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1
Costa Conrado, Ana. "Modelling the radially polarised annular stator of a piezoelectric travelling wave ultrasonic motor based on the shear effect". Journal of Intelligent Material Systems and Structures 30, nr 8 (14.03.2019): 1225–38. http://dx.doi.org/10.1177/1045389x19829833.
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This article deals with the mathematical–analytical model of a radially polarised stator, part of a piezoelectric travelling wave ultrasonic motor based on the shear effect. The stator is treated with a Reissner–Mindlin plate model containing piezoelectric terms. The so-obtained mathematical description of the disc stator takes into account its geometry, kinematics and characteristics that influence efficiency and torque. Rayleigh–Ritz discretisation is used to obtain eigenfrequencies and eigenmodes of the stator plate. In addition, there are often teeth over the contact surface of ring-shaped stators to minimise the friction losses during operation of the motor, and possible vibration modes are compared with respect to the deflexion of the contact points. In the laboratory, measured eigenfrequencies of the free vibrations of the plate corroborate the numerical method. Particularly, the generation of travelling waves requests the excitation of two degenerated vibration modes in a certain electrode configuration. A voltage inverter was designed for this purpose.
2
Henderson, G. H., i S. Fleeter. "Forcing Function Effects on Unsteady Aerodynamic Gust Response: Part 2—Low Solidity Airfoil Row Response". Journal of Turbomachinery 115, nr 4 (1.10.1993): 751–59. http://dx.doi.org/10.1115/1.2929310.
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The fundamental gust modeling assumption is investigated by means of a series of experiments performed in the Purdue Annular Cascade Research Facility. The unsteady periodic flow field is generated by rotating rows of perforated plates and airfoil cascades, with the resulting unsteady periodic chordwise pressure response of a downstream low-solidity stator row determined by miniature pressure transducers embedded within selected airfoils. When the forcing function exhibited the characteristics of a linear-theory vortical gust, as was the case for the perforated-plate wake generators, the resulting response on the downstream stator airfoils was in excellent agreement with the linear-theory models. In contrast, when the forcing function did not exhibit linear-theory vortical gust characteristics, i.e., for the airfoil wake generators, the resulting unsteady aerodynamic responses of the downstream stators were much more complex and correlated poorly with the linear-theory gust predictions. Thus, this investigation has quantitatively shown that the forcing function generator significantly affects the resulting gust response, with the complexity of the response characteristics increasing from the perforated-plate to the airfoil-cascade forcing functions.
3
Dennis, John Ojur, Almur Abdelkreem Saeed Rabih, Mohd Haris Md Khir, Mawahib Gafare Abdalrahman Ahmed i Abdelazez Yousif Ahmed. "Modeling and Finite Element Analysis Simulation of MEMS Based Acetone Vapor Sensor for Noninvasive Screening of Diabetes". Journal of Sensors 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/9563938.
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Diabetes is currently screened invasively by measuring glucose concentration in blood, which is inconvenient. This paper reports a study on modeling and simulation of a CMOS-MEMS sensor for noninvasive screening of diabetes via detection of acetone vapor in exhaled breath (EB). The sensor has two structures: movable (rotor) and fixed (stator) plates. The rotor plate is suspended on top of the stator by support of four flexible beams and maintaining certain selected initial gaps of 5, 6, 7, 8, 9, 10, or 11 μm to form actuation and sensing parallel plate capacitors. A chitosan polymer of varied thicknesses (1–20 μm) is deposited on the rotor plate and modeled as a sensing element for the acetone vapor. The minimum polymer coating thickness required to detect the critical concentration (1.8 ppm) of acetone vapor in the EB of diabetic subjects is found to be 4–7 μm, depending on the initial gap between the rotor and stator plates. However, to achieve sub-ppm detection limit to sense the acetone vapor concentration (0.4–1.1 ppm) in the EB of healthy people, up to 20 μm polymer thickness is coated. The mathematically modeled results were verified using the 2008 CoventorWare simulation software and a good agreement within a 5.3% error was found between the modeled and the simulated frequencies giving more confidence in the predicted results.
4
Rundo, Massimo, i Nicola Nervegna. "Geometry Assessment of Variable Displacement Vane Pumps". Journal of Dynamic Systems, Measurement, and Control 129, nr 4 (24.10.2006): 446–55. http://dx.doi.org/10.1115/1.2718245.
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The paper brings to evidence the effect that geometry of the stator ring of variable displacement radial pumps bears on performance characteristics of these units. The type of motion of the stator ring (linear or rotational), the location of the center of rotation, the porting plate integral with the casing or with the stator ring all have remarkable effects on the pump steady state and dynamic performance. At steady state, an influence exists on the attainable minimum displacement and on the deviation of discharge pressure from the desired setting when displacement is being controlled. In turn, dynamic performance is affected by changes in port plate timing as stator position and displacement undergo transitions. Specific attention is then committed to variable displacement vane pumps for internal combustion engines lubrication where an additional and foremost effect is investigated concerning the issues entailed by internal forces distribution on the stator ring that originate from incomplete chambers filling at high rotational pump speed.
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Chen, Chao, i Chongmin She. "Creep Effect Analysis at the Friction Interface of a Rotary Ultrasonic Motor". International Journal of Applied Mechanics 07, nr 02 (kwiecień 2015): 1550031. http://dx.doi.org/10.1142/s1758825115500313.
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Theoretical and experimental studies for the creep mechanism at the friction interface between rotor and stator of traveling wave type rotary ultrasonic motors (TRUM) are performed in this work. A modeling method is developed to investigate the creep and the distributed contact pressure in the friction interface for the piezoelectric composite stator with complex geometries. The annular laminated structure of the stator is discretized into a semi-analytical plate element in the radial direction, and the teeth on top of the stator are modeled by the finite element (FE) method. Then a coupled approach for the continuous plate and FE discretized teeth is proposed to investigate the interface contact mechanism. Finally, the accelerated aging tests for TRUM are conducted to study the creep effect in the friction layer during the long-term storage, the startup state is investigated experimentally by the transient characteristics measurement system. It is shown that transient characteristics of TRUM are strongly affected by the creep effect at the friction interface. The vibration response of the stator is weakened by the creep of the contact layer, and the amplitude of the piezoelectric composite plate decreases with increasing creep percentage. It is theoretically and experimentally proved that the creep percentage of over 20% can lead to the startup failure of TRUM.
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Karabay, H., J. X. Chen, R. Pilbrow, M. Wilson i J. M. Owen. "Flow in a “Cover-Plate” Preswirl Rotor–Stator System". Journal of Turbomachinery 121, nr 1 (1.01.1999): 160–66. http://dx.doi.org/10.1115/1.2841225.
