高速轮轨黏着机理及特性的研究

吴兵 金学松 温泽峰 王衡禹 赵鑫

摘 要：该研究建立了水油介质污染条件下并考虑接触表面粗糙度影响的三维高速轮轨黏着数值模型；建立了考虑弹塑性接触和摩擦温升情况下的二维高速轮轨黏着模型；初步建立了考虑流变、弹塑性变形及温升的二维高速轮轨黏着模型。 在三维模型中，轮轨间的液体介质可沿着横向和纵向流动，且粗糙峰沿横向和纵向分布的影响同时能得到考虑，与实际情况相符。考虑到三维模型的复杂性，在求解雷诺方程时采用多重网格法求解，利用多重网格积分法求解膜厚方程以加快求解速度。然后利用数值模型，以我国CRH2型高速列车的参数为基础，对轮轨黏着进行了数值模拟计算，研究了轮轨间存在水、油污染时，列车运行速度及轮轨表面粗糙度等对轮轨黏着特性的影响规律。数值结果表明：（1）水介质存在时列车运行速度增大会引起中心膜厚增大而引起黏着系数的急剧减小。（2）粗糙度增大引起膜厚比的减小，从而引起黏着系数的增大。纵向表面纹理有利于黏着特性的发挥。（3）将数值模型的部分结果与较低速度下的试验结果进行了对比，吻合较好，验证了数值模型在低速条件下的可靠性。 在建立考虑弹塑性接触和摩擦温升情况下的二维高速轮轨黏着模型时，基于H.Chen的简化模型基础上加入了入口区温升、固体粗糙峰间的摩擦温升以及考虑Zhao等提出的微观粗糙峰间的弹塑性影响。对运行速度、接触压力等对黏着系数的影响进行了讨论。主要得出以下几个结论：（1）速度增大导致接触区内膜厚的增大，降低了固体承载比率，因而黏着系数下降。（2）接触压力越大导致固体部分接触压力增大，但是增大的量比总载荷增大的量小，固体峰承载的比率还是下降的，直接导致黏着系数的下降。速度相对于接触压力而言对黏着系数的影响更大。（3）弹性模型过高地估计了黏着系数，这对于保障列车行驶安全是不利的。（4）该模型考虑热效应的数值结果与日本新干线上的实测数据接近。该研究初步建立了一个同时考虑热效应（流体膜剪切及固体粗糙峰摩擦产生）、微观粗糙度弹塑性变形及流体的流变效应的高速轮轨黏着二维数值模型。采用多重网格法求解模型中的雷诺方程，以提高运算效率。整个求解流程采用压力-温度两场交叉求解，直到求得收敛解。利用该模型得到合理的数值结果。

关键词：高速铁路 轮轨黏着 弹性流体动力学

Abstract：This project develops three numerical models to investigate wheel/rail adhesion of high-speed railway under water and oil contamination. The first one is a 3D numerical model considering surface roughness； The second one is a simple numerical model considering the elastic-plastic deformation of asperity contact and the flash temperature rise； The third one is a 2D numerical model comprising the rheology of liquid， the elastic-plastic deformation of asperities and the temperature across the film and solid.In the 3D model， the liquid could flow along the lateral and the longitudinal directions. The multilevel method is used to solve Reynolds equation， and in order to improve the efficiency， the multilevel multi-integration algorithm is applied to solve the film thickness equation. The results show that （1） The increasing train speed leads to the dramatically decrease of the adhesion coefficient.（2） The increasing roughness amplitudes leads to the increase of the adhesion coefficient. A longitudinally oriented roughness on the wheel/rail surfaces can increase the adhesion coefficient （3） The numerical solutions approximately coincide with the experimental results. An improved numerical model considering the elastic-plastic deformation of asperities，the viscous heating in the inlet zone and the flash temperature is developed under wet condition to estimate the wheel/rail adhesion of high-speed railway.The main conclusions are as follows：（1）The increase of train speed also causes the decreasing of the adhesion coefficient.（2）The asperity load always increases with contact pressure， but this increase is generally less than that in the contact pressure，which leads to the decreasing of the adhesion coefficient. The train speed has a bigger impact on the adhesion coefficient than the contact pressure.（3）The elastic model overestimates the adhesion coefficient.The present results are consistent with the experimental results.A primary 2D model considering temperature，the elastic-plastic deformation of asperities and the non-Newtonian property of liquids is developed to investigate the adhesion coefficient of high-speed railway.The numerical solution is achieved by a pressure–temperature iteration between the Reynolds equation and the energy equations until the two are convergence. The results obtained by the present model are reasonable.

Key Words：High-speed railway；Wheel-rail adhesion；Elastohydrodynamics

阅读全文链接（需实名注册）：http：//www.nstrs.cn/xiangxiBG.aspx？id=49154&flag=1