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1
Mao, Jie. "Falling film absorption on horizontal and coiled tubes /". The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942182324639.
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Elsayed, Ahmed Mohamed. "Heat transfer in helically coiled small diameter tubes for miniature cooling systems". Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2907/.
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This thesis describes experimental and theoretical investigation on the use of small diameter helically coiled tubes for the evaporator of miniature refrigeration systems. A detailed review of past experimental and theoretical work on boiling heat transfer inside helically coiled tubes is presented. As most of past work was conducted on helical coils with tube diameters larger than 6 mm, a brief review of the flow boiling heat transfer process inside straight tubes with small diameters of less than 3 mm is also presented. An experimental facility was constructed and instrumented to investigate the flow boiling of refrigerant R134a in helically coiled tubes with diameters ranging from 2.8 mm to 1.1 mm and coil diameter ranging from 30 mm to 60 mm. The experimental results showed that decreasing the tube diameter increases the boiling heat transfer coefficient by up to 58% while decreasing the coil diameter increased the boiling heat transfer coefficients more significantly by up to 130% before dryout. Dimensional analysis using Pi theorem and Artificial Neural Network (ANN) techniques were used to develop correlations to predict the flow boiling heat transfer coefficients inside helically coiled tubes. The ANN method produced a better prediction of the experimental results with ±30%. The experimental facility was equipped with a reciprocating compressor and a manual expansion device and instrumented to assess the performance of miniature vapour compression refrigeration system. A mathematical model of this miniature system was developed, validated and then used to optimise the system performance in terms of the geometry of the helical coils used in the evaporator and condenser. It was shown that the smaller the coil diameter, the better the performance of cooling system. For the same evaporator length, the larger the tube diameter, the larger surface area and better COP. Smaller tube diameters showed better performance at lower area ratios. However, smaller tube diameters showed lower performance at high area ratios due to the large pressure drop caused by smaller tubes in case of using high area ratios. Finally, the addition of AL2O3 nanoparticles to pure water was investigated using computational fluid dynamics technique (CFD) in terms of heat transfer and pressure drop of single phase laminar and turbulent fluid flow in both straight and helically coiled tubes. The tested AL2O3 nanofluid in helical coils produced up to 350% increase in the heat transfer coefficient of the laminar flow compared to pure water in straight tubes for the same flow conditions. However, insignificant enhancement of the heat transfer was obtained in the turbulent flow regime. Also, the use of high AL2O3 nanofluid concentration of above 2% was found to produce significant pressure drop penalty factor of 5 times that of pure water in straight tubes.
3
Zhang, Hongyang. "Experimental Study of Cuttings Transport in Coiled Tube Micro-Borehole Drilling". Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/68365.
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This research presented an experimental study of the cuttings transport in vertical micro boreholes. The cuttings settling and transport velocities were obtained under various conditions of cuttings (size, concentration) and fluid properties (flow rate, rheology) and annulus geometry. The results showed that it is inaccurate to predict the cuttings transport velocity based on the cuttings settling velocity. The lab results were compared with a series of field tests in both vertical annulus and curved pipe.
4
Wiedmeyer, Viktoria [Verfasser], i Kai [Gutachter] Sundmacher. "Continuous crystallization in a helically coiled flow tube crystallizer / Viktoria Wiedmeyer ; Gutachter: Kai Sundmacher". Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219965286/34.
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Wiedmeyer, Viktoria Verfasser], i Kai [Gutachter] [Sundmacher. "Continuous crystallization in a helically coiled flow tube crystallizer / Viktoria Wiedmeyer ; Gutachter: Kai Sundmacher". Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219965286/34.
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Mishani, Siamak. "Investigation of fatigue failure in composite versus steel coiled tube for application in mine site drilling". Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59665.
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Composite coiled tubing could be an economic alternative to the use of steel for exploration drilling due to its potentially greater reliability and higher fatigue life. This PhD study investigated the fatigue life of steel versus composite tubes using both numerical modelling and laboratory scale tests. Results were validated by statistical analysis and confirmed that composite tubing has a higher fatigue life, and potentially opens up a new market place for composite drill pipe.
7
Prabhanjan, Devanahalli G. "Influence of coil characteristics on heat transfer to Newtonian fluids". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36910.