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This paper describes a combined theoretical, computational, and experimental study of the flow in an adiabatic preswirl rotor–stator system. Preswirl cooling air, supplied through nozzles in the stator, flows radially outward, in the rotating cavity between the rotating disk and a cover-plate attached to it, leaving the system through blade-cooling holes in the disk. An axisymmetric elliptic solver, incorporating the Launder–Sharma low-Reynolds-number k–ε turbulence model, is used to compute the flow. An LDA system is used to measure the tangential component of velocity, Vφ, in the rotating cavity of a purpose-built rotating-disc rig. For rotational Reynolds numbers up to 1.2 × 106 and preswirl ratios up to 2.5, agreement between the computed and measured values of Vφ is mainly very good, and the results confirm that free-vortex flow occurs in most of the rotating cavity. Computed values of the preswirl effectiveness (or the nondimensional temperature difference between the preswirl and blade-cooling air) agree closely with theoretical values obtained from a thermodynamic analysis of an adiabatic system.
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Dong, Peng, Shengdun Zhao, Shuqin Fan, Muzhi Zhu i Peng Zhang. "Double-rotator and valve plate distribution radial piston pump". Assembly Automation 40, nr 2 (3.11.2019): 265–71. http://dx.doi.org/10.1108/aa-12-2018-0270.
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Purpose The drive shaft and the distribution shaft of a traditional radial piston pump are in a cantilever state. To solve this problem, this paper aims to present a radial piston pump with through shaft driving and valve plate distribution. Design/methodology/approach The working principle of the pump is discussed in detail. In this radial piston pump, valve plate distribution parts are designed to distribute oil to the piston chambers, and the distribution shaft is replaced. A bearing is installed between the stator and rotator to reduce the friction. The transmission shaft is supported by two bearings to ensure smooth operation. The support force of the transmission shaft is optimized. In addition, the flow pulsation principle is presented. To accomplish the change, the displacement of the radial piston pump, the proportional control system is designed. Findings After completing the machining and assembly of the pump, an experimental study was carried out. The results show that the output flow of the pump is basically the same as the theoretical flow. Originality/value The friction between the slipping shoes and the stator is greatly reduced due to the function of rolling bearings. The higher stability of the driveshaft is obtained for the reason of double-sided support. The radial piston pump has a novel structural design in reducing the friction between the shoes and the stator and improving the stability of the transmission shaft.
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Chen, Chao, i Ru Juan Chen. "Analysis and Design of Stator of Traveling Wave Type Rotary Ultrasonic Motor". Advanced Materials Research 199-200 (luty 2011): 805–10. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.805.
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Due to its compact sizing, fast response and good control performance traveling wave type rotary ultrasonic motor (TRUM) has significant potentials for applications in robot actuation. In order to considering the complex geometries, this paper presents modeling approach for micro-TRUM stator. First piezoelectric composite stator is partitioned into three substructures, two of which are modeled as several continuous annular plates by semi-analytical method. Without losing the complex geometries, the stator teeth as another substructure are modeled by means of finite element (FE) approach. Based on both component-mode synthesis and dynamic reduction, the coupled method for continuous plate and FE discretized teeth is presented in order to consider dynamic behavior of composite stator with good accuracy and short computation time. It allows combination of the continuous parameters and FE discretized substructures, and the mathematical model representing the complete stator is derived. Finally the prototype is manufactured according to the presented method. The validation of the analysis and design method is attained through the experiments for the manufactured stator. It is pointed that radial friction can be capable to increase s for the ultrasonic motor with smaller dimension. It explains why micro-TRUM has a fast heat output at the contact interface.
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Gherman, Bogdan, Oana Dumitrescu i Valeriu Dragan. "Transonic flow study in a centrifugal compressor using perforated airfoils". Aerospace Research in Bulgaria 32 (2020): 110–21. http://dx.doi.org/10.3897/arb.v32.e10.
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In this paper, the effect on a perforated plate on a centrifugal compressor is investigated using numerical simulation. The performances and fluid flow are compared for two different vaned diffusers, a base case where there are no perforated plates and a case where a perforated plate is inserted in the rotor casing at exit and the stator blade. The impact of this geometry change on the compressor performances it is studied in the case of adverse angles of attack at stator vane. Near wall refinement ensures the accuracy resolution of the boundary layer with a y+ value of one unit corroborated with a growth ratio of 1.1:1. Menter’s SST model was used in all numerical cases performed, as implemented in ANSYS CFX. Following the results of the baseline diffuser, the optimal position of the perforated cavity was determined.
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Kuchynskyi, K. A., V. A. Kramarskyi, D. I. Hvalin i V. A. Mystetskyi. "STUDY OF PHYSICAL PROCESSES IN A TURBOGENERATOR END ZONE AT THE MECHANICAL DAMAGES OF STATOR CORE FASTENING". Praci elektrodinamiki Nacionalanoi akademii nauk Ukraini Institutu 2020, nr 57 (2.12.2020): 65–72. http://dx.doi.org/10.15407/publishing2020.57.065.
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With the help of mathematical simulation of mechanical processes in the stator core fastening system of a powerful turbogenerator end zone obtained appropriateness of basic parameters changes at the break of clamp prisms heads of the stator core. It is determined that the sudden break of one or more clamp prisms leads to longitudinal oscillation of their other working heads and stiff connected with them press plate, accordingly. Although such oscillation is insignificant but propagates along the entire surface of the press plate with a maximum value in the break zone and subsequent decrease with distance from this zone and therefore can be detected with the help of existing vibration sensors by installing them on the press plate. It is possible to use a limited number of sensors due to the propagation of vibration along the entire surface of the plate. But because the vibration changes are insignificant, in this case, there is a complexity of control that requires the use of high-sensitivity sensors and great informative computing equipment. According to the sensors indices, it is possible to determine the number of breaks for clamp prisms heads of the stator core and the number of them working heads, accordingly. Besides, this effect can be used to diagnose the un-compression of the stator core tooth zone. Since one of the important ways to improve the control and diagnostics of turbogenerators is the detection, the presence of such knowledge will allow making the optimal decision for further measures. References 8, figures 8, tables 2.
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Vikharev, S. N., i VA Morkovin. "Research of the drawing of bars plate in the refiners". Journal of Physics: Conference Series 2094, nr 4 (1.11.2021): 042038. http://dx.doi.org/10.1088/1742-6596/2094/4/042038.
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Abstract Object of research of article is the drawing of bars plate in the refiners at refining of chips and wood pulp. On the basis of the theory of contact interaction of bars influence of the drawing of plate on characteristics of contact processes is investigated. The friction coefficient between plate decreases at increase in density of contact of bars. At increase in an angle of crossing of bars rotor and stator and refining of pulp with concentration up to 6% the coefficient of friction decreases. At increase in an angle of crossing of bars chips and pulp with concentration over 10% the coefficient of friction increases. Therefore it is recommended to increase the angle of crossing of bars rotor and stator at refining of pulp of low concentration, and at refining of pulp of concentration over 10% and chips - to reduce, up to a radial arrangement.
