采用格子Boltzmann方法模拟了微通道在滑移区内不同Knudsen数下的微气体Poiseuille流,分析了微气体流动的速度分布以及流量与压降的关系,并给出了相对滑移长度和Poiseuille数随Knudsen数的变化特性。研究结果表明,微气体Poiseuille流的速度轮廓呈抛物线分布,但是边界速度大于0,出现速度滑移现象;随着Knudsen数的增加,微气体Poiseuille流的相对滑移长度也相应增加,摩擦阻力系数相应减小,微通道壁面对气体流动的影响逐渐减弱。
A two-dimensional model of micro Poiseuille gas flow in the slip regime with different Kundsen numbers is developed by using lattice Boltzmann method. The velocity distribution of the micro gas flow and the relationship between flow rate and pressure drop are all analyzed. The effects of Knudsen number on the relative slip length and Poiseuille number are also analyzed and discussed. The results indicate that in micro gas Poiseuille flow, the velocity distribution is in a parabolic fashion and the velocity on the wall boundary is bigger than zero, where the velocity slip occurs. In addition, a larger Knudsen number results in a longer relative slip length and smaller friction factor, which implies a decreasing effect of the wall boundary on micro gas flow.