Impingement cooling in rotating two-pass rectangular channels with ribbed walls Academic Article uri icon


  • Impingement cooling was studied on ribbed walls in rotating two-pass rectangular channels with a sharp 180-deg turn. Two rows of circular jets impinged opposite to the direction of rotation in one channel and in the same direction of rotation in the other channel. Square cross-sectioned ribs were periodically attached to the target walls and inclined at a 45-deg angle to the direction of spent airflow. Rib pitch to height and rib height to channel hydraulic diameter ratios were fixed at 10 and 0.125, respectively. After impingement, spent air (crossflow) traveled radially outward and inward in the first and the second impingement channel, respectively. Jet Reynolds numbers and rotation numbers varied from 4 103to 1 104and 0 to 0.0133, respectively. As the jet Reynolds number increased from 4 103to 1 104, the ratios of channel-averaged ribbed to smooth surface Nusselt numbers increased from 13 to 47% for the nonrotating test. For the rotating test, however, these ratios changed from 9 to 44% as the jet Reynolds number increased. Rotation-induced Coriolis and centrifugal forces altered the pressure distribution, but the jet velocity distribution was not significantly affected. However, those rotation-induced forces decreased the Nusselt number values up to 20% in the ribbed impingement channels.

published proceedings


author list (cited authors)

  • Akella, K. V., & Han, J. C.

complete list of authors

  • Akella, KV||Han, JC

publication date

  • July 1999