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A water bath thermal Processor was designed and built to study the influence of helical coil characteristics on heat transfer to Newtonian fluids like water and base oil with three different viscosities. The system consisted of a thermally insulated water bath, an electric heater, pump to re-circulate water in the bath and for pumping the processing fluid through the coil, copper helical coils and a storage tank for the processing fluid.Comparative study has shown that the outer and total heat transfer coefficients were significantly lower in natural than in forced convection water bath. However, inner heat transfer coefficient was not significantly affected. Flow rate as low as 0.001 m.s-1 in the water bath improved the outer and total heat transfer coefficients by 35 and 22% respectively. One could expect a higher rate with an increase in water re-circulation rate inside the water bath. Percent rise in heat transfer was limited to seven with respect to inner heat transfer. With the Pearson correlation, it was possible to express total heat transfer rate directly in terms of outer and inner rates. Significant interactions were observed between variables and constants.
Experiments with 2 pitch cases were conducted with water to water heat transfer using coils to determine the Nusselt number correlation for natural convection. Characteristic lengths were changed in the models. The Nusselt number was under-predicted by 25 to 37% for water bath temperatures of 75° and 95°C respectively. Flow rate inside the coil had slight effect on Nusselt number due to change in the temperature gradient along the length of the coil.
Studies conducted with three base oils have shown significant difference in viscosity after heating the oil for several turns. Each fluid was heated in a distinct flow regime. The observed Nusselt number inside the coil for low Reynolds number was as high as an order of magnitude than the predicted values calculated by Seider-Tate relation for laminar flow. Vorticies formed associated with the eddy structure could very well be the cause for this kind of rise in the value.
Preliminary study conducted has shown a higher rise in temperature of processing fluid in case of helical coil compared to that of a straight tube. Larger the diameter of the tube better was the heat transfer. An elevated bath temperature had higher heat transfer.
8
Geier, Martin. "Influência dos parâmetros envolvidos no processo de união por interferência de tubos por cravamento eletromagnético". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/96295.
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A união por conformação eletromagnética de perfis tubulares de alta condutividade elétrica é um processo inovador e limpo que pode substituir com sucesso os processos convencionais de união baseados na fixação mecânica por parafusos, rebites, soldagem e adesivos estruturais. Esta tecnologia funciona a temperatura ambiente, permite a união de materiais diferentes e oferece potencial para promover novas aplicações na montagem de estruturas leves. Neste trabalho busca-se compreender a união por interferência de tubos por cravamento eletromagnético em termos de seus principais parâmetros com o objetivo de identificar a influência na resistência global das uniões e estabelecer a faixa útil de condições operacionais do processo. Inicialmente são apresentados os fundamentos teóricos do processo de conformação eletromagnética e suas principais variantes operacionais, seguido de um resumo do estado atual do conhecimento da aplicação desta tecnologia na união de perfis tubulares no qual é verificado que os parâmetros mecânicos são a tensão residual no mandril, a área e forma da zona de união e o coeficiente de atrito entre os componentes. Entretanto, tais parâmetros estão relacionados de forma complexa com o processo de cravamento eletromagnético, a começar pela energia e a distribuição do pulso de pressão magnética gerados pela máquina e ferramenta que “disparam” o processo de conformação, a folga inicial entre componentes, o material dos componentes e, a geometria, forma e rugosidade do mandril. O estudo experimental foca a união por interferência de tubos de alumínio (AA6082-O) com mandris de aço (AISI 1045) e alumínio (AA6082 nos estados O e T6) investigando de forma gradual a influência de parâmetros do processo na resistência mecânica (à tração) deste tipo de uniões. Os resultados obtidos demonstram que a resistência mecânica da união e os modos de falha associados são diretamente relacionados com os parâmetros de processo e condições do mandril. Além disso, outras importantes contribuições são apresentadas em relação à instrumentação para medição de fluxo magnético e eficiência global do processo e para o desenvolvimento e aplicações industriais desta tecnologia.Joining of tubular profiles with high electrical conductivity by electromagnetic forming (EMF) is an innovative and clean technology that can successfully replace conventional joining technologies based on mechanical fixing with fasteners, rivets, welding and structural adhesives. The technology works at room temperature, allows joining dissimilar materials and offers potential to foster new applications in the assembly of lightweight tubular frame structures. This work investigates the interference-fit joining of tubes by electromagnetic crimping in terms of its major parameters with the aim of identifying their influence on the overall strength of the joints and establishing the useful range of process operating conditions. Initially, the theoretical principles of EMF and its main operational process variants are presented, followed by a summary of the current state of the knowledge of its application in the joining of tubular profiles in which it is found that the mechanical parameters are the residual stress at the joint interface, the area and shape of the joint interface and the friction coefficient between the joining partners. However, these parameters are related in a very complex way with the electromagnetic crimping process parameters, starting with the charging energy and by the machine and tool which generates the distribution of the magnetic pressure pulse that “triggers” the forming process, the initial gap between joining partners, the mandrel properties such as material, geometry, shape and surface roughness. The experimental study focuses the interference-fit of aluminum tubes (AA6082-O) on mandrels made of different materials and metallurgical conditions (AISI 1045, AA6082-O and AA6082-T6) and, therefore, the process is analyzed by the gradual influence of other process parameters aiming to achieve high strength joints. Results show that the joint strength and the associated failure mechanisms are directly related to process parameters and mandrel conditions. In addition, other important contributions are presented regarding the instrumentation for measuring the magnetic flux and overall process efficiency and to the development and implementation of this technology in industrial processes.
