mixed convection in an inclined channel with a discrete heat source.

Abstract

In this work, it is studied the mixed convection in an inclined rectangular channel.
A constant-flux heat source q of finite length is placed on the lower surface of the channel,
while its remaining part is adiabatic. The upper surface in contact with the fluid is kept at a
constant cold temperature Tc . At the inlet, it is imposed a constant velocity profile Uo as well
as a constant temperature To profile. The ranges performed have been as follows: 1≤Re≤500,
103≤Gr≤105, and 0°≤γ≤90°. The set of governing equations have been discretized and solved
using the Galerkin finite element method with the Penalty formulation in the pressure terms
and the Petrov-Galerkin perturbations in the convective terms. Two comparisons have been
performed to validate the computational code. It has been shown that the effect of the
inclination angle on the velocity and temperature distributions plays an important role on the
heat transfer for low Re and high Gr. For high Re, the effect of the orientation is negligible.
In general, it has also been discovered that an inclination angle around 60° and 75° provide
the most desirable work conditions when cooling is aimed. Some cases have presented the
reversed flow for low Re and high Gr. The flow reversal does not noticeably influence the
heat transfer coefficient on the module. The results shown here encourage the use of inclined
boards in cabinets, however some other geometrical aspects should be accounted.