低压高负荷涡轮叶栅的大涡模拟

LARGE EDDY SIMULATION FOR LOW-PRESSURE HIGHLOADED TURBINE BLADE

了解预测转捩与层流分离泡,对于低压高负荷叶片设计特别重要。为此,采用大涡模拟方法,对典型高负荷叶栅T106进行了模拟。计算描述了层流分离泡,给出了壁面压力、壁面摩擦力系数的分布,从而准确预测了T106压力面上的层流分离、转捩、湍流再附现象。计算同时刻画了层流分离泡的非定常性质,给出了瞬时压力,进行了频谱分析,确定主频为2500 Hz,并观察到了瞬时涡等有意义的现象。计算同时表明二维大涡模拟计算结果可以复现出湍流的许多重要现象并且精度可以满足工程需要。

It is vital for designing low-pressure high-loaded turbine blade to understand the transition and laminar bubble. Therefore, large eddy simulation was used to simulate classical high-loaded turbine blade T106. The computations show the laminar separate bubble, mean pressure coefficient and mean skin-friction coefficient distribution on the blade. Then, the locations of the laminar separation, the transition and the reattachment are predicted around 0.83, 0.92 and 0.95 respectively, that are good agreement with experiment. Further, The unsteady laminar bubble is described by instantaneous pressure and instantaneous vortex. Frequency spectra at trailing edge show that the main frequency is 2500 Hz. The computations also show that large eddy simulation in two dimensions can reproduce many important turbulent characters such as transition, and have satisfied accuracy for engineering.