非设计工况下1＋1／2对转涡轮性能研究

为了研究和改善1 1/2对转涡轮性能,本文对1 1/2对转涡轮两种转速下不同落压比共16种工况进行了数值研究,并与实验结果进行了对照.结果表明近设计工况下计算结果和实验值吻合较好.1 1/2对转涡轮出口背压对高压转子性能影响较小,对低压转子性能影响较大,这导致变工况下1 1/2对转涡轮高低压轴出功比变化较大.通过对某典型非设计工况和设计工况下的流场结构的分析发现非设计工况下1 1/2对转涡轮高压动叶中发生了明显的流动分离.高低压动叶不能很好地匹配,需要采取合理的流动控制措施去改善已有1 1/2对转涡轮的变工况性能.

RESEARCH OF THE PERFORMANCE OF A VANELESS COUNTER ROTATING TURBINE ON THE OFF-DESIGN CONDITIONS

To improve the performance of the vaneless counter-rotating turbine(VCRT),numerical simulation had been carried out to investigate the flow in the VCRT at different pressure ratios of two turning speeds,and the numerical results were compared with the experimental data.Numerical results show good agreement with test data on the design condition and conditions which are close to the design condition.Outlet pressure of the VCRT has greater influence on the performance of low pressure rotor,but smaller influence on that of high pressure rotor,which results in the work ratio of the high pressure turbine to low pressure turbine of the VCRT increased gradually when the condition is farther and farther from the design point.Finally,the flow structure of the farthest off-design condition in experimental test at the speed of 5000 r/min was compared with that of the design condition.Results show that serious separations produce in the high pressure rotor on off-design condition.High pressure rotor and low pressure rotor cannot match well at far off-design conditions, thereby,performance of the turbine get worse there.Appropriate flow control technology is necessary to be taken to improve the performance of the VCRT on off-design condition.