To take into account the couple stress effects,a modified Reynolds equation is derived for dynamically loaded journal bearings with the consideration of the elasticity of the liner. The numerical results show that the...To take into account the couple stress effects,a modified Reynolds equation is derived for dynamically loaded journal bearings with the consideration of the elasticity of the liner. The numerical results show that the influence of couple stresses on the bearing characteristics is significant. Compared with Newtonian lubricants,lubricants with couple stresses increase the fluid film pressure,as a result enhance the load-carrying capacity and reduce the friction coefficient. However,since the elasticity of the liner weakens the couple stress effect,elastic liners yield a reduction in the load-carrying capacity and an increase in the friction coef-ficient. The elastic deformation of the bearing liner should be considered in an accurate performance evaluation of the journal bearing.展开更多
The instability of the rotor dynamic system supported by oil journal bearing is encountered frequently, such as the half speed whirl of the rotor, which is caused by oil film lubricant with nonlinearity. Currently, mo...The instability of the rotor dynamic system supported by oil journal bearing is encountered frequently, such as the half speed whirl of the rotor, which is caused by oil film lubricant with nonlinearity. Currently, more attention is paid to the physical characteristics of oil film due to an oil-lubricated journal bearing being the important supporting component of the bearing-rotor systems and its nonlinear nature. In order to analyze the lubrication characteristics of journal bearings efficiently and save computational c[~brts, an approximate solution of nonlinear oil film forces of a finite length turbulent journal bearing with couple stress flow is proposed based on Sommerfeld and Ocvirk numbers. Reynolds equation in lubrication of a finite length turbulent .journal bearing is solved based on multi-parametric principle. Load-carrying capacity of nonlinear oil film is obtained, and the results obtained by different methods are compared. The validation of the proposed method is verified, meanwhile, the relationships of load-carrying capacity versus eccentricity ratio and width-to-diameter ratio under turbulent and couple stress working conditions are analyzed. The numerical results show that both couple stress flow and eccentricity ratio have obvious influence on oil film pressure distribution, and the proposed method approximates the load-carrying capacity of turbulent journal bearings efficiently with various width-to-diameter ratios. This research proposes an approximate solution of oil film load-carrying capacity of turbulent journal bearings with different width-to-diameter ratios, whicb are suitable for high eccentricity ratios and heavy loads.展开更多
In the design of the fatigue strength of dynamically loaded bearing in the equipmentssuch as internal combustion engines and roimg mun, the solution to the stress distribution on thebushing alloy layer is an important...In the design of the fatigue strength of dynamically loaded bearing in the equipmentssuch as internal combustion engines and roimg mun, the solution to the stress distribution on thebushing alloy layer is an important and difficult problem. In this paper, a new method has beenproposed by coupling BEM with etheticity method, The algorithm and its implementation were deseribed in details The calculation results verify that this up-dated method can provide us a moresimple and effective tool for solvingthe fatigue stress of the bushing alloy with tangible benefit oftime-saving and high computation accuraey. It may open a new vista in bearing fatigue strength design.展开更多
齿轮传动涡扇发动机(geared turbo fan engine,GTF)的星型齿轮传动系统使用滑动轴承作为支承。GTF滑动轴承在高速高比压工况下工作,油膜压力较大,导致轴承会发生弹性变形。考虑滑动轴承的弹性变形以及润滑油温黏效应等的影响,基于计算...齿轮传动涡扇发动机(geared turbo fan engine,GTF)的星型齿轮传动系统使用滑动轴承作为支承。GTF滑动轴承在高速高比压工况下工作,油膜压力较大,导致轴承会发生弹性变形。考虑滑动轴承的弹性变形以及润滑油温黏效应等的影响,基于计算流体动力学方法建立了高速高比压织构滑动轴承的三维热弹流润滑分析模型,研究了考虑弹性变形影响的织构滑动轴承热流体润滑性能,并对比了织构滑动轴承和无织构滑动轴承的热弹流润滑性能。结果表明:考虑弹性变形的影响后,在相同大偏心率工况下织构滑动轴承的最大油膜压力、承载力和最大油膜温度均会明显降低,周向承载区域明显扩大,且温度和油膜压力在圆周方向上的变化也更加平缓;对比织构滑动轴承和无织构滑动轴承,两者的最大油膜压力、承载力、最大油膜温升和摩擦系数无明显差异,但油膜承载区的弹性变形有明显减小。展开更多
基金Project (No. 571123) supported by the Scientific Research SpecialFoundation for the Excellent Youth Teacher of Shanghai University byEducation Committee of Shanghai, China
文摘To take into account the couple stress effects,a modified Reynolds equation is derived for dynamically loaded journal bearings with the consideration of the elasticity of the liner. The numerical results show that the influence of couple stresses on the bearing characteristics is significant. Compared with Newtonian lubricants,lubricants with couple stresses increase the fluid film pressure,as a result enhance the load-carrying capacity and reduce the friction coefficient. However,since the elasticity of the liner weakens the couple stress effect,elastic liners yield a reduction in the load-carrying capacity and an increase in the friction coef-ficient. The elastic deformation of the bearing liner should be considered in an accurate performance evaluation of the journal bearing.
