Investigation of Film Cooling Effectiveness of Dual-fanned Hole with Various Exit Widths

Abstract

AbstractFilm cooling effectiveness downstream of one row of holes of 30 degree inclination angle was measured by using a steady-state thermochromic liquid crystal technique at blowing ratios of 0.5, 1.0, 1.5 and 2.0, respectively. Three kinds of dual-fanned holes which have the same expanded entrance width and the different expanded exit widths were tested. The configuration of only expanded entrance, but cylindrical exit hole, was tested to examine the effect of the expanded entrance on film cooling performance. The numerical simulation for the three expanded exit configurations was carried out explaining the mechanism of film cooling by the flow and thermal field. The only expanded entrance has a weak influence on film cooling effectiveness. The ${W_o} = 1.5d$ configuration provides a lift of film cooling effectiveness compared to ${W_o} = 1.0d$ configuration. Film cooling effectiveness is not sensitive to the change of configurations from ${W_o} = 1.5d$ to ${W_o} = 2.0d$. Film cooling effectiveness for ${W_o} = 2.5d$ performs significantly better than the other configurations due to the presence of the anti-vortex. The effect of dual-fanned exit width on film cooling effectiveness is strongly dependent on the blowing ratios.