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Kang, Jin Gu, Moon Chan Kim, I. Rok Shin i Woo Seok Jin. "FEASIBILITY STUDY ON EFFECT OF STRUCTURAL FLEXIBILITY OF ASYMMETRIC PRE-SWIRL STATOR ON PROPULSION PERFORMANCE FOR KRISO CONTAINER SHIP (KCS)". Brodogradnja 72, nr 4 (1.10.2021): 103–19. http://dx.doi.org/10.21278/brod72406.
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The use of energy-saving devices is the most effective method for decreasing CO2 emissions, which is an increasingly concerning environmental issue. The asymmetric pre-swirl stator has been developed as an energy-saving device and has been successfully applied to various types of vessels. In the present study, a flexible material was applied to an asymmetric pre-swirl stator to determine the variation in the flow around stator and its efficiency. A fluid–structure interaction (FSI) analysis system was developed using the Star-CCM+ (fluid) and the Abaqus (structure). The proposed analysis system was validated by comparing the experimental results using a flexible plate in a flowing fluid. The flexible stator was applied to a 3,600 TEU KRISO Container Ship to determine the improvement in its performance compared to the previous optimum value achieved with a rigid stator. Although this application was conducted on a model scale and the deformation was small, the results of the flexible stator indicated the possibility of not only increasing the efficiency but also decreasing the vortex risk around stator blade.
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Li, Huai Yong, i Li Zhong Xu. "Dynamics Analysis of the Bar-Type Piezoelectric Motor Stator". Applied Mechanics and Materials 117-119 (październik 2011): 390–93. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.390.
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In this paper, the modal and the harmony response analyses of the stator of the bar-type piezoelectric motor are done by using the finite element method. The influences of the motor’s structural parameters and the voltage applied to ceramic plate on the characteristics of the stator are discussed. Some useful results are given. This provides theoretical basis for the structure optimization design of the motor.
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Woo, Jemin, Bongsu Hahn i Changsun Ahn. "Position Estimator Design for a MEMS Top-Drive Electrostatic Rotary Actuator". Sensors 20, nr 24 (10.12.2020): 7081. http://dx.doi.org/10.3390/s20247081.
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The capacitance and rotor angle of a MEMS top-drive electrostatic rotary actuator do not have a linear relationship due to the non-ignorable fringe effect and low aspect ratio of the electrodes. Therefore, the position estimation is not as straightforward as that for a comb-drive linear actuator or a side-drive rotary actuator. The reason is that the capacitance is a nonlinear and periodic function of the rotor angle and is affected by the three-phase input voltages. Therefore, it cannot be approximated as a simple two-plate capacitor. Sensing the capacitance between a rotor and a stator is another challenge. The capacitance can be measured in the electrodes (stators), but the electrodes also have to perform actuation, so a method is needed to combine actuation and sensing. In this study, a nonlinear capacitance model was derived as a data-driven model that effectively represents the nonlinear capacitance with sufficient accuracy. To measure the capacitance accurately, the stator parts for actuation and those for sensing are separated. Using the nonlinear model and the capacitance measurement, an unscented Kalman filter was designed to mitigate the large estimation error due to the periodic nonlinearity. The proposed method shows stable and accurate estimation that cannot be achieved with a simple two-plate capacitor model. The proposed approach can be applied to a similar system with highly nonlinear capacitance.
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Wang, Yu Ping, Zeng Hui Zhao, Xiang Dong Zhao i Yan Guo Wang. "Research on the Three-Dimensional Elliptical Motion of Rotary Traveling Wave Ultrasonic Motor". Advanced Materials Research 97-101 (marzec 2010): 3519–22. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.3519.
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The model of a particle on the stator tooth side of traveling wave type rotary ultrasonic motor is established based on the plate theory, which shows that trajectories of particles on the surface of the stator teeth are essentially three-dimensional Oblique elliptical motion. Take the RTUM60 type ultrasonic motor as an example, the three-dimensional elliptical motion of stator tooth’s endpoint is studied through numerical experiments, and the results show the energy loss caused by the radial sliding between stator and rotor is considerable. The influences of tooth height on effective elliptical motion, the velocity in the three direction under Cylindrical coordinate system and radial slip are also discussed, which conclude that the model can be used for further study on the contact model design and optimization traveling wave type ultrasonic motor.
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Wu, Y., X. Zhu i Z. Du. "Experimental investigation on the momentumless wake using trailing edge blowing". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, nr 8 (1.08.2008): 1477–86. http://dx.doi.org/10.1243/09544062jmes1033.
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A developed plate stator model with and without trailing edge blowing (TEB) is studied using experimental methods. Wake characteristics of flow over the stator in the three-dimensional wake regimes are studied using hot-wire anemometry (HWA) and particle image velocimetry (PIV) techniques. First, the mean velocity profiles have been measured in the wake of the stator using HWA. Four wake characteristics have been obtained through momentum thickness judgments: pure wake, weak wake, momentumless wake, and jet. These velocity profiles show some differences in momentum deficit for the four cases. Then, the velocity spectra of the pure wake and momentumless wake obtained through the HWA measurements showed that TEB can eliminate the shedding vortex of the stator. Characteristic length scales based on the wake turbulent intensity profiles showed that the momentumless wake can reduce the wake width and depth. PIV measurement is carried out to measure the flow field of the four wakes. Finally, the application of TEB approaching momentumless wake status is used on an industrial ventilation low-pressure axial fan to assess noise reduction. The results show that TEB can make the outlet of the stator uniform, reduce velocity fluctuation, destroy the vorticity structure downstream of the stator, and reduce interaction noise level of the stator and rotor.
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Darques, K., A. Tounzi, A. Benabou, S. Shihab, J. Korecki, W. Boughanmi i D. Laloy. "Iron Loss Quantification in the Aim of the Estimation of Eddy Currents in Clamping Devices". European Journal of Electrical Engineering 23, nr 6 (31.12.2021): 481–86. http://dx.doi.org/10.18280/ejee.230608.
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In high power electrical machines, the leakage magnetic flux due to end windings induces eddy currents in clamping devices. However, it is quite difficult to quantify these losses. In order to study the effect of different clamping materials and the impact of the magnetization direction, an experimental mock-up composed of a stator and a clamping plate has been developed. An axial coil generates a circumferential magnetic flux in the stator core at different frequencies. Eddy current losses in the clamping plates are deduced from a power balance by subtracting Joule losses and iron losses from the total measured losses. Iron losses are deduced from 3D FE calculations while the impact of the frequency on B(H) curve is taken into account. Losses in the clamping device are then analyzed depending on experimental parameters.
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Goda, Kento, Hidekazu Kajiwara i Manabu Aoyagi. "Examination of Hemispherical Shell Stator for Lightweight Spherical Ultrasonic Motor". International Journal of Automation Technology 16, nr 4 (5.07.2022): 478–87. http://dx.doi.org/10.20965/ijat.2022.p0478.
