화학공학소재연구정보센터
International Journal of Heat and Mass Transfer, Vol.52, No.5-6, 1268-1275, 2009
Suitability of three different two-equation turbulence models in predicting film cooling performance over a rotating blade
The suitability of three different two-equation turbulence models in predicting film cooling effectiveness on a rotating blade was investigated and they are the commonly used standard k-epsilon model, the k-omega model and the shear stress transport k-omega model. To fulfill this target, both numerical simulation and the experimental investigation were carried out for a rotating blade having a flat test surface with a 4 mm diameter straight circular cooling hole in 30 degrees inclined injection. The blade rotated at five different speeds of 0, 300. 500, 800 and 1000 rpm. The momentum ratio was set to be 0.285 and the Reynolds (ReD) number based on the mainstream velocity and hydraulic diameter of the mainstream channel is 1.45 x 10(5). The averaged density ratio was chosen to be 1.026 with air as both the coolant and the mainstream. Comparison between the numerical work and the experimental results indicated that (1) the rotating speed is the most critical parameter influencing the film cooling effectiveness distributions and the pressure surface could be remarkably different from the suction surface. (2) as for the algebraic averaged film cooling effectiveness, numerical predictions of the three turbulence models all overshoot compared with the experimental results, (3) among the three turbulence models, the standard k-epsilon model gave the poorest prediction. (C) 2008 Elsevier Ltd. All rights reserved.