Experimental investigation on heat transfer characteristics in a ribbed leading edge channel of turbine blade

Abstract

To investigate the structure of the leading edge of turbine blade with film outflow and its internal heat transfer law, the heat transfer characteristics of the triangular channel with half-ribbed structure at the leading edge with different Reynolds numbers (Re = 6000 ∼ 30000) and outflow ratios (OFR = 0 ∼ 0.8) are researched by using the transient liquid crystal (TLC) measurement technique. The results show that when the outflow ratio is 0, the high heat transfer area is mainly distributed in the region behind the ribs and the edge of the rib tip. The heat transfer is weaker in the area away from the ribs, and the high heat transfer area behind the ribs first weakens and then strengthens along the flow direction. With the increase of outflow ratio, the high heat transfer zone near the film holes increases. The heat transfer in the area near the stagnation point of the leading edge is enhanced, and the overall high heat transfer zone is more uniformly distributed. Under the large outflow ratio, more coolant flows out of the film holes, resulting in a small downstream flow rate and reduced velocity. The area of low heat transfer near the tip of the blade increased, and heat transfer decreased. With the increase in Reynolds number, the heat transfer of the internal cooling channel is significantly enhanced, and the area of the high heat transfer zone is expanded.