MHD mixed convection heat transfer of nanofluid containing oxytactic microorganisms inside a vertical annular porous cylinder

Abstract

For the first time, MHD mixed convection heat transfer of nanofluid containing oxytactic microorganisms is investigated inside a vertical annular porous cylinder. In this work, governing equations presented by Kuznetsov concerning the nanofluid flow inside porous media in the presence of microorganisms are initially extended for the case of cylindrical coordinates, and then numerically solved using the FVM approach. Having conducted a comparison with previous studies, the numerical method's accuracy has been successfully validated. The simulations are undertaken for different parameters including bioconvection Rayleigh number, Hartmann number, product of Reynolds and Prandtl numbers, bioconvection Peclet number, traditional and bioconvection Lewis numbers, aspect ratio, and radius ratio for the case of horizontal magnetic field exertion. Obtained results are presented in terms of graphical streamlines, isothermal lines, isoconcentration of nanoparticles, oxygen, and microorganisms as well as physical quantities of interest. Based on outcomes, it is concluded that microorganisms’ presence results in heat transfer attenuation, while an increase in the Hartmann number leads to the average Nusselt number amelioration.