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A multi-degree-of-freedom, spherical ultrasonic motor (MDOF-SUSM) has been proposed to reduce the size and weight of actuator systems capable of MDOF motion. The MDOF-SUSM is expected to be used in manipulators and spacecraft because of its noiseless, self-holding, and non-magnetic properties. Previous studies have shown the feasibility of the MDOF-SUSM using a spherical stator, but the weight of the device was problematic. This paper describes a hemispherical shell stator devised to reduce the weight of the MDOF-SUSM. For the prototype stator, a suitable vibration mode search and an excitation method were investigated using finite element analysis (FEA). A combination of l2m1-mode and l1m0-mode was selected and found to be excitable by an arched piezoelectric ceramic plate bonded to the opening. A stator support mechanism using four tuning forks was also devised. The vibration characteristics of the prototype stator were experimentally investigated. The results of FEA and displacement measurement confirmed the formation of multiple natural vibration modes that can be used for rotation. Rotation with three degrees of freedom was confirmed to be possible by combining the vibration modes. In short, a hemispherical shell stator for the MDOF-SUSM was created, and it is lighter in weight than the MDOF-SUSM that used a spherical stator.
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Ha, T. W., i D. W. Childs. "Annular Honeycomb-Stator Turbulent Gas Seal Analysis Using a New Friction-Factor Model Based on Flat Plate Tests". Journal of Tribology 116, nr 2 (1.04.1994): 352–59. http://dx.doi.org/10.1115/1.2927233.
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A new empirical friction-factor model for honeycomb surfaces based on flat plate test results has been developed as a function of Mach number and dimensionless pressure and honeycomb geometry variables. A rotordynamic analysis for centered, turbulent-annular-honeycomb-stator seals has been developed incorporating the new empirical friction-factor model for honeycomb-stator surfaces. The results of the new analysis in predicting the rotordynamic and leakage characteristics have been compared to: (a) Moody’s friction-factor model analysis, and (b) experimental data for short (L/D = 1/6, 25.4 mm long) seal. The comparisons show that the new honeycomb friction-factor model greatly improves the predictions of leakage and rotordynamic coefficients compared to Moody’s friction-factor model, especially, for direct and cross-coupled stiffness.
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Sato, Kaiji. "Effect of Multilayering on Thrust Force Characteristics in Compact Linear Switched Reluctance Motors with a Simple Layer Structure". International Journal of Automation Technology 7, nr 5 (5.09.2013): 482–88. http://dx.doi.org/10.20965/ijat.2013.p0482.
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This paper describes the effect of multilayering on thrust force characteristics in compact Linear Switched Reluctance Motors (LSRMs) having a simple, flat shape. The Layer Structure Linear Switched Reluctance Motors (LS-LSRMs) basically comprise simple layer structure components such as a thin mover and a flat stator core for simple fabrication and for saving space. The use of the simple layer structure components facilitates the simple fabrication of multilayer actuators to generate a large thrust force. Themover consists ofmagnetic pieces sealed with nonmagnetic materials. The stator core is a single layer magnetic plate with fine beams. The force characteristics of two LS-LSRMs with one or two stator core layers were examined numerically. Then, their prototypes were fabricated and their force characteristics were measured. The results indicated that the multilayer structure was effective in increasing the effective thrust force.
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Zhou, Xiang Yu, Wei Shan Chen i Jun Kao Liu. "Design and Characteristics of a New Thin Cross Type Rotary Ultrasonic Motor". Applied Mechanics and Materials 543-547 (marzec 2014): 1537–41. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.1537.
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A new thin cross type rotary ultrasonic motor has been proposed for further study of this type motors characteristics. As a stator, eight semi-circular piezoelectric ceramics were attached on the upper and bottom sides of a thin hollow cross brass plate. The stator was excited by two sinusoidal voltages with a phase difference of 90° and elliptical trajectories were generated at the contact points to drive a shaft rotor. The driving principle of the motor was illustrated by degenerating two orthogonal in plane vibration modes. Based on FEM analysis, the vibration shapes and frequencies of operation modes were simulated and the relationships between the maximum displacements of the contact points and various motor parameters were obtained. A prototype was fabricated and characteristics of the motor were measured. The relationship among rotation speed, pre-pressure and voltage are no-linear. The maximum rotation speed with no load was 22.9 rpm. The merits and shortcomings of the thin cross type rotary ultrasonic motor were discussed.
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He, Song, William Omell i Michael Gandham. "Dynamic force measurement to assess NVH performance of electric motors". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 264, nr 1 (24.06.2022): 27–34. http://dx.doi.org/10.3397/nc-2022-673.
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The electromagnetic (EM) force induced motor whine is a major noise source of hybrid and electric vehicles. Experimental quantification of dynamic EM force is highly desirable to assess the NVH performance of electric motors. However, it is difficult to measure EM forces directly on the stator teeth. This paper describes a new indirect method to measure the dynamic forces at stator mounting ear locations. First, high-precision tri-axial piezoelectric force ring sensors are selected and calibrated to measure dynamic forces under compressive mean loading. Next, special motor housings are designed and built to accommodate force sensors between the stator ears and the base mounting plate. Force sensors are then aligned with the stator circumferential directions to measure dynamic forces in radial, tangential and axial directions as a function of motor torque and speed. The new technology is successfully implemented for electric motors of GM's Spark and Bolt EVs. Measured dynamic forces correlate well with finite-element analytical results and show consistent trends with noise and vibration responses. This confirms the dynamic mounting force can be used as an effective and measurable indicator to optimize NVH designs for electric motors.
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Barlow, D. N., Y. W. Kim i L. W. Florschuetz. "Transient Liquid Crystal Technique for Convective Heat Transfer on Rough Surfaces". Journal of Turbomachinery 119, nr 1 (1.01.1997): 14–22. http://dx.doi.org/10.1115/1.2841004.
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The local heat transfer coefficients are obtained on a rough planar surface simulating in-service turbine stator vane sections. A transient experimental technique is presented that permits the determination of local heat transfer coefficients for a rough planar surface using thermochromic liquid crystals. The technique involves the use of a composite test surface in the form of a thin foil of stainless steel with roughness elements laminated over a transparent substrate. Tests are conducted on a splitter plate to provide momentum boundary layer thicknesses to roughness heights appropriate for actual turbine stator vanes. Data are reported for two roughness geometries and two free-stream velocities. The range of Reynolds numbers along with the ratio of average roughness value to momentum thickness matches conditions encountered on the pressure side of the first-stage stator vanes in current high performance turbofan engines. A numerical simulation is conducted to validate the test method. Results for the rough surfaces investigated are compared with an available empirical relationship.
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Kim, J. W., C. H. Park, S. S. Jeong, M. H. Kim, T. G. Park i H. H. Chong. "Driving Characteristics of a Simple Square-Frame Ultrasonic Motor". Applied Mechanics and Materials 110-116 (październik 2011): 210–16. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.210.
