Magnetohydrodynamic natural convection of a reacting hybrid nanofluid in a porous wavy‐walled cavity

Abstract

Natural convection of a chemically reacting hybrid nanofluid in a closed wavy‐walled cavity embedded in a porous medium is investigated with an inclined magnetic field. The left wall of the cavity is assumed to be wavy and the walls are maintained at the surrounding temperature. Governing equations are transformed into dimensionless equations which are solved using the finite difference method. To validate the solving procedure, a grid sensitivity test and a comparison with published results have been carried out. Streamlines, isotherms, and isolines of concentration are discussed for varying Rayleigh number (Ra), Hartmann number (Ha), Frank‐Kamenetskii number (Fk), Darcy number (Da), combined buoyancy parameter (N), and nanoparticle volume fractions (φ1 and φ2). Streamlines show clockwise and anticlockwise vortices irrespective of the parameters. For Fk = 0.5, the maximum stream function (ψmax) is 0.64 and the maximum temperature (θmax) is 0.20 while for Fk = 2, ψmax and θmax are 4.08 and 1.36, respectively. Besides, for Ha = 0, ψmax and θmax are 1.61 and 0.379, however, for Ha = 100, ψmax is 0.90 and θmax is 0.377. Maximum temperature is increased with an increase in Ra, N, and Fk, whereas it is decreased with the augmentation of Ha and Da. Isolines of concentration show reverse characteristics of temperature. An increase in Ra, Da, and Fk enhances the intensity of streamlines but the opposite is observed for higher Ha, N and volume fractions. Moreover, the eyes of the vortices are distorted in the direction of the magnetic field.