Shaped film cooling holes are used extensively for film cooling in gas turbines due to their superior performance in keeping coolant attached to the surface, relative to cylindrical holes. However, few studies have examined the impact of the orientation of the shaped hole axis relative to the main flow direction, known as a compound angle. A compound angle can occur intentionally due to manufacturing, or unintentionally due to changes in the main flow direction at off-design conditions. In either case, the compound angle causes the film cooling jet to roll up into a strong streamwise vortex that changes the lateral distribution of coolant, relative to the pair of vortices that develop from an axially oriented film cooling hole.  In this study, large eddy simulation (LES) using the Wall-Adapting Local Eddy Viscosity (WALE) model was performed on the publically available 777 shaped film cooling hole, at two orientations (0°, 30°) and two blowing ratios (M=1, 3). Laterally averaged film effectiveness was largely unchanged by a compound angle at a blowing ratio of 1, but significantly changed at a blowing ratio of 3.  For both blowing ratios, the lateral distribution of film was more uniform with the addition of a 30° compound angle.  Total unsteadiness in the jet was increased with the compound angle, although it is not clear if this was due to only random fluctuations or an overall global unsteadiness in the streamwise vortex core position. These conclusions were similar at both blowing ratios examined. 


Large Eddy Simulation of the 7-7-7 Shaped Film Cooling Hole at Axial and Compound Angle Orientations

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

Turbo Expo - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.