Nonlinear mixed convective MHD Casson nanofluid flow through the spinning disk-cone device subject to impacts of gyrotactic microorganisms

The aim of current study is to examine the fluid flow by considering these two apparatuses combined in a single mathematical model. The effects of Brownian motion and thermophoresis also applied to the flow problem. The triple diffusive mixed convection Casson nanofluid flow has been considered through the space between cone and disk, using impacts of microorganisms and magnetic effects. This work is significant for enhancing heat and mass transfer control in rotating systems, with applications in bio-reactors, thermal engineering, polymer processing, and magnetically regulated non-Newtonian fluid technologies. The main equations have solved through Homotopy Analysis Method (HAM) in dimensionless form. In this study, fluid velocity augments with higher Grashof numbers but decreases with stronger magnetic and Casson effects. Temperature and concentration rise with thermophoresis, while Brownian motion enhances temperature but reduces mass diffusivity. Microorganism behavior weakens with higher bioