抄録
Detailed studies are conducted on heat transfer distribution around the leading edge of a blunt test model with discrete cooling holes, where the model is subjected to periodically incoming wakes as well as free-stream turbulence with various levels of intensity. The cooling holes have a configuration similar to those of typical turbine blades except for the spanwise inclination angle. A spoke-wheel type wake generator is used in this study. In addition, three types of turbulence grids are used to elevate the free-stream turbulence intensity. Heat transfer measurements are executed for several temperature differences between the free-stream and the secondary air to determine film-affected heat transfer distributions around the test model. We adopt three blowing ratios of the secondary air to the mainstream. For each of the blowing ratios, the heat transfer distribution is obtained under the influence of periodic wake passage as well as free-stream turbulence. Heat transfer near the stagnation region is enhanced due to the wakes and free-stream turbulence, while the effect of the injected secondary air is minimal. Downstream the cooling holes, heat transfer is greatly affected by the injected secondary air, which tends to follow the correlation for turbulent boundary layer.
