Three-dimensions Numerical Simulation Of Flow Field In Exhaust Passage Of Large Steam Turbine

This passage simulates the exhaust passage in600MW unit applied to Fluentprogramme based on the single equation model of Spalart-Allmaras, taking the velocityof rotation of exhaust steam from last stage and variation of exhaust steam because ofvariable working conditions into consideration. The result demonstrates that there aresignificant differences between exhaust passage integrated model and single model ofexhaust hood or condenser throat, which displays specially on the exhaust pressure lossand flow field on the outlet of condenser throat. After that, optimization and modificationare put out on the width of diffuser outlet, tilt angle of inner wall of diffuser outlet,installation site of low-pressure heater in the condenser throat and installation site of feedwater pump small turbine. Meantime, devices with different structures are equipped onthe top of upper exhaust hood and inlet of condenser throat accordingly. By this way, it isexpected to improve the flow field in the passage and raise unit efficiency. The result ofstudy is of important reference value to the future design, optimization and modificationof exhaust passage.