Experimental and Numerical Investigation for the Effect of the Protrusion Shapes in the Crater of a Cylindrical Hole on Film Cooling Effectiveness

The impacts of a unique film-cooling design with the protrusion shape on the shaped crater implanted in the cylindrical hole on the film-cooling efficacy over a flat plate have been investigated experimentally and numerically in the current work. Similar to the single cylindrical hole, the injection angles (30°, 45°, and 90°) are chosen. An infrared camera was used to measure the test plate's surface temperature. The blowing ratios used in the experimental investigations were from 0.5 to 1.5. The effects of the hole configuration shape on overall adiabatic film-cooling efficacy may be predicted by the simulated findings based on the steady RANS with The Shear Stress Transport (SST) \(\:k-\omega\:\) turbulence model and increased wall treatment. According to the experimental and numerical results, the film-cooling efficacy is significantly increased in both axial and lateral directions when a simple hole is replaced with a protrusion form on the shaped crater implanted in the cylindrical hole. The rising anti-kidney-shaped vortex pair in the arc protrusion model is responsible for the numerical and experimental results, which show improved lateral coolant coverage and higher area-averaged cooling performance at larger blowing ratios. Since the downstream flow field is dominated by the kidney-shaped vortex pair, the trapezoid protrusion model offers the lowest area-averaged cooling efficacy. The rectangle protrusion model has the biggest overall pressure loss coefficient for the aerodynamic loss. In general, Rectangle protrusion and a contoured cratered hole are advised.