Numerical study of heat-flux boundary in nanofluid-filled cavity

Abstract

The effects of heat-flux boundary on a two-dimensional square enclosure using copper–water nanofluid governed by natural convection have been studied. The Maxwell model was employed to investigate the effect of nanofluid inside the enclosure for different values of particle concentration. The governing equations were modeled using the finite-difference technique. The pertinent parameters of the study are Grashof numbers (5 × 104–5 × 106) based on heat-flux value (1–100 KW/m2), nanoparticle concentration (ϕ ≤ 8%) and inclination angle. Comparisons with previously published work on the basis of special cases were made and found to be in excellent agreement. The results show that change in the wall on which heat-flux boundary condition was considered significantly affected the flow patterns and heat transfer. Counter-rolling rolls of stream-lines and conduction-type isotherms were found when the heat flux was at the top wall. Addition of nanoparticle in the base fluid decreases the Nusselt number. The effect of nanofluid particle concentration increment is more pronounced at high values of Grashof number.