Impact of nanoparticles’ aggregation in a convective flow of non-Newtonian nanofluid in a microchannel: irreversibility analysis

The main theme of this work is to investigate the influence of nanoparticle aggregation on the production of entropy and flow behaviours in a non-Newtonian nanoliquid in an upright microchannel, which comprises a porous material, buoyancy force, and nonlinear radiation. The Darcy-Forchheimer model has been taken into account. The Convective and Navier slip conditions were implemented at the boundary. The present scrutiny is connected with the aggregation of nanoparticles as represented by the Krieger-Dougherty and Maxwell-Bruggeman models, which address the formation of nanolayers. These models precisely represent viscosity and thermal conductivity. These models demonstrate how particle-filled materials conduct, including enhancing viscosity in suspensions to maximising conductivity within composites. Runge–Kutta–Fehlberg 4th–5th order approach has been employed to convert nonlinear differential equations into a system of ordinary differential equations utilising numerical research and adequate similarity factors. The results suggest that raised values of the material parameter lessen the flow field. The greater values of the Grashof number amplify the flow field. Enhancements in the temperature parameter have a notable effect on the thermal field. The Darcy number accelerates the entropy generation but mitigates the Bejan number. In the velocity distribution, entropy generation and temperature distribution, aggregating nanoparticles have a superior influence but have a less significant impact on the Bejan number.