Turbulent heat transfer in an axisymmetric cavity with a small expansion ratio
Abstract
Local heat transfer measurements are reported for an axisymmetric cavity (an abrupt expansion followed by an abrupt contraction) with an expansion ratio of 1.25. The cavity wall was a heated thick aluminum cylinder which produced a nearly uniform wall temperature boundary condition. Heat flux measurements were made with a balancetype sensor flush mounted in the wall. The flow upstream of the cavity was nearly fully developed hydrodynamically. Reynolds numbers (based on the cavity diameter, D) of 11,800, 17,500, and 41,100 were used. Cavity lengths ranged from 4.25 to 10 step heights, (H = (Dd)/2). The maximum heat transfer occurred at the downstream corner of the shortest cavity studied (L/H of 4.25) where the local Nusselt number was approximately four times that of fully developed values. As expected, the heat transfer enhancement is much less for D/d = 1.25 than was observed in earlier studies with a cavity expansion ratio of 2.5 (where the maximum Nusselt number in the downstream corner region was 11 times the fully developed value).
 Publication:

In: Heat transfer in turbulent flow (A9354620 2434
 Pub Date:
 1990
 Bibcode:
 1990httf.rept...37B
 Keywords:

 Cavity Flow;
 Heat Transfer Coefficients;
 Turbulent Heat Transfer;
 Backward Facing Steps;
 Boundary Conditions;
 Convective Heat Transfer;
 Ducted Flow;
 Wall Temperature;
 Fluid Mechanics and Heat Transfer