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中文核心期刊

过渡区气体微尺度流动的格子Boltzmann模拟

Lattice boltzmann simulation of gas micro-flows in transitional regime

  • 摘要: 采用格子Boltzmann方法(LBM)对过渡区内的微尺度气体流动进行了模拟研究. 在已有滑移区微流动LBM模型中引入Knudsen层速度修正,选取合适的修正函数表达式并依据动理论确定了可调参数的合理取值. 在边界条件的处理格式上,采用了适合过渡区模拟的高阶滑移边界的替代格式来捕捉过渡区微流动的滑移速度,避免了直接求解高阶速度导数项的数值困难. 通过对两类不同的微流动进行模拟的结果表明:与数值解吻合得较好,尤其是对Kn>0.5微流动滑移速度的预测,与已有LBM的模拟结果相比有明显的提高.

     

    Abstract: In this paper, gas micro-flows in transition regime havebeen investigated by lattice Boltzmann method (LBM). On the basis ofexisting LBM models for micro-flows simulation, the velocity correctionfunction for Knudsen layer was introduced into the model. And theappropriate expression of velocity correction was chosen with the suitableparameter according to the kinetic theory. In the treatment of boundarycondition, to avoid the difficulties posed by computing the higher-orderderivatives of the velocity, we took a substitute approach of higher-orderslip scheme to capture the slip velocity in transitional regime. The presentresults of two types of micro-flows agree well with the numerical solutions,and are evidently better than those with the former LBM simulations,especially in the case of Kn>0.5.

     

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