Numerical Study Of Wet Steam Two Phase Non-Equilibrium Condensation Flow In Turbine

The wet steam two phase non-equilibrium condensation flow in turbine will lead to the problems of blade erosion and losses in efficiency. In order to improve the turbine’s economy and operation reliability, it is of great significance to study heat and mass transfer mechanism and the thermal imbalance character in the high speed condensation flow. In this thesis, spontaneous condensation flow have been analyzed and discussed by numerical simulation in the Laval nozzle, plane cascade and turbine stage and three-dimensional turbine straight cascade.A validated numerical calculation in the spontaneous condensation flow in the Laval nozzle and plane cascade was performed to show the numerical model’s feasibility and accuracy, and good agreement was obtained between the numerical results and experimental data. The main thermodynamic parameters which had great impact on shock strength and nozzle and condensation properties were discussed. The differences between low superheated flow and subcooled condensing flow in White cascade calculations were studied, and the distribution of aerodynamic parameters and liquid parameters were shown.A spontaneous condensation flow within turbine stage was simulated to analyze the law of condensation flow under different inlet conditions, and its impact on the aerodynamic performance parameters, such as inlet flow angle, out let flow angle and so on, were analyzed both in the stator and rotor cascade.A3D numerical simulation of condensation flow in a turbine straight cascade were performed. Under three-dimensional turbulent conditions, the thermodynamic characteristic and flow pattern of the non-equilibrium phase change at different cross-section of high leaf in the steam flow was revealed. The influence of boundary layer on the surface of end wall and blade on condensing flow were analyzed.