C.P. No. 1303 PROCUREMENT EXECUTIVE, MINISTRY OF DEFENCE AERONAUTICAL RESEARCH COUNCIL CURRENT PAPERS Film Cooling Effectiveness from Rows of Holes under Simulated G& Turbine Conditions

SUMMARY Experiments are reported in which film cooling tests are carried out using coolent injection through rows of discrete holes. A shock tunnel is used to provide a transient mainstream flow at stagnation temperatures of 5m°K, 1000°K and 2COO'K. Wall heat transfer rates are measured with and without coolant injection using thin film gauges. Mainstream Mach numbers of 0.2, 0.5 and 0.7 are employed. Mach numbers, Reynolds numbers, gas-to-wall temperature ratios and flow temperatures typical of those found in gas turbines are thus within the range of the experimental conditions. The experimental results are analysed using the boundary layer film cooling model parameter G and the mass and momentum flux ratios as correlating parameters. The latter gives good correlation of the experimental data, and a useful comparison with data obtained by other workers under different conditions. The correlated data may also be used as a prediction for film cooling in any situation, and as a test for new theoretical models of the film cooling process.