基金Supported by National Natural Science Foundation of China(Grant No.51375380)Open Project of State Key Laboratory for Strength and Vibration of Mechanical Structures of China(Grant No.SV2014-KF-08)Shaanxi Provincial Natural Science Foundation of China(Grant No.2013JQ7008)
文摘The instability of the rotor dynamic system supported by oil journal bearing is encountered frequently, such as the half speed whirl of the rotor, which is caused by oil film lubricant with nonlinearity. Currently, more attention is paid to the physical characteristics of oil film due to an oil-lubricated journal bearing being the important supporting component of the bearing-rotor systems and its nonlinear nature. In order to analyze the lubrication characteristics of journal bearings efficiently and save computational c[~brts, an approximate solution of nonlinear oil film forces of a finite length turbulent journal bearing with couple stress flow is proposed based on Sommerfeld and Ocvirk numbers. Reynolds equation in lubrication of a finite length turbulent .journal bearing is solved based on multi-parametric principle. Load-carrying capacity of nonlinear oil film is obtained, and the results obtained by different methods are compared. The validation of the proposed method is verified, meanwhile, the relationships of load-carrying capacity versus eccentricity ratio and width-to-diameter ratio under turbulent and couple stress working conditions are analyzed. The numerical results show that both couple stress flow and eccentricity ratio have obvious influence on oil film pressure distribution, and the proposed method approximates the load-carrying capacity of turbulent journal bearings efficiently with various width-to-diameter ratios. This research proposes an approximate solution of oil film load-carrying capacity of turbulent journal bearings with different width-to-diameter ratios, whicb are suitable for high eccentricity ratios and heavy loads.
文摘In the design of the fatigue strength of dynamically loaded bearing in the equipmentssuch as internal combustion engines and roimg mun, the solution to the stress distribution on thebushing alloy layer is an important and difficult problem. In this paper, a new method has beenproposed by coupling BEM with etheticity method, The algorithm and its implementation were deseribed in details The calculation results verify that this up-dated method can provide us a moresimple and effective tool for solvingthe fatigue stress of the bushing alloy with tangible benefit oftime-saving and high computation accuraey. It may open a new vista in bearing fatigue strength design.
文摘齿轮传动涡扇发动机(geared turbo fan engine,GTF)的星型齿轮传动系统使用滑动轴承作为支承。GTF滑动轴承在高速高比压工况下工作,油膜压力较大,导致轴承会发生弹性变形。考虑滑动轴承的弹性变形以及润滑油温黏效应等的影响,基于计算流体动力学方法建立了高速高比压织构滑动轴承的三维热弹流润滑分析模型,研究了考虑弹性变形影响的织构滑动轴承热流体润滑性能,并对比了织构滑动轴承和无织构滑动轴承的热弹流润滑性能。结果表明:考虑弹性变形的影响后,在相同大偏心率工况下织构滑动轴承的最大油膜压力、承载力和最大油膜温度均会明显降低,周向承载区域明显扩大,且温度和油膜压力在圆周方向上的变化也更加平缓;对比织构滑动轴承和无织构滑动轴承,两者的最大油膜压力、承载力、最大油膜温升和摩擦系数无明显差异,但油膜承载区的弹性变形有明显减小。