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Anderson, Brian Eric. "Derivation of Moving-Coil Loudspeaker Parameters Using Plane Wave Tube Techniques". BYU ScholarsArchive, 2004. https://scholarsarchive.byu.edu/etd/17.
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Small-signal moving-coil loudspeaker driver parameters are traditionally derived through electrical impedance measurement techniques. These parameters are commonly called Thiele/Small parameters, after Neville Thiele and Richard Small who are credited with developing industry-standard loudspeaker modeling techniques. However, because loudspeaker drivers are electro-mechano-acoustical transducers, it should be possible to measure their parameters in physical domains other than the electrical domain. A method of measuring loudspeaker parameters from the acoustical domain will be developed. The technique uses a plane wave tube to measure acoustical properties of a baffled driver under test. Quantities such as the transmission loss through the driver are measured for a driver placed in the tube using the two-microphone transfer-function technique. Models have been developed to curve fit the resulting data, from which small-signal loudspeaker parameters are subsequently derived. This thesis discusses the acoustical measurement theory, apparatus, and system modeling methods (via equivalent circuits). It also compares measured parameters to those derived using electrical techniques. Parameters derived from both approaches are compared with reference values to establish bias errors. Sequential measurements are also compared to reveal random errors in the derivation processes.
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Lagat, Christopher Kipchumba. "Evaluation and selection of an optimum material for coil tubes in CT drilling technology for hard rocks in mineral exploration". Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/116.
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The PhD study aimed at evaluating and selecting optimum material for coiled tubes in CT drilling technology for hard rocks in mineral exploration. Numerical computer modelling, using Abaqus and Hypersizer software packages, was undertaken to analyse stress distribution and investigate the effect of fibre orientation and stacking sequence of fibre layers that constitute the composite tube laminate. Cyclic bending tests using a fatigue testing machine and mechanical tensile tests were carried out to validate the simulation results.
11
Dugat, Fabrice. "Étude de l'assèchement dans des tubes verticaux à rainures hélicoidales chauffées symétriquement ou dissymétriquement". Grenoble INPG, 1997. http://www.theses.fr/1997INPG0005.
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Ce travail est motive par la demande des fabricants de chaudieres sur le comportement des tubes a rainures helicoidales en matiere d'assechement de paroi. Cette these a permis de concevoir, de construire et d'exploiter un dispositif experimental permettant de faire des tests d'assechement dans des tubes rainures avec un chauffage uniforme et non-uniforme radialement. Grace a l'utilisation originale du chauffage par induction et d'un fluide de simulation, le hfc-134a, l'installation est souple d'utilisation et les resultats experimentaux sont nombreux, precis et reproductibles. La confrontation des resultats obtenus pour les tubes lisses aux differents modeles de la litterature est concluante et permet de valider les differentes hypotheses experimentales : uniformite axiale de la densite de flux de chaleur, utilisation des regles de similitude de ahmad pour le hfc-134a. Ces resultats mettent en evidence l'influence de la vitesse massique et l'existence d'une valeur critique de cette vitesse a partir de laquelle les performances des tubes a rainures helicoidales sont interessantes (l'augmentation de la densite de flux de chaleur a l'assechement par rapport au tube lisse augmente de 20% a plus de 100 ou 200%). Ils ont permis d'eliminer un certain nombre d'hypotheses sur l'amelioration des performances. L'analyse physique presente les phenomenes importants et met en evidence les nombres adimensionnels intervenant dans la correlation permettant de calculer la densite de flux de chaleur a l'assechement pour un tube rainure.
12
Earnhart, Nicholas Edmond. "Modeling and validation of a syntactic foam lining for noise control devices for fluid power systems". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50151.
