Energy Conversion for Gas Isentropic Compression Process with High Speed Rotation

2013 ◽  
Vol 336-338 ◽  
pp. 899-906
Author(s):  
Haakon Karlsen ◽  
Tao Dong

Energy conversion from rotational to thermal is investigated for a compressible ideal gas. The high speed rotation is considered as the driven force of the isentropic compression. The analytical model explaining the thermodynamic parameters (pressure, pressure gradient, density, and especially temperature) are developed. The analytical results are compared with the simulation data obtained from Finite Element Analysis, which employs compressible Navier-Stokes equations and heat equation. A good accordance between the analytical and FEA results has been observed. And it shows a predictable beginning and end state for the isentropic rotation process.

1987 ◽  
Vol 109 (1) ◽  
pp. 71-76 ◽  
Author(s):  
J. O. Medwell ◽  
D. T. Gethin ◽  
C. Taylor

The performance of a cylindrical bore bearing fed by two axial grooves orthogonal to the load line is analyzed by solving the Navier-Stokes equations using the finite element method. This produces detailed information about the three-dimensional velocity and pressure field within the hydrodynamic film. It is also shown that the method may be applied to long bearing geometries where recirculatory flows occur and in which the governing equations are elliptic. As expected the analysis confirms that lubricant inertia does not affect bearing performance significantly.


2013 ◽  
Vol 631-632 ◽  
pp. 1068-1072
Author(s):  
Yan Wu ◽  
Yan Ma

When the intermediate cuttings cut the wood, the efficiency of the vibration of the circular saw web was low so that the saw web always broke off. Moreover, the high-speed rotation would cause the vibration of the complete machine and result in the initial failure of the machine. Therefore, seeing from the problems from the analysis above and practice, the new design of the current micro intermediate cuttings seemed especially important. In the thesis, the author made a new arrangement of the micro intermediate cuttings of machinery tools, carrying out three-dimensional modeling and simulation of the complete machine and made an analysis of the dynamic cutting process by means of analyzing the working condition of circular saw web.


2020 ◽  
Vol 5 (4) ◽  
pp. 448-456
Author(s):  
Levi Ryan Mallin ◽  
Simon Mark Barrans

Machines incorporating high-speed electrical machines (HSEM) are becoming increasingly common place in applications including air handling, energy storage and medical devices. They are of increasing interest within the automotive field for air handling applications. HSEM’s use surface-mounted permanent magnet (PM) rotors, manufactured from rare earth metals. However, these PM’s have low tensile strength and are susceptible to failure under the centrifugal load produced at high speed rotation. Retaining sleeves which are an interference fit around the magnets, provide compression and hence resistance to tensile stress. The ability to predict the stresses within the rotor assembly is essential for robust design. This review paper examines existing analytical calculations and finite element analysis (FEA) models. The analytical approaches include both plane stress and plane strain models and the limitations of these are discussed. For relatively long rotors, a generalised plane strain approach is suitable, however it is seldom used. In addition, this latter approach has not been extended to assemblies where the magnets are assembled onto a carrier or shaft. Optimisation of rotors has been addressed in a relatively small number of papers. However, further work is required in this area to ensure that the optimised rotors can be manufactured.


2011 ◽  
Vol 188 ◽  
pp. 457-462 ◽  
Author(s):  
Shu Lin Wang ◽  
Wei Zhan Zhang ◽  
Qin Zhang ◽  
G. Liu ◽  
Z.J. Yang

On the basis of finite element analysis, the static transmitted torque of Hydraulic Expansion Toolholder is validated. At the same time fluid analysis software is used to investigate the oil pressure changes in oil chamber wall because of different rotation speed. Then through the fluid-solid coupling, the article analyzes the chuck clamping performance on the factors of expansion chuck and tool clearance, rotation speed, and hydraulic oil pressure when toolholder on the state of high rotation speed.


1978 ◽  
Vol 21 (158) ◽  
pp. 1306-1310 ◽  
Author(s):  
Akio NAGAMATSU ◽  
Masaho FUKUDA

Author(s):  
Luca Bertocchi ◽  
Matteo Giacopini ◽  
Daniele Dini

In the present paper, the algorithm proposed by Giacopini et. al. [1], based on a mass-conserving formulation of the Reynolds equation using the concept of complementarity is suitably extended to include the effects of compressibility, piezoviscosity and shear-thinning on the lubricant properties. This improved algorithm is employed to analyse the performance of the lubricated small end and big end bearings of a connecting rod of a high performance motorbike engine. The application of the algorithm proposed to both the small end and the big end of a con-rod is challenging because of the different causes that sustain the hydrodynamic lubrication in the two cases. In the con-rod big end, the fluid film is mainly generated by the relative high speed rotation between the rod and the crankshaft. The relative speed between the two races forms a wedge of fluid that assures appropriate lubrication and avoids undesired direct contacts. On the contrary, at the con-rod small end the relative rotational speed is low and a complete rotation between the mating surfaces does not occurs since the con-rod only oscillates around its vertical axis. Thus, at every revolution of the crankshaft, there are two different moments in which the relative rotational speed between the con-rod and the piston pin is null. Therefore, the dominant effect in the lubrication is the squeeze caused by the high loads transmitted through the piston pin. In particular both combustion forces and inertial forces contribute to the squeeze effect. This work shows how the formulation developed by the authors is capable of predicting the performance of journal bearings in the unsteady regime, where cavitation and reformation occur several times. Moreover, the effects of the pressure and the shear rate on the density and on the viscosity of the lubricant are taken into account.


2012 ◽  
Vol 542-543 ◽  
pp. 828-832 ◽  
Author(s):  
Jing Fang Yang ◽  
Xian Ying Feng ◽  
Hong Jun Fu ◽  
Lian Fang Zhao

Tire dynamic balance detection plays an important part in tire quality detection area. This paper uses the two-sided balance method to obtain the unbalance of the tire. According to the engineering practice, builds kinetic model and then introduces the calculating principle and operating procedures. In order to accurately determine the influence coefficient, a calibration method without tire is put forward. Further more, this new method is able to eliminate the unbalance caused by non-quality factors to some extent. But this method is presented based on the relative position invariance of the upper rim and lower rim, even both of them are under high-speed rotation situation. Finally, the experimental data acquired from both of the two methods are compared. The calibration method without tire is proved to be more feasible, efficient and accurate.


2003 ◽  
Vol 439 ◽  
pp. 156-162
Author(s):  
A. Da Camara ◽  
Joaquín Lira-Olivares ◽  
Soo Wohn Lee ◽  
H.D. Park ◽  
Y.S. Park

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