Entropy optimization and heat transfer in thin film flow of electromagnetic micropolar nanofluid using Maxwell–Bruggeman and Krieger–Dougherty models

Abstract

The investigation of heat transmission and entropy optimization in the thin-film flow of electromagnetic micropolar nanofluids has important implications in industrial lubrications, surgical instruments, and improved cooling systems. The Maxwell–Bruggeman and Krieger–Dougherty models are employed in this study to provide the nanoparticle aggregation/without aggregation attributes affecting the fluid characteristics. The Krieger-Dougherty model examines the modified viscosity caused by concentration of nanoparticle and accumulation, whereas the Maxwell-Bruggeman model assesses the effective thermal conductivity. The flow of micropolar nanofluid is assumed unsteady and laminar. The fundamental equations that govern the flow model are coupled into differential equations by applying appropriate similarity variables. The modeled problem have been solved through the implementation of the Runge–Kutta numerical technique. The findings elucidate that the micropolar effects such as Eringen parameter, spin gradient viscosity, and microrotation have a significant impact on the thin film thermodynamic behavior and flow kinetics. The electromagnetic fields alters the flow and thermal behavior significantly. It has been established that uniform dispersion of nanoparticles is crucial for optimizing thermal efficiency and reducing problems associated with aggregation and without aggregation. It is observed that when agglomeration is considered, the skin friction, entropy and Nusselt number increases significantly.

Keywords

• Microploar nanofluid
• Thin film
• Electric and magnetic fields
• Spin gradient viscosity
• The Maxwell–Bruggeman and Krieger–Dougherty models