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Excessive fluid-borne noise in hydraulic systems is a problem the fluid power industry has long struggled to address. Traditional noise control devices such as Helmholtz resonators, tuning coils, and Herschel-Quincke tubes are generally too large for fluid power systems unless the speed of sound in the device can be reduced. A compliant lining can achieve this effect, but compliance (and lossy compliance) has had little attention in noise control in general, and in fluid power in particular. One means to achieve compliance in these devices, especially at elevated pressures, is through a liner made of syntactic foam, which in this case is a urethane host matrix with embedded hollow, polymer microspheres. The material properties at elevated pressure are unknown by the liner manufacturer, but are known to be pressure- and temperature-dependent. Therefore, the effect of hydrostatic pressures from 2.1-21 MPa and temperatures from 20-45 C on the liner properties, thus the device performance, are studied. For a Helmholtz resonator, a theoretical model is fit to experimentally-measured transmission loss of the device using a least-squares routine, which solves the inverse problem for the complex bulk modulus of the liner. These material properties are used to compare a predictive model of a tuning coil to experimental data, and in a parameter study of a Herschel-Quincke tube. The compliance of the liner is found to lower the effective sound speed by an order of magnitude and decrease the volume of the cavity of a Helmholtz resonator by up to two orders of magnitude. This work is expected to result is more compact noise control devices for fluid power systems.
13
Ivaneev, Aleksandr. "Utilisation complémentaire des techniques de fractionnement flux-force asymétrique et en colonne tournante pour la caractérisation d'échantillons environnementaux de particules". Electronic Thesis or Diss., Pau, 2020. http://www.theses.fr/2020PAUU3035.
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Les particules environnementales, particulièrement nanoparticules (NP), présentent un risque potentiel pour la santé humaine et les écosystèmes en raison de leur ubiquité, de leurs caractéristiques et de leurs propriétés spécifiques. Plus particulièrement les NP ont une mobilité extrêmement élevée dans l'environnement, une capacité à associer, voire à concentrer des éléments toxiques et à pénétrer dans les organismes vivants. Les nanoparticules doivent donc être considérées avec une attention particulière dans les études environnementales. Néanmoins, l'étude des NP dans l'environnement demeure un défi pour la chimie analytique. En effet, les nanoparticules dans un échantillon environnemental polydispersé peuvent représenter seulement un millième ou moins de la masse de l'échantillon global. Par conséquent, une masse d'échantillon considérable doit être manipulé pour séparer une quantité de nanoparticules suffisante pour leur caractérisation dimensionnelle et leur quantification. L’ensemble des techniques de fractionnement par flux−force (FFF) peut servir de base pertinente pour le développement d'une méthodologie applicable à l'étude des NP environnementales.Cette thèse de doctorat se concentre sur l'utilisation des techniques de fractionnement flux-force asymétrique et en colonne tournante (A4F et CTFFF, respectivement) dans l’étude d’échantillons environnementaux de particules. Les résultats obtenus mettent en évidence les avantages de l'utilisation de ces techniques appliquées à des nanoparticules de cendres volcaniques. Il convient de souligner que la technique de CTFFF a une capacité de séparation accrue par rapport à l’A4F, tandis que l’A4F a une grande résolution. La CTFFF a été utilisée pour la séparation de NP d’échantillons de cendres volacniques. Une nouvelle procédure de fractionnement en colonne tournante a également été proposée. La caractérisation dimensionnelle et élémentaire de ces NP a été réalisée en utilisant le couplage entre l'A4F, la diffusion de la lumière multi-angle et l'ICP-MS. Complémentairement, la stabilité de ces nanoparticules y est abordéeEnvironmental particles, especially nanoparticles (NPs), have a potential risk for human health and ecosystems due to their ubiquity, specific characteristics and properties (extremely high mobility in the environment, abilities of accumulation of toxic elements and penetration in living organisms) and, hence, should be scrutinized. The study of environmental NPs remains a challenge for analytical chemistry. In fact, NPs in a polydisperse environmental sample may represent only one thousandth or less of the bulk sample. Consequently, a considerable sample weight must be handled to separate amount of NP fraction sufficient for their dimensional and quantitative characterization. The group of field-flow fractionation (FFF) techniques can serve as a relevant basis for the development of methodology applicable to the study of environmental NPs.This doctoral thesis focuses on the use of asymmetrical flow and coiled tube field-flow fractionation techniques (A4F and CTFFF, respectively) in the investigation of environmental particulate samples. The results obtained demonstrate the advantages of these techniques applied to the study of volcanic ash nanoparticles. It should be highlighted that CTFFF technique has an increased separation capacity as compared to A4F, while A4F has an increased resolution. CTFFF was applied to the separation of NPs from environmental samples and a new coiled tube field-flow fractionation procedure was proposed. Dimensional and elemental characterization was carried out using A4F coupled to laser light scattering and ICP-MS. Furthermore, the results related to the investigation of stability of environmental nanoparticles are also given
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Rosa, Vitor da Silva. "Transferência de calor e scale-up de tanques com impulsores mecânicos em operação com fluidos não-newtonianos". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-12032018-141529/.
