Numerical Simulation Of The Two-phase Steam Flows With Spontaneous Condensation

Steam turbine plays a dominant role in power generation industry in the world. In order to improve the efficiency and operation reliability of steam turbines, it is necessary to study the nonequilibrium two-phase steam flow.A calculating model of wet steam flows under the hypothesis of inter-phase zero speed slip has been derived on the basis of classical nucleation and droplets growth theory. A numerical simulation of thermal nonequilibrium transonic two-phase flows in a nozzle with spontaneous condensation was performed and the parameter distribution of wet steam along the axis was described. The calculation accurately predicted the position of rapid condensing. An analytical comparison has been made of the theoretical and experimental results of the pressure change along the flow. The results were presented showing the effects of pressure, superheating and expansion rate on water droplets status and pressure shock waves, which is related to the wetness loss coefficient of steam turbine.