Liquid crystal thermography applied to jet impingement heat transfer for leading edge of blade

Liquid crystal thermography is applied to examine the jet impingement heat transfer of concave surface simulating the turbine blade. The test results show that for small nozzle-to-plate spacing, the Nusselt number in the stagnation region increases with increasing curvature. The heat transfer is enhanced compared to that for a semi-circular surface. For the parameter range studied, the Nusselt number is larger than that of a semi-circular surface by 12%. When the relative nozzle spacing equals to 2.27, there exists a maximum for a plot of Nusselt number versus nozzle to plate spacing. Heat transfer correlations are obtained.