Experimental investigation on heat transfer in complex internal cooling blade channel with leading-edge

Heat transfer characteristics of complex serpentine channels with leading-edge impingement in static turbine blade were investigated using the transient thermochromic liquid crystal technique under different Reynolds numbers. Distributions of local heat transfer coefficient at different positions were obtained on both pressure and suction sides. Experimental results show that: local heat transfer between two ribs is stronger than that in smooth region on inner surface of blade channels. A single heat transfer peak occurs between two adjacent ribs along the flow direction. With increase of Reynolds number, heat transfer is enhanced on all surfaces and centrifugal effect of fluid is strengthened in non-rib area downstream the bend, resulting in uneven distribution of local heat transfer there. However, ribs after the bend can reduce this effect significantly. Besides, mainstream speed changes caused by expansion and contraction of channel cross-section also influence the values and distributions of local heat transfer.