关键词: 间隙射流；气膜冷却；端壁传热；数值模拟

Abstract: The effects of the slot purge flow on the cooling and heat transfer characteristics of a gas turbine blade end-wall were numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with [k-ω] turbulence model. Upon numerical validation with experimental data，the effects of mass flow ratio (MFR) and orientation of the slot purge flow on flow structure，film cooling effectiveness and heat transfer of the end-wall were numerically analyzed. The results indicate that the coolant is mainly restricted to fore part of the passage near the suction side due to the effect of secondary flow near the end-wall. When the MFR of the slot purge flow is less than 1%，the main flow can ingest into the slot to suppress the horseshoe vortex (HSV) and the thermal load near the throat of the passage is enhanced. While with the increment of the MFR，the area of region covered by coolant increased，and when the MFR is larger than 1%，the ingestion of the main flow disappeared and the slot purge flow would enhance the HSV and the end-wall heat transfer of the fore part of the passage. In addition，the thermal load of fore part of the end-wall is reduced owing to the slot purge flow. With the increment of the purge flow orientation，the separation vortex caused by the purge flow become intense to enhance the heat transfer of fore part of the end-wall，the film cooling effectiveness of the end-wall is also reduced，therefore the thermal load of the end-wall is enhanced. Especially at MFR=1.5%，when the ejection angle increased from 30° to 90°，the end-wall average film cooling effectiveness is reduced by 53.4%.

Key words: Slot purge flow；Film cooling；End-wall heat transfer；Numerical simulation