冲击孔板和扰流柱组合结构流动传热特性的实验和数值研究

The flow and heat transfer characteristics of the composite structure with impingement perforated plate and pin-fins in the cooling channel at the trailing edge of a turbine blade were experimentally and numerically studied. The pin-fins in a staggered array were arranged on the end face of the trailing edge. The perforation ratio varied between 0.07 and 0.44，and the jet-to-surface varied from 1.5 to 4. Reynolds number，based on the hydraulic diameter of the inlet channel，was tested within the range values from 1 600 to 4 000. The convective heat transfer coefficient distribution of the surface in the pin-fin channel was obtained by using the transient liquid crystal temperature measurement technique. The effects of perforated ratio and impingement distance on the flow structure and convective heat transfer characteristics of the pin-fin channel were analyzed. The results showed that the average heat transfer of the composite structure can be significantly improved by the strong impingement jet formed at a small perforation rate，but could greatly increase the flow loss. The impingement distance and perforation rate had a significant influence on the heat transfer and pressure loss characteristics of the impingement and pin-fin composite structure. The Nusselt number of the composite structure was 2.0—9.4 times that of the smooth channel，with a friction factor of 136—1 800 times that of the smooth channel. The experimental correlations between heat transfer enhancement factors and key parameters of the combined structure were obtained.