blade cross-section to practical levels for performance improvement in a tiltrotor aircraft. The concept is based on load path changes for the centrifugal forces by utilizing non-structural masses readily available on a conventional blade, such as the leading edge balancing mass. A multilevel optimization technique based on the simulated annealing method is applied to improve the performance of the XV15 tiltrotor aircraft. A cross-sectional analysis tool, VABS together with a multibody dynamics code, DYMORE are integrated into the optimization process. The optimization results revealed significant improvements in the power requirement in hover while preserving cruise efficiency. It is also shown that about 21% of the improvement is provided through the sliding mass concept pointing to the additional flexibility the concept provides for tailoring of the structure without any additional weight penalty on the system.

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21

Amirian, Hossein. "Design of a novel rotary compact power pack for the series hybrid electric vehicle : design and simulation of a compact power pack consisting of a novel rotary engine and outer rotor induction machine for the series hybrid electric vehicle powertrain." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4446.

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Hybrid electric vehicles significantly reduce exhaust emissions and increase fuel economy. Power packs are the most fundamental components in a series powertrain configuration of a hybrid vehicle, which produce the necessary power to run the vehicle. The aim of this project is to design a compact power pack for a series hybrid vehicle, using virtual prototyping. The hybrid electric vehicle characteristics and configurations are analysed, followed by an explanation of the principles of induction machines. A new type of rotary induction machine with an outer rotor construction is designed to be coupled with the novel rotary internal combustion engine with rotating crankcase in order to form the compact power unit for the hybrid vehicle. The starting and generation performance of the designed machine is analysed by an electric machine simulator, called JMAG. ADVISOR software is studied and utilised to simulate the overall vehicle performance, employing different categories of power packs in the powertrain. Results show that the proposed compact power pack has the best performance in terms of fuel economy, emissions and battery charging compared to the existing power unit options. Over the city cycle, fuel economy is increased by up to 47 % with emission reduced by up to 36 % and over the highway cycle, fuel economy is increased by up to 69 % with emission reduced by up to 42 %.

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Gündüz, Mustafa Emre. "Software integration for automated stability analysis and design optimization of a bearingless rotor blade." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33916.

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The concept of applying several disciplines to the design and optimization processes may not be new, but it does not currently seem to be widely accepted in industry. The reason for this might be the lack of well-known tools for realizing a complete multidisciplinary design and analysis of a product. This study aims to propose a method that enables engineers in some design disciplines to perform a fairly detailed analysis and optimization of a design using commercially available software as well as codes developed at Georgia Tech. The ultimate goal is when the system is set up properly, the CAD model of the design, including all subsystems, will be automatically updated as soon as a new part or assembly is added to the design; or it will be updated when an analysis and/or an optimization is performed and the geometry needs to be modified. Such a design process takes dramatically less time to complete; therefore, it should reduce development time and costs. The optimization method is demonstrated on an existing helicopter rotor originally designed in the 1960's. The rotor is already an effective design with novel features. However, application of the optimization principles together with high-speed computing resulted in an even better design. The objective function to be minimized is related to the vibrations of the rotor system under gusty wind conditions. The design parameters are all continuous variables. Optimization is performed in a number of steps. First, the most crucial design variables of the objective function are identified. With these variables, Latin Hypercube Sampling method is used to probe the design space of several local minima and maxima. After analysis of numerous samples, an optimum configuration of the design that is more stable than that of the initial design is reached. The process requires several software tools: CATIA as the CAD tool, ANSYS as the FEA tool, VABS for obtaining the cross-sectional structural properties, and DYMORE for the frequency and dynamic analysis of the rotor. MATLAB codes are also employed to generate input files and read output files of DYMORE. All these tools are connected using ModelCenter.

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Leusink, Debbie. "Advanced numerical tools for aerodynamic optimization of helicopter rotor blades." Thesis, Paris, ENSAM, 2013. http://www.theses.fr/2013ENAM0010.

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La conception aérodynamique des pales du rotor principal d’un hélicoptère doitsimultanément prendre en compte plusieurs objectifs relatifs aux critères du vol stationnaire etvol d’avancement. Cette thèse vise à développer une boucle d’optimisation automatiséecombinant des algorithmes d’optimisation avancés et des outils de simulation. Deux outils desimulation sont employés pour la prédiction des performances rotor : le code de mécanique devol HOST, ainsi que le code de Mécanique des Fluides Numérique (MFN) elsA. Une analyse deces outils est effectuée pour des cas test bien documentés afin d’estimer leur capacité à prédiredes tendances de performances rotor en fonction de la géométrie de pale. L’influence desparamètres numériques est également caractérisée. Aussi, une stratégie d’optimisation estdéveloppée, permettant la prise en compte de plusieurs objectifs et de contraintes complexes,ainsi que la détermination d’optima globaux pour ce problème multimodale. Suivant cescritères, un algorithme génétique (AG) est sélectionné. Afin de réduire le nombre d’évaluationsnécessaires, une stratégie d’optimisation multi-fidélité est proposée : une optimisationpréliminaire utilisant l’AG et HOST est utilisée pour la réduction de l’espace des paramètres ensélectionnant la zone de haute performance. Ensuite, une surface de réponse est construiteavec des calculs haute-fidélité des pales de haute performance comme vu par l’étapepréliminaire. L’optimisation est finalement effectuée sur cette surface de réponse haute-fidélité.L’approche proposée résulte en une augmentation significative des performances rotor, tout enrespectant le critère industriel relatif au nombre de calculs coûteux comme MFN. L’approcheproposée se révèle être un outil efficace pour la conception de pales du rotor principald’hélicoptère
The aerodynamic design of helicopter rotor blades requires taking into accountedmultiple objectives simultaneously, to provide a compromise solution for the conflictingrequirements associated to hover and forward flight conditions. The present work aims atdeveloping an automated optimization based on the combination of advanced optimizationalgorithms and simulation tools. As a preliminary step, candidate simulation methods andoptimization algorithms are assessed in detail. Two simulation methods are employed for thecomputation of rotor performance: the in-house Helicopter Overall Simulation Tool (HOST),based on the blade element method, and ONERA’s Computation Fluid Dynamics (CFD) codeelsA. An in-detail analysis of both simulation tools for well documented test cases is carried out,with focus on their capability of predicting trends of the global rotor performance as a function ofblade geometry. The impact of computation settings is also characterized. Then, an optimizationstrategy is developed, allowing the incorporation of multiple objectives and complex constraints,and the detection of global optima for multi-modal problems. Based on these criteria, a geneticalgorithm (GA) is selected. To reduce the number of simulations required to find optimalsolutions, a Multi-Fidelity Optimization (MFO) strategy is proposed: a preliminary low-fidelity GAoptimization stage based on HOST simulations is used to reduce the design space by selectinga high-performance subspace. Then, a CFD-based surrogate model is constructed on thereduced design space by using a sample of high-performance blade from the low-fidelity step.The final optimization step is run on the high-fidelity surrogate. The proposed MFO approachresults in significant rotor performance improvements while using a far lower number of costlyCFD evaluations of the objective functions with respect to a full GA optimization. The proposedapproach is shown to represent an efficient design tool for industrial helicopter rotor blade