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A novel design of a simple square-frame USM (ultrasonic motor) was proposed. The stator of the motor consists of a square-frame shape elastic body and four rectangular plate ceramics. The four ceramics were attached to outer surfaces of the square-frame elastic body. The same phase voltages were applied to the ceramics on horizontal surfaces, and 90 degree phase difference voltages were applied to the ceramics on vertical surfaces. When the four outer edges of stator were clamped, the bending vibrations of the right angled bars were transformed into travelling vibrations and elliptical displacements were generated at the center of the bars. To find an optimal size of a stator, that generates elliptical displacement at the centers of the inner surfaces, the finite element analysis program ATILA was used. The analyzed results were compared to the experimental results. As result, the model EL10W3T0.5_CL7 which generates the maximum elliptical displacement was chosen by analyzing the resonance mode according to changes in frequency.
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Desanti, A. F., D. A. Asfani, M. N. Yuniarto i Y. U. Nugraha. "Comparison and Analysis of Stator Plate Holder on Yokeless and Segmented Armature Machine". Journal of Physics: Conference Series 1577 (lipiec 2020): 012039. http://dx.doi.org/10.1088/1742-6596/1577/1/012039.
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Huang, Shi Biao. "Innovative Design and Simulation for a Novel Vane Pump". Advanced Materials Research 328-330 (wrzesień 2011): 354–59. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.354.
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A novel structure of vane pump is brought forward, a new assembly relation among vane, sleeve, port plate and stator is created, mechanical bearing condition of new-type vane is preferable than traditional vane, vane is kept clearance with stator all the time as long as dimensions of those parts are reasonable. Modal analysis and optimized design for vane is made with finite element analysis software ANSYS. By simulating analysis for pump, simulation result shows that this novel vane pump is feasible. Compared with traditional pump, wear and vibration of novel vane pump can be reduced, volumetric efficiency of pump can be enhanced remarkably, the novel vane pump has certain application value.
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Ho, Y. H., i B. Lakshminarayana. "Computation of Unsteady Viscous Flow Through Turbomachinery Blade Row Due to Upstream Rotor Wakes". Journal of Turbomachinery 117, nr 4 (1.10.1995): 541–52. http://dx.doi.org/10.1115/1.2836566.
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A time-accurate, two-dimensional, pressure-based, Navier–Stokes solver for incompressible flow is developed and used to carry out the numerical simulation of rotor–stator interaction. A low-Reynolds-number form of the two-equation turbulence model is used to account for the turbulence effects. In order to improve the accuracy of the numerical scheme, a central differencing plus an artificial dissipation scheme is implemented to provide precise control of numerical dissipation. An inner loop iteration scheme is used at each time step to account for the nonlinear effects. The computation of unsteady flow through a flat plate cascade subjected to a transverse gust reveals that the choice of grid spacing and the amount of artificial dissipation is critical for accurate prediction of unsteady phenomena. The rotor–stator interaction problem is simulated by starting the computation upstream of the stator, and the upstream rotor wake is specified from the experimental data. The results show that the stator potential effects have appreciable influence on the upstream rotor wake. The predicted unsteady wake profiles are compared with the available experimental data and the agreement is good. The numerical results are interpreted to draw conclusions on the unsteady wake transport mechanism in the blade passage.
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Dong, Shuxiang, S. Cagatay, K. Uchino i D. Viehland. "A `Center-Wobbling' Ultrasonic Rotary Motor Using a Metal Tube-Piezoelectric Plate Composite Stator". Journal of Intelligent Material Systems and Structures 13, nr 11 (listopad 2002): 749–55. http://dx.doi.org/10.1177/1045389x02013011006.
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Mou, Shann Chyi, Li Hui Yang i Jin Sing Huang. "Design and Analysis of the Novel Plate Modal Motor". Applied Mechanics and Materials 325-326 (czerwiec 2013): 431–36. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.431.
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In this paper, we demonstrated a lightweight compact motor operating at 70 ~ 100 kHz. The motor is simpler than an electric motor in structure and lower power consumption but higher speed than that of conventional peizoelectric motors. Driver for the PMM is impressively simple. A wave generator and amplifier are all that it takes to supply the piezoelectric ceramic with voltage. Finite element model was developed using ANSYS for the purpose of prediction of the resonance frequency of the vibration mode for the motor driving stator. The periodic plate modal deformation is passed on to a driving bolt, which causes it to oscillate with a movement resembling that of a turning vibrator. The rotor attached to the motor presses its tip on to driving bolt to be driven. The motor is continually being modified to enhance the performance and efficiency. It has a lot of merits such as slim shape, easy holding for motor structure and low manufacturing cost.
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Chen, Xiuqi, Wei Wei, Hongbin Mu, Xu Liu, Zhuo Wang i Qingdong Yan. "Numerical Investigation and Experimental Verification of the Fluid Cooling Process of Typical Stator–Rotor Machinery with a Plate-Type Heat Exchanger". Machines 10, nr 10 (2.10.2022): 887. http://dx.doi.org/10.3390/machines10100887.
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This paper discusses the heat transfer process for a typical stator–rotor machinery-hydrodynamic retarder from the perspective of computational fluid dynamics and experimental means. Fluid cooling is an essential step in the working process of hydrodynamic retarders, and changes in viscosity along with temperature rise will affect the performance of braking. To investigate the heat transfer process of stator–rotor machinery, a novel computational fluid dynamics (CFD) method, combined with a dynamic thermophysical property transfer algorithm, is proposed. A heat-flow coupling numerical method with experimental verification is proposed, in which the density and the viscosity are variable with the temperature in an effectiveness–number of transfer units (P-NTU) method. The results show that the numerical results are in good agreement with the experimental data, with a 0.1–2.5% error. The influence of an asymmetric structure on heat transfer characteristics is discussed. The results show that the optimal braking performance, along with the liquid cooling performance, is achieved under outlets with an inlet passage set as 90 degrees.
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Shipilevskiy, G. B., i A. M. Strokov. "Electro-hydraulic devices for control of transmission frictional mechanisms". Izvestiya MGTU MAMI 7, nr 1-1 (10.01.2013): 248–53. http://dx.doi.org/10.17816/2074-0530-68383.
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Electrohydraulic devices are widely applied for control of transmission frictional mechanisms containing multi-plate wet clutches or brakes. Depending on function and conditions of engaging there are devices of relay or proportional operation. The last one use electromagnets of proportional action where attractive force between rotor and stator depends only on current magnitude in a winding. Such devices can be direct action devices or servo-action ones.
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Liu, Wei Hua, Yin Wang, Wei Qing Huang i Qing Jun Ding. "A Linear Stepping Piezoelectric Motor Using Inertial Impact Driving". Applied Mechanics and Materials 226-228 (listopad 2012): 693–96. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.693.
