鉴于在增压直喷汽油机中,常因油气分离器分离效率低下导致机油进入燃烧室形成的局部热点而引起“超级爆震”,以及采用CFD进行油气分离器效率分析仿真又存在计算较难收敛和对计算资源要求较高等问题,本文中介绍了另外一种两相流计算方法一欧拉-拉格朗日算法.首先采用欧拉算法进行油气分离器的气相流场计算,然后以此计算结果为基础,将机油粒子引入其中,采用拉格朗日粒子追踪算法对液相流场进行分析,求得粒子在流场中的运动规律和状态,间接求出油气分离器的分离效率.通过方案对比,选择出油气分离器的最佳结构.%In supercharged GDI engine, due to the low efficiency of oil-air separator, oil droplets enter combustion chamber and form local hot spots leading to ' super knock' , and using CFD simulation in analyzing the efficiency of oil-air separator has the drawbacks of convergence difficulty and high demands on computing resources. In view of that, an alternative two-phase flow calculation scheme—Euler-Lagrangian algorithm is presented in this paper. The specific ideas of the algorithm is that firstly Euler algorithm is used to calculate the gaseous-phase flow field of oil-air separator, then based on the calculation results oil particles are introduced and using Lagrangian particle tracking algorithm to analyze liquid-phase flow field and find out the rule of particle movement in flow field and indirectly evaluate the separation efficiency of oil-air separator. Finally the best structure of oil-air separator is sorted out through schemes comparison.
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