Thermo-Magnetic Bioconvection Flow in A Semi-Trapezoidal Enclosure Filled With A Porous Medium Containing Oxytactic Micro-Organisms: Modelling Hybrid Magnetic Bio-Fuel Cells

Venkatadri, K; Rajarajeswari, P; Anwar Bég, O; Ramachandra Prasad, V; Leonard, H J; Kuharat, S

Abstract

Hybrid fuel cells are becoming increasingly popular in 21st century energy systems engineering. These systems combine multiple features including various geometries, electromagnetic fluids, bacteria (micro-organisms), thermo-solutal convection and porous media. Motivated by these developments in the present work we simulate the two-dimensional magnetohydrodynamic (MHD) natural triple convection flow in a semi-trapezoidal enclosure saturated with electrically conducting water containing oxytactic microorganisms and oxygen species. Darcy?s model is deployed for porous media drag effects. The primitive governing partial differential conservation equations for mass, momentum, energy, oxygen species and motile micro-organism species density are transformed using a vorticity-stream function formulation and non-dimensional variables into a nonlinear boundary value problem. A numerical solution is obtained using a finite difference method with incremental time steps. The mathematical model features a number of controlling parameters i.e. Prandtl number, Rayleigh number, Bioconvective Rayleigh number, Darcy parameter, Hartmann (magnetic body force) number, Lewis number, Péclet number, Oxygen diffusion ratio, fraction of consumption oxygen to diffusion of oxygen parameter. Transport characteristics (streamlines, isotherms, oxygen iso-concentration and motile micro-organism concentration) are computed for several of these parameters. Microorganisms? impact on the rate of heat transfer at the boundaries is found to be beneficial or destructive, depending on combination of other parameters in the simulations. Additionally, Nusselt number and oxygen species Sherwood number are computed at the hot vertical wall. The simulations are relevant to hybrid electromagnetic microbial fuel cells.

• Journal Article Type: Article
• Acceptance Date: Dec 19, 2024
• Online Publication Date: Feb 6, 2025
• Publication Date: Feb 6, 2025
• Deposit Date: Dec 19, 2024
• Publicly Available Date: Mar 7, 2025
• Journal: ASME Journal of Heat and Mass Transfer
• Print ISSN: 0022-1481
• Electronic ISSN: 1528-8943
• Publisher: American Society of Mechanical Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 147
• Issue: 1
• Pages: 1-25
• DOI: https://doi.org/10.1115/1.4067607
• Keywords: Vorticity-stream function, semi-trapezoidal enclosure, hybrid fuel cells; Oxytactic bacteria, bioconvection; magnetohydrodynamics (MHD), porous medium; oxygen consumption