IMPINGEMENT COOLING IN ROTATING 2-PASS RECTANGULAR CHANNELS

Impingement cooling was studied on smooth target walls in rotating two -pass rectangular channels with a sharp 180-deg turn. Jets impinged op posite to the direction of rotation in one channel, and in the same di rection of rotation in the other channel, Spent air moved in the radia lly outward direction in the first impingement channel and radially in ward in the second impingement channel. Jet Reynolds numbers and rotat ion numbers varied from 4 x 10(3) to 1 x 10(4) and 0 to 0.0133, respec tively. Rotation changed the pressure level and distribution, but did not significantly alter the jet velocity distribution in the two-pass impingement channel. However, rotation-induced Coriolis and centrifuga l forces decreased the Nusselt number values 20 and 25% in the impinge ment channels and turn region, respectively. Nusselt number values in the turn region were 60% higher when compared with those in the imping ement channels for higher jet-now rates and over the range of rotation speeds tested.