Influence of Joule Heating and Nonlinear Thermal Radiation on the Electrical Conductivity of Second‐Grade Hybrid Nanofluid Flow Over a Stretching Cylinder

ABSTRACT This study examines the heat and mass transfer rates of an electrically conducting second‐grade hybrid nanofluid over a stretching cylinder, focusing on the effects of Joule heating, nonuniform heat sources, and nonlinear thermal radiation. The hybrid nanofluid, composed of silver nanoparticles and aluminum oxide in ethylene glycol, enhances thermal conductivity and heat transfer efficiency in second‐grade fluid flows, making it suitable for applications in heat exchangers, aerospace, renewable energy, and electronic cooling systems. The novelty of the research lies in the comparative analysis of flow characteristics, heat and mass transfer rates, and the influence of key phenomena such as nonlinear thermal radiation, Joule heating, nonuniform heat sources, chemical reactions, Soret number, thermophoresis, and Brownian motion on velocity and temperature profiles in ‐ethylene glycol and ‐ethylene glycol hybrid nanofluids. Using a similarity transformation, the governing partial differential equations are reduced to ordinary differential equations and solved numerically using MATLAB's bvp4c package. Results are validated against existing data, showing good agreement. Graphical representations of the influence of various physical parameters on velocity, temperature, and concentration profiles are presented, along with their effects on the skin friction coefficient, local Nusselt number, and Sherwood number. The findings show that curvature effects increase the boundary layer thickness for momentum, temperature, and concentration. Enhanced nonlinear thermal radiation improves heat transfer, particularly in high‐temperature conditions. Increased internal heat sources elevate fluid temperature, and higher nanoparticle concentrations improve heat transfer, resulting in a higher local Nusselt number. In conclusion, hybrid nanofluids in ethylene glycol outperform mono‐nanofluids in heat transfer efficiency, offering better performance for engineering applications. The findings apply to thermal management, electronic cooling, energy storage, manufacturing, biomedical treatments, and heat transfer optimization in power generation and aerospace engineering.