TRANSITION TO TURBULENT-FLOW IN CURVED AND STRAIGHT CHANNELS WITH HEAL TRANSFER AT HIGH DEAN NUMBERS

Heat transfer in a channel with a straight portion followed by a porti on with mild curvature, an aspect ratio of 40, and 0.979 radius ratio is studied at Dean numbers from 700-1100. The effects of curvature, st reamwise development, Dean number, and flow tripping are illustrated b y the data. Important Nusselt number increases occur due to laminar-to -turbulent transitional phenomena in the straight portion of the chann el. Downstream of these increases, how approaches fully turbulent beha vior, and Nusselt numbers collect into families of curves which show w eak dependence on Dean number and strong dependence on normalized stre amwise distance. (C) 1998 Elsevier Science Ltd. All rights reserved.