旋转状态下气膜冷却换热特性的实验研究

 基于一个平板叶片模型对旋转状态下气膜冷却现象的换热特性进行了实验研究，得到不同吹风比情况下气膜冷却换热系数随主流雷诺数和旋转数变化的分布规律。实验利用热色液晶(TLC)测温技术对叶片表面的二维温度场进行测量，采用空气和二氧化碳模拟不同冷气与主流的密度比，并使用无线遥测技术对旋转系中的温度信号加以采集。结果表明：由于受到离心力与哥氏力的综合作用，叶片压力面与吸力面上的强化换热区域向高半径处发生偏转，且偏转趋势在吸力面上更为明显；随着主流雷诺数的增大，压力面上的换热系数不断增大，而在吸力面上则先减小后增大；此外，主流雷诺数的变化对压力面和吸力面上强化换热区域的偏转现象没有明显影响。

Heat Transfer Measurements on a Rotating Film Cooling Model

An experimental study is performed to investigate the local heat transfer coefficient distribution on a flat blade model under rotating operating conditions. The steady-state thermochromic liquid crystal (TLC) technique is employed to measure the two-dimensional surface temperature, and all the signals from the rotating reference frame are collected and transmitted to the stationary receiver by a telemetering instrument via a wireless connection. During the experiment, both air and CO₂ are used as coolants. Detailed distributions of h/h₀, which is the ratio of heat transfer coefficient with film cooling to that without, are presented at various mainstream Reynolds numbers (Re_D) and rotation numbers (Rt). Results show that the rotational effect has a significant influence on heat transfer coefficient distribution. The profiles of h/h₀ deflect towards high-radius locations both on the pressure surface and suction surface, and the deflective tendency of h/h₀ is more evident on the suction surface. All the values of h/h₀ enhance with increased Re_D on the pressure surface, while the distribution of h/h₀ declines at first but then augments again on the suction surface. Furthermore, the variation of Re_D has little influence on the deflective profiles of h/h₀.