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With the rapid development of modern precision manufacturing industry,actuators with high resolution and long stroke are needed in many application fields. Linear piezoelectric motors adopting inertial impact driving mechanism has been driving the interests of many researchers for simple structure and compact size. To increase the efficiency of this type of stepping linear motor, a motor using two piezoelectric stacks was proposed in this work. Two piezoelectric stacks were placed in vertical and were pre-tightened by an elastic thin plate. Support for the stator was designed. Operation principle of this motor was analyzed. To validate this operation principle, a prototype was fabricated and testing on this prototype was conduct too. By applying saw wave voltage signal to piezoelectric stacked in this prototype, the stator of the motor is able to push its mover move with pace length of 2 micrometer.
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Venkateswaran, S. "Experimental Study of Casing Boundary Layers in a Multistage Axial Compressor". Journal of Fluids Engineering 113, nr 2 (1.06.1991): 240–44. http://dx.doi.org/10.1115/1.2909486.
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Measurements of the casing boundary layers were obtained in a four-stage, low speed axial flow compressor, to verify the ‘law of the wall’ applicability to these complex flows. Some of the available shear stress models of the two-dimensional flows have been examined towards the quantitative assessment of skin friction. The shear stress prediction obtained from the Ludwieg-Tillmann relation applied to the streamwise or untwisted profile agreed closely with the measured shear stress by the hot wire. The skin friction was fairly constant for rotor and stator flows and was close to the flat plate values. The boundary layer profiles exhibited a well pronounced semi-logarithmic region with the universal constants of the law of the wall far removed from the standard two dimensional values, especially for rotor flows. Stator flows showed signs of similarity to two dimensional flows.
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OHNO, Yuuji, Kenjiro TAKEMURA i Takashi MAENO. "124 Development of a Multi-Degree-of-Freedom Ultrasonic Motor using a Square Plate Stator". Proceedings of the Machine Design and Tribology Division meeting in JSME 2001.1 (2001): 111–12. http://dx.doi.org/10.1299/jsmemdt.2001.1.111.
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Prasad, D., i J. M. Verdon. "A Three-Dimensional Linearized Euler Analysis of Classical Wake/Stator Interactions: Validation and Unsteady Response Predictions". International Journal of Aeroacoustics 1, nr 2 (sierpień 2002): 137–63. http://dx.doi.org/10.1260/147547202760236941.
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A comprehensive validation of the linearized Euler analysis, LINFLUX, for wake/blade row interaction is carried out. The flow configuration is that of the benchmark problem for rotor-stator interaction proposed at the Third Computational Aeroacoustics Workshop. It consists of an unstaggered, annular, flat-plate blade row excited by the vortical gusts associated with the wakes shed from an upstream rotor. The numerical results for the unsteady pressure responses of the stator are compared with semi-analytic lifting surface and lifting line solutions. The validation is first conducted for narrow-annulus flows, where the numerical results are shown to agree well with classical two-dimensional solutions over a range of frequencies. We then carry out a detailed comparison of the three-dimensional LINFLUX results with the lifting surface results of Namba and Schulten for a blade row with a hub-to-tip ratio of 0.5. This study encompasses gust excitation frequencies for which the stator responses vary from cut off to propagating, as well as gusts with varying degrees of spanwise variation. The numerical and semi-analytical analyses yield results for the stator pressure response, including the complex amplitudes of the propagating and least attenuated, evanescent, pressure modes that are in very good agreement. The effect of increasing the spanwise phase variation of the gust is generally, but not necessarily, to reduce the power associated with the acoustic response of the blade row. A comparison of the present numerical results with those obtained from a stripwise application of classical linear theory reveals that the latter approach can be erroneous and, therefore, of questionable applicability to realistic turbomachinery unsteady flows.
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Cheng, G.-M., K. Guo, P. Zeng i Y.-M. Sun. "Development of a two-degree-of-freedom piezoelectric motor using single plate vibrator". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, nr 4 (14.09.2011): 1036–52. http://dx.doi.org/10.1177/0954406211417368.
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A two-degree-of-freedom piezoelectric motor using only one piezoelectric ceramic was proposed based on two vibration modes (B32 and B23) of a rectangular plate piezoelectric vibrator. The working principle was elaborated. Analytical and numerical models were established in order to design the piezoelectric vibrator. Calculations with finite element method were carried out using ANSYS software to validate the analytical models and demonstrate the elliptical trajectory of the four contact points between the stator and the sphere. Experimental result on the prototype shows that the numerical result including resonance frequency and elliptical motion of the motor indicate good agreement with the experimental one. The rotation speed around an axial along the direction of length of the rectangular piezoelectric vibrator of the motor is 37.7 r/min under the drive voltage 90 V and excitation frequency 44 kHz.
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Kensytskyi, O. H., D. I. Hvalin i K. O. Kobzar. "The Mathematical Model of Coupling Calculation the Electromagnetic Field and Heats of End Zone Powerful Turbogenerator". ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 62, nr 1 (4.02.2019): 37–46. http://dx.doi.org/10.21122/1029-7448-2019-62-1-37-46.
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A quasi-three-dimensional field mathematical model of the electromagnetic field and heat transfer processes in end zone of a powerful turbogenerator has been developed. A model is the intermediate version between two-dimensional and three-dimensional solutions and is based on the numeral calculations in transversal and longitudinal sections of turbogenerator, interconnected by a complex of boundary conditions. On the first stage, a two-dimensional field model of the electromagnetic field in transversal section of central zone of a turbogenerator is considered. Then, taking into account the field distribution in central part, the magnetic field in longitudinal section is simulated. In response to the symmetry of the machine along axial and radial directions, the calculation area of end zone is considered as a half of the rotor section along its axis and the section of the stator core tooth in the tangential direction (circumferentially). Having taken the distribution of electromagnetic parameters obtained in the load mode of the machine as the initial data, the thermal losses in the elements and nodes of the end zone are determined. As a result of solving the joint problem of calculating the electromagnetic field and heat exchange processes, the distribution of heating has been obtained not only on the surface, but also inside the structural parts of the end zone. In particular, it has been found that the maximum temperature of 97.3 °C takes place in the tooth area of the end package of the stator core. This is explained by the combined effect of the main radial field, the axial leakage flux of the frontal portions of the stator and rotor windings, as well as by the “buckling” of a portion of the main flux out of the air gap. In addition, the pressure plate shielding effect is the cause of local field concentration in the toothed zone of the end package. The presented model makes it possible as early as at the design stage to evaluate the efficiency of design solutions for the formation of the end zone of the turbogenerator stator for different load modes of the machine, including the modes of consumption of reactive power.
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Kang, B. K., B. S. Kwak, M. J. Yoon, J. Y. Jeon, B. S. Kang i T. W. Ku. "Tool Design and Numerical Verification for Thick Plate Forming of Hollow-Partitioned Steam Turbine Nozzle Stator". Transactions of Materials Processing 25, nr 6 (1.12.2016): 379–89. http://dx.doi.org/10.5228/kstp.2016.25.6.379.
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Chang, S. J., i J. Chen. "Optimal Design of the Single-Mode Piezoelectric Actuator". Applied Mechanics and Materials 479-480 (grudzień 2013): 324–28. http://dx.doi.org/10.4028/www.scientific.net/amm.479-480.324.
