Effects of fins on magnetohydrodynamic conjugate natural convection in a nanofluid-saturated porous inclined enclosure

摘要

The magnetohydrodynamic conjugate heat transfer characteristics of a ferrofluid-filled porous inclined enclosure heated differentially have been investigated numerically in the present work. Two-conducting fins are attached to the hot wall of the cavity and the horizontal walls are insulated. The ranges of dimensionless flow controlling parameters are taken as: modified Rayleigh number (10 ≤ Ra* ≤ 10~4), length of the fins (a = 0.3, 0.5, 0.7), gap between the two fins (b = 0.3, 0.5, 0.7), and Darcy number (10~5 ≤ Da ≤ 10~(-2)), volume fractions of nano-particles (0 ≤ ≤ ≤ 0.06), Hartmann number (0 ≤ Ha ≤ 50), and the cavity inclination angles (0 ≤ γ ≤ 90°). The finite element method has been used to solve the governing equations and the present code have been validated with previously published work. The results show that the average Nusselt number increases by increasing the modified Rayleigh number, Darcy number, fins length while it decreases by increasing the Hartmann number. For any range of modified Rayleigh numbers, the highest fin length and the widest gap between the fins can be a superior heating strategy. At a fixed fin length, the lower gap between the fins is of a better choice to boost heat transfer when the cavity inclination angle increases up to 30°.