Authors: Maziar Dehghan
Publish Date: 2015/09/04
Volume: 110, Issue: 3, Pages: 461-482
Abstract
The forced convective thermal response of channels partially filled with porous materials is analytically studied It is assumed that internal heat generations exist within both the fluid and solid phases Effects of internal heat generations within the both phases on the thermal response of the channel resulting in the heat flux bifurcation phenomenon are discussed for the first time No study previously analyzed the heat flux bifurcation in a nonDarcian porous medium with heatgenerating porous materials To obtain the most general thermohydraulic behavior the Darcy–Brinkman equation of motion and the twoenergy model local thermal nonequilibrium along with two practical thermal boundary conditions models A and B are used Consequently two possible thermal responses are obtained for each phase Results show that insertion of a porous material inside a heatconvecting fluid leads to have a more uniform temperature distribution which translates to a lower thermal resistance and an enhanced heat transfer Furthermore it is seen that increasing the porous material thickness increases the ratio of heat transferred by the porous medium compared to that convected by the clear fluid flow In addition the internal heat generations drastically change the temperature distribution Finally it is shown that the internal heat generations can inverse the heat flux direction at the porous–fluid interface the heat flux bifurcation phenomenon Criteria for the heat flux bifurcation for a partially porousfilled channel are presented under the Darcy’s law of motion
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