Numerical Investigation of Heat Transfer Coefficient in a Low Speed 1.5-Stage Turbine

The paper numerically investigated the heat transfer coefficients over the rotating blades in a 1.5-stage turbine. The hexahedral structured grids and k-epsilon turbulence model were applied in the simulation. A film hole with diameter of 0.004 m, angled 36 degrees and 28 degrees tangentially to the suction side and pressure side in streamwise respectively, was set in the middle span of the rotor blade. Simulations are done at three different rotating numbers of 0.0239, 0.0265 and 0.0280 with the blowing ratio varying from 0.5 to 2.0. The effects of mainstream Reynolds number and density ratio are also compared. Results show that increasing blowing ratio can increase the heat transfer coefficient ratio on the pressure side, but the rule is parabola on the suction side. Besides, increasing rotating number and Reynolds number is positive while increasing density ratio is negative to the heat transfer on both the pressure side and the suction side.