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A literatura corrente possui informações limitadas sobre o projeto da área de troca térmica de tanques com jaqueta, serpentina helicoidal, serpentina espiral e chicana tubular vertical, em operação com fluidos não-Newtonianos. A presente tese teve por objetivo principal analisar a transferência de calor, potência consumida e ampliação de escala em tanques com impulsores mecânicos na agitação de fluidos não-Newtonianos com duas superfícies de transmissão de calor, chicana tubular vertical e serpentina em espiral. O trabalho também visou fornecer métodos de ampliação de escala de tanques com agitação para fluidos não-Newtonianos que sigam o modelo reológico da lei das potências. A unidade experimental contemplou dois tanques de acrílico, com volume de 10 litros e 50 litros, respectivamente, chicanas tubulares verticais e serpentina em espiral. Os impulsores mecânicos utilizados foram o axial com 4 pás inclinadas a 45° e o radial turbina com 6 pás planas. Como fluidos utilizaram-se soluções aquosas de carboximetilcelulose (0,5%, 1,0% e 1,5%), solução aquosa de carbopol 940 (1,5%), solução aquosa de sacarose (50%) e água. Todos os experimentos foram conduzidos em batelada. Com os dados obtidos, empregou-se o uso de regressões para a obtenção da Equação de Nusselt, as quais forneceram valores de coeficiente de determinação ajustados entre 0,83 e 0,89 com Reynolds no intervalo de 20 a 405000, Prandtl na faixa de 4 a 6400 e índice reológico do modelo da lei das potências entre 0,45 e 1,00. Observou-se que no aquecimento realizado com a chicana tubular vertical, o impulsor radial forneceu coeficientes de convecção 20% acima quando comparado com o impulsor axial, entretanto o consumo de potência foi cerca de 66% maior em relação ao impulsor axial. No caso da serpentina espiral, o impulsor axial promoveu coeficientes de convecção por volta de 15% superiores em relação ao impulsor radial com um consumo de potência 65% menor. Desse modo, em processos em que não é necessária uma elevada turbulência, recomenda-se o uso do impulsor axial com a serpentina espiral, porém, se o processo demandar uma turbulência significativa, deve-se usar o impulsor radial com a chicana tubular vertical. Em uma última análise, os modelos não-lineares obtidos para ampliação de escala forneceram erros entre 11% e 20% na predição da rotação no tanque industrial, os quais são válidos para Reynolds modificados de Metzner e Otto (1957) na faixa de 20 a 4000 e para fluidos não-Newtonianos pseudoplásticos com índices reológicos entre 0,45 e 1,00.Current literature has limited information on the design of the thermal exchange area of tanks with jacket, helical coil, spiral coil and vertical tuber baffle, in operation with non-Newtonian fluids. The main purpose of this thesis was to analyze heat transfer, power consumption and scale-up in tanks with mechanical impellers in the agitation of non-Newtonian fluids with two heat transfer surfaces, vertical tube baffle and spiral coil. The work also aimed to provide methods of scale-up tank scale with agitation for non-Newtonian fluids that follow the rheology model of the law of powers. The experimental unit included two acrylic tanks, with a volume of 10 liters and 50 liters, respectively, vertical tube baffles and spiral coil. The mechanical impellers used were the 45° pitched blade turbine (PBT) and the Rushton turbine (RT). Aqueous solutions of carboxymethylcellulose (0.5%, 1.0% and 1.5%), aqueous solution of carbopol 940 (1.5%), aqueous solution of sucrose (50%) and water were used as fluids. All the experiments were conducted in batch. With the obtained data, we used the regressions to obtain the Nusselt Equation, which provided coefficient of determination values adjusted between 0.83 and 0.89 with Reynolds in the range of 20 to 405000, Prandtl in the range of 4 to 6400 and rheological index of the power law model between 0.45 and 1.00. It was observed that in the heating performed with the vertical tube baffle, the RT provided convection coefficients 20% higher when compared to the axial impeller, however the power consumption was about 66% higher in relation to the PBT. In the case of the spiral coil, the PBT promoted convection coefficients around 15% higher than the RT with 65% lower power consumption. Thus, in processes where high turbulence is not required, it is recommended to use the PBT with the spiral coil, but if the process requires significant turbulence, the RT must be used with the vertical tubular chassis. In a final analysis, the nonlinear models obtained for scaling provided errors between 11% and 20% in the prediction of rotation in the industrial tank, which are valid for Metzner and Otto (1957) modified Reynolds in the range of 20 to 4000 and for non-Newtonian pseudoplastic fluids with rheological indexes between 0.45 and 1.00.
