NUMERICAL SIMULATION OF THE EFFECT OF EXPANSION RATEAND PRESSURE ON TWO-PHASE WET STEAM FLOW WITHSPONTANEOUS CONDENSATION

摘要

A calculating model of wet steam flows under the hypothesis of inter-phase zero speed slip has been derived onrnthe basis of classical nucleation and droplets growth theory. A numerical simulation of thermal nonequilibriumrntransonic two-phase flows in a nozzle with spontaneous condensation is performed and the parameterrndistribution of wet steam along the axis is described. The calculation accurately predicted the position of rapidrncondensing. The results were presented showing the effects of the expansion rate and pressure on subcooling,rnwater droplets status and pressure shock waves, which is related to the wetness loss coefficient of steam turbine.rnIt can be expected that controlling the expansion rate in turbines could reduce energy loss.