Cooling characteristics of full coverage film holes with opposite lateral ejection angles

Numerical investigations were performed to study the full coverage film cooling structure on the flow field characteristics, wall surface heat transfer coefficient, adiabatic wall film cooling effectiveness and integrated cooling effectiveness under consideration of heat conduction. Results indicates that kidney vortex pair generated in the flow field of film cooling with opposite lateral ejection angles makes the film spread wider laterally. Despite of raised heat transfer in this condition, the integrated cooling effectiveness increases as high adiabatic wall cooling effectiveness reduces the heat conduction. Under blowing ratio of 1.0, the slant hole with opposite lateral ejection angle of 45° has the highest integrated cooling effectiveness. The integrated cooling effectiveness of slant hole with opposite lateral ejection angle of 30° is the highest when blowing ratio of 1.5 and 2.0. Compared with corresponding slant hole with single lateral ejection angle, the film cooling with opposite lateral ejection angle of 15° has lower integrated cooling effectiveness. The cooling effectiveness of slant hole with opposite lateral ejection angles of 45° and 60° respectively are both comparable to the integrated cooling effectiveness of the corresponding structures with single lateral ejection angle. When compared with slant hole with single lateral ejection angle of 30°, the film cooling with opposite lateral ejection angle of 30° has higher integrated cooling effectiveness.