Entropy generation in a third-grade hydromagnetic fluid of generalised Arrhenius two-step exothermic reaction with convective cooling

The study considers laminar, boundary layer flow of hydromagnetic exothermic third-grade chemical reacting fluid with variable viscosity in a permeable medium. In the presence of bimolecular kinetics and Arrhenius activation energy, the viscoelastic fluid undergoes two-step exothermic reaction with thermal radiation and asymmetric convective cooling. The non-Newtonian fluid flow through a channel is influenced by thermal buoyancy force. The convective heat exchange between the channel surface and the ambient temperature obeys Newton’s law of cooling. The weighted residual technique is used to analytically compute the numerical values for the dimensionless nonlinear governing equations. The solutions are used to determine the velocity, temperature, Bejan number and rate of entropy production. It is observed that an enhanced thermodynamic equilibrium reduced the entropy generation. Also, the fluid viscoelastic material diminished the flow in the occurrence of two-step.