基于热色液晶技术的尾迹对涡轮动叶表面换热系数影响研究

The effects of unsteady wake on the heat transfer coefficient of the turbine blade without film holes is studied using the Thermochromic Liquid Crystal (TLC) measurement technique. The turbulence intensity of the free-stream is 2% and 20% respectively, and the wake Strouhal number is varied from 0 to 0.36. Results show that as the wake Strouhal number increases, the heat transfer coefficient of the pressure surface increases by up to 142%, the heat transfer coefficient of the leading edge increases by up to 7% and that of the suction surface increases by up to 186% for the case of free-stream turbulence intensity Tu=2%. At the case of Tu=20%, the influence of the wake is weakened and the heat transfer coefficient of the pressure surface increases by up to 10%, the heat transfer coefficient of the leading edge increases by up to 10% and that of the suction surface increases by up to 26%. The unsteady wake causes an earlier laminar to turbulent boundary layer transition on the suction surface and the transition length increases. Overall, the wake causes an increase in the heat transfer coefficient of the turbine blade and the effect of wake on the suction surface is greater than that on the pressure surface.