三维湿蒸汽自发凝结流动的数值模拟

Numerical Simulation of 3D Wet Steam Flow with Spontaneous Condensation

采用完全欧拉坐标系下的数值模型描述湿蒸汽两相自发凝结流动过程,对某汽轮机低压部分三维静叶栅中内复杂的自发凝结流动进行了模拟和分析。与忽略自发凝结的计算结果相比,叶片表面的压力分布有所不同,吸力面侧尤为明显;自发凝结的发生引起气流角的变化,直接导致作功能力的变化;由于流动参数沿径向分布不均,自发凝结引起的湿度沿径向分布也明显不同;计算结果同时显示边界层对自发凝结有很大的影响。

The two-phase flow process of we steam spontaneous condensation is described with the numerical model under absolute Euler coordinate system. The numerical simulation and analysis were applied for 3 D complex spontaneous condensing flow inside the static cascade in low pressure stage of a turbine. By comparison with the calculated results of neglecting the spontaneous condensation, the pressure distributions on blade surface is different, especially on the suction surface. The occurring of the spontaneous condensation caused the flow angle and the work capacity of turbine to be Change. The radium distributions of wetness fraction caused by spontaneous condensation were uneven bacause of the asymmetry of the flow field parameters along radium distribution. The calculating results also showed that the boundary layer had great affection on spontaneous condensation.