Heat transfer characteristics of fan-shaped hole effusion cooling for a constant hole exit width - Numerical simulation and experimental validation

摘要

In order to study the effusion cooling mechanism of fan-shaped holes with a constant exit width, numerical simulations and the corresponding experimental verifications are carried out on a flat plate with ten rows of fan shaped film cooling holes. The entrance diameter and the exits width of the cooling holes are kept at D and 3D, respectively. While the thickness of the flat plate is kept at 10D/3. The holes are arranged in a staggered pattern with the constant stream-wise and span-wise spacing of 8.5D and 6.5D, respectively. The hole inclination angles of 20 degrees, 25 degrees and 30 degrees, the hole expansion angles of 10 degrees and 13 degrees, and the blowing ratios ranged from 0.5 to 7.5 are considered. Shear stress transport k - omega turbulence model is adopted for the numerical simulation. The numerical results are validated experimentally using thermo-chromic liquid crystal technology, showing good agreements. Through the simulation, the effects of the inclination angle and the expansion angle of the holes as well as the blowing ratio on the film cooling effectiveness are analyzed and discussed in detail. A correlation for the area averaged effectiveness is developed for the prediction of row-by-row superposition effects of effusion cooling with fan-shaped holes.