Flow Simulation And Design Research Of The Radial Inflow Turbine In Micro Gas Turbine System

In recent years more and more scientists and engineers attach great importance to the research and the development of the micro gas turbine (MGT) ,for its special advantages of high efficiency, high reliability, compact structure and low emission. Based on the research of the structural design of the radial inflow turbine, a key component in the micro gas turbine, the design programs of the radial inflow turbine include volute, guide vane and the impeller were developed. Flow simulation platform for the flow inside the inflow turbine was developed with the powerful CFD software STAR-CD and some accessorial software such as Pro/Engineer and ICEM-CFD. Flow inside the turbine of WD095 micro gas turbine was analyzed using the simulation platform. Main features of the flow field were obtained and problems affecting the efficiency of the machine were analyzed. The numerical results indicate that the design of the stator is rather successful but the impellor still has room to be modified.Based on the flow simulation results of the original design, design optimization of the radial inflow turbine was carried out in this thesis. Effect of the geometry parameters of the volute on the performance of the turbine was discussed with three numerical samples. Correlation between the mass flow of the radial inflow turbine and the guide vane outlet angle was obtained with a series of numerical experiments. In the design of the impeller, main focus was on the effect of the design parameter "t", which controls the parabolic profile of the blades, on the performance of the turbine. Optimization of parameter "t" yielded a 2.18% increase of the turbine efficiency. As the short blade in the original design had some adverse effect of the flow in the impeller, the short blade was redesigned with a different method. Results indicate that the flow inside the impeller has been improved greatly. Final optimization results indicate that the efficiency of the inflow turbine has been increased by 2.60 percents on the basis of the origin design.The research results presented in this thesis may provide some guidelineconclusion for the aerodynamic design of the inflow turbine. The numerical analytic platform for the flow in the inflow turbine developed proved to be a powerful and practical tool in the design of the inflow turbine that can shorten the design cycle and cut the design cost effectively.