Poiseuille and thermal transpiration flows of a dense gas between two parallel plates
Poiseuille and thermal transpiration flows of a dense gas between two parallel plates
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DOI：
10.1017/jfm.2023.270
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发表时间：
2023-05
影响因子：
3.7
通讯作者：
Masanari Hattori
中科院分区：
文献类型：
--
作者：
Masanari Hattori
本文从Enskog动力学方程出发，在漫反射边界条件下，研究了稠密气体在两平行平板间的Poisonille流动和热蒸腾流动。与理想气体的情况相反，密度和压力梯度以及流动方向上的法向应力分量在垂直于致密气体的板的方向上是不均匀的。非均匀的正应力梯度也有助于加速或减速的热蒸腾流小努森数。得到了不同努森数和不同分子直径与板距比时的质量流、热流和净质量流的分布。在Poiffille流的分析中，恢复了具有小力的力驱动流的大部分特征。然而，对于致密气体的情况下，力驱动的和本压力驱动的流动之间的差异，即使在线性化的制度，特别是在微观水平上的小的力和压力梯度观察。的速度分布函数的行为，特别是，在其中，他们接近的玻尔兹曼方程的分子直径变得更小的方式，澄清。
Abstract The Poiseuille and thermal transpiration flows of a dense gas between two parallel plates are investigated on the basis of the Enskog kinetic equation under the diffuse reflection boundary condition. In contrast to the case of an ideal gas, the density and the gradients of pressure and the normal stress component in the flow direction are not uniform in the direction normal to the plates for a dense gas. The non-uniform normal stress gradient contributes also to the acceleration or deceleration of the thermal transpiration flow for small Knudsen numbers. The profiles of mass and heat flows as well as the net mass flows are obtained for various Knudsen numbers and ratios of the molecular diameter to the distance of plates. In the analysis of the Poiseuille flow, most characteristics of a force-driven flow with a small force are recovered. However, for the case of a dense gas, differences between the force-driven and the present pressure-driven flows are observed even within the linearized regime for small force and pressure gradient, especially at the microscopic level. The behaviour of the velocity distribution functions, in particular, the way in which they approach the ones for the Boltzmann equation as the molecular diameter becomes smaller, is clarified.