Investigation of film cooling flow characteristics in gas turbines with PIV method

In this study, the hybrid effects of slot film cooling, effusion film cooling and dilution hole mechanism were investigated together in a combustion chamber liner scaled with a 1/9. There is no a detail work about full flow kinematics in a great majority of the literature done on film cooling. In this thesis, as well as the thermal measurement studies the detailed flow structures are discussed and contributed to fill the gap in the literature. The flow structures in cross flow mechanism, that occurs due to hot air from the main stream and the cold air from the compressor, the results such as velocity maps, swirl contours and flow vectors were obtained with Particle Image Velocity (PIV) method in the test setup. Real-time surface temperature distributions were also visualized by IR thermography and for different blowing ratios film efficiency coefficients were evaluated from the pixel temperature values. Also, numerical validation of the hybrid effects on the optical air tunnels was performed with CFD analysis for 2 different configurations (slot film + effusion, slot film + effusion + dilution) and 3 different blowing ratios. Flow structures such as jet lift-off, CRVP, horseshoe vortices, kidney vortices and recirculation bubbles were observed with both PIV and CFD analyzes. Under the corresponding test conditions, when looking at the spanwise averaged thermal efficiency ratios in the slot, film and dilution hybrid plates, the best thermal efficiency is seen for effusion plate at a 0.24 kg/min blowing ratio and for the dilution plate at a 0.35 kg/min blowing ratio.