叶片前缘有气膜孔的冲击冷却研究

Impingement Cooling with Film Coolant Extraction in the Airfoil Leading Edge Regions

为了确定涡轮叶片前缘阵列射流冲击到穿孔靶面的传热特性,本文采用六个放大比例的模型,进行了一系列的实验研究。在广泛的实际有兴趣的参数组合范围内,分别对各种模型,获得了压力损失和N_u数与射流雷诺数的关系式。这些组合参数包括:射流雷诺数,叶片前缘曲率半径与孔径的比,射孔间距与孔径的比以及射流冲击间隙与孔径的比。并利用实验数据,分析了各项几何参数的影响。

An extensive experimental study is conducted to determine the heat transfer characteristics of arrays of air jets impinging on perforated target surfaces in turbine blade leading edge regions by six large-scale models. The relations of pressure loss and Nuselt number to jet Reynolds number are obtianed in wide range of parameter combinations of interest in cooled airfoil practice for various models,respectively. There parameter combinations are covered in test matrix, including combinations of variations in jet Reynolds number,airfoil,leading edge curvature radius-to-diameter ratio,jet pitch-to-diameter ratio and jet impingement gap-to-diameter ratio. A modified Reynolds number Re* based on the coolant flow per unit area of target surface is used to regulate experimental data and to analyse effects of geometric parameters.