Effect of L-shaped heat source and magnetic field on heat transfer and irreversibilities in nanofluid-filled oblique complex enclosure

Abstract

In this paper, the natural convection heat transfer of water/alumina nanofluid is investigated in a closed square cavity. An oblique magnetic field is applied on the cavity of angle $$\gamma$$ γ . There is also radiation heat transfer in the cavity. The cavity includes a high-temperature source of L-shape. A low-temperature source as a quadrant of a circle is placed at the corner of the cavity. All other walls are well insulated. The novelty of this work is a low-temperature obstacle embedded in the cavity. Simulations are conducted with a Fortran code based on the control volume method and simple algorithm. Entropy generation rate, Bejan number, and heat transfer are studied by changing different parameters. Results indicate that the highest rates of heat transfer and entropy generation have occurred for the perpendicular magnetic field at high values of the Rayleigh number. At these Rayleigh numbers, the minimum value of the Bejan number is obtained for 15° magnetic field. The magnetic field variation can lead to a change up to 53% in Nusselt number and up to 34% in generated entropy. In a weak magnetic field, the involvement of the radiation heat transfer mechanism leads to an increase in the heat transfer rate so that the Nusselt number can be increased by ten units considering the radiation heat transfer when there is no magnetic field. The maximum heat transfer rate occurs in the horizontal cavity and the minimum value in the cavity of 60° angle. For water, these values are 10.75 and 9.98 for 0 and 60 angles, respectively. Moreover, a weak magnetic field increases the heat transfer rate in the absence of the radiation mechanism, while it is reduced by considering a strong magnetic field.

Natural Convection Heat Transfer and Entropy Generation Analysis in Saltbox Roof under Summer Conditions

“…Alnaqi et al (2020) studied the natural convection and entropy generation in a cubical cavity and observed that total entropy fairly increased with an increase in Rayleigh number until a certain value, when it then rose significantly. Similar studies have also been carried out (Bondareva et al, 2017;Hussein et al, 2016;Yang et al, 2021;Zhang et al, 2021;Ishak et al, 2021;Oztop et al, 2017). Natural convection in Saltbox roof is analysed for a hot climate region, with the aim of helping designers improve the thermal comfort in such conditions.…”

Darcy-Forchheimer Flow of Water Conveying Multi-Walled Carbon Nanoparticles through a Vertical Cleveland Z-Staggered Cavity Subject to Entropy Generation

“…In a study on Casson fluid flow due to double-diffusive natural convection in staggered cavities, Hussain et al [ 14 ] discovered that when entropy creation is significant, the overall entropy output increases with increasing the Casson number. Zhang et al [ 15 ] explored a cavity with a high-temperature L-shaped source using Fortran code based on the control volume approach and a simple algorithm. The smallest value of the Bejan number was found at a magnetic field of 15°.…”

Comparative analysis of entropy generation and heat transfer in a tilted partially heated square enclosure using the finite difference method

“…Several examinations have taken into account the influence of an external magnetic field in recent times (Mansour et al. , 2019; Moolya and Satheesh, 2020; Zhang et al. , 2021; El-Shorbagy et al.…”

“…Iftikhar et al (2023) examined how MHD affects convective flow and heat transfer characteristics in a U-shaped cavity containing both water and ferrofluid. Several examinations have taken into account the influence of an external magnetic field in recent times (Mansour et al, 2019; Entropy generation Moolya and Satheesh, 2020;Zhang et al, 2021;El-Shorbagy et al, 2021;Algehyne et al, 2023).…”