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Tannous, Mickhael. "Développement et évaluation d'approches de modélisation numérique couplées 1D et 3 D du contact rotor-stator." Ecole centrale de Nantes, 2013. http://www.theses.fr/2013ECDN0015.

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Les problèmes de machines tournantes présentant un contact rotor-stator sont généralement traités dans la littérature à partir de modèles localement 1D. Ceci conduit à un temps de simulation acceptable, mais les approximations correspondantes sont difficiles à évaluer. Or le contact est limité en espace et en temps, il peut donc en être de même pour l'utilisation d'unemodélisation 3D. Une stratégie, nommée bascule, permettant d’utiliser un modèle poutre et un autre 3D (ou un modèle mixte poutre-3D), pendant deux phases différentes de la même simulation, est donc développée. Elle est mise en oeuvre de façonnon-intrusive, en dynamique transitoire, pour des systèmes présentant ou non une rotation d’ensemble, avec une résolution par intégration temporelle implicite. La bascule est validée par comparaison avec une solution 3D de référence obtenue en effectuant la simulation entière sur le modèle 3D. On analyse ensuite, sur des problèmes de contact rotor-stator, les résultats des modèles 1D et 3D, dans différentes situations de contact plus ou moins sévères. Les vibrations du rotor sont dues à un balourd et sa vitesse de rotation est imposée constante. Il apparaît que les écarts entre les résultats des modèles 1D et 3D sont peu visibles sur les orbites du rotor. En revanche les limitations du modèle 1D sont mises en évidence. En effet, l’hypothèse de section rigide du rotor entraine des approximations dans la distribution spatiale et l’intensité des efforts de contact. La modélisation 3D en revanche permet de représenter certains effets locaux au voisinage de la zone de contact
Rotor dynamic problems with rotor to stator contact interactions are dealt with in the literature by 1D local models. This leads to an affordable simulation time, but the corresponding approximations are difficult to assess. Since the contact is limited in space and time, the same strategy can therefore be used with 3D models. A strategy, called switch, allowing the use of a beam model and a 3D model (or beam-3D mixed model), at two different stages of the same simulation, is developed. It is implemented in a non-intrusive way for the simulation of transient dynamic problems, with or without an overall rotation, solved by an implicit time integration scheme. The switch is validated by comparison with a 3D reference solution obtained by performing the full simulation on the 3D model. We, then, compare and analyze the results of 1D and 3D rotor-stator contact problems, for different contact conditions more and less severe. The rotor vibrations are due to rotating imbalance at a given constant rotating speed. It appears that the differences between the 1D and the 3D results are not obvious on the rotor orbits. However, the limitations of the 1D simulation are highlighted. Indeed, the rigid body section assumption in a beam model of the rotor leads to approximations in the spatial distribution of the contact forces and their intensity. The 3D model, however, can present some local effects in the vicinity of the contact zone

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25

Yliniemi, L. (Leena). "Advanced control of a rotary dryer." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514252810.

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Abstract Drying, especially rotary drying, is without doubt one of the oldest and most common unit operations in the process industries. Rotary dryers are workhorses which are easy and reliable to operate, but neither energy-efficient nor environmentally friendly. In order to conform better to the requirements of modern society concerning working conditions, safety practices and environmental aspects, the development of control systems can provide opportunities for improving dryer operation and efficiency. Our in depth understanding of rotary drying is poor, because it is a very complex process that includes the movement of solids in addition to thermal drying. Thus even today rotary dryers are controlled partly manually, based on the operator's "eye" and experience, and partly relying on conventional control methods. The control of a rotary dryer is difficult due to the long time delay, which means that accidental variations in the input variables can disturb the process for long periods of time before they are reflected in the output variables. To eliminate such disturbances at an early stage, increasing interest has been shown in more sophisticated control systems such as model-based constructs, fuzzy logic and neural nets in recent years. Although it has proved difficult and time-consuming to develop model-based control systems, due to the complexity of the process, intelligent control methods based on fuzzy logic and neural nets offer attractive solutions for improving dryer control. These methods make it possible to utilize experience, knowledge and historical data, large amounts of which are readily available. The aim of this research was to improve dryer control by developing new hybrid control systems, one consisting of a fuzzy logic controller (FLC) and PI controller and the other of a three-layer neural network (NN) and PI controller. The FLC and NN act as supervisory controllers giving set points for the PI controllers. The performance of each was examined both with simulations and in pilot plant experiments. The pilot plant dryer at the University of Oulu closely resembles a real industrial situation, so that the results are relevant. Evaluation of these results showed that the intelligent hybrid controllers are well suited for the control of a rotary dryer, giving a performance in which disturbances can be eliminated rapidly and operation of the dryer can thereby be improved, with the aim of enhancing its efficiency and environmental friendliness.

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26

Barr, Peter Vernon. "Heat transfer processes in Rotary kilns." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26772.

