影响柴油机喷雾数值模拟精度的若干因素分析

为探明影响柴油机喷雾数值模拟精度的若干因素,采用通用商业软件FLUENT对柴油机喷雾特性进行了CFD模拟计算,分别研究了网格尺寸、喷雾粒子数和最大时间步长对油束几何形状及油束贯穿距的影响.结果表明,网格划分的精度和喷雾粒子数量的多少对计算结果的正确性和油束的几何形状有直接的影响,网格尺寸过大或喷雾粒子数过少则喷雾几何形状失真.最大时间步长对数值模拟的精度在一定的范围内影响是比较小的.

Analysis of some factors effecting on numerical simulation precision of a diesel spray

In order to find out the effect factors on the numerical simulation precision of a diesel spray,the diesel spray characteristics are simulated by FLUENT which is a general commercial CFD numerical analysis code.The effects of the grid size,the spray droplet quantity and the maximum time step on spray shape and penetration are investigated respectively.The simulation results show that the precision of computational meshes and the quantity of spray droplet directly influence the correctness of the calculation results and the geometric shape of a spray.The larger grid size or the smaller droplet quantity result in the distortion of the geometric shape of a spray.The maximum time step has a little influence on the numerical simulation precision within a limit time step.