Seminars

In gas turbine engines, film cooling holes are often fed by an internal crossflow, with flow normal to the direction of the external flow around the airfoil. Many experimental studies have used a quiescent plenum to feed model film cooling holes and thus do not account for the effects of internal crossflow. In this study, an experimental flat plate facility was used to study the effects of internal crossflow on a row of cylindrical compound angle film cooling holes. There are relatively few studies available in literature that focus on the effects of crossflow on film cooling performance, with no studies examining the effects of this particular geometry. A crossflow channel allowed for coolant to flow alternately in either direction perpendicular to the mainstream flow. Experimental conditions were scaled to match realistic turbine engine conditions at low speeds. Cylindrical compound angle film cooling holes were operated at blowing ratios ranging from 0.5 to 2.0 and at a coolant-to-mainstream density ratio of 1.5. The results from the crossflow experiments were compared to a baseline plenum-fed configuration. It was found that significantly greater film cooling effectiveness was achieved for crossflow counter to the direction of coolant injection. Additionally, thermal fields above the film-cooled surface showed differences in coolant spread for the different crossflow directions.