Effect of rarefaction on a gas flow of reactive gas mixtures over a catalytic wall

考虑了反应二元气体混合物在催化平面壁上的流动，并从理论上研究了气体稀薄的影响。对玻尔兹曼方程的模型方程进行渐近展开，得到了小Knudsen数下的近连续统方程及其壁面处的边界条件。结果表明，向壁面方向的扩散速度只取决于壁面的反应速率，而速度和温度的滑移系数随组分的速率变化较大。利用所得到的方程和边界条件，研究了两板间的高速流动（Couette流动），阐明了稀薄对传热和流动的影响。对催化壁上的三元混合物进行了类似的计算。结果表明，壁面温度的跳变随各组分浓度比的变化而变化，其值可能为正，也可能为负。从多组分气体Knudsen层边缘的振动能量平衡出发，导出了振动温度的滑移条件。将该条件应用于高超声速飞行器非平衡粘性激波层的分析。本文从理论上分析了两组分气体混合物通过圆管从储层到真空的自由分子流动，探讨了流动通量和反应速率与管长的关系。管壁具有催化作用，因此气体混合物的反应继续产生第三种物质。如果管长约为管半径的两倍，则表明产物的速率几乎与管长无关。采用分子动力学方法处理气壁相互作用的边界条件，对稀薄气体的Couette流动进行了分析。结果表明，当Knudsen数较大时，与漫反射边界条件偏差较大。通过实验研究了高壁温圆管内的流动，了解了通量与克努森数的关系。结果表明，电导随温度的升高而减小。少

The flow of a reactive binary gas mixture over a catalytic plane wall is considered and the effect of rarefaction of the gas is investigated theoretically. The near-continuum equation as well as its boundary condition at the wall for small Knudsen numbers are obtained by applying the asymptotic expansion to a model equation of the Boltzmann equation. The results show that the diffusion velocity normal to the wall depends only on the reaction rate at the wall and that the slip coefficients of velocity and temperature vary considerably with the rate of the compositions. The high speed flow between two plates (Couette flow) was investigated using the equations and the boundary conditions obtained to clarify the effect of rarefaction on the heat transfer and flow. The similar calculation was made of the ternary mixture over a catalytic wall. It is shown that the jump of the temperature at the wall varies with the concentration ratio of the components and may have a positive or negative val … More ue according to the ratio.The slip condition of vibrational temperature is derived from the vibrational energy balance at the egde of the Knudsen layr for multi-component gas. The condition is applied to the analysis of the nonequilibrium viscous shock layr of a hypersonic vehicle.The free molecular flow of two component gas mixtures through a circular tube from a reservoir to a vacuum is analyzed theoretically to investigate the flux and reaction rate dependence on the tube length. the tube wall is catalytic and hence the reaction of gas mixtures proceeds to make the third species. The rate of product is shown to be almost independent on the tube length if it is aboutt two times as large as the tube radius.The Couette flow of a rarefied gas is analyzed with the boundary condition in which the gas-wall interaction is treated by the molecular dynamics method. The result shows the big deviation with the diffuse reflection boundary condition especially for large Knudsen number.The flow through a circular tube of high wall temperature is investigated experimentally to know the flux dependence on the Knudsen number. It is shown that the conductance decreases with increasing the temperature. Less