冷气喷射对缩放型流道涡轮叶栅性能及流场影响的数值研究

Numerical Simulation of the Coolant Injection Influences the Flowfield Performance in a Convergent-Divergent Turbine Cascade

本文利用数值模拟方法详细研究了缩放型流道叶栅中从六个不同轴向位置处以不同的质量流量比喷射冷气对叶栅流场性能的影响,对比分析了能量损失系数、叶表静压分布、流道内马赫数分布等,结果表明冷气喷射对叶栅性能的影响和内伸波的影响是不同的。叶栅性能的变化主要是由于冷气喷射导致叶型损失的变化引起的,当冷气从吸力面内伸波作用位置附近及前缘滞止线附近喷射时,冷气与主流的掺混剧烈且持续到叶栅出口处,使得叶栅损失增加;当冷气从压力面和吸力面喉口位置处射流时,叶栅损失减小。在吸力面内伸波反射点附近射流时,由于冷气的滞止作用使得冷气孔前的压力增大,进而减小内伸波前后压差,减弱内伸波强度。

A detailed numerical simulation has been carried out to analyze the influence of the coolant injection on the flowfield performance of a convergent-divergent turbine cascade. The coolant jetted respectively out of six rows of cooling holes with different mass flow ratios. Through comparative analysis of the energy toss coefficient, the surface static pressure distribution, the Math number change in the flow passage, and so on, many physical phenomena are observed. The influence of the coolant injection on the cascade performance and the inner-extending shock （IES） is different. The change of the cascade loss is mainly caused by the different profile loss, when the coolant injects from the suction surface where the IES impinges and the leading-edge stagnation line, the mixing process is drastic and durable which makes the mixing loss and the wake loss both are increasing, when it injects froin the pressure surface and the throat of the suction surface, the cascade loss decreases. Only when the coolant jets out of the suction surface where the IES impinges, the IES strength is weakened due to the increased pressure in front of the cooling holes.