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International Journal of Rotating Machinery
Volume 4 (1998), Issue 3, Pages 175-188
http://dx.doi.org/10.1155/S1023621X98000153

Heat/Mass Transfer Distribution in a Rotating Two-Pass Square Channel Part I: Regional Heat Transfer, Smooth Channel

Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123, USA

Received 22 January 1997; Revised 13 February 1997

Copyright © 1998 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Naphthalene sublimation experiments have been conducted to examine the effect of rotation on the regional heat]mass transfer distribution for turbulent air flow in a rotating smooth two-pass square channel that has a 180 turn with sharp corners. The Reynolds number ranges from 5,500 to 14,500 and the rotation number goes up to 0.24. The test channel models the first two passes of serpentine internal cooling passages of gas turbine blades. Flow around a sharp turn causes larger heat]mass transfer increase in the turn and in the second pass than flow around a smooth turn. In the first pass with radially outward flow, rotation increases the heat]mass transfer on the trailing wall and decreases the heat/mass transfer on the leading wall. The reversed trend in the second pass with radially inward flow is evident only after four hydraulic diameters downstream of the turn exit. With rotation, there is an abrupt increase of the regional heat]mass transfer in the upstream portion of the turn on the leading wall. The regional heat]mass transfer on the trailing wall, however, increases along the streamwise direction in the turn, as in the stationary channel case. In the turn and immediately downstream of the turn, the shape of the heat/mass transfer distribution in a rotating channel is invariant over the range of rotation number studied. In a rotating channel, decreasing the Reynolds number increases the heat]mass transfer on the trailing wall and decreases that on the leading wall in the first pass, and increases the heat/mass transfer on both walls in the turn and immediately downstream of the turn.