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Plánková, Tereza. "Moderní technologické prvky pro trubkové výměníky tepla". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-416433.
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The aim of this diploma thesis is to get acquainted with modern technological elements currently used in shell-and-tube heat exchanger in the shell-side and tube-side, thermal-hydraulic calculation of selected elements and comparison of thermal-hydraulic properties with classically used competing technological elements. The work deals mainly with EM baffle in the tube-side and tube inserts like the twisted tape type (and its modifications) and coiled wire in the tube-side. The theoretical part is focused on acquaintance with classical technological elements in shell-and-tube heat exchanger and with basic thermal-hydraulic calculations, practical part then on acquaintance with modern elements and thermal-hydraulic calculation of selected elements. These calculations are then compared with the results of the thermo-hydraulic calculation of similar elements.
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Smith, Elliot John. "Self-assembled rolled-up devices: towards on-chip sensor technologies". Doctoral thesis, Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-74453.
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By implementing the rolled-up microfabrication method based on strain engineering, several systems are investigated within the contents of this thesis. The structural morphing of planar geometries into three-dimensional structures opens up many doors for the creation of unique material configurations and devices. An exploration into several novel microsystems, encompassing various scientific subjects, is made and methods for on-chip integration of these devices are presented.
The roll-up of a metal and oxide allows for a cylindrical hollow-core structure with a cladding layer composed of a multilayer stack, plasmonic metamaterial. This structure can be used as a platform for a number of optical metamaterial devices. By guiding light radially through this structure, a theoretical investigation into the system makeup of a rolled-up hyperlens, is given. Using the same design, but rather propagating light parallel to the cylinder, a novel device known as a metamaterial optical fiber is defined. This fiber allows light to be guided classically and plasmonically within a single device. These fibers are developed experimentally and are integrated into preexisting on-chip structures and characterized.
A system known as lab-in-a-tube is introduced. The idea of lab-in-a-tube combines various rolled-up components into a single all-encompassing biosensor that can be used to detect and monitor single bio-organisms. The first device specifically tailored to this system is developed, flexible split-wall microtube resonator sensors. A method for the capturing of embryonic mouse cells into on-chip optical resonators is introduced. The sensor can optically detect, via photoluminescence, living cells confined within the resonator through the compression and expansion of a nanogap built within its walls.
The rolled-up fabrication method is not limited to the well-investigated systems based on the roll-up from semiconductor material or from a photoresist layer. A new approach, relying on the delamination of polymers, is presented. This offers never-before-realized microscale structures and configurations. This includes novel magnetic configurations and flexible fluidic sensors which can be designed for on-chip and roving detector applications.
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Austen, David Steven. "Combined free and forced convection during laminar flow through helically coiled circular tubes of substantial pitch". 1986. http://hdl.handle.net/1993/15350.
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林世挺. "Thermal and Flow Analysis of a Coiled-Tube Type Heat Exchanger". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/28327436500870964448.
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Narasimhaswami, Shankar. "Cooling of QPS modular coils using embedded copper tubes". 2006. http://etd.utk.edu/2006/NarasimhaswamiShankar.pdf.
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Kebonte, Shiko A. "Condensation heat transfer and pressure drop coefficients of R22/R142b in a water cooled helicaly coiled tube-in-tube heat exchanger". Thesis, 2012. http://hdl.handle.net/10210/6181.
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M.Ing.Heat transfer and pressure drop characteristics during in-tube condensation of nonazeotropic mixtures of R22/R142b in a smooth helically coiled copper tube with an inside diameter of 8.11 mm are investigated. The experimental results are compared with prediction from correlation. The coefficient of performance of.the heat pump built and used for experiments has been studied. The mass flux of the refrigerant was varied during the course of the experiments. At similar mass flow rate of fluids, the average heat transfer coefficients for mixtures were lower than those for pure refrigerant R22 used as reference for comparison. Also, the heat transfer coefficients of all the refrigerants increased with increasing mass flux.
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Lo, Yu-Sheng, i 羅宇盛. "Performance Analysis of Helical Coils Tube Furnace". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/10732122591822224120.
