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本文采用离散速度方向模型对微型摆式发动机摆臂与腔体间隙内的微尺度气体流动开展了数值研究,分析了摆臂运动对间隙内压差驱动下气体流动阻力和流量的影响规律,并探究了气体稀薄性对间隙泄漏规律的影响.研究发现,当摆臂运动方向与压降方向相同时,稀薄气体效应导致的速度滑移相对于气体流动阻力对流量的变化起主导作用;当摆臂运动方向与压降方向相反时,由于微尺度下壁面作用的增强,在边界附近出现气体回流,且在气流进出口处出现涡结构.“,”Numerical simulations on clearance flows between the swing arm and the engine body were completed by the Discrete Velocity Direction(DVD) model in a Micro Internal Combustion Swing Engine.The influences of the movement of the swing arm on the gas flow resistance and fluxes driven by the pressure difference within the gap were investigated and the effects of rarefication were discussed.The results show that when the swing arm moves in the same direction with the drop of pressure,the velocity slip caused by rarefication plays a leading role in the variation of gas flow resistance and fluxes.When the swing arm moves in the opposite direction with the drop of pressure,the recirculation flow and vortex occurred near the boundary and entrance respectively because of the enhancement of the wall effects.