COMPARISON STUDY OF DIFFERENT VISCOUS DISSIPATION EFFECTS ON FORCED CONVECTION HEAT TRANSFER IN A POWER LAW FLUID SATURATED POROUS MEDIUM

Based on the Darcy-Brinkman-Forchheimer flow model, this study analyzed and compared the viscous dissipation effects during the process of a forced and fully developed convection heat transfer in a flat channel. The channel was filled with a kind of porous medium saturated by a power law fluid. Three different terms were considered to analyze the viscous dissipation, namely, the Darcy term, Al-Hadharami term, and Forchheimer term. In this comparative study, we have taken the Forchhemier term into consideration since some researchers thought it might have an indirect effect on the dissipation function, although others argued. The dimensionless calculation expressions of the axial velocity distribution and temperature distribution were deduced, and solved numerically by employing the classical Runge-Kutta fourth-order scheme subject to uniform heat flux. Variations of the dimensionless temperature are examined and discussed, which is the function of the Brinkman number, Darcy number, Forchheimer inertial parameter, and power law index. It is found that the temperature profiles were quite close to the velocity profiles and obviously influenced by the relative magnitude of these dimensionless parameters. The results also indicated that the rate of heat transfer was significantly affected by different viscous dissipation terms.