Film Cooling Performance for Cylindrical Holes Embedded in Contoured Craters: Effect of the Crater Depth

Abstract

The present study deals with the flow field and cooling performance for flat-plate cylindrical film cooling holes embedded in contoured craters, especially considering the effect of the crater depth. A. test matrix of the crater depth ranging from 0.25 to 1.25 times of the cylindrical hole diameter and the blowing ratio ranging from 0.5 to 2.0 is used in CFD computations. The numerical results show that the flow fields downstream from the hole exit can be altered significantly due to interaction between the ejected coolant and contoured crater. The cooling performance depends on both the specific crater depth and blowing ratio; however, the cratered hole is always superior to the cylindrical hole in terms of the area-averaged cooling effectiveness regardless of the crater depth and blowing ratio. The cratered hole with a. crater depth equal to the hole diameter is recommended.