论文标题
具有振动模式的分子气的稀疏流量的动力学模型
A kinetic model for rarefied flows of molecular gas with vibrational modes
论文作者
论文摘要
提出了一个动力学模型，用于具有旋转和温度依赖性振动自由度的分子气体的稀有流。当不存在翻译和内部模式之间的能量交换时，该模型将减少到玻尔兹曼方程，以捕获分子间电位的影响。此外，不仅要回收运输系数，而且还回收了它们的基本放松过程。我们的动力学模型的准确性通过几种稀有气流的直接模拟蒙特卡洛方法验证，包括冲击波，傅立叶流动，COUETTE流以及由Maxwell的恶魔驱动的蠕变流。然后采用动力学模型来研究热诱导的流。通过调整Boltzmann碰撞算子中的粘度指数，我们发现分子间电位显着影响速度和Knudsen力。有趣的是，在过渡流程中，当粘度指数从0.5（硬球气）变为1（麦克斯韦气体）时，施加加热光束上的knudsen力可以逆转方向。该发现可用于设计微观机械系统的微观结构驱动和气体传感。
A kinetic model is proposed for rarefied flows of molecular gas with rotational and temperature-dependent vibrational degrees of freedom. The model reduces to the Boltzmann equation for monatomic gas when the energy exchange between the translational and internal modes is absent, thus the influence of intermolecular potential can be captured. Moreover, not only the transport coefficients but also their fundamental relaxation processes are recovered. The accuracy of our kinetic model is validated by the direct simulation Monte Carlo method in several rarefied gas flows, including the shock wave, Fourier flow, Couette flow, and the creep flow driven by Maxwell's demon. Then the kinetic model is adopted to investigate thermally-induced flows. By adjusting the viscosity index in the Boltzmann collision operator, we find that the intermolecular potential significantly influences the velocity and Knudsen force. Interestingly, in the transition flow regime, the Knudsen force exerting on a heated beam could reverse the direction when the viscosity index changes from 0.5 (hard-sphere gas) to 1 (Maxwell gas). This discovery is useful in the design of micro-electromechanical systems for microstructure actuation and gas sensing.
