Multi-Parameters Sensitivity Analysis of Overall Cooling Effectiveness on Turbine Blade and Numerical Investigation of Internal Cooling Structures on Heat Transfer

Abstract

Turbine blade overall cooling effectiveness is a conjugate result under the influence of various parameters. In order to analyze the overall cooling effectiveness more accurately, we have to categorize all the influencing parameters. This paper builds a one-dimensional conjugate heat transfer model with four parameters which are adiabatic film cooling effectiveness, heat transfer coefficient ratio between blade external surface (hg) and internal surface (hi), internal coolant warming factor (Tg−Tw,iTg−Tc), Biot number. The effects of different internal cooling structures, film hole inclined angle and blowing ratio on flow and heat transfer characteristic were numerically investigated based on flat-plate film hole model and impingement-effusion model, where 3-D steady RANS method with SST k-ω model was used. V-rib, 45° inclined rib, 90° rib and dimple were adopted to compare with smooth internal channel. The results show that four dimensionless parameters (adiabatic film cooling effectiveness, heat transfer coefficient ratio, warming factor, Biot number) are positively correlated with overall cooling effectiveness. The overall cooling effectiveness is the most sensitive to adiabatic film cooling effectiveness, followed by warming factor. This indicates that the adiabatic film cooling effectiveness is the worthiest to improve. The numerical results show that the ribs and dimple structures have little influence on the distribution of adiabatic film cooling effectiveness and Biot number on the mainstream side. The 45° rib presents higher overall cooling effectiveness.