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The general operation of a piezoelectric ultrasonic actuator is to convert the cyclic motion of the piezoelectric plate to a linear motion at the rotor or slider. The conventional piezoelectric ultrasonic actuator has two symmetric exciter electrodes on the front surface and each electrode covers one half of the front surface. The rear surface has only one electrode that severs as a common drain. In this paper, the design and simulation of the novel single-mode piezoelectric actuator with asymmetric electrodes were presented. The accomplishment of this study is to find the optimal dimensions of the piezoelectric plate and the asymmetric electrodes, and the stator tip on the piezoelectric ultrasonic actuator would have the larger vibrating amplitude. From the simulation experiment results, the optimal dimensions of the piezoelectric plate are 20×10×1 mm with 12 mm exciter electrode length, and the vibrating amplitude is from 0.73μm increasing to 0.91μm.
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Basílio, A., Rui Igreja, Paulo Inácio, C. J. Dias i José N. Marat-Mendes. "Development of an Ultrasonic Motor Based on a Piezoelectric Ceramic Sandwiched between Two Laminate Composite Plates". Materials Science Forum 514-516 (maj 2006): 221–24. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.221.
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Ultrasonic motors are of great interest since their operation is not affected by a magnetic field. On this work the development of a prototype of a smart ultrasonic motor and its characteristics will be presented. The stator of the motor is formed by a cantilever made of PZT ceramic plate sandwiched between two unidirectional CFRP composite sheets. The composite sheets are oriented to 45º and -45º in the longitudinal direction. By application of a sinusoidal electric field to the piezoelectric ceramic plate, it vibrates. The anisotropy of the CFRP composite sheets induces an expansion/torsion movement. This effect is transformed into rotation by friction. The study of adequate voltages and frequencies of the applied electric field allows the optimization of the rotating motor performance.
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Aigner, Matthias, James Olson i Peter Wild. "Measurement and interpretation of spatially registered bar-forces in LC refining". Nordic Pulp & Paper Research Journal 35, nr 4 (18.11.2020): 600–610. http://dx.doi.org/10.1515/npprj-2020-0064.
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AbstractA high resolution rotary encoder and a piezo electric force sensor are implemented in a 16-inch laboratory-scale low consistency refiner to explore the effect of plate gaps on bar-force profiles. The sensor replaces a short length of a stator bar and measures normal and shear forces applied during the passage of each rotor bar. The rotary encoder data is used to locate the rotor bars relative to the stator bar in which the sensor is located. Previous work with this type of force sensor focuses primarily on the distribution of the maximum force measured during the passage of each rotor bar over the sensor or bar passing event, BPE. In this work, force profiles for bar passing events are registered to the position of rotor bars relative to the stator bar in which the sensor is located. These registered force profiles are measured for a range of plate gaps and two different pulp furnishes. The angular reference provided by the encoder makes it possible to generate mean force profiles. As force data for individual BPEs is highly variable, these mean force profiles have potential to shed light on the fundamental mechanisms of mechanical refining. For large gaps, there is a late peak in the force profiles that occurs toward the end of the bar passing event. For gaps that are less than the critical gap, below which fiber cutting occurs, there is an early peak in the force profiles that occurs at the start of the bar passing event. It is hypothesized that the early peak represents the corner force and, therefore, that corner force is causal in the onset of fiber cutting. To explore this hypothesis, a model is presented connecting corner force and friction force to the progression geometric variables during the bar passing event such as the bar edge length engaged at any point in the bar passing event and the area covered by the rotor bar on the force sensor at any point in the bar passing event.
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Aigner, Matthias, James Olson, Yu Sun i Peter Wild. "Effects of plate wear on bar forces and fiber properties in a mill scale LC-refiner". Nordic Pulp & Paper Research Journal 37, nr 1 (26.11.2021): 54–65. http://dx.doi.org/10.1515/npprj-2021-0064.
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Abstract A set of piezo electric force sensors is implemented in a 52-inch mill-scale low consistency refiner to explore the effect of refiner plate wear on bar force sensor measurements. The sensor replaces a short length of a stator bar and measures normal and shear forces applied during the passage of each rotor bar. In previous work with this type of force sensor, force profiles for individual bar passing events (BPE) were investigated. In the work presented here, force profiles for individual BPEs are identified based on key features in the time domain force data. The individual bar force profiles are classified as single peak events which feature one peak corresponding to the fiber compression force and as dual peak events corresponding to fiber compression force and the corner force. The bar passing events are then analysed, based on dual peak ratio and time to peak of the early peak in the dual peak events. Force measurements are evaluated over the full run time of a set of refiner plates. Findings are compared with refiner plate wear measurements and discharge fiber analysis. It is shown that the decrease in the prevalence of the corner force correlates with the wear of the leading edge of the refiner bars or bar rounding of the run time of the refiner plate. This is accompanied by a decrease in plate performance which is represented by a decrease in fiber length and freeness reduction for the same refiner load.
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Prasad, Braj Bhushan, Fabian Duvigneau, Daniel Juhre i Elmar Woschke. "Application of Particle Dampers on a Scaled Wind Turbine Generator to Improve Low-Frequency Vibro-Acoustic Behavior". Applied Sciences 12, nr 2 (11.01.2022): 671. http://dx.doi.org/10.3390/app12020671.
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The purpose of this paper is to introduce a honeycomb damping plate (HCDP) concept based on the particle damping technique to reduce the low-frequency vibration response of wind turbine generators. The HCDP cells contain granular materials and are mounted at different positions on the generator to reduce the transmission of vibrations from stator ring to stator arm. To investigate the efficiency of the HCDP concept in the laboratory, a small-scale replica inspired by the original wind turbine generator is used as reference geometry. The efficiency of the vibration attenuation by using the HCDP concept is experimentally investigated with the help of a laser scanning vibrometer device. In this contribution, the influence of four different granular materials on the vibration attenuation is experimentally investigated. Furthermore, the influence of HCDP positioning on the transmission path damping is analyzed. Apart from this, the effect of single-unit (SU) and multi-unit (MU) HCDP on the frequency response of the generator is also studied. The experimental approach in this paper shows good damping properties of the HCDP concept for reducing the vibration amplitude.
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Marinaro, Gianluca, Emma Frosina, Adolfo Senatore, Kim A. Stelson i Yuhao Feng. "3D CFD numerical analysis of vane dynamic effects on the pressure ripple in a variable displacement vane pump". E3S Web of Conferences 197 (2020): 07001. http://dx.doi.org/10.1051/e3sconf/202019707001.
