过膨胀超音速蒸汽浸没射流凝结的实验研究

EXPERIMENTAL STUDY OF OVER-EXPANDED SUPERSONIC STEAM JET IN SUBCOOLED WATER

针对入口压力为0.20～0.60 MPa的饱和蒸汽在20～70℃过冷水中形成的过膨胀超音速蒸汽浸没射流凝结进行了实验研究。观察到了渐缩形、收缩-膨胀-收缩形、收缩-膨胀-发散形和发散形汽羽,汽羽形状主要由入口蒸汽压力和过冷水温度决定,给出了汽羽凝结形态分布图。同时,给出了汽羽的轴向和径向温度分布规律,在靠近喷嘴附近,温度变化幅度比较大,在远离喷嘴处,温度变化趋于平缓;汽羽的轴向温度分布与汽羽的形状密切相关。

The condensation of over-expanded supersonic steam jet in subcooled water is experimentally investigated. The inlet steam pressure and subcooled water temperature are in the range of 0.2-0.6 MPa and 20-70℃, respectively. Four different steam plume shapes, including contraction, contraction-expansion-contraction, contraction-expansion-divergent and divergent shapes, are observed in present test conditions. The results indicate that, the steam plume shape is controlled by the inlet steam pressure and water temperature, and the condensation regime map is given. Moreover, the axial and radial temperature distributions along the steam plume and in the surrounding water are measured. The temperature intensely varies near the nozzle exit, and tends to gradually decay to the ambient water temperature. The results indicate that the axial temperature distributions represent the steam plume shapes.