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

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.