A comparative study of the film cooling hole configuration effects on the leading edge of asymmetrical turbine blade

摘要

The focus of this comparative-numerical study is to investigate the effects of advanced cooling hole geometries on film cooling effectiveness. Computational results are presented for a row of coolant injection holes on each side of an asymmetrical turbine blade model near the leading edge. Six film cooling configurations are considered in the present study, namely: (1) a cylindrical film hole, (2) a shaped film hole, (3) a uniform film slot, (4) a convergent film slot, (5) a crescent film hole, and (6) a trenched film hole. All simulations are conducted for the same density ratio of 1.0 and the same inlet plenum pressure. A new parameter, Rc, is defined to measure the rate of blade coverage by the film cooling. Results show that, at the suction side, except for the trenched case, all configurations provide an increase of film effectiveness, specially the crescent slot case which provides the highest increase over the baseline case. On pressure side, the five configurations produce better quality of cooling and an enhancement which reaches 60% for the crescent hole case. The best blade coverage by the film cooling is allotted to the two cases: uniform and converge slot configurations.