| The micro-steam turbine has the characteristics of small size,moderate weight and high power density.It can be used in special fields such as ships,torpedoes and submersibles,and has important research significance.In this paper,aiming at structural characteristics and technical requirements of micro steam turbine,aerodynamic design of the high power density micro steam turbine is carried out.A three-dimensional model with Curtis stage structure is established.The flow performance and parameter variation of steam turbine blade are studied by numerical simulation method.The simulation analysis of single passage of Curtis stage under full admission is carried out.The aerodynamic performance and parameter distribution of blades are studied.It is found that the nozzles undertake most of the enthalpy drop in Curtis stage,and the influence of supersonic flow of scaling nozzle on steam flow is analyzed in detail.Combined with the aerodynamic design scheme,the factors affecting the flow performance of steam turbine are analyzed.The tip clearance flow of the blade is studied,and distribution characteristics of flow and pressure in the clearance are revealed by three-dimensional numerical calculation.On this basis,active control mode of casing injection is adopted to change the flow structure and reduce the flow loss in tip clearance.The results show that reducing the height of tip clearance as well as choosing reasonable casing injection speed can not only reduce tip clearance loss but improve the performance of steam turbine.The flow in the micro steam turbine Curtis stage under partial admission is simulated numerically.The flow characteristics of every blade,the parameter distribution of inlet and outlet sections and the circumferential non-uniformity of the flow are studied.The power and efficiency of the partial admission turbine are analyzed.It is concluded that the micro steam turbine still has good performance under partial admission. |
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