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基于存在自发凝结的湿蒸汽两相流动,开发了基于汽液两相双流体模型和k-ε-k_p湍流模型的计算方法,并对喷管和二维叶栅进行数值验证,结果表明本文所开发的方法具有较高的可靠性。对某汽轮机末级除湿静叶考虑除湿槽结构的二维流场进行了数值研究,指出在叶片表面开设除湿槽结构,能够显著影响涡轮叶栅内的非平衡凝结流动。由于除湿槽对水滴的抽吸作用使得叶栅内成核率峰值降低,且变化幅度减小,因此成核过程更为稳定。除湿槽结构使得叶栅内部大水滴数目减少,尾迹区水滴平均半径减小,叶栅出口湿度下降。
Based on the two-phase flow of wet steam with spontaneous condensation, a calculation method based on two-phase two-fluid model and k-ε-kp turbulence model is developed. The numerical simulation of nozzle and two-dimensional cascade is carried out. Developed method has high reliability. The two-dimensional flow field considering the dehumidification tank structure of the final stage dehumidification vane of a steam turbine is numerically studied. It is pointed out that dehumidification tank structure can be opened on the surface of the vane, which can significantly affect the non-equilibrium condensation flow in the turbine cascade. The nucleation process is more stable due to the suction effect of the dehumidification tank on the water droplets, which leads to the decrease of the nucleation rate in the cascade and the decrease of the change rate. The dehumidification tank structure makes the number of large water droplets inside the cascade decrease, the average radius of the water drop in the wake area decreases, and the humidity at the exit of the cascade drops.