Abstract: 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.

Key words: film cooling, heat transfer, flat blade, thermochromic liquid crystal, rotation