长大货物列车空气管系3维充气模型的数值仿真

应用计算流体动力学中的有限体积法,建立长大货物列车空气管系的3维充气特性模型。该模型能同时求解主管、支管的压力和速度,不用类似1维模型引进经验公式或辅助边界条件帮助求解,避免了1维模型中人为解藕不当而出现的各种问题。利用交错网格算法和长大列车空气管系直径与长度的尺度效应,灵活设置压力和速度的自由度,选取压力和速度的控制容积来离散3维模型的控制方程。离散后的代数方程表明,3维模型的计算量与1维模型的计算量几乎相同。提出了一种改进的算子分裂算法求解压力速度耦合方程,数值试验表明,当时间步长很大时算法依然稳定和健壮。用研究开发的程序,将计算结果与国内外长大列车充气特性的有关试验结果进行了对比分析,验证所提出的理论和算法的正确性。

Numerical Simulation of 3D Air-Charging Model of the Heavy Haul Train Air Brake Pipes System

By means of finite volume method, which is one of computational fluid dynamics method (CFD), 3D air-charging characteristics model of the heavy haul train air brake pipes system is built. The model can calculate the pressure and the velocity of the main pipe and the branch pipes simultaneously without introducing some empirical forma or auxiliary boundary conditions used in 1D model, which will avoid all kinds of problems arising in 1D model. Based on the staggered grid algorithm and the size effect of diameter to length of the air pipes system of heavy haul train, the degree of freedoms of the pressure and the velocity are set flexibly. In addition, the governing equations are discretized by flexibly choosing the control volumes for the pressure and the velocity. The algebraic equations after discretization show that the computation cost of the 3D model is almost the same as that of 1D model. A new modified operator splitting method is presented to solve the coupled equations of the pressure and the velocity, and numerical test shows that it is very stable and robust with large time step. A programme is developed on the basis of the above theory and algorithm, and the correctness has been proved by comparing the numerical results with experimental results of heavy haul trains home and abroad.