Comparative aerothermal performance of two rotating triple-pass channels with lateral flow exit roughened by skewed ribs and pin-fins with and without internal effusion

• Published in: International journal of thermal sciences 2023-06, Vol.188, p.108243, Article 108243
• Main Authors: Chang, Shyy Woei, Hsu, Cheng Jui
• Format: Article
• Language: English
• Subjects: Internal effusion; Rotating trailing edge cooling
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2023.108243

The experimental study examines the aerothermal performances of two rotating triple-pass serpentine channels with the identical smooth inlet pass and downstream ribbed and pin-fin passes of different channel aspect ratios with and without the near-wall bypass flows between the ribbed and pin-fin passes. Relative to the static-channel references, the continuously elevated and the initially decreased and then increased trends of Nusselt number variations respectively propagate on the unstable and stable endwalls of each rotating pass when the rotation number increases. The buoyancy effect elevates local Nusselt number without altering the pattern of heat transfer distribution on each rotating endwall. In the rotating pin-in channels with (without) effusion, the combined Coriolis-force and buoyancy effects modify the average Nusselt numbers on their leading and trailing endwalls to 1–1.36 (0.99–1.41), and 1.04–1.54 (1.02–1.61) times the static-channel levels. The aerothermal performance indices of the pin-fin pass are elevated by effusion to 2.66–2.08 and 2.08–2.66 times non-effusion values at the static and rotating conditions. •Near-wall internal effusion improves aerothermal performance of the pin-fin channel in static/ rotating condition.•Endwall average Nu and f of static pin-fin channel with effusion are 1.44–1.68 and 0.25–0.33 times non-effusion values.•Average Nu on rotating ribbed and pin-fin endwalls with (without) effusion are 2.52–4.07 (2.15–3.88) and 5.22–11.88 (3.58–8.2) times Dittus-Boelter levels.•At the worst hot-spot cooling scenarios, rotating-to-static Nu ratios on smooth, ribbed and pin-fin endwalls are 0.69 (0.68), 0.69 (0.66), and 0.63 (0.61) with (without) effusion.