粗糙微通道内稀薄气体流动与换热的蒙特卡洛直接模拟

Prediction of flow and heat transfer in rough micro channels with direct simulation Monte Carlo method

采用Delaunay三角化方法对计算区域进行网格划分,开发了适合于非结构化网格的蒙特卡洛直接模拟程序,并对程序的正确性进行了验证.在此基础上模拟分析了粗糙元为三角形的平行平板间微通道内稀薄气体的二维流动与换热.通道进出口压力固定,上下平板温度恒定.计算分析了粗糙元高度、宽度以及分布密度的影响.结果表明:微通道内粗糙元对流动与换热有明显的扰动;随着粗糙元的变大,速度跳跃显著,甚至出现漩涡,增加了通道内的压力损失;但粗糙元增强了微通道壁面与气体之间的换热.

The computational domain was meshed by Delaunay triangulation method.A Monte Carlo direct simulation program was developed for unstructured grids and its validity was checked.On that case,the two-dimensional flow and heat transfer of rarefied gas in parallel plate micro-channels with triangular roughness elements were simulated.The pressure of the micro-channels＇ inlet and outlet and the temperature of the plates above and below were constant.The influences of the height,width and distribution density of roughness elements were computed and analyzed.The results show that roughness elements in the micro-channels can create obvious disturbance for the flow and heat transfer.The greater the roughness elements,the more visible the oscillation of velocity,even vortexes occur,which increases the pressure loss;but roughness elements can enhance the heat transfer.