带有端隙密封导叶的可调涡轮非稳态流场分析

Unsteady Flow Field Analysis of a Variable Nozzle Turbine with an End-Clearance-Sealed Guide Vane

本文基于端隙密封导叶(ESGV),利用数值模拟的方法研究ESGV涡轮在脉冲进气条件下的内部流场和性能,分析了ESGV对可调涡轮内部流动的影响.结果表明,整个脉冲周期内,ESGV涡轮能够有效抑制间隙泄漏流,并且,高压脉冲周期内的ESGV间隙泄漏损失降低程度大于低压脉冲周期的对应值.ESGV优化了转子进气入射角度,其转子前缘流动分离现象更弱,转子出口高熵区面积更小,整个涡轮级ESGV的流动损失更小,最终导致一个脉冲周期内的ESGV涡轮的平均效率提升了13.4%.

Herein,based on the structure of end-clearance-sealed guide vane(ESGV),the inner fluid flow and performance of an ESGV turbine under a pulse condition is studied using numerical simulation,and the effect of the ESGV on the inner flows are analyzed.The results show that within the whole pulse cycle,the turbine can effectively inhibit the involved clearance leakage flow and that the degree of reduction in the clearance leakage loss is greater in the high-pressure pulse period than in the low-pressure pulse period.Further,the ESGV optimizes the intake angle of the involved rotor,resulting in weaker flow separation at the leading edge of the rotor,a smaller high-entropy area at the rotor outlet,and smaller flow losses in the whole turbine stage ESGV.Consequently,the average efficiency of the ESGV turbine in one pulse cycle is increased by 13.4%.