Aerodynamic Optimization Study for a Radial-Inflow Organic Turbine With High Expansion Ratio

This paper presents an aerodynamic study for a radial-inflow organic turbine with an expansion ratio of 8,using NURBS curve technology combined with CFD simulation.The use of NURBS curve,which controls and further optimizes the transonic nozzle profile,effectively reduce the total pressure loss coefficients of the nozzle vane.In transonic operation condition,the flow field in the optimized nozzle is completely under positive pressure gradient.Therefore the optimization improves the transonic expansion flow at nozzle throat,lowers the maximum Mach number,and increases the overall stage efficiency of the organic turbine.Meanwhile,after optimizing the profile of the meridional flow path,the width of the flow path increased more smoothly,along with the disappearance of the separation on the suction side of the original blade profile,which also improves the efficiency of the organic turbine.