三组分气体超声速凝结过程数值模拟与实验研究

结合液滴成核与生长模型，以及气、液流动控制方程建立了超声速凝结流动数学模型，对空气+水+乙醇三组分（双可凝）气体超声速流动条件下凝结特性进行了数值计算，研究了三组分气体超声速凝结特性影响因素，通过与空气+水双组分（单可凝）气体对比，分析了第二种可凝组分对凝结成核的影响，并开展了实验验证与对比分析。结果表明：随着三组分气体中乙醇含量的升高，Laval喷管内成核率、液滴数均增大，但成核区收窄，液滴生长区向前移动；在入口可凝气体为饱和状态下，升高入口温度与压力均能促进凝结的发生，使Wilson点向喉部移动，进而提高出口气体湿度；与双组分气体相比，三组分气体发生凝结的Wilson点更靠近喉部，出口湿度更大，说明三组分气体发生凝结时，两种可凝气体的凝结过程是相互促进的；Laval喷管沿程压力及Wilson点测试结果与数值计算结果吻合较好，说明所建立的数学模型具有较高的准确性。

Numerical Simulation and Experimental Study on Supersonic Condensation Process of Ternary Mixture

Based on droplet nucleation-growth model and gas-liquid flow control equation, gas supersonic condensation flow mathematical model of air + water + ethanol ternary mixture (double condensable) was established. Numerical simulation of supersonic condensation process was carried out to investigate the impact factors in supersonic condensation. Compared with air + water binary gas mixture (single condensable), the impact of the secondary condensable component on condensation process was studied. It has been demonstrated that the nucleation rate and droplet number increase when ethanol content goes up, but the nucleation zone becomes narrow and the droplet growth zone moves forward. When the condensable components are saturated at the inlet, higher pressure and temperature favor inlet liquid condensation. In addition, the Wilson point moves to the throat, and the humidity of the outlet gas increases. Compared with binary mixture, the Wilson point of condensation is closer to the throat and the outlet humidity is greater in the ternary mixture. This indicates that the condensation of water and ethanol can affect each other. The experimental data of pressure and Wilson point agree well with the numerical simulation results. Therefore, it can be concluded that the established mathematical model is reliable and simulation results are accurate.