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.