Discrete Symmetry Analysis of Magnetohydrodynamic Convective Heat and Mass Transfer With Joule Heating in Cylindrical Porous Annular Microchannels

ABSTRACT Magnetohydrodynamic natural convection with coupled heat and mass transfer in a porous cylindrical annular microchannel is investigated in the presence of Joule heating. The inner and outer walls are maintained at different temperatures and concentrations, and velocity slip together with thermal and concentration jump conditions are imposed at the boundaries. Using a discrete symmetry analysis, the governing equations are converted to a self‐similar formulation describing the velocity, temperature, and concentration fields. The properties of key dimensionless parameters, together with the Grashof, Darcy, Knudsen, and Prandtl numbers, along with the magnetic field strength and Joule heating are examined. Increased buoyancy flesh out upward flow near the heated surface, while rarefaction effects reduce heat transfer through enhanced slip and temperature jump. Higher Darcy numbers intensify circulation within the annulus, particularly near the heated wall. Results are further validated with a neural‐network‐based approach, with agreement delayed through error and regression analyses.