Effects of slip conditions on forced convection and entropy generation in a circular channel occupied by a highly porous medium: Darcy extended Brinkman-Forchheimer model

Fully developed forced convection in a circular channel filled with a highly porous medium saturated with a rarefied gas and uniform heat flux at the wall is investigated in the slip-flow regime, using the Darcy extended Brinkman-Forchheimer momentum equation and the entropy generation due to heat transfer and fluid friction is formulated. The expressions for velocity and temperature distribution have been obtained in terms of an asymptotic expansion for large Darcy numbers, assuming both velocity and temperature slip at the wall. The effects of slip and other parameters are examined on the Nusselt number and entropy generation rate. For small slip at the wall, it is noted that the velocity slip increases the Nusselt number and the temperature slip decreases it. The entropy generation number attains high values in the region close to the channel wall and the velocity and temperature slip parameters reduce it.

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