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碩士國立屏東科技大學
車輛工程系所
101
As modern industry booms, how to achieve energy recovery is an objective consistently pursued. In industrial applications, helical coiled heat exchanger is frequently used to recover waste heat. In a helical coiled tube, the fluid is heated by its surrounding waste heat. Therefore, this heat recovery method is beneficial not only to environmental protection but also to energy cost reduction. This thesis investigates the feasibility of a special coating applied on the interior surfaces on a furnace and the heat exchanger in it to improve the amount of waste heat recovery by increasing the heat radiative emissivity as well as identifies the optimal surfaces for coating. In the beginning, this work has constructed the model using graphics software before performing computer simulations which were followed by a parametric analysis using Taguchi method. The result obtained with optimized parameters indeed corresponds to the greatest amount of total heat transfer and radiative heat transfer. In terms of heat transfer, coating only the surface between the third and twenty-fourth laps yields a reduction in the amount of both total and radiative heat transfer in comparison with the optimized case by 0.93% and 3.34%, respectively. However, the area of coating actually decreases by approximately 46.34%. If the coated area is taken into major consideration, coating only the incline and vertical surfaces of the center blockage may reduce the coated area by 78.56% comparing to the optimal case while the amount of both total and radiative heat transfer only decrease by 5.2% and 11.96%, respectively.
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Owu, Delight Mawunyo. "Numerical simulation for the cooling of QPS modular coils with embedded copper tubes and subsequent experimental verification". 2009. http://etd.utk.edu/2009/May2009Theses/OwuDelightMawunyo.pdf.
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Chen, Cheng-An, i 陳誠安. "Heat transfer enhancement of circular tube inserted with spring coil". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/60340391091122717456.
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碩士國立中興大學
機械工程學系所
102
Heat transfer and pressure drop data in smooth tubes inserted with various wire coils were measured respectively. Water and air were individually considered as working fluid. The wire diameter (e) and pitch (p) of the wire coils were in the range 1 - 1.8 mm and 18 - 32 mm respectively. For tightness between the wire coil and tube wall, three tubes with different inner diameters (12.8, 13.4 and 13.8 mm) were adopted. This work not only established correlations of Nu and f, but also examined performance indexes (r 1 , r 2 and r 3 ) of the test tubes. The r 1 represents the ratio of Nu values between a test tube and a smooth tube; the r 2 denotes the ratio of Nu/f values; the r 3 stands for the ratio of heat transfer rates based on per unit of consumed mechanical power. For air, the correlation of Nu value was found to be Nu = 0.00585(Re)m [(e / d )2 -0.0042]-0.24 ( p / d )-0.22 where m1= 0.51 + 6.16( e / d )-23.15( e / d ) 2 . For water, Nu = 2.55(Re)0.57 ( e / d )α3 ( p / d )-1.13= -0.17( p / d ) + 0.65 . For both air and water, a common f correlationwhere α 3 was acquired as follows: f = 36.13Re −0.36 (e / d )[ln( p / d )]−0.52 . The Nu and r 1 values increase with the e/d value, but increase with a decrease of the p/d value. As the e/d value decreases or the p/d values increases, the r 2 and r 3 values tend to increase. For air, the r 2 and r 3 values moderately increase with the Re value. For water, the r 2 and r 3 values decrease with an increase of the Re value. Keywords: heat transfer enhancement;wire coil;Nusselt number;friction factor;performance index
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Telikicherla, Kandala Bhargav. "Numerical simulation ( a lumped transient model) for QPS modular coils with embedded copper tubes and subsequent experimental verification". 2009. http://etd.utk.edu/2009/May2009Theses/TelikicherlaKandalaBhargav.pdf.
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Turaga, Mal. "Experimental performance evaluation of multi-row, plate finned-tube, direct expansion air cooling and dehumidifying coils". Thesis, 1989. http://spectrum.library.concordia.ca/5845/1/NL51339.pdf.
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Chen, Po-sung, i 陳柏松. "Microstructure analysis for nickel- base metal powder fusion coated inside the injection tube by using induction coil heating method". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/9544mu.
