FILM COOLING PERFORMANCE AND HEAT TRANSFER OVER AN INCLINED FILM-COOLED SURFACE AT DIFFERENT DIVERGENT ANGLES WITH ESPECT TO THE HIGHLY TURBULENT MAINSTREAM

摘要

Experiments have been performed to study and obtain the adiabatic-wall film cooling effectiveness and the heat transfer over a film-cooled surface that is made inclined at various angles with respect to a highly turbulent flow. The vertical temperature distribution was measured to infer the flow structure and the rate of mixing of film jet with the freestream. The freestream turbulence intensity is controlled which ranges from 1.0% to 26.4%, the inclination or the divergent angle of the film-cooled surface ranges from 0° to 20°, the blowing parameter from 0.5 to 2.0. It is found that the mixing of the film jet with the freestream is significantly enhanced by both the freestream turbulence intensity and the divergent angle of the film-cooled surface, which leads to the decrease in the film cooling effectiveness and the increase in the heat transfer. However, the inclination angle has more effect on the film cooling performance while the turbulence intensity has more effect on the heat transfer under the film. More detailed discussion will be presented. Correlations for both the film cooling effectiveness and the heat transfer under the film-cooled surface have been very successful and will be provided.