Numerical Study on the Impact of Joule Heating and Arrhenius Activation Energy on Coupled Heat and Mass Transfer in Nanofluid Flow Over a Heated Needle

The consideration of a bullet‐like body is significant because streamlined geometries are widely encountered in aerospace, aeronautical, automotive, underwater, and high‐speed engineering applications where the interaction between fluid flow and a curved solid surface strongly influences aerodynamic performance and thermal transport. Blood, crystals, polymer solutions, colloidal suspensions, and lubricants with microstructures and additives are examples of fluids where both microscopic and macroscopic motions are crucial. In such fluids, microrotation, couple stress, and microinertia effects are exhibited, and the flows of such fluids require an additional conservation law, the law of conservation of angular momentum. Owing to the engineering applications, thermal transport in micropolar fluids containing nanoparticles is modeled under boundary flow of incompressible and constant thermal properties under pressure and temperature, and the governing problems are solved numerically using the BVP4C solver to analyze the effects of Joule heating and thermal radiation. The Nusselt number and the skin friction coefficient are plotted against changes in the parameters. The temperature and velocity fields are examined to analyze their trends. In line with realistic reactive transport phenomena, increasing the Arrhenius activation energy increases species diffusion by lowering concentration gradients. Hence, in the boundary layer region, the concentration increases and the Sherwood number decreases when the activation energy increases. Joule heating and the space‐dependent heat source all have a significant impact on thermal distribution. Both the fluid temperature and the thickness of the thermal boundary layer are greatly increased by an increase in the parameters related to Joule heating and the heat source. Higher heat generation, however, lowers the local Nusselt number, signifying a slower rate of surface heat transfer (the Nusselt number). In line with realistic reactive transport phenomena, increasing the Arrhenius activation energy increases species diffusion by lowering concentration gradients. Thus, in the boundary layer region, the concentration increases, which leads to a decrease in the Sherwood. The Lorentz force is an opposing force that decelerates the flow and causes an increase in the skin friction coefficient. Owing to the opposing effects of the Lorentz force, the momentum boundary layer thickness increases as the intensity of the magnetic field is increased. Moreover, in respect of heat, tri‐nanofluid performs better thermally than di‐ and mono‐nanofluids.