An Experimental Investigation On Cooling Performance Of Laminated Configuration Using Infrared Thermal Imaging Technique

To investigate the geometrical performance of laminated film cooling configurations, surface temperature distributions of three different specimens with the true size of gas turbine components were measured by an infrared thermal imaging system. To measure surface temperature exactly, a digital thermocouple with high accuracy was used, and a correction relationship between the infrared thermal imaging technique and the thermocouple was established. To describe the overall cooling effect contributed by coolant impingement, heat conduction and convection, an algorithm of digital imaging signal was used, and the two-dimensional temperature drops from initial wall to cooled wall were directly obtained. The experiments were carried out at a hot gas wind tunnel, through comparisons of the cooling performance of the three specimens, the effects of the number and diameter of columnar ribs, the angle of film holes, the Reynolds number and Nusselt number of free stream on the overall cooling effectiveness were discussed. The results present the influence of coolant injection rate on the cooling performance of the laminated configuration. It is demonstrated that the infrared thermal imaging technique is effective method to study cooling performance of laminated configurations,and the effect of the film hole angle on the cooling effectiveness is higher than that of the ribs.