Conjugate CFD analysis of three trailing-edge cooling configurations.

摘要

Conjugate CFD analyses based on the shear-stress-transport turbulence model were used to study three coolant-passage configurations for the trailing edge: Triple Impingement, Multi-Mesh, and Zig-Zag. All configurations were studied under engine-relevant conditions with a back pressure of 25 bar, external hot-gas temperature of 1,755 K, and coolant temperature at the trailing-edge inlet of 673 K. Parameters investigated include the heat-transfer coefficient on the hot-gas side of the trailing edge (2,000, 4,000, and 6,000 W/m2-K) and the pressure drop across the trailing edge (1 to 5 bar). Results are presented that show the flow induced by each configuration and how that flow affects the surface heat transfer and pressure drop. Also, the performance of the three configurations was compared.;For a given pressure drop, the Triple-Impingement configuration has the second lowest cooling flow rate because of the area constrictions in the flow passage to form the jets for jet impingement. Also, it has the lowest heat transfer rate despite the three jet impingements. The Multi-Mesh has the lowest cooling flow rate but the second highest heat-transfer rate because it has the highest surface area for heat transfer. The Zig-Zag has the highest cooling flow rate because there is little resistance in the flow passage and the highest heat-transfer rate because the cooling flow rate is so high. For a given cooling flow rate, the Multi-Mesh has the highest pressure loss and the highest heat-transfer rate because it has the highest surface area for friction and heat transfer. Zig-Zag has the lowest pressure loss and the second highest heat-transfer rate. Triple Impingement has higher pressure drop than Zig-Zag, but lower heat-transfer rate.;The Multi-Mesh configuration was found to achieve the highest cooling with the lowest cooling flow. For a given mass flow rate, the Multi-Mesh is about 5% better than Zig-Zag and 10% better than Triple Impingement in the amount of heat transferred. For a given pressure drop, the Zig-Zag configuration is the best design because it has the lowest pressure loss and so will yield the highest heat-transfer rate from the highest cooling flow rate unless high cooling flow is undesirable. For a given pressure drop, the Zig-Zag is about 30% better in heat transfer than Triple Impingement and the Multi-Mesh, but uses about 100% more cooling flow rate than does Multi-Mesh and Triple Impingement.