ABSTRACT
A computational study is reported on flow and heat transfer from 3x3 arrays of circular air jets impinging on a concave surface with 4x4 arrays of effusion holes. The effect of spacing between the jet holes (in longitudinal and circumferential direction) are analyzed for two spent air exit configurations; (i) the flow exits through the effusion holes and along the edges of the concave surface, (ii) the flow exits only through the effusion holes. The pressure distribution is higher for the configuration with the air exiting only through effusion holes. Three peaks in local Nusselt number are identified and explained. The average Nusselt number increases by about 40% when c/D is increased from 4.05 to 10.8. The average Nusselt number for the exit configuration with all edges open is about 6% to 9% higher that that of the exit configuration with flow exit only through effusion holes.
Keywords: Gas turbine blade cooling, Impingement cooling, Effusion holes, CFD.
