大流量调节范围变几何涡轮气动优化设计研究

Variable geometry turbine with large flow regulation range is a crucial component of advanced variable cycle engine in the future. Numerical simulation was employed to analyze the flow loss characteristics of a single-stage variable geometry turbine with a flow regulation range exceeding 170% during extensive flow regulation，and the meridian flow channel，velocity triangle，guide vane and rotor blade profile of the turbine were optimized based on the loss source. The results showed that the efficiency of the optimized turbine was improved within the range of 100%—170% flow regulation， and the efficiency of the turbine at small flow points was 8.8% higher than that before optimization. The design of larger leading-edge diameter and negative angle of attack could help reduce the blade profile loss at small flow rate. Compared with the contraction design，the guide vane meridian channel flat design significantly reduced the tip and root clearance of the guide vane and effectively cut down the leakage loss. Increasing the outlet Mach number of the rotor could help reduce the end wall loss of the rotor blade root and improve the rotor efficiency.