Heat transfer enhancement of diffusion slot jet on the staggered pin-fins array channel flow

Pin-fins array plays an important role in gas turbine blade trailing edge cooling by enhancing both heat transfer and structural strength. Previous studies have shown that jet impingement effect can further improve pin-fins array channel cooling performance; but most investigations focused on perforated plate jets positioned upstream of the pin-fins array. The present study proposes a, diffusion slot impingement jets integrated with staggered pin-fins array are numerically analyzed to reveal the underlying flow and thermal behaviors. The effects of slot configuration, slot-width-to-pin-diameter ratio ( W slot /d = 1.5 and 2), and deviation angle are examined within a Reynolds number range of 5000–50,000. The results indicate that the diffusion-slot jet increases the Nusselt number around the first two rows of pin fins to approximately 2-3 times that of the baseline case. At Re Dh = 30,000, the staggered diffusion-slot configuration with W sl ot /d = 1.5 and θ = 30° (Case 8) achieves the highest averaged Nusselt number and provides the strongest downstream heat transfer enhancement. In contrast, the non-deviated rectangular slot (Case 2) achieves the highest thermal-hydraulic performance factor among the representative configurations because of its lower friction penalty. Overall, the diffusion-slot configurations increase the averaged Nusselt number by approximately 14%-50% relative to the baseline case. The TPF of the heat transfer-optimal Case 8 improves by approximately 10%-25%, whereas the TPF -optimal Case 2 achieves an improvement of approximately 26%-50% over the investigated Reynolds-number range compared with the baseline case.