LOCAL HEAT-TRANSFER IN ROTATING SMOOTH AND RIBBED 2-PASS SQUARE CHANNELS WITH 3 CHANNEL ORIENTATIONS

This paper presents experimental heat transfer results in a two-pass s quare channel with smooth and ribbed surfaces. The ribs are placed in a staggered half-V fashion with the rotation orthogonal to the channel axis. The channel orientation varies with respect to the rotation pla ne. A change in the channel orientation about the rotating frame cause s a change in the secondary flow structure and associated pow and turb ulence distribution. Consequently, the hear transfer coefficient from the individual surfaces of the two-pass square channel changes. The ef fects of rotation number on local Nusselt number ratio distributions a re presented. Heat transfer coefficients with ribbed surfaces show dif ferent characteristics in rotation number dependency from those with s mooth surfaces. Results show that staggered half-V ribs mostly have hi gher heat transfer coefficients than those with 90 and 60 deg continuo us ribs.