Half space problems of evaporation and condensation for a binary mixture of inert gases are investigated when the dynamics is governed by a system of Navier–Stokes equations, obtained as hydrodynamic limit of a BGK-type description with dominant elastic collisions. Typical methods of qualitative theory of dynamical systems are used to investigate the one-dimensional stationary problem and to classify the solutions both in subsonic and supersonic cases. Numerical results for a mixture of noble gases are presented; the shock wave structure, representing transition between a subsonic and a supersonic steady flow in thermodynamic equilibrium, and the occurrence of under- and overshoots are discussed.

中文翻译：

---

稀有气体的二元混合物的蒸发-冷凝问题

当动力学由Navier–Stokes方程组控制时，研究了惰性气体二元混合物蒸发和冷凝的半空间问题，该方程是作为具有主要弹性碰撞的BGK型描述的流体力学极限而获得的。使用动力学系统定性理论的典型方法研究一维平稳问题，并对亚音速和超音速情况下的解进行分类。给出了稀有气体混合物的数值结果。讨论了代表热力学平衡中亚音速和超音速稳态流之间过渡的冲击波结构，以及下冲和过冲的发生。