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An experimental investigation of rotary kiln heat transfer processes was carried out and a unified heat transfer model developed to describe the individual processes and their interaction. A 0.406 m ID by 5.5m refractory lined pilot kiln firing natural gas was utilized for a series of 23 heat transfer trials. Limestone, petroleum coke and two Ottawa sands were heated using a wide range of firing rates while rotation rate, kiln inclination, kiln loading and bed depth were held nearly constant. The bed material was in the rolling mode for all trials. Measurements were made to obtain the net heat transfer rates for the bed material, the freeboard gas, the refractory wall and, unique to the study, the heat flux at the inside wall surface as a function of circumferential position. High rates of net heat input to the bed material, Q[sub b], which occurred very near to the kiln entrance, were found to decline quickly with axial distance and, for an inert bed, the ratio of Q[sub b], to Q[sub ss], the rate of energy loss through the kiln wall, tended toward the ratio of the exposed bed surface area to the exposed wall surface area. At the onset of the limestone calcination reaction Q[sub b], increased sharply without a corresponding increase in Q[sub ss]. Over the fully instrumented portion of the kiln, which extended from 1.32m to 5.0m, the rate of heat transfer from the covered wall to the bed, Q[sub cw →cb], was < 30% of the rate to exposed bed surface from the freeboard. With an inert bed the net exchange Q[sub cw →cb], was found to decline with axial distance and negative values were encountered beyond the kiln mid-point. The onset of bed calcination reversed this trend and positive values of Q[sub cw →cb], were always recorded in the calcination zone. The temperature of the bed material and the inside wall surface were found to be closely-coupled and the actual temperature difference could not be determined due to the limitations of the measuring technique. The onset of bed calcination was always characterized by significant increases in both the net heat input rate to the bed material and the amount of temperature cycling at the inside wall surface. A zone-type real gas model was developed for the radiative heat exchanges in the freeboard and the results presented in the form of radiative heat transfer coefficients. For the pilot kiln, firing at 10% excess air, the coefficient for radiative heat transfer from the freeboard gas to the exposed wall or bed surfaces was calculated to range from 2 15 →55 W/m²K for gas temperatures from 800 →1800 K. Model predictions for a prototype kiln of 4 m ID indicated an increase in the gas to surface radiation by a factor ~ 3. The coefficients for radiative exchange among the freeboard surfaces in the pilot kiln were significantly larger than for the gas to surface exchange while, in the prototype, they were of comparable magnitude. For the inert bed trials the convective component of the freeboard surface heat flux was calculated by subtracting the calculated radiative contribution from the net surface flux. Convection to the exposed bed surface was found to be enhanced relative to the exposed wall surface although less than reported previously. Coefficients for heat transfer between the covered wall and covered bed were shown to be significantly reduced in a refractory lined kiln relative to an unlined metal drum. A finite difference model of the refractory and bed material, incorporating the derived heat transfer coefficients, was verified using the pilot kiln data and extended to examine the relationship existing among the heat transfer processes at any kiln cross-section. Both the close-coupling of the pilot kiln bed and wall temperatures and the high rate of net bed heat input occurring near the kiln entrance and in the presence of a calcining bed were explained by the unified model. Model predictions were obtained for a 4m ID prototype kiln and aspects of kiln thermal performance identified which have important repercussions for the operation of rotary kilns.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

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Tackie, Emmanuel Nii. "Elutriation of particles from rotary kilns." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27549.

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The elutriation of fine materials from the solids bed in rotary kilns was studied in a laboratory scale steel cylinder of 0.2m in diameter and 2.4m in length. The cylinder was charged with a batch of fine alumina particles having a mean size of 64jum and the average elutriation rate measured at different air flow rates, rotational speeds and percentage of solids fill. All measurements were done at room temperature. To show the effect of fines concentration and segregation in the solids bed, a binary mixture of fine alumina and coarse Ottawa sand was used. Local dust concentration profiles were measured in the freeboard through a probe equipped with a filter. Design factors such as the geometry of the kiln exit dams, were found to influence dust carryover into the cleaning equipment by accelerating the flowing gas and or obstructing the flow of solids in the gas phase. Wall roughness and imperfections also affected elutriation especially at higher rotational speeds by exposing trapped fines directly into the flowing gas. Dust concentration measurements revealed that most of the solids in the gas phase travelled in saltation within about 2 cm above the bed surface. With the wall effect eliminated by an insert, increasing the rotational speed was found to exhibit a negative effect on the elutriation rate. Dust concentrations were higher in the gas phase above the lower edge of the rotating bed than at the upper edge or midpoint. However, while the concentration above the rest of the bed remained fairly constant with increased rotational speeds, at the lower edge of the bed it decreased. Banding segregation occurred in the beds composed of fine and coarse particles. Elutriation increased with the number of fine bands formed which was proportional to the concentration of fines. The location of the bands from the exit also influenced elutriation. Saltating particles returning to the bed close to the exit had a better chance of ejecting other particles if they landed on fine bands than they would if they landed on coarse bands. Gas velocity exhibited the strongest influence on elutriation rate. A correlation of experimental results showed a velocity dependence of U⁶ regardless of initial fines concentration in the bed. An entrainment mechanism has been formulated based on the collision of saltating particles on the solids bed. Subsequently, a simple mathematical model was developed to describe the influence of the operating variables on elutriation. The model predictions were verified with the experimental data and the scanty data in the literature. The model requires knowledge of the saltation height and the threshold shear stress for particle movement. Model predictions for typical industrial kilns are presented. The predictions are in fairly good agreement with values reported in a survey of industrial kiln operations made prior to the experimental program, given that the effect of kiln internals was not accounted for in the model.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

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Bosco, Bruno, and Jimmy Larsson. "Development of a Rotary CNC System." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177373.

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The Rotary CNC system is a novel way to position a tool in the XY-plane. The system is meant to be used in areas such as 3D-printing, laser cutting, CNC milling and other rapid prototyping equipment. Benets include lower production cost, less moving parts and a small physical footprint. This thesis has provided a "Proof of Concept" prototype of the Rotary CNC system. It has been shown that the system is a viable alternative to current CNC system designs in the eld of PCB routing.

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Karantonis, Dean Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Control of a rotary blood pump." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/43474.

