A Cooling Efficiency Model and Numerical Research of Multiparameter Film Cooling

Based on the validated simulation method of film cooling and multiphase flow simulation method, a multi-level three-dimensional simulation of forward-leaning fan-shaped film hole, cylindrical film hole with different injection angles, and film hole containing water vapor are established to discuss the effects of film hole structure parameters, hole distance, blowing ratio, injection angle, and water vapor volume on film cooling efficiency. The cooling efficiency of forward-leaning fan-shaped film hole increases as the exit length of film hole increases. After adding water vapor, the cooling efficiency of fan-shaped film hole decreases, and the influence of hole axis length and exit length on cooling efficiency is weak. For the cylindrical film hole, the larger the injection angle of film hole, the larger the film coverage area under the same blowing ratio. After adding water vapor, with the increase of the blowing ratio, the film coverage area increases first and then decreases. However, the film coverage area decreases with the increase of cooling injection angle for film holes containing water vapor. The cooling efficiency of the film hole with and without water vapor is related to the vapor velocity in the rising direction and the velocity in the mainstream direction, respectively. A model of film cooling efficiency with air blowing ratio and injection angle is established and verified with experimental data, based on the law that the average cooling efficiency in the main flow direction grows exponentially with the sine of the injection angle.