Effects of Leading Edge Shape on Effusion Film Cooling

Abstract

This study investigated the effusion film cooling on a turbine leading edge model. The pressure-sensitive paint (PSP) technique was employed to analyze the film cooling effectiveness. Three different leading edge profiles were tested, including a semicylinder and two elliptical models. Effusion cooling was achieved by employing closely spaced small holes, and stereolithography was utilized to create the perforated region. The study examined the impact of different blowing ratios (0.4, 0.8, and 1.2) while maintaining a unity density ratio. For benchmark testing purposes, three rows of film cooling holes on these leading edge models were also studied for traditional film cooling scenarios. The film cooling rows consisted of 15 holes positioned at the stagnation line (0 deg) and ±30 deg away from it. All test models were placed in a low-speed wind tunnel for experimentation at a Reynolds number of 100,000. Two different streamwise spacings of the effusion holes were examined in this study. The results indicate that effusion cooling was more effective in cooling compared to traditional film cooling methods. When considering the same leading edge shape, the adiabatic cooling effectiveness of effusion cooling was 30–100% higher than that of traditional film cooling. It was observed that increasing the streamwise spacing had a negative impact on the cooling effectiveness, regardless of the leading edge profile being used. Furthermore, variations in blowing ratio did not significantly affect the effectiveness of effusion cooling, and no noticeable blow-off of coolant was observed.