关键词: 水蒸气, 跨音速流动, 非平衡相变, 激波, 温度特性

Abstract: In the present study, a conservative compressible numerical model coupling with dynamic model for non-equilibrium phase change and Virial Equations of steam, was developed and used to predict the spontaneous condensation phenomenon with homogenous nucleation in the supersonic steam flow. In order to capture the transient characteristics of the supersonic flow and the condensation shock effect, the improved high resolution Roe-FDS scheme was used. The influence of inlet steam temperature on the homogenous nucleation and the condensation shock was revealed, and the impact of temperature change on the thermodynamic characteristic was investigated. In the research, it is found that the inlet temperature has a significant influence on the non-equilibrium phase change in the supersonic steam flow. With a lower inlet temperature, the non-equilibrium homogenous nucleation occurs more early and the radius of droplets is bigger. When the inlet temperature decreases, the onset of the non-equilibrium condensation will move to the outlet of the nozzle, and the temperature will decrease rapidly to make the expansion steam achieve a higher Mach number, saturation ratio and supercooling temperature, and then the non-equilibrium condensation will occur eventually with a higher nucleation rate.

Key words: steam, transonic flow, non-equilibrium phase change, shock, temperature characteristics