Structure Design And Experimental Research Of Small Expansion Ratio Kadial-inward-flow Turbine With Variable Nozzle

Radial inflow turbine transformates pressure energy of compressed gas into the shaft power to drive the load. It is widely used in practical engineering. In this design, turbine with small expansion and full flow and adjustable nozzle vane, can realize the online adjustment of power. Based on the turbine structure design, the velocity triangle theory,2D and3D numerical simulation and experiment research, the paper discusses the rotor speed relation between the static blade and rorating blade and at the same time studies the influence of the structure parameters and operation parameters on the turbine efficiency, getting the optimal radial inflow turbine structure.The main work and conclusion is as follows:(1) According to the working principle and design process of the radial inflow turbine, I write a computer program to design the radial inflow turbine. The basic parameters of the turbine were determined by the program; According to the procedure for determining the structure parameters, the variable nozzle and little expansion ratio turbine is designed; at the same time, in the process of using CFD software to study numerical model, the preparation of a UDF program is achieved to constantly output required parameters for turbine.(2) A2D numerical simulation method for three kinds of static cascades and four species leaf type were analyzed and three dimensional numerical simulation is used to analysis on parameters of the angle of the nozzle, the nozzle cascade number, the leaf number and the impeller tip clearance and so on. The optimal combination is determined.(3) Through the experimental verification of correctness of numerical model, we can know that under different nozzle angle, turbine efficiency of the simulation and experimental results show a same value trend. The experimental results and the simulation value have a good consistency. The numerical modle is correct.(4) The experimental study on the effect of different structure parameters and operating parameters on the turbine efficiency, the results show that:as the angle increases, the turbine efficiency under various pressure increases first and then decreases; bending type blade is better than straight impeller type; with the pressure rise, efficiency first increased and then decreased, the0.3MPa efficiency reaches the maximum value; expansion ratio in the1.15is the best; along with the increase of the turbine flow rate,the turbine rorating speed increases gradually and turbine efficiency decreases; turbine optimal performance is:efficiency is56%, rorating speed is2900r/min. Radial inflow turbine designed in this paper can be achieved in a small expansion ratio conditions as the driven equipment. It can achieve online to adjust the power and to achieve continuous production. The paper provides a reliable basis for the practical application of adjustable centripetal turbine.