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A numerical three-dimensional CFD analysis of a variable displacement vane pump has been conducted, investigating the effects on the pressure ripple caused by the vane detaching from the pressure ring. The volume of the fluid over the vane tip has been re-meshed at every time step as a function of the forces acting on the bottom and the top of each vane. The numerical model has been developed using the commercial tool, Simerics MP+, including turbulence and cavitation models. The validation of the model has been done comparing numerical and experimental data. It has been observed that the detachment of the vane occurs during the transition zones when unwanted pressure spikes are generated by a nonoptimized valve plate design. The prediction of vane detachment is crucial for designing a quieter and more durable pump. Vane collision on the stator ring can be a source of noise producing premature wear of both components. Vane detachment from the stator ring has a large effect on pressure ripple even if the volumetric efficiency is only slightly influenced.
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Freese, Michael, i Stefan Kulig. "Influence of constructional turbo-generator end region design on end winding inductances". Archives of Electrical Engineering 61, nr 2 (1.06.2012): 199–210. http://dx.doi.org/10.2478/v10171-012-0017-z.
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Influence of constructional turbo-generator end region design on end winding inductancesThe paper introduces a comprehensive investigation in end winding inductances of large two-pole turbo-generators. With the aid of an analytic-numeric approach, where Neumann's formula is applied, the influence of geometric characteristics of double-layer stator end windings with involute shape is analysed. This parameter study results in approximation formulas for the stator self and mutual inductances at strand level as well as for the common used end winding leakage inductance. In order to consider field affecting components as pressure plate, flux shield, rotor shaft and rotor retaining ring, finite elements models for two machines (250 MVA and 1150 MVA) are created and computed. The results are integrated in the developed approximation formulas. Finally the simulation results of machine 1 are compared to the data of two different measurements. All approaches introduced in this paper show good correlation. The high speed of the analytic-numeric calculation is combined with the accuracy and opportunity to consider field affecting components within the extensive finite element computation successfully.
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Levitskyi, А. S., Ie O. Zaitsev i N. L. Sorokina. "CONIC SPRINGS BLOCK CALCULATION FOR PRESSURE STABILIZATION POWER ACCUMULATOR OF POWERFUL TURBOGENERATOR STATOR CORE". Praci Institutu elektrodinamiki Nacionalanoi akademii nauk Ukraini 2023, nr 64 (8.05.2022): 81–87. http://dx.doi.org/10.15407/publishing2023.64.081.
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The results of an analytical review of modern methods and means of restoring and stabilizing the pressing pressure of the stator core of a powerful turbogenerator (TG) during operation are presented. The advantages and features of the use of power accumulators (PA) with blocks of disk springs for pressure stabilization, which are installed under the tightening nuts or instead of them on the threaded ends of the tightening prisms, are described. A number of TG and PA parameters that must be known to calculate the mechanical characteristics of the conic springs unit are outlined. It is shown that the optimal method of assembling disc springs into blocks in CA is combined (series-parallel). Based on the specified design parameters, the dependence of the force created by the disc spring and the spring block on the spring thickness was obtained. The dependence of the force of the spring block on the displacement of the pressure plate of the stator core for different values of the spring thickness was determined. The method of calculating the strength of disc springs is given. Ref. 12, fig. 9.
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F Mohd Zulkeple, M., A. R Abu Talib, E. Gires, M. T Hameed Sultan i M. S Ramli. "Heat transfer performance of multiple holes impingement cooling technique". International Journal of Engineering & Technology 7, nr 4.13 (9.10.2018): 43. http://dx.doi.org/10.14419/ijet.v7i4.13.21327.
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This research presents the possibility of the jet impingement cooling technique configuration for stator of turbine blade under the transient heat transfer condition. The main goal of this study is to investigate the impingement cooling plate holes configuration and Reynolds number (Re) effect on the heat transfer which can be observed from the color play of the thermochromic liquid crystal (TLC). The findings proved that with the present of the small holes in between the main larger holes capable to enhance the heat transfer across the target surface. However, some criteria of the design need to be taken into count as it may produce different heat transfer performance of the impingement cooling technique. Therefore, in the range of predetermined design parameters, only several combinations that prevailed to achieve maximum heat transfer across the target plate.
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Oyegbile, B., P. Ay i S. Narra. "Optimisation of micro-processes for shear-assisted solid–liquid separation in a rotatory batch flow vortex reactor". Journal of Water Reuse and Desalination 6, nr 1 (6.08.2015): 125–36. http://dx.doi.org/10.2166/wrd.2015.057.
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This paper reports the study of micro-processes in a novel pre-treatment technique using a pellet forming batch flow vortex reactor of cylindrical shape that consists of axially revolving rotor plates between fixed stator plates. The suspension was first mixed with high molecular weight synthetic polymers by stirring for approximately 50 seconds and then agitated for 20 minutes. The process was optimised for a number of operating conditions including polymer type and dosing regimen, rotation speed, wall-plate gap distance, residence time and suspension filling method. The results of the investigation show that optimising a number of process variables that influence floc formation and growth, along with specific apparatus construction and geometry, help to maintain the suspension in a metastable state that is crucial for the formation of pellet-like compact agglomerates with better dewaterability and uniform aggregate size. A maximum dry solids content of 28.3% after gravity dewatering through a 0.5 mm sieve was recorded during the investigation, with a maximum particle removal efficiency of 97.5%.
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Hao, Shuang Hui, Zi Li Tang, Rui Zheng Long i Ming Hui Hao. "Optimal Design of High Power Linear Permanent Magnet Synchronous Motor for Aircraft Launch". Advanced Materials Research 455-456 (styczeń 2012): 1160–68. http://dx.doi.org/10.4028/www.scientific.net/amr.455-456.1160.
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Design optimization and analysis of the high power linear permanent magnet synchronous motor for aircraft launch are presented in this paper. This motor has a decentralized stator that runs the entire length of travel. A plate with an array of permanent magnets is used as the secondary. This structure enables easier manufacture, flexible system assembling, and autonomous decentralized control employed for energy saving. The thrust and cogging force of the motor are highly affected by the motor structural parameters. The influences of these structural parameters on the thrust and cogging force are analyzed by finite element analysis method; experiment studies are carried out to support the theoretical analysis.
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Power, G. D., J. M. Verdon i K. A. Kousen. "Analysis of Unsteady Compressible Viscous Layers". Journal of Turbomachinery 113, nr 4 (1.10.1991): 644–53. http://dx.doi.org/10.1115/1.2929130.
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The development of an analysis to predict the unsteady compressible flows in blade boundary layers and wakes is presented. The equations that govern the flows in these regions are transformed using an unsteady turbulent generalization of the Levy–Lees transformation. The transformed equations are solved using a finite difference technique in which the solution proceeds by marching in time and in the streamwise direction. Both laminar and turbulent flows are studied, the latter using algebraic turbulence and transition models. Laminar solutions for a flat plate are shown to approach classical asymptotic results for both high and low-frequency unsteady motions. Turbulent flat-plate results are in qualitative agreement with previous predictions and measurements. Finally, the numerical technique is also applied to the stator and rotor of a low-speed turbine stage to determine unsteady effects on surface heating. The results compare reasonably well with measured heat transfer data and indicate that nonlinear effects have minimal impact on the mean and unsteady components of the flow.