凹槽叶顶非定常间隙泄漏流动和传热的数值研究

NUMERICAL STUDY OF UNSTEADY TIP LEAKAGE FLOW AND HEAT TRANSFER IN A SQUEALER TIP BLADE

应用数值方法研究了燃气透平中凹槽状叶顶非定常泄漏流动和传热问题。计算采用GE-E3发动机高压透平第一级动叶,叶顶间隙高度取1%叶高,叶顶凹槽深度取2%叶高。通过施加非定常边界条件模拟上游静叶尾迹,分析了非定常流动对动叶叶顶传热的影响。结果表明,叶顶附近的流场波动主要出现在叶顶前部及尾缘附近。叶顶凹槽底部传热系数变化主要出现在凹槽前部。定常计算获得的叶顶面积平均传热系数与非定常计算的时均结果相差很小。

A numerical study was performed to simulate the unsteady tip leakage flow and heat transfer in the first stage turbine blade of GE-E3 engines with squealer tip. The blade tip gap height was specified as 1% of the blade span, and the tip groove depth was specified as 2% of the blade span. The unsteady inlet boundary condition was used to simulate the upstream wake. The effects of the unsteadiness on tip leakage flow and heat transfer were investigated. Results show that the flow unsteadiness near the tip is mostly located near the leading edge and the trailing edge. The variety of the tip heat transfer coefficient on the groove bottom mainly occurs in the front. The relative difference of the area-averaged heat transfer coefficients obtained from steady results and time-averaged unsteady results is less than 0.4%.