COMPARISON OF CALCULATED AND MEASURED HEAT-TRANSFER COEFFICIENTS FOR TRANSONIC AND SUPERSONIC BOUNDARY-LAYER FLOWS

The present study compares measured and computed heat transfer coeffic ients for high-speed boundary layer nozzle flows under engine Reynolds number conditions (U-infinity = 230 divided by 880 m/s, Re = 0.37 di vided by 1.07 x 10(6)). Experimental data have been obtained by heat t ransfer measurements in a two-dimensional, nonsymmetric, convergent-di vergent nozzle. The nozzle wall is convectively cooled using water pas sages. The coolant heat transfer data and nozzle surface temperatures are used as boundary conditions for a three-dimensional finite-element code, which is employed to calculate the temperature distribution ins ide the nozzle wall. Heat transfer coefficients along the hot gas nozz le wall are derived from the temperature gradients normal to the surfa ce. The results are compared with numerical heat transfer predictions using the low-Reynolds-number k-epsilon turbulence model by Lam and Br emhorst. Influence of compressibility in the transport equations for t he turbulence properties is taken into account by using the local aver aged density. The results confirm that this simplification leads to go od results for transonic and low supersonic flows