Analysis of thermal performance and irreversibility of double-diffusive buoyancy-driven nano-suspension subject to local thermal non-equilibrium model

Abstract

In fact, local thermal equilibrium (LTE) would be unsuitable when it comes to nuclear reactors, electronic equipment, space devices, geothermal engineering, and high-conductivity foams, due to prominent temperature discrepancy between the two constituents (solid and nanofluid) in porous material. Local thermal non-equilibrium (LTNE) situation may be considered in above real world applications. In view of above relevance, the effects of LTNE model on double-diffusive natural convection (DDNC) within a fluid-saturated porous container loaded with the TiO2-H2O nanofluid and emplacing four cooling and hot channels in Forchheimer-Brinkman-extended Darcy medium have been investigated in the present study. The momentum, heat and mass equations are solved by finite element method. Irreversibility in the two constituents (nanofluid and solid) of the porous structure has been analyzed. The significant outcomes are that fluid circulations enhance due to rise in porosity of the medium. Fluid friction entropy EnFF,T ameliorates significantly by 1514.16 % and 872.97 % with increase in Rayleigh number and porosity of the medium. It is clear that Nuloc,nf,Nuave,nf, Nuloc,s&Nuave,s enhance significantly with rise of buoyancy and thermal conductivity ratio, interstitial solid/fluid heat transfer coefficient.

Keywords

• LTNE
• DDNC
• Irreversibility
• Nanofluid
• Interstitial solid/fluid heat transfer coefficient