超音速分离管中水蒸气凝结相变的数值研究

基于超音速分离管中混合气体流动属于伴随凝结相变的可压缩、跨音速的特点,建立了考虑传质效应与非平衡凝结过程的数学模型,并采用数值方法对伴随水蒸气凝结的超音速分离管中的流动进行分析研究。以空气、水蒸气及液态水为流动介质,采用两相流动中的VOF模型结合凝结相变模型以及组分传输模型,研究不同进出口参数及不同水蒸气含量对凝结流场的影响。研究结果表明,所建立的分离管内部非平衡凝结相变模型可以较好的再现超音速流中的凝结成核及液滴生长过程;数值计算结果表明,入口压力、温度及水蒸气含量对分离管内流动凝结过程有直接且重要的影响。因此在进行超音速分离管设计时,考虑温度压力参数的同时,考虑水蒸气含量对分离管性能的影响也是非常重要的。

Numerical investigation of water vapor condensation and phase transition in supersonic separator

A numerical analysis of water vapor condensation and phase transition inside a supersonic separator which is characterized by compressibility, expansion, cooling effect and high water vapor mass fraction is described. Air, water vapor and water liquid were chosen as working medium. The established numerical model combines the models of turbulence, two phase flow, condensation phase transition and species transport in order to obtain accurate results. The effects of different operation parameters including pressure, temperature, and water vapor mass fraction were also studied. It was found that the calculated results are in reasonably good agreement with the data obtained from the literature. Besides, it was observed that the current model is able to reproduce condensation shock wave, the nucleation and droplet growth process within the supersonic separator. The results also show that the condensation process inside the supersonic separator varies obviously due to the change of the initial inlet conditions. So the results revealed that it is important to consider the influences of temperature, and pressure together with water vapor mass fraction of the inlet for optimizing supersonic separator design and estimate the separation performance.