International Journal of Thermofluids (Jan 2025)
Investigation of natural convection heat transfer in MHD fluid within a hexagonal cavity with circular obstacles
Abstract
The present study investigates magnetohydrodynamic (MHD) heat and mass transfer in a innovative model comprising a hexagonal cavity with varying numbers of circular obstacles. Understanding these dynamics is crucial for optimizing thermal systems in various engineering applications. The insights gained from this research can lead to improved designs in areas such as heat exchangers and energy-efficient materials. The upper boundary is maintained at a high temperature, while the lower boundary is kept at a low temperature. The remaining boundaries are considered adiabatic. Some obstacles are heated, while others maintain a constant temperature. The finite element method is employed to solve the governing partial differential equations of the system. This research focuses on the impact of innovative geometry, variations in Rayleigh and Hartmann numbers on flow patterns, temperature distribution and concentration fields. The number of circular obstacles varies from 3 to 7, and in each scenario, there is a specific number of heated obstacles. The findings indicate that flow behavior, temperature distribution and concentration fields are generally symmetric along the X = 1 axis. The maximum flow rate within the isoconcentration contours occurs when the Rayleigh number is at its peak and the Hartmann number is at its minimum, with only the lower obstacles being heated. In this case, the average Nusselt number also reaches its maximum possible value, which is 3.606. An increase in the number of obstacles can enhance the heat transfer rate and the average Nusselt number by up to 14 %. Velocity fluctuations are maximized in scenarios with fewer obstacles, provided that only the lower obstacles are heated, compared to other configurations. The results align with previous studies and validate the effectiveness of this approach for various geometries.
