Simulation Study On Steam Jet Condensation Flow

Steam non-equilibrium condensation phenomenon, which not only reduces the efficiencyin steam turbines, but also has water erosion damage on blade, exists widely in electric power,chemical, refrigeration and other engineering fields and more and more attentions are paid onthe impact. Due to rapid expansion, the steam non-equilibrium condensation, which involvesnot only problems such as phase transformation, heat transfer, mass transfer, but alsoproblems such as condensation shock wave, aerodynamic shock wave and the interactionbetween shock wave and boundary layer, which makes the flow process complex, is easilyhappened in steam transonic flow and the research about the condensation is quietly active.Based on existing CFD numerical simulation software, the steam non-equilibriumcondensation numerical model (double fluid numerical model) that considers the steamnon-equilibrium condensation process is established through introducing steamnon-equilibrium condensation model and real steam thermodynamic properties calculationmodel and is proved accurate and reliable. On the basis of the steam non-equilibriumcondensation numerical model, the high speed steam flow involes non-equilibriumcondensation in the nozzle and the ejector has been researched by numerical simulation. Thecontent is as follws:(1) The accuracy and reliability of the established steam non-equilibrium condensationnumerical model has been proved by contrasting the simulation results and the existingexperimental data.(2) Based on the structure design theory of the steam jet pump and the water and steamthermodynamic properties calculation formula IAPWS-IF97, the steam ejector structurecalculation program is established and the accuracy and reliability is proved.(3) Based on the steam non-equilibrium condensation flow numerical model, the steamnon-equilibrium condensation transonic flow in the nozzle is researched by numericalsimulation. The producing process and reason of steam non-equilibrium condensation andcondensation shock wave are analyzed. Combined with the change of pressure, rate,temperature, condensation and so on, the influence of the nozzle inlet pressure, inlettemperature, backpressure and surface tension on the steam transonic non-equilibriumcondensation flow in nozzle is researched and the influence of working parameters on thecondensation, condensation shock wave and aerodynamic shock wave and the interactionbetween the condensation shock wave and aerodynamic shock wave are discussed in detail.(4) Based on the steam transonic non-equilibrium condensation flow numerical model,the condensation flow in the steam ejector and the influence of backpressure, inlet workingsteam pressure, inlet working steam temperature and mixing chamber length on thecondensation flow and working performance of the ejector are researched. The influence of working paremeters and structure parameters on steam condensation and aerodynamic shockwave is analyzed.