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碩士國立中山大學
機械與機電工程學系研究所
95
For the induction heating process of bi-metallic tubes, the inner tube of alloy-layer is much easier to cause a lot of defects of cavities due to the fact that heating power, maximum temperature value and the time frame of temperature retention were chosen improperly. This research focuses on the effect of maximum temperature value and the time frame of temperature retention on the micro-structure and defects of cavities of the Nickel-based alloy-layer. The experiments of this study are divided into two parts. In the domain of the experiment in simulation fashion, Nickel-based alloy powders were put into the specimens of AISI 4140 steel. Radio Frequency (RF) oven were used to smelt Nickel-based alloy powders in the vacuum conditions over the maximum temperature range of 920~1180℃respectively. After that, the time frame of temperature retention was conducted from 0 to 10 minutes. Then, the furnace-cooling went down to 700℃ then air-cooling down to the room temperature. Nickel-based alloy-layer, microstructure, component analysis, defects of cavities of the interface between Nickel-based alloy-layer and steels, and diffusion of interfaces were analyzed using optical microscopes (OM) and scanning electron microscopes (SEM). From the experiments, it was found that Nickel-based alloy-layer consisted of γ-Ni、CrB、Cr7C3 over the maximum temperature range of 920~1050℃whether temperature retention is performed or not. According to the findings of metallographic observation, the increase of coarsening and the reduction of the capacity of CrB and Cr7C3 become more obvious as maximum temperature value and the time frame of temperature retention become large. In addition, the whitening layer (diffusion zone) formed between the interface of alloy-layer and steels become much wider as maximum temperature value and the time frame of temperature retention become large. Secondly, the field experiment method was also applied in this paper. The tube rich in Nickel-based alloy powders was heating to analyze induction coil in various conditions: heating power (200~285KW), maximum temperature value (1020~1040℃), the time frame of temperature retention (10, 30, 50sec), and the rotating speed (1000~1300rpm). The results of the experiments indicated that the surface of the alloy-layer cause defects of vermicular cavities since the volume of liquid cannot fill out the crack of cavities completely due to lower temperature when there is insufficient time; too long periods of the time frame of temperature retention lead to the tough and huge dendrites to obstacle the flowing of liquid and the solidification of shrinkage cavity. According to the observation of the microstructure, the larger the maximum temperature value and the time frame of temperature retention were, the more the dendrites formed. The formation of dendrites causes not only the uneven distribution of hardening phase of CrB and Cr7C3 of the alloy-layer but also the reduction of hardness of the alloy-layer. The dendrites are typically formed from the interface to the surface of the alloy-layer. Besides that, the alloy-layer mainly consists of γ-Ni, Ni3B, Ni3Si, CrB, and Cr7C3 via X-ray Diffraction (XRD). Among them, the main hardening phases are CrB and Cr7C3 which is the main reason that the alloy-layer has high-level hardness. As maximum temperature value and the time frame of temperature retention become large, the whitening layer (diffusion zone) was formed between the interface of alloy-layer become much wider because the faster the elements of the based materials (tube) diffused and the wider the intermetallic compound formed among the interfaces. After heated for 800 seconds over the temperature range of 750~1030℃, iron element was diffused all over the alloy-layer. The increase of coarsening and the reduction of the capacity near interface and interface become more obvious as maximum temperature value and the time frame of temperature retention become large.
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Morales, Santiago Adolfo. "Investigation of high strain rate behavior of metallic specimens using electromagnetic inductive loading". Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-4032.
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Aerospace EngineeringThe aim of this thesis is to explore the high strain rate behavior of metallic specimens using electromagnetic inductive loading as the means to inflict the required high strain rate deformation on laboratory scale specimens, allowing for controlled, repeatable experiments to be performed. Three separate experiments were designed and performed, using helical and spiral coils as the sources of radial and unidirectional loading. The first experiment evaluated the effect of applying a polymer coating on 30.5 mm diameter, Al 6061- O tube samples, in two lengths, 18 and 36 mm. The expanding tube experiment was used to apply a radial loading on the specimens and record the event. Several optical techniques were then used to evaluate the behavior of the samples. Coatings of polyurea and polycarbonate were used. It was observed that the polycarbonate coating seemed to have a more profound effect on the behavior of the metal, by applying a larger restraining pressure on the tube surface during the expansion process, and thereby modifying the stress state of the specimen. The second experiment looked to design an experimental arrangement to test the plane strain, high strain rate behavior of Al 6061-O tubes of different lengths. A 112 mm long solenoid was designed and manufactured, and testing was performed on 30.5 mm diameter Al 6061-O tubes in lengths of 50, 70 and 90 mm. It was observed that the coil behaved similar to shorter ones at low voltages and that the longer the specimen used, the more its deformation path approached a plane strain condition. Finally, a third experiment was performed to develop an experiment to accelerate a plate to high linear velocities, as a means to evaluate the use of a flat spiral coil as the driver for future experiments based upon electromagnetic inductive loading. A prototype coil was manufactured and installed into a converted expanding tube experimental setup. Three samples were tested in several sizes, and materials: aluminum and steel. Speeds in the range of 45 to 251 m/s were obtained, validating the apparatus as a viable method to provide a unidirectional loading.
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