Jet in crossflow: Experiments on the interaction of flow-structure and cooling efficiency

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The effect of imperfections in film-cooling nozzles on the flow fields and cooling effectiveness is studied. Measurements are performed using laser induced fluoresce, particle image velocimetry and thermo-chromic liquid crystal sheets. Different positions, shapes (square, triangular and round) and sizes (5- 25% blockage) of imperfections are used to investigate the role of the nozzle geometry at different velocity ratios (0.15-1.50) with a fixed nozzle angle (37o). Results will show that the position and size of the geometry disturbance are determining factors in the resulting cooling effectiveness, through their effect on the vortex-structures at the nozzle outlet. In some cases, the imperfect holes lead to a significantly improved performance, while in some other cases they deteriorate it.