Thermal and mass transfer analysis of Casson-Maxwell hybrid nanofluids through an unsteady horizontal cylinder with variable thermal conductivity and Arrhenius activation energy

Abstract

In this study, the flow, thermal transfer, and mass transport of Casson-Maxwell hybrid nanofluids are explored. The governing PDEs are converted into nonlinear ODEs using similarity transformations and then solved using MATLAB's Bvp4c scheme. Various non-dimensional parameters’ influences on fluid behaviour and transport are investigated. Results indicate that higher curvature parameter values boost velocity, temperature, and concentration fields, enhancing mass and heat transfer as well as fluid motion. The unsteadiness parameter affects velocity profiles and heat/mass transfer processes. Thermal and mass relaxation times, alongside parameters like thermophoresis, Brownian motion, variable thermal conductivity, Arrhenius activation energy, chemical reaction, and temperature difference ratio, significantly shape temperature and concentration profiles and optimise heat and mass transfer rates. Additionally, combining the Casson and Maxwell hybrid nanofluid models shows marked changes in skin friction performance: absolute skin friction rises by 30%, while heat transmission increases by almost 11% compared to the Casson-Maxwell nanofluid model.