Prediction of film cooling with a liquid coolant

A numerical method of analyzing film cooling with a liquid coolant is presented. The model assumes a turbulent boundary-layer flow for the hot gas stream and a Couette flow in the liquid coolant film. A marching procedure is employed for solution of the equations of mass, momentum, enthalpy and species conservation. Numerical results for an air-water system are presented. The effects of flow conditions on the film cooling mechanism are discussed. An increase in free-stream temperature, free-stream volocity, or coolant temperature causes reduction in the film-cooled length while an increase in coolant flow rate causes a proportionate increase in the film-cooled length. The comparison with the limited experimental data indicates that the observed trends are well predicted. However, more detailed data are required to validate and refine the prediction procedure, particularly with regard to the flow within and on surface of the coolant film.