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101.
An analytical model of a tilting pad bearing was developed based on the short bearing assumption with the turbulence effect
included. In order to determine its influence on the dynamic behavior of the rotor, this model was compared against one without
the turbulence effect through a simulation of a Jeffcott/Laval rotor supported by a couple of bearings. Both models were also
used to determine the influence of geometric parameters on tilting pad bearing making use of the aforementioned system at
different rotor speeds.
When analyzing the results, the parameters which presented the largest influence were: pad preload, number of segments, radial
clearance, pad position, and pad pivoting angle. As the pad moment of inertia and the pivoting distance have changed the shaft
motion only a few microns, their effects can be neglected. The bearing model with turbulent flow effect has generated higher
hydrodynamic forces when compared to the one without this effect, which remarks the importance of considering such phenomenon
during the analysis of the high speed hydrodynamic bearings. 相似文献
102.
小孔节流气体静压润滑的离散化和计算收敛 总被引:23,自引:6,他引:17
通过在雷诺方程式中增加一流量项,以避免求解雷诺方程时,为满足流量条件而求解压力梯度所带来的噪声和误差,并将不同坐标系内的雷诺方程式变换成为相同形式,以简化数值计算;对加权余量法和变分求极值法这2种将微分方程离散化的方法进行了分析;探讨了小气膜时出现发散的原因并提出了应对措施。 相似文献
103.
104.
105.
The Effect of Bubbly Oil on the THD Lubrication of Tilting-pad Journal Bearings Subjected to Rotating Unbalance Load 总被引:1,自引:0,他引:1
Little work has been published on the contribution of entrained air and/or gas bubbles on the lubricant viscosity and hence on the hydrodynamic performance of bearings. In this work, a thermo-hydrodynamic analysis of the performance of dynamically loaded tilting-pad journal bearing lubricated by bubbly oil is carried out. The non-steady Reynolds equation for compressible fluid and the energy equation are solved iteratively using finite difference method to study the effect of air bubbles on the bearing performance characteristics. The effect of bubbles content on the lubricant viscosity is considered.The results showed that the value of maximum pressure slightly increases with increasing the bubble ratio up to 0.2, while the film thickness deteriorates at very high bubble content. The pressure peak moves in the downstream direction with the increase of bubble ratio 1, which would be of great importance in deciding the pivot location in tilting-pad bearings. 相似文献
106.
107.
Oil film temperature distribution is a key factor in the solution of thermal problems in journal bearings. It allows to find the maximum oil film temperature, thermal distortions of bearing structure and heat flow to and from bearing. The paper describes the results of theoretical investigations into the basic factors in the solution of thermal problems, i.e. the oil film temperature distribution and maximum oil film temperature. The 4-lobe journal bearing operating at laminar oil film as well as in aligned conditions of journal and bush axis was considered. The oil film temperature distribution and maximum oil film temperature have been obtained from the numerical solution of bearing geometry, Reynolds, energy and viscosity equations. The results obtained and the applied code of computation lead to the solution of thermal problems of bearing operation. 相似文献
108.
This paper develops a new concept to enhance the adaptive capability of rotating machinery to the rubbing conditions through active auxiliary bearings. To demonstrate the feasibility of this idea, a model with a Jeffcott rotor and an active auxiliary bearing, which accounts for both the dynamics of the auxiliary bearing and the deformation on the contact surface, is investigated. The dynamics and the stability of the non-linear piecewise-smooth passive rotor/stator (auxiliary bearing) system are first studied. Then, two control approaches are proposed with the aim to reduce the rubbing severity during the rotor/stator rubbing. It is shown that by using an optimal controller, the harmful heavy rubbing between the rotor and the stator can be well stabilized to the mild light rub through the active auxiliary bearing, and the already established rotor-to-stator rubbing can even be released by using PD-controllers. 相似文献
109.
An infinitely wide lubricated bearing consisting of connected surfaces of second‐grade fluid is analyzed in the present study. The velocity and pressure fields are obtained by a homotopy analysis method (HAM). Two cases, namely, inclined and parabolic slider bearings are considered. The viscoelastic effects play an important role even under the assumption of the order of the magnitude of the variable. However, inertial term does not contribute. Graphical results are interpreted. Comparison between the numerical values for the inclined and parabolic slider bearing is also presented. In addition to that for a meaningful solution, the graphs of convergence parameter, residual error, and numerical comparison are also presented. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27: 1231–1241, 2011 相似文献
110.
A. G. Revenko 《X射线光谱测定》2012,41(3):117-124
This journal, X‐Ray Spectrometry, celebrates its 40th anniversary this year. The state of the publications on X‐ray spectral analysis from 1972 onward is considered. The distribution of materials over countries is presented, as published in X‐Ray Spectrometry for 40 years, in 5‐year time intervals: 1972–1976, 1977–1981, and so on. The participation of Russian scientists contributing to the publications in this journal is discussed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献