The Study And Analyses Of Numerical Simulation On Three-nozzle Steam Jet Pump

Steam jet pump is a typical fluid machinery,which has succeed in converting lowpressure steam into high pressure steam,and which can also provide vacuum. Thetraditional single nozzle steam jet pump would worsen when the operation conditions aredifferent from the design value.However, the multi-nozzle steam jet pump can keep thestable operation in a certain extent,due to the shunt effect on motive steam.And it can playits strengths in the practical application.The traditional theoretical and experimentalresearch methods could not clearly describe these complications.In this paper, numericalsimulation method was adopted,with the help of STAR-CCM+software,the the influence ofthe operating conditions and geometry parameters changing on the three-nozzle steam jetpump performance was investigated from the flow structure changing point of view, whichcan provide a theoretical basis for improving the multi-nozzle steam jet pump workperformance and optimum design of structure.The main research content in this paper are as follows:(1)analysis concerning aboutthe influences of operating conditions on the flow field structure and performance ofpump;(2)analysis of nozzle position, the nozzle axis intersection points, mixing chambercontraction angle, diffuser length effect on the flow field structure and the performance ofpump;(3)the three-nozzle steam jet pump and the classic single nozzle steam jet pumpentrainment ratio were compared and analyzed under the same operating parameters;(4)thethree-nozzle steam jet pump and the traditional single nozzle steam jet pump entrainmentratio were compared at the same operating conditions.The simulation results show that, the three-nozzle steam jet pump could work morestably when the motive steam pressure fluctuates; under the same suction pressure, theentrainment ratio in the three-nozzle steam jet pump is smaller than those in the singlenozzle steam jet pump; and the corresponding diffuser critical backing pressure in thethree-nozzle steam jet pump is smaller than those in the single nozzle steam jet pump. Atthe same time, the optimum operation and geometric parameters of the three-nozzle steamjet pump were obtained, so that it should have clear effect on energy-saving.In a word, the research on flow fields within the three-nozzle steam jet pumpcan help to understand the influences of the operation conditions and geometry parameters on the work performance. It also provide theoretical basis for maintaining stable working, performance improvement, and optimization of structure for multi-nozzle steam jet pump.