NUMERICAL STUDY ON COOLING CHARACTERISTICS OF DOUBLE-ROW CYLINDRICAL HOLES ON UPSTREAM ENDWALL

摘要

In this paper film-cooling effectiveness of two rows of cylindrical holes located on the endwall upstream of a vane is investigated numerically. Five different cooling schemes, including three schemes of double rows cylindrical holes (β=-45°, 0°, 45°), and two schemes of Double-jet film cooling (DJFC) holes (β=-45°, 45° and β=45°, -45°), are arranged on the endwall at four blowing ratios (M = 0.5, 1.0, 1.5, 2.0). Both primary effect (on downstream endwall) and secondary effect (on pressure and suction surfaces) of the endwall film cooling are considered. 1CEM is used to mesh the computational domain, and simulation is carried out by ANSYS 14.0. The result shows that cooling jets with compound angles can effectively suppress lifting-off and increase film-cooling effectiveness. In addition, at low blowing ratios, it is difficult for jets no matter what directions to cool the neighborhood of the leading edge and the pressure side due to the effect of horseshoe vortices. However, passage vortices have different effects on the cooling jets with different compound angles which will result in different film coverage on both endwall and airfoil.