Impact of internal heat generation/absorption on MHD conjugate flow of aqueous‑MWCNT nanofluid in a porous annulus

Abstract

This study deals with a numerical investigation of conjugate heat transfer phenomena in a porous enclosure subjected to magnetic field with internal heat generation/absorption. The physical domain of the numerical model encompasses a vertical annulus with a thick inner cylinder wall, where the porous annular region is saturated with an aqueous-MWCNT nanofluid. In this model, the momentum equation includes the non-Darcy viscous terms and additional body term to accurately represent the influence of porous media and magnetic fields on the flow behavior. To estimate conjugate heat transfer phenomena, the energy conservation equations for the solid wall and the fluid-saturated porous region are solved simultaneously. The finite difference technique is used to solve the non-dimensionalized governing equations, and validated against existing studies. Using the proposed model, a series of numerical calculations is performed for various parameters including Hartmann number , Darcy number , thermal conductivity ratio , dimensionless solid wall thickness , nanoparticle concentration , and dimensionless internal heat generation/absorption rate . The numerical results reveal that a significant improvement in thermal transport can be achieved by increasing either Da or Kr: An increment in Da from to , for example, results in 95.6% increase in the flow circulation rate. Either a decrease in Q or an increase in also contributes to enhancing the heat dissipation rate. For instance, there is a 16.6% reduction in heat dissipation rate for internal heat generation case compared to internal heat absorption case. On the other hand, an increase in either Ha or results in a suppression in flow and heat transport. Among the considered range of parameters, greater heat dissipation could be obtained for Da = , Kr = 10, , and Ha . These findings can expand our understanding of natural circulation and heat transfer within the fluid-filled enclosures and serve as building block for efficient thermal design guidelines in diverse applications.

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