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Implantable rotary blood pumps (RBPs) are an emerging technology designed to provide sufferers of heart failure with a viable treatment option which improves their medical prognosis and quality of life. The broad aim of this thesis is to address the need for a pump control strategy, and develop a solution whereby the implant recipient??s physiological requirements are continuously monitored in a non-invasive manner and met with an appropriate response by the RBP. Employing only the non-invasive signal of instantaneous pump impeller speed to assess flow dynamics, five physiologically significant pumping states have been identified in acute ex vivo porcine experiments (N=6). Two broader states, corresponding to normal and ventricular suction conditions, were readily discernable in clinical data from human implant recipients (N=10). Employing a classification and regression tree (CART) model, an automated real-time algorithm was developed to detect pumping states with a high degree of sensitivity and specificity. Both suction and normal states were detected without error in data from the animal experiments, and with a peak sensitivity/specificity, for detecting suction, of 99.11% / 98.76% in the human patient data. Algorithms to non-invasively estimate RBP flow and differential pressure in both steady- and pulsatile-flow environments were developed. Taking the pump feedback signals of speed and power, together with the blood haematocrit (or equivalent viscosity) level, as input parameters, several estimation models were developed via polynomial surface fitting and/or system identification methods, yielding clinically acceptable results (mean flow errors of 3.09% and 5.49%, and mean pressure errors of 1.80% and 6.47%, for the steady- and pulsatile-flow cases, respectively). An RBP control algorithm based on a non-invasive indicator of the implant recipient??s activity level has been proposed and evaluated in a software simulation environment. An Activity Level Index (ALI) forms the basis of an adaptive control module operating within a hierarchical multi-objective framework which imposes several constraints on the pump??s operating region. Three class IV heart failure cases of varying severity were simulated under rest and exercise conditions, and a comparison with other popular RBP control strategies was performed. Simulations of the proposed control algorithm exhibited the effective intervention of each constraint, resulting in an improved flow response and the maintenance of a safe operating condition, compared with other control modes.

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Paone, Matthew Paul. "Rotary-axial spindles for precision machining." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/18715.

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This thesis presents the design, analysis, fabrication, instrumentation, and control of a new type of machine tool spindle. Its primary contributions include the design and experimental demonstration of: two rotary-axial spindle prototypes, MIMO current control for a 1 kW linear power amplifier, sensorless rotary motion feedback, a novel method for increasing ADC resolution, and loop-shaping motion control systems. Some machining operations, such as face grinding, require rotational and feed motion to remove material. Conventional machine tools accomplish this by attaching a spindle which has thrust and journal support to a feed drive which also has thrust and lateral support systems. In modern machine design, the trend is towards increasing the stiffness of each individual element. However, the inherent serial duplication of support presents a fundamental limitation to stiffness and precision. The rotary-axial spindle architecture alleviates this problem by discarding the feed drive and spindle thrust bearing, replacing them both with a high force electromagnetic actuator. This provides millimeter range stroke for the spindle shaft, resulting in a single inertial element capable of both rotary and axial motion. This topology has several advantages. It allows kHz range bandwidth and hundreds of N/μm dynamic stiffness, improves acceleration, reduces structural bending moments, and eliminates thermal effects of fluid thrust bearings. Two prototypes are developed to demonstrate this technology. The first is a small scale rotary-axial spindle. Driven by a four-channel 1 kW linear power amplifier with decoupled current loops, the magnetic thrust bearing can handle 600 N peak axial loads over a 1 mm stroke. A novel method for increasing ADC resolution achieves sub-5 nm RMS positioning noise. Loop shaping compensation of the position loop results in 100 N/μm minimum dynamic stiffness and 2.6 kHz closed loop bandwidth. To control the spindle speed, a sensorless rotary motion feedback algorithm was developed. It produces results equivalent to a 1000 line rotary encoder. The second prototype is a full size machine tool. It demonstrated 6 kN continuous axial load capacity, 340 N/μm minimum dynamic stiffness, 800 Hz bandwidth, and 7 nm RMS positioning noise over a 1.5 mm stroke.

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Peck, Jonathan Philip. "Performance monitoring of rotary blasthole drills." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75895.

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Rotary blasthole drills operating in a western Canadian surface coal mine were instrumented with microprocessor-based monitoring equipment. During routine production drilling, the performance parameters of penetration rate, torque, rotary speed, pulldown and bailing air pressure were monitored at sampling intervals of 10 centimeters (4 inches). The acquired digital data were subsequently correlated with both geological and geomechanical rock properties permitting a detailed examination of machine-rock interaction. The results from a statistical analysis of the drill data identified unique ranges of performance parameters for the sandstone, siltstone, mudstone and coal units encountered at the mine. Correlation of these ranges with geophysical logs in the monitored boreholes, enabled a further calibration of drilling parameter variation to rock type. A relationship between drill performance parameter responses and rock compressive and shear strength was established. This correlation demonstrated the possibility of estimating rock strength properties based on drill performance data. Trend analysis techniques applied to the monitored drill data permitted a further understanding of the nature of tricone bit wear for the particular study environment. The applications of drill monitoring techniques are illustrated in terms of geological exploration, mine planning, tricone bit selection and wear evaluation, and drill automation and control.

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Binkley, Jeremiah, Michael Moreno, and Ronald Zenga. "Minimum NSS to Select Rotary Wing." Thesis, Monterey, California. Naval Postgraduate School, 2008. http://hdl.handle.net/10945/7050.

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EMBA Project Report
EXECUTIVE SUMMARY: The Navy and Marine Corps Rotary-wing community is experiencing unprecedented expansion while becoming more technically complex than ever before. As a result, the quality of pilots required by each Rotary-wing community has increased as well. Currently, the only pipelines that require a minimum Navy Standard Score (NSS) for selection are: USMC Jet (52); Navy Tailhook (50); and USMC Tilt-rotor (40). The remaining pipelines, E6 (Navy only), Multiengine, and Rotary-wing do not require a minimum NSS for selection. Traditionally, students who were not selected for a community with an NSS cutoff were selected into E6, Multi-engine, or Rotary-wing, with Rotary-wing receiving the lowest performers. This method of selection, while far from scientific, was accepted due to the fact that a Naval Flight Student (NFS) had to achieve a minimum NSS of 35 to advance from Primary Flight training. With the implementation of Multi-Pilot-Training- Syllabus (MPTS) in both Primary (2000), and Advanced Flight Training (2004), the minimum NSS requirement to advance from Primary Flight Training was removed. To ensure the lowest attrition rate possible without sacrificing the quality of students selected for rotary-wing, the consultants on this study sought to determine whether there should be a minimum NSS to select a NFS for the rotary-wing pipeline. This study analyzed data for a three-year period for students who selected Rotary-wing. Data for NFSs who were attrited for deficient performance was analyzed to determine their median and average NSS. The median and average NSS of a Helicopter Advanced training flight attrite was 35 with a standard deviation of 6.17. If a minimum NSS of 35 is applied it would have reduced the flight attrites by 21 students, or 55 percent, and overall attrition by 31 percent. This would have also resulted in a loss of 148 NFS over three years. Although applying a minimum NSS one standard deviation above the median would have reduced the number of flight attrites by 89 percent, it would also have adverse effects on student production by eliminating 432 students over the three-year period. Conclusions • This study serves as the starting point to transform a historically anecdotal argument on the validity of NSS correlation to NFS performance into an empirical and analytical discussion. • The statistical data supports establishing a minimum NSS of 35 to select Rotary-wing. Recommendations • Conduct additional research to determine the validity of establishing a minimum NSS for selecting Rotary-wing and determine the placement of lower performing NFSs. • Fleet Replacement Squadrons establish a database to record individual student performance in order to historically compare students.

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Chargin, David Anthony 1974. "Rotary fast tool servo component design." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9403.

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Lam, Basil Pui Man. "Convective heat transfer in rotary kilns." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613325.

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Xu, Guoda, John Bartha, Sean Zhang, Wei Qiu, Freddie Lin, Stuart McNamee, and Larry Rheaume. "Electro-Optic Hybrid Rotary Joint (EOHRJ)." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606501.

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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
An advanced electro-optic hybrid rotary joint (EOHRJ) has been developed in Phase II of an AF SBIR effort with Physical Optics Corporation (POC) to replace cable wrap structure for multi-channel rotation-to-fixed (RTF) signal transmission. The EOHRJ meets AFFTC and other range special needs with a generic, high performance, rotary joint solution. At the moment, we have successfully installed and tested the EOHRJ on our KTM tracker system with the following capabilities: 1) able to accommodate hundreds of transmission channels, including electrical power, control, feedback, and low-speed signals; 2) able to accommodate multiple channel, high data rate (over gigabits per second), and bi-directional signal transmission; 3) able to be reliable for harsh environmental operation, adaptive to stringent sized requirement, and accommodating existing electrical and mechanical interfaces. The completed EOHRJ contains three uniquely integrated functional rings. The first and the outmost one is power ring, which provides RTF transmission channels for over 50 high voltage and high current channels. The second and the middle one is low speed electrical signal ring, which provides RTF transmission for over hundred control, feedback, and low speed data signals. The third and the inmost one is optical fiber slip ring, which, incorporating with current advanced signal multiplexing technologies (either time division or wavelength division multiplexing ) is able to provide multiple channel, high data rate, and bi-directional signal transmission. At the moment, the prototype module of the tree-layer EOHRJ has been successfully assembled in Air Force’s tracker system, and is providing a satisfactory performance. This paper presents our joint work on this project.

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Dunn, Wiley E. "Rotary Head Recorders in Telemetry Systems." International Foundation for Telemetering, 1989. http://hdl.handle.net/10150/614666.

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International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California
Although magnetic recording devices employing rotary head technology have been around for many years, specific products were not developed with the bit error performance to satisfy the instrumentation recorder needs of the telemetry community. Only recently have a number of new products and new product development programs materialized which offer positive indications that telemetry systems will soon benefit from the higher data rates and storage capacities. The lack of standards in development of rotary head technology has led to development of a variety of design approaches by various manufacturers and system designers. If this trend continues, the telemetry community will not enjoy the media compatibility which has contributed so much to the success of the IRIG instrumentation recorder. The ability to remove a tape recorded on one vendors recorder and replay the tape on a different ground station containing a second vendors recorder is a capability that should be retained with the advent of the new machines. Two standards have evolved defining tape characteristics and the format of information on tape for instrumentation rotary head recorders. For the instrumentation tape media to be truly transportable between telemetry ground stations, standard signal and data formal interfaces must also be developed.

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Piernik, Magdalena. "Kultura organizacyjna klubów Rotary w Polsce." Doctoral thesis, Katowice : Uniwersytet Śląski, 2007. http://hdl.handle.net/20.500.12128/5115.

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Niniejsza praca traktuje o kulturze organizacyjnej. Podjęcie takiej tematyki jest naturalną konsekwencją moich wcześniejszych zainteresowań – socjologią organizacji i zarządzaniem zasobami ludzkimi. Wielokrotnie podczas rozważań na temat roli człowieka w organizacji miałam wrażenie, że aby w pełni ją zrozumieć warto spojrzeć na organizację przez pryzmat kultury. Wprawdzie kultura organizacyjna jest trudna do wyabstrahowania i zdefiniowania, wręcz nieuchwytna, jednak niezwykle istotna. Analizowane zagadnienie traktuję jako „inną grupę soczewek, przez którą można oglądać organizację”1. Jej znaczenie zostało już docenione zarówno przez teoretyków, jak i praktyków życia gospodarczego. Stąd w ostatnich latach zauważyć można spore zainteresowanie tematyką kultury organizacyjnej. Badacze skupiają się jednak głównie na kulturach przedsiębiorstw. Stowarzyszenia pozostają wciąż słabo zbadane. Dlatego uważam je za ciekawy przedmiot badań. Moim zamiarem badawczym było pokazanie problematyki kultury organizacyjnej w polskich klubach Rotary. Praca stanowi fotografię kultury tej organizacji z 2005 roku. Istnieje kilka powodów takiego wyboru przedmiotu badań. Motywem osobistym była inspiracja mojego taty, który jest rotarianinem i wielokrotnie opowiadał mi o klubie, do którego należy. Uznałam tę organizację za nowe w Polsce i ciekawe zjawisko. Kluby Rotary są interesujące dla badacza kultury organizacyjnej ponieważ, inaczej niż w przedsiębiorstwach nastawionych na zysk, gdzie przeważają więzi rzeczowe, cechuje je wysoka dbałość o stosunki międzyludzkie i silna więź towarzyska. Interesujące jest, czy prawidłowości zaobserwowane przez badaczy przedsiębiorstw zachodzić będą także w kulturze stowarzyszenia. Ponadto kluby Rotary skupiają znaczących przedsiębiorców i ludzi wybitnych w swoich zawodach. Można więc przypuszczać, że istnieją związki pomiędzy ich kulturą organizacyjną a normami kulturowymi polskiego biznesu. Rozprawa doktorska ma charakter teoretyczno – empiryczny. Składa się z pięciu rozdziałów. Pierwszy wyjaśnia pojęcie kultury organizacyjnej. Punktem wyjścia jest rozumienie organizacji jako systemu społecznego. Dalej następuje przegląd definicji kultury organizacyjnej oraz szczegółowa analiza definicji autorstwa Edgara Scheina. Omówiono także przejawy kultury organizacyjnej oraz jej wymiary i typologie w ujęciu różnych autorów. Rozdział drugi opisuje proces tworzenia się kultury w organizacji; funkcje, jakie spełnia; jej związki z innymi elementami organizacji i kulturą narodową. Rozdział trzeci stanowi krótką prezentację Rotary. Zaczynam od omówienia samej formuły klubu. Przedstawiona została historia organizacji, jej działalność, struktura klubu, przyjęty sposób zarządzania i podejmowania decyzji. Szczególną uwagę zwracam na kwestie związane z członkowstwem w klubie Rotary – prawa i obowiązki, jakie z tego faktu wynikają. Kolejny, czwarty rozdział prezentuje metodologiczne aspekty postępowania badawczego. Ostatni, najbardziej obszerny, przedstawia zgromadzony podczas badań własnych materiał empiryczny. Kulturę organizacyjną polskich klubów Rotary analizuję w oparciu o jej sześć wymiarów wyodrębnionych podczas pierwszej, eksploracyjnej fazy badań. Opisowi każdego z wymiarów poświęcony został jeden podrozdział.

