Investigation of velocity profiles for effusion cooling of a combustor liner

Effusion cooling of combustor liners for gas turbine engines is quite challenging and necessary to prevent thermal distress of the combustor liner walls. The flow and thermal patterns in the cooling layer are affected by the closely spaced film-cooling holes. It is important to fully document how the film layer behaves with a full-coverage cooling scheme to gain an understanding into surface cooling phenomena. This paper discusses experimental results from a combustor simulator tested in a low-speed wind tunnel. Engine representative, non-dimensional coolant flows were tested for a full-coverage effusion plate. Laser Doppler velocimetry was used to measure the flow characteristics of the cooling layer. These experiments indicate that the full-coverage film cooling flow has unique and scaleable velocity profiles that result from the closely spaced effusion holes. A parametric study of the cooling flow behavior illustrates the complex nature of the film flow and how it affects cooling performance.