高膨胀比有机工质向心透平气动优化研究

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

本文采用NURBS曲线参数化表达和控制几何型线,结合CFD数值实验,对膨胀比为8的有机工质向心透平进行气动优化研究。跨声速喷嘴叶型型线经气动优化后,喷嘴内处于顺压梯度的加速流动状态,喉部跨声速膨胀流动得到改善,流场最大Ma降低,全工况下的叶栅总压损失系数显著减小,跨声速工况下的级组效率明显提高。叶轮子午流道型线经优化后,流道宽度变化更均匀平滑,原动叶轮吸力面分离被消除,透平级组效率也有提高。

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.