Investigating the effects of fan-shaped cooling hole geometry parameters on film cooling effectiveness for internal coolant cross-flow using CFD

Abstract

The geometry and distribution of cooling holes play a vital role in the effectiveness of the surface cooling of gas turbine blades, as well as in the design and operation of modern gas turbines. The geometry parameters of a cooling hole affect the downstream temperature and flow fields, as well as the adiabatic film cooling effectiveness distribution. To gain a better view on the way the cooling holes' performance is affected, cross-flow (with internal cooling flow direction normal to the external hot gas flow) CFD simulations were performed for fan-shaped cooling holes. Initially, an existing cooling hole geometry was considered, while then the cooling hole geometry was rotated around the symmetry axis of its cylindrical part. The simulation results revealed that the cooling hole rotation affects adiabatic effectiveness positively at low and intermediate blowing ratios. The observation that the cooling flow attaches to the walls of the rotated holes more effectively is the main reason for the increase in the cooling effectiveness.