Numerical simulation of thermo-magnetic convection and entropy production in a ferrofluid filled square chamber with effects of heat generating solid body

[Display omitted] •MHD natural convection and entropy generation in a ferrofluid filled cavity with a heat generating solid block is analyzed.•Control volume method on a uniform staggered grid with simple algorithm is used to solve the control equations.•Magnetic Lorentz force effects repress the convective flow and heat transfer rate.•Entropy production minimization is achieved by means of irreversibility ratio.•Aspect ratios of the solid body and MHD effect are good controlling parameter for both heat transfer and entropy production.•The current model is often encountered in microelectronics, solar collectors and cooling of electronic contrivances. Thermo-magnetic convection and entropy production are the most widely used subjects of study in the field of an effective design tools for cooling electronic devices. The present work focuses on numerical simulation of thermo-magnetic convection cooling of the heat-generating solid block placed in a magnetite suspended nanoliquid filled chamber. The surfaces of the horizontal borders of the chamber are thermally insulated whilst the vertical borders are cooled at a constant temperature. The finite volume technique with a simple algorithm on a uniform staggered grid is employed to transform the governing non-linear PDE into a set of discretized equations. The liquid motion, thermal transmission, and entropy production are discussed for various pertinent parameters such as solid volume fractions of the nano-additive (φ=0.01−0.04), aspect ratio of a heat-generating solid body (As=0.25−4), thermal conductivity ratio of the heat generating body (0.1≤k*≤5.0), Hartmann number (Ha=0−50) and irreversibility ratio (Ω=0.001−0.1). Isolines of temperature, stream function, normalized entropy along with profiles of mean Nusselt number and mean entropy production outcomes are demonstrated graphically. The results showed that reduction in aspect ratio increases the cooling efficiency due to the hindrance-free effect and produces a high heat transfer rate. Minimum entropy production occurs at low thermal conductivity ratio (k*=0.1). The thermal performance criterion also justifies that the least aspect ratio manifests better thermal performance.