Experimental investigation of the influence of trailing edge outflow rate allocation on the heat transfer in turbine blade internal cooling channel

Detailed local heat transfer distribution and average heat transfer variation trend of five different trailing edge outflow rate allocation ratios, with the inlet Reynolds number of 27 000 and 24 000 and in proportionally enlarged model according to similarity principle, were acquired by using transient liquid crystal measurement technique. The purpose of this experimental study is to understand the effect on the heat transfer characteristics of high-pressure turbine blade internal cooling channel with different trailing edge outflow rate allocation ratios. The results show that different trailing edge outflow rate allocation ratios will affect the local heat transfer distribution in trailing edge tunnel remarkably and in middle tunnel obviously, but in leading edge tunnel invisibly; the spanwise average heat transfer in the middle and trailing edge tunnels is enhanced firstly and then depressed with the increase of trailing edge outflow rate allocation ratio, and enhanced mostly at the ratio of 25%, but invisibly in leading edge tunnel; the average heat transfer of each tunnel and measurement surface is strengthened firstly and then depressed while increasing the trailing edge outflow rate allocation ratio, and is also strengthened mostly at the ratio of 25%; different trailing edge outflow rate allocation ratios affect the average heat transfer in each tunnel, mostly in trailing edge tunnel, about 30%; posteriorly in middle tunnel, about 20%; and leastly in leading edge tunnel, only 10%.