Heat transfer enhancement in gas turbine blade trailing-edge internal cooling channel with high aspect ratio twisted fins arranged on sidewalls

High-efficiency cooling is crucial for improving the thermal efficiency of gas turbines. To fully utilize the secondary flow for heat transfer enhancement on the heated wall, a high aspect ratio low drag twisted blade-like fin, arranged on the sidewalls of the channel, is proposed in this study. The effects of the number of twists, twist angle, and fin arrangement on flow and heat transfer performance, as well as its mechanism, are investigated at Reynolds number (Re) from 14000 to 36000. The relative Nusselt number (Nu/Nu₀) reaches a maximum value of 3.00, and the comprehensive thermal performance (TP) is higher than 1 in all cases, with a maximum value of 1.72. Compared to the circular pin-fin, the optimal configuration of the twisted fin, demonstrates a 15 %–17 % increase in heat transfer performance, a 76 %–79 % reduction in flow drag, and a 86 %–96 % improvement in comprehensive thermal performance. The number of twists has a minor effect on heat transfer performance but significantly affects flow drag. The twist angle has a crucial impact on both heat transfer performance and flow drag, while the effect of fin arrangement is relatively smaller. In the sidewall arrangement, the secondary flow in the endwall direction is significantly greater than that in the sidewall direction, which is very favorable to the endwall heat transfer performance, and high heat transfer performance enhancement can be obtained with small flow drag.