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Smith, Wayne Anthony. "Commissioning a 400 Hz rotary inverter." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/9226.

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Includes bibliographical references (leaves 113-115).
This dissertation covers the commissioning and testing of an aircraft's constant frequency alternator as the power supply for the Blue Parrot radar. The Blue Parrot is an X-band radar which forms part of the navigation and weapon-aiming system onboard the Buccaneer S-50 SAAF aircraft. The radar set uses a source of three-phase power at 400 Hz, which the constant frequency alternator can supply with the aid of certain auxiliary systems. The auxiliary systems include a prime mover, blower fan and a telemetering system. The prime mover has high starting currents which were reduced significantly by the use of a soft-starter. During testing, the constant frequency alternator started overheating and a blower fan was selected based on its thermal requirements. Significant cooling of the constant frequency alternator's case temperature was achieved by the use of a blower fan and shroud. The generator control unit monitors and regulates all parameters on the unit except for case temperature and blower fan pressure. A telemetering system was designed and built to monitor and display these parameters.

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Wilson, Miriam Ruth. "An autonomous chemically-fuelled rotary motor." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/an-autonomous-chemicallyfuelled-rotary-motor(0383eb87-ae6a-49e8-9a14-4406de0b5b90).html.

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Biological processes commonly use molecular motors to drive chemical systems away from equilibrium thus enabling work to be done. This has inspired efforts to create synthetic rotary motors which mimic the key properties of their biological counterparts, namely autonomy and directionality with the use of a chemical fuel. Thus far, attempts to combine all three properties in a synthetic rotary motor have proven unsuccessful. This thesis describes the design, synthesis and operation of an autonomous, chemically-fuelled, directional rotary motor. In this two-compartment [2]catenane an information ratchet mechanism operates. Directional transport of the small macrocycle around the larger one is promoted by an acylation reaction using a sterically demanding pyridine-based catalyst. To achieve autonomy, conditions for a one-pot, directional, de-acylation/re-acylation reaction were developed. Under autonomous operation conditions the macrocycle displacement was followed by 1H NMR. Chapter One describes the previous strategies that have been employed to realise unidirectional rotary motion in synthetic systems and aims to give the reader an overview of the relevant literature in the field of synthetic rotary motors. Chapter Two describes the concept and design of the project. Previous work which formed the basis for this research is also discussed. The synthesis and successful operation of a molecular information ratchet fuelled by chemical energy is reported. Chapter Three describes the first autonomous, synthetic rotary motor fuelled by chemical energy. The autonomous nature of the operation is determined by 1H NMR, mass spectrometry and HPLC.

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Chabak, Kelson D. "Conceptual study of rotary-wing microrobotics." Wright-Patterson: Air Force Institute of Technology, 2008. http://handle.dtic.mil/100.2/ADA487086.

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Yliniemi, Leena. "Advanced control of a rotary dryer." Oulu : University of Oulu, 1999. http://herkules.oulu.fi/isbn9514252810/.

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Originally presented as the author's thesis.
Title from Web page (viewed June 23, 2003). Originally published in print: 1999. (Acta Universitatis Ouluensis. C, Technica ; no. 138). Includes bibliographical references.

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Honorato, Gerlane Carla. "Concep??o de um secador rotat?rio para secagem do cefalot?rax do camar?o." Universidade Federal do Rio Grande do Norte, 2006. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15937.

