动叶顶部间隙对1+1/2对转涡轮性能的影响

本文对1+1／2对转涡轮中动叶顶部间隙大小对涡轮性能的影响进行了详细的数值模拟。对涡轮总体性能参数、节距平均出口气流角、出口节距平均相对马赫数以及不同叶高的负荷进行了对照,发现间隙对1+1／2对转涡轮性能影响明显,尤其是当间隙较大时。当低压动叶间隙宽度达到高压动叶前缘叶高的4．5％时,低压动叶间隙中流动普遍超音,在设计1+1／2对转涡轮时需要加以重点考虑。

INFLUENCE OF ROTOR TIP CLEARANCE ON PERFORMANCE OF VANELESS COUNTER-ROTATING TURBINE

A detailed unsteady numerical simulation has been carried out to investigate the influence of the rotor tip clearance on the performance of a 1+1/2 counter-rotating turbine (vaneless counter-rotating turbine (VCRT)). Through analyzing the total parameters of performance, the distribution of pitch-averaged outlet air angle, and pitch-averaged outlet relative Mach number and the loadings at different span etc. in VCRT, it can be found that, the tip clearance of the rotors can impose a clear influence on the VCRT's total performance, and the bigger of the clearance, the more of the influence. When the width of the tip clearance is equal to 4.5% of the rotor span, the flow in tip clearance is supersonic in the most area, which is needed to pay more attention in designing VCRT.