高速轮轨黏着特性数值分析

发布时间：2018-01-02 01:23

本文关键词：高速轮轨黏着特性数值分析　出处：《西南交通大学》2011年硕士论文　论文类型：学位论文

【摘要】：“十一五”期间我国高速铁路的发展取得了辉煌的成就。随着列车运行速度的不断提高,轮轨间的低黏着问题越发明显。由低黏着引起的轮轨表面擦伤、剥离、扁疤等损伤时有发生。轮轨黏着是关系高速铁路行车安全和正常运营的关键问题。因此,开展高速轮轨黏着特性的研究具有重要的工程应用价值和理论指导意义。本文首先基于全膜弹性流体动力润滑理论,考虑轮轨实际接触载荷和尺寸,研究轮轨表面光滑时,计算分析了轮轨间存在“第三介质”油和水时的轮轨接触状态,获得了全膜润滑下的轮轨接触压力和膜厚分布,得到了实际膜厚大小的数量级。然后,基于部分膜弹性流体动力润滑理论和Patir-Cheng的平均流量模型,建立了高速轮轨黏着特性数值分析模型,计算分析了在考虑轮轨表面粗糙度情况下的高速轮轨黏着特性。由于数值稳定性问题,对于油润滑情况下的计算采用Newton-Raphson方法,对于粘度较低的水时采用稳定性比较好的多重网格法。利用数值模型,研究了列车运行速度、轮轨表面粗糙度、轴重和轮径等对轮轨黏着特性的影响规律。对比了水润滑和油润滑下黏着系数随速度的变化情况,从膜厚比的角度解释了水润滑下的黏着系数比油润滑下的黏着系数低的原因。由于轮轨黏着理论和数值分析的困难性,以上数值模型假设为二维线接触模型。通过数值计算,可以得出以下结论： (1)由全膜润滑弹流计算获得的实际膜厚的量级可以看出膜厚和粗糙度基本处于同一等级,所以轮轨间的接触处于部分膜润滑的过程。轮轨黏着问题研究应考虑部分膜的情况。 (2)通过部分膜弹流润滑计算获得了水和油润滑下的压力和膜厚分布。发现油和水润滑时的压力分布与Hertz接触压力不一样,油润滑时存在二次峰,水润滑没有二次峰,固体接触压力和膜厚基本成倒影关系。 (3)油和水润滑情况下,速度对黏着系数的影响都是一样。随着速度的增大,黏着系数均会降低。相同条件下,水润滑下的黏着系数要比油润滑下的大得多,这和试验结果相似。这是由于水膜厚度比油膜厚度小得多,产生的粗糙峰压力要比油大得多。 (4)油和水润滑情况下,随着粗糙峰高度的增大,黏着系数均增大。轮轨表面纹理方向对黏着系数影响较大,横向纹理的中心膜厚要比纵向纹理的大,而横向纹理的黏着系数要比纵向纹理的小。 (5)油和水润滑情况下,随着轴重的增大,黏着系数逐渐降低；随着轮径的增大,黏着系数逐渐增大。
[Abstract]:"11th Five-Year" during the development of high-speed railway in China has made brilliant achievements. With the increase of train speed, low adhesion problem between wheel and rail is more and more obvious. The wheel rail surface abrasion caused by the low adhesion stripping wheelflats damage has occurred. Wheel rail adhesion is a key issue in high speed railway traffic safety and normal operation. Therefore, it has important engineering application value and theoretical significance to carry out research on the adhesion between the wheel and rail.
Firstly, based on the full elastohydrodynamic lubrication theory, considering the actual wheel rail contact load and size, study of wheel rail surface smooth, are calculated and analyzed. The wheel rail contact state third medium "oil and water contact, contact the full film lubrication under the pressure and film thickness distribution was obtained, by orders of magnitude the actual size of the film thickness. Then, the average flow model of partial elastohydrodynamic lubrication theory and based on Patir-Cheng, a numerical analysis model of high speed rail adhesion characteristics were calculated considering surface roughness under the condition of high speed wheel rail adhesion characteristics. The numerical stability problem for calculating oil lubrication under the condition of the Newton-Raphson method for low viscosity water using multigrid method good stability. Using the numerical model of the train speed, the wheel rail surface rough Roughness, axle load and wheel diameter of wheel rail adhesion characteristics. Compared the changes of adhesion coefficient under water lubrication and oil lubrication with the velocity, explain the adhesion coefficient under water lubrication than the adhesion coefficient under oil lubrication film thickness ratio from low angle. Because of the difficulty of wheel rail adhesion theory and numerical analysis of the above numerical model is assumed for 2D line contact model.
Through the numerical calculation, we can draw the following conclusions:
(1) the magnitude of the actual film thickness obtained from the full film lubrication Elastohydrodynamic calculation can be seen that the film thickness and roughness are basically in the same level, so the contact between wheels and rail is in the process of partial membrane lubrication.
(2) the water pressure and film thickness distribution and lubrication condition was obtained by partial elastohydrodynamic lubrication calculation. Hertz pressure distribution and contact pressure of oil and water lubrication oils are not the same, there are two peaks, two peaks without water lubrication, solid contact pressure and film thickness like reflection relation.
(3) the oil and water lubrication conditions affect the speed of the adhesion coefficient are the same. As the speed increases, the adhesion coefficient is reduced. Under the same condition, the adhesion coefficient under water lubrication than under oil lubrication is much larger, and the test results are similar. This is because the water film thickness ratio the oil film thickness is much smaller than the rough peak pressure of oil is much larger.
(4) when the oil and water are lubricated, the adhesion coefficient increases with the increase of the height of the roughness peak. The direction of the wheel rail surface has greater influence on the adhesion coefficient. The thickness of the center grain of the transverse texture is larger than that of the longitudinal texture, and the adhesion coefficient of the transverse texture is smaller than that of the longitudinal texture.
(5) under the lubrication of oil and water, with the increase of the axle load, the adhesion coefficient gradually decreases, and the adhesion coefficient increases with the increase of the wheel diameter.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH117.2

【引证文献】