西部环境下内燃机活塞下区气流场数值研究

Numerical Study of Influence of Sand and Dust in Western China on Gas Flow Field Below Engine Piston

运用商用软件ANSYS,模拟了典型西部环境恶劣因素沙尘对活塞下区气流场的影响,分析了沙尘颗粒的速度、直径、浓度和密度对活塞下区气缸壁压力和气流速度的影响。研究表明:存在影响活塞下区气缸壁压力和气流速度场的临界沙尘颗粒直径和临界速度,较大的沙尘颗粒直径和速度是导致缸壁应力和变形增加的主要因素;沙尘颗粒的存在会使其周围的流场产生负压;随着沙尘颗粒的密度和浓度的增加,活塞下区气缸壁所受最大压力会相应增大,且气流入口处压力增加较快。

The influence of a sand and dust on the bottom gas flow field for a piston in an engine was numerically simulated by means of ANSYS software. The influence of the velocity, diameter, density and concentration of the sand and dust particle on the pressure of cylinder wall and gas velocity field were analyzed. The calculation results show that a high velocity and bigger diameter of a sand and dust particle are the main causes to give rise to the bigger cylinder wall deformation, with a critical velocity and diameter which influence the gas flow field at the piston bottom. Also, it can be found that the maximal pressure value of a cylinder wall increases with the increasing density and concentration of a sand and a dust particle in the flow field, and a bigger pressure domain exists in the inlet of the flow field.