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Made available in DSpace on 2014-12-17T15:01:58Z (GMT). No. of bitstreams: 1 GerlaneCH.pdf: 2523624 bytes, checksum: 25636f184895db3ffd64ba319ced9381 (MD5) Previous issue date: 2006-11-27
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The present work has as objective the knowledge of the process of drying of the cephalothorax of shrimp to give support the industry to make possible the use of this byproduct. In this sense, the process conditions in this tray dryer and spouted bed were analyzed. With these results, it was projected and constructs a dryer with specific characteristics for the drying of the cephalothorax. The desorption isotherms were obtained by the dynamic method in the temperatures of 20, 35 and 50? C and in the interval of 10-90% of relative humidity. It was observed that the product in form of powder can be conserved with larger stability for lower relative humidity to 40%. The curves of drying of the dryer of fixed bed were adjusted for the models: single exponential, biparametric exponential and Page. The model biparametric exponential more adequately described all the drying conditions studied. The tests carry out in spouted bed showed high drying rate for the material in the paste form in beds active dynamicly-fluid, provely the necessity of a feeding in shorter intervals of time to increase the thermal efficiency of the process. The projected dryer, be considered the obtained results, it was a rotary dryer with inert bed, feed co-current, discharge in cyclone to take place the separation gas-solid, and feed carry out in intervals of 2 minutes. The optimization of the equipment projected it was accomplished used the complete factorial experimental design 24, this had as independent variables temperature velocity of the air, feed flow rate and encapsulated concentration (albumin), as variables answers the thermal efficiency, the moisture content of obtained powder, total time of test and the efficiency of production of powder in several points of processing. The results showed that the rotary dryer with inert bed can present, also, good results if applied industrially
O presente trabalho tem como objetivo o conhecimento do processo de secagem do cefalot?rax do camar?o de forma a dar respaldo a ind?stria para viabilizar o aproveitamento deste subproduto. Neste sentido, foram analisadas as condi??es de processo em secador de bandeja e leito de jorro. Tomando como base estes resultados, foi projetado e constru?do um secador com caracter?sticas espec?ficas para a secagem do cefalot?rax. As isotermas de dessor??o foram obtidas pelo m?todo din?mico nas temperaturas de 20, 35 e 50? C e na faixa de 10-90% de umidade relativa. Foi observado que o produto em p? pode ser conservado com maior estabilidade para umidade relativa inferior a 40%. As curvas de secagem do secador de leito fixo foram ajustadas pelos modelos: exponencial simples, biparam?trico e de Page. O modelo exponencial biparam?trico descreveu mais adequadamente todas as condi??es de secagem estudadas. Os ensaios realizados no jorro mostraram uma alta taxa de secagem para o material na forma de pasta em leitos fluidodinamicamente ativos, mostrando a necessidade de uma alimenta??o em intervalos de tempo mais curtos para aumentar a efici?ncia t?rmica do processo. O secador projetado, a partir dos resultados obtidos, foi um secador rotat?rio com recheio de inerte, alimenta??o cocorrente, descarga em um ciclone para promover a separa??o g?s-s?lido, e alimenta??o realizada em intervalos de 2 minutos. A otimiza??o do equipamento projetado atrav?s do planejamento fatorial completo 24, teve como vari?veis independentes a temperatura e a velocidade do ar, a vaz?o de alimenta??o e a concentra??o de encapsulante (albumina), e, como vari?veis respostas a efici?ncia t?rmica, a umidade do p? obtido, o tempo total do ensaio e a efici?ncia de produ??o do p? em diversos pontos do processamento. Os resultados mostraram que o secador rotat?rio com recheio de inerte tamb?m pode apresentar bons resultados se aplicado industrialmente

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Záviška, Radek. "Savoniova větrná turbína." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231799.

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The diploma thesis is focused on designer works of Savounius rotor for Raječko location. Finish of this design work is equipment, which will be used in this location as decentralized source of electrical energy. In thesis are written manufacturing processes as so as the process of design part including the calculation part, which is focused on characteristic quantity of Savonius rotor. Thesis is finished by econominal assessment of project.

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Sutkowy, Mark Louis Jr. "Relationship between Rotor Wake Structures and Performance Characteristics over a Range of Low-Reynolds Number Conditions." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534768619864476.

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45

Bosworth, Jeff. "Investigation of a stop-fold tiltrotor." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29662.

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Thesis (M. S.)--Aerospace Engineering, Georgia Institute of Technology, 2010.
Committee Chair: Hodges, Dewey; Committee Member: Bauchau, Olivier; Committee Member: Sankar, Lakshmi. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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46

Suffridge, Calvin Buford. "Cleaning Efficiency of Nickel Titanium GT and .04 Rotary Files when used in a Torque Controlled Rotary Handpiece." VCU Scholars Compass, 2002. https://scholarscompass.vcu.edu/etd/5533.

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This study determined if the cleaning efficiency of NiTi rotary files in an endodontic electric handpiece using a no torque control setting was superior to that obtained when using the torque control feature. Fifty extracted human anterior teeth with straight canals were divided into two groups of 20 and two control groups of 5. Canals were instrumented with GT and .04 Profile NiTi files until a size 35 advanced to working length. Samples were sectioned, the apical 6 mm of the canal was photographed (x20) and projected onto a 3 x 4 foot grid with squares measuring 0.5 inches each. Total debris was the percentage of the number of squares containing debris versus the total number of squares. Results showed that the teeth in the torque controlled group showed an average of 24.99% debris vs. 15.55% for the teeth in the no torque group. The difference was not statistically significant.

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Duran, Celio. "Modélisation du comportement dynamique non-linéaire et transitoire de turbomoteur avec multitouches rotor/stator." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0144.

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Cette thèse traite de la dynamique non-linéaire multi-contact des ensembles rotor/stator et s’applique en particulier aux tur-bomoteurs d’hélicoptère conçus par Turboméca, groupe Safran. L’amélioration des performances des turbines à gaz pousse les constructeurs à réduire les jeux fonctionnels rotor-stator no-tamment, tout en garantissant robustesse et fiabilité. Cela nécessite de développer des modèles les plus précis possible afin de prévoir et maîtriser des situations à risques telles que les interactions rotor/stator entre les parties fixes et tournantes déclen-chées principalement, dans le cas des turbomoteurs d’hélicoptère, par la perte d’aubes. La partie 1 présente une synthèse bibliographique des principaux phénomènes physiques rencontrés suite à une touche ro-tor/stator en s’appuyant sur l’expérimentation et le calcul. Un bilan sur les différents modèles numériques de gestion du con-tact frottant est détaillé. La dualité entre méthodes temporelles et fréquentielles est aussi abordée comme la méthode de la ba-lance harmonique et les schémas d’intégration temporelle de la famille de Newmark. Il est aussi décrit deux outils d’analyse fréquentielle : le spectrogramme pour analyser l’évolution d’un spectre fréquentiel dans le temps, le full-spectrum pour pren-dre en compte les précessions du rotor. La partie 2 se focalise sur des systèmes dynamiques académiques : un oscillateur forcé à double butées, un rotor de Jeffcott et un rotor à 3 disques avec tous deux une interaction disque/carter. Compte tenu du caractère transitoire du comportement des turbomoteurs, il s’agit de tester des méthodes d’intégration temporelle pas à pas et aussi des lois de contact. Il en ressort que la méthode de Newmark à accélération moyenne, et les lois de contact type « pénalité amortie » combinées à une régularisation de la raideur et de l’amortissement par une fonction arc tangente sont pertinentes. La modélisation de rotor en flexion en ré-gime transitoire et avec plusieurs touches possibles est réalisée avec la méthode des éléments finis et l’intégration des mé-thodes et techniques précédentes. L’ensemble de la modélisation est mise en œuvre sous l’environnement Matlab et se traduit au final par un logiciel nommé ToRoS (Touche Rotor-Stator). Le turbomoteur de l’Ardiden 1H fait l’objet de la dernière partie. Le logiciel ToRoS développé est utilisé pour prévoir la dyna-mique transitoire de sa turbine libre soumise à de multiples touches, consécutifs à un départ d’aubes. Les lois de contacts ap-pliquées dépendent du type de contact : disque/carter, labyrinthe/stator, palier/butée. Durant la descente en vitesse, la ligne d’arbre adopte, en fonction du niveau de balourd, de la vitesse de rotation, des paramètres du contact et du frottement, un comportement avec un contact quasi-permanent en précession directe
This PhD thesis deals with the nonlinear transient dynamic response of rotor/stator assemblies in the case of multi-contacts, it is applied on Turbomeca’s helicopter turbo-engine. In order to improve gas turbine performances, constructors have to reduce rotor/stator clearances, while continuing to maintain component’s reliability, durability and safety. It implies the development of models to predict and control unsafe situations as, rotor/stator interactions between fixed and rotating parts, mainly triggered by a blade-loss in helicopters turbo-engine case. The first part of this document is concerned with a bibliographical summary of the main physical phenomena observed after a rotor/stator interaction, this is supported by experiments and numerical calculations. A review of the various sliding contact numerical models is presented. The duality between time and/or frequency simulation response methods as, harmonic balance method vs Newmark time integration scheme is discussed. Then two numerical tools for frequency domain analysis are described: the spectrogram to analyze frequency spectrum as a function of the time, the full-spectrum for analyzing the rotor whirl motions. The second part is focused on the time response simulation of some academic systems: an excited oscillator with two end-stops, a Jeffcott rotor and finally a 3 disks rotor both subjected to disk/casing interactions. Given the transient behavior exhibited by turbo-engine rotors following a rotor/stator contact, the purpose is to test several step-by-step time integration scheme combined with different contact laws. This analysis has shown that the Newmark scheme with constant acceleration used with damped contact penalty laws combined to stiffness and damping coefficients smoothed by arctangent functions are relevant. The rotor bending modeling during transient motion considering possible multi-contacts with the stator is realized using the finite element method and the previously reviewed contact modeling methods. The simulation is implemented under Matlab environment and is named ToRoS. (Rotor/Stator Touch). Finally, the developed modeling is applied to the Ardiden 1H turbo-engine. The ToRoS software is used to predict the transient dynamic response of the free power turbine subjected to multi-contacts, after a sudden blade-loss which is modeled by a sudden unbalance. Contact laws are applied and depend on contact type and location: disk/casing, seals, thrust bearing. Depending on the mass unbalance level, the speed of rotation, the contact and friction parameters, the rotor can be in a quasi-permanent contact state in forward whirl while the rotation speed is running-down

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48

Köseoğlu, Seda, and Hasan Parlak. "Capacity calculator of rotary draw tube bending." Thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-19807.

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Plastic deformation of tubes can be achieved in numerous ways. One of the most useful type is CNC tube bending machines which is used in many industries such as aerospace, automotive, HVAC systems and so on. It is important that all components of system should mate properly after producing and because of this bend shaping requires sensitive operation on each components to ensure regularity of production processes with high quality end-product. Thus, the CNC tube bending industry to become widespread. However it brings some troubleshooting like wrinkling, springback, breakage and ovalisation. This failures depends on geometry of the material such as bending radius, tube thickness and also friction factor between dies and the tube. Effects of all parameters should be examined before generating the theory for a best solution. Therefore, prediction of the required moment for the proper bending process with low cost and shortened production time is needed. All of these requirements can be achieved through a C++ form application program.

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Wallin, Johan. "Tribological testing of rotary drill bit inserts." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-179970.

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The aim of this thesis work was to design and evaluate a wear test method for cemented carbides inserts used in rotary drilling. An appropriate in-house wear test method would provide a better understanding of the wear mechanisms limiting tool life in real drilling. The test method should be easy to use and be able to distinguish between wear of insert materials with different microstructure and properties. The literature study showed few published articles about wear tests and mechanisms concerning rotary drill bit inserts. These methods included two standard wear tests; ASTM G65 and ASTM B611. Furthermore, a modified ASTM G65 test was found as well as an impact-abrasion test. In this work the modified ASTM G65 test, using a rock counter surface, was evaluated in order to understand if the method would mimic the wear of cemented carbides used in rotary drilling. The test method was further developed and showed high repeatability. Measured weight losses showed that the test could distinguish between two common rotary grade materials with a small difference in hardness but with different microstructures. The wear of the tested materials was analyzed with scanning electron microscopy and compared with rotary drill bit inserts collected from the field. The modified test method proved able to produce wear by mechanisms very similar to those found on field worn inserts. Identified wear mechanisms included cracking, fragmentation and spalling of WC grains as well as embedded fragments of WC grains on the surface. In addition, the binder phase was removed and adhered material from the counter surface was detected.

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50

Gustafsson, Thomas. "Modelling and control of rotary crane systems." Doctoral thesis, Luleå tekniska universitet, Signaler och system, 1993. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16918.

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This thesis is devoted to the modelling and control of rotary crane systems. The goal is to design a control system that assists the operator to move a cargo without oscillations and to correctly align the cargo at the final position. The control system is divided into two independent parts, one dealing with the alignment of the load with the aid of a power swivel or a cargo rotating device, and a second that deals with the elimination of load oscillations. Both design and implementation of the control algorithms on a full scale crane are considered. In the cargo alignment system a linear cascade controller is considered that is shown to have near time-optimal performance for a system with saturation in both the angle and the angular rate of the power swivel. In the second part a weakly coupled pair of state feedback controllers with a nonlinear compensator is used to eliminate the load oscillations in two dimensions. In the third part of the thesis a software tool for simulation and real time control is presented. The development of the program started as a spin-off to the crane projects.
Godkänd; 1993; 20070417 (tgu)

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Dissertations / Theses on the topic 'Rotari'

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