Performance Improvement of Trailing Edge Internal Cooling with Drop-Shaped Pin Fin Array

Abstract

In this paper, flow and heat transfer in a blade trailing edge cooling channel with differently shaped pin fin arrays were investigated numerically in a Reynolds number range from 10,000 to 50,000. A novel internal structure, a drop-shaped pin fin array with varied chord-lengths, is proposed in order to improve the thermal performance of the cooling channel. The numerical method was validated by the experimental data in the open literature. The steady numerical simulation was carried out in conjunction with the k-ω shear stress transfer (SST) turbulence model for the periodic cooling channel. A hexahedral mesh with high quality was adopted for domain discretization to obtain high-precision results. To investigate the mechanism of pressure loss and heat-transfer enhancement, the velocity fields at different locations were studied in detail, and the friction factor and Nusselt number were obtained and analyzed comprehensively. It was found that the friction factor ratio (f/f0) of the channel with drop-shaped pin fins is 32.5% lower than that with circular pin fins, and the thermal performance factor (TPF) is 7.6% higher. Compared with circular pin fins, the drop-shaped pin fins can significantly improve the overall thermal performance at relatively high Reynolds numbers. The research results show that the newly proposed cooling scheme has great potential in application in a real modern advanced gas turbine blade.