Effect of unsteady wake transportation on film cooling flowfield of rotating turbine blade

Unsteady flowfield of the turbine blade with film cooling was investigated numerically under different blowing rates with the wake simulated by the cylinder rod. The effect of unsteady wake transportation on the film cooling flowfield was analyzed. Results show a zone with low velocity forms due to the total pressure defection and velocity defection. The disturbance of the unsteady dominates the formation of the cooling film when the unsteady wake is transported to the position near the cooling hole, which results in the obvious reduction of the cooling effectiveness near the cooling hole. The cooling gas can be transported to the farther downstream region due to effect of the unsteady wake, and the recovery range of the cooling gas along the spanwise direction is wider than the time without unsteady wake passing, therefore better cooling effectiveness exists on the pressure surface when the unsteady wake is transported to the position near the cooling hole on the pressure surface. The effect of the unsteady wake on the cooling effectiveness increases with the increment of the width of the unsteady wake. The effect of the unsteady wake is larger on the pressure surface than that on the suction surface.