Effect of wall heat flux distribution on laminar mixed convection in the entrance region of a horizontal rectangular duct
Abstract
Using a vectorized, finitedifference marching technique, the steadystate continuity, momentum, and energy equations are solved numerically to evaluate the effects of buoyancy on forced flow in a horizontal duct of aspect ratio A = 2. The thermal boundary conditions consist of eight distinct heating configurations for which selective duct surfaces are either adiabatic or uniformly heated, with identical conditions applied to the side walls. Heating from the sides and/or from above results in a single pair of counterrotating circulation cells. However, with heating from below, multiple pairs of counterrotating circulation cells develop. For each heating condition, the developing crossstream morphology of the buoyancydriven secondary flow is presented and used to interpret the longitudinal Nusselt number distribution.
 Publication:

Numerical Heat Transfer
 Pub Date:
 June 1988
 Bibcode:
 1988NumHT..13..427M
 Keywords:

 Convective Flow;
 Ducted Flow;
 Entrances;
 Finite Difference Theory;
 Heat Flux;
 Laminar Mixing;
 Wall Temperature;
 Aspect Ratio;
 Boundary Conditions;
 Boundary Value Problems;
 Buoyancy;
 Computational Fluid Dynamics;
 Morphology;
 Fluid Mechanics and Heat Transfer