朱宏，王传毅，肖进

上海交通大学动力机械与工程教育部重点实验室

摘要: 应用大涡模拟方法对一台二冲程发动机缸内冷态湍流流场进行了三维瞬态数值分析，并与PIV测试结果进行了对比。结果表明：本文建立的三维模型能够自然再现缸内冷态流动的随机大尺度涡流情况，具有较高的可靠性。通过分析不同截面各瞬态的湍流空间平均积分尺度的模拟研究结果，认为同一时刻，横向截面距离气缸顶部越近，其涡流平均尺度越大，且x方向积分尺度分量明显大于y方向积分尺度分量；而对于不同时刻的横向和纵向截面，前者平均积分尺度随活塞上行而减小，后者变化不明显。

关键词: 二冲程；大涡模拟；积分尺度；STAR-CD

Abstract: Large eddy simulation (LES) was performed to investigate the in-cylinder turbulent flows of a two-stroke engine, which revealed a high reliability of the 3D model in reflecting the random large scale turbulence of the cold flows when compared with PIV measurement data. According to the simulation results about transient turbulent integral length scales (ILS) at different sections, the ILS of the horizontal section simultaneously increases as it gets closer to the cylinder head, and the scale component of X-direction is significantly bigger than that of Y-direction; the ILS of the horizontal section decreases as the piston moves up, while that of the vertical section remains indeterminate.

Key words: Two-Stroke; LES; Integral Length Scale (ILS); STAR-CD