Atmospheric air is a popular working fluid in gas power plants and turbomachinery which always contains water vapor. The vapor condensation occurs in transonic flow when the temperature drops below dew point during the accelerating expansion and affects the performance of equipment and safety. The unsteady condensation model based on nucleation and droplet growth model, and the Shear Stress Transport (SST) viscous turbulence model for moist air condensing in transonic flows was proposed. The prediction accuracy of steady and unsteady condensing flows was validated by experimental data and theory. The unsteady frequency and fluctuation intensity of pressures for symmetric and asymmetric condensing oscillation modes were discussed. A new formula (f⁰ = 1.992Φ₀^1.539w_s^0.3853) of dimensional frequency related with inlet relative humidity and saturated vapor mass fraction was obtained. Then, periodic mass flux, pressure loss and droplet mass generation rate distributions at different carrier gas pressure were analyzed. The pressure loss coefficient represents the energy loss. As the carrier gas pressure increases, the mass flow rate increases, but the energy of condensation-induced shock decreases. Combined with the analysis of the distribution of liquid mass fraction, it is also found that Mach number and pressure fluctuation are induced by condensation wave due to heat release. Finally, the velocity phase diagrams and heat addition of per unit volume at different oscillation modes were assessed. It reveals the maximum heat addition amounts of per unit volume for three symmetric modes are 1.28 × 10³, 1.48 × 10³ and 1.54 × 10³ MW m⁻³ along the increase of humidity.

大气是在燃气发电厂和涡轮机械中普遍包含的水蒸气的工作流体。在加速膨胀过程中，当温度降到露点以下时，在跨音速流中会发生蒸气凝结，并影响设备的性能和安全性。提出了基于成核和液滴生长模型的非稳态凝结模型，以及跨音速流中湿空气凝结的剪切应力传递（SST）粘性湍流模型。实验数据和理论验证了稳态和非稳态冷凝流的预测精度。讨论了对称和非对称冷凝振荡模式的非定常频率和压力波动强度。一种新的式（˚F ⁰  =1.992Φ ₀ ^1.539w ^_小号^0.3853获得了与入口相对湿度和饱和蒸气质量分数有关的尺寸频率）。然后，分析了不同载气压力下的周期性质量通量，压力损失和液滴质量生成率分布。压力损失系数代表能量损失。随着载气压力的增加，质量流量增加，但是凝结引起的冲击的能量减少。结合对液体质量分数分布的分析，还发现马赫数和压力波动是由放热引起的凝结波引起的。最后，评估了在不同振荡模式下的每单位体积的速度相图和热量添加。它揭示了三种对称模式下每单位体积的最大热量添加量为1.28×10³，1.48×10 ³和1.54×10 ³  MW米^-3沿着湿度的增加。