Conjugate heat transfer of impingement cooling using conical nozzles with different schemes in a film-cooled blade leading-edge

Abstract

In this paper, the effect of utilizing different schemes of conical nozzles for impingement cooling is studied in the conjugate heat transfer in a film cooled blade leading-edge. Three conjugate cooling schemes (tangential, inline normal, staggered normal) are analyzed and compared at different nozzle Reynolds numbers from 5000 to 25,000 and different temperature ratios from 0.5 to 0.85. The SST k-Omega turbulence model and a very fine unstructured mesh are validated and applied for all simulations. Based on the design, the staggered normal scheme can protect the most critical zone of a blade subjected to the highest temperature (stagnation area) better than the other cooling schemes. The internal cooling performance increases with the nozzle Reynolds number under a fixed temperature ratio. At identical nozzle Reynolds number, the internal heat transfer increases with the temperature ratios from 0.5 to 0.675 while it decreases over 0.675 up to 0.85. The staggered normal scheme achieves an increase in overall Nusselt number by 5.26–9% and by 9.78–21.27% compared to the tangential scheme and inline normal scheme, respectively over the applied range of nozzle Reynolds number. The staggered normal scheme achieves the highest cooling performance internally and externally among the other cooling schemes.