Energy-saving method of heat transfer enhancement during magneto-thermal convection in typical thermal cavities adopting aspiration

Abstract

Abstract: In the area of energy-efficient system development, the paper presents a novel approach aiming to enhance heat transfer during magnetohydrodynamic convection in thermal cavities by implementing a technique of free aspiration. Through two small openings, the proposed free aspiration naturally allows a partial admission of fresh fluid into the cavity (from its immediate surroundings) and eventually vents the admitted fluid out the cavity without any pumping device. The efficacy of aspiration technique, whether viable under different problem conditions, is worked out for various classical configurations like differential heating, corner heating, and split heating. The mathematical formulations are derived by applying the Maxwell model (for magnetic fields) and the Brinkman–Forchheimer–Darcy model (for porous media). The evolved complex and coupled mathematical equations (involving the laws of continuity, momentum, and energy) are solved by an indigenously developed computing code. The study is conducted exhaustively addressing both a porous domain and a clear domain in terms of pertinent design parameters—Hartmann number (Ha = 0–100), porosity (ε = 0.1–1), Darcy number (Da = 10−7–10−3), Darcy–Rayleigh number (Ram = 0.1–103), and Rayleigh number (Ra = 103–106). The obtained results conclusively bring out an improved trend of heat transfer for all three thermal cavities due to the aspiration (without any pumping means). Even with the existence of flow-hindering porous substance and magnetic force, the augmentation in heat transfer could be as high as seven times more compared to their respective non-aspiration cases. Graphic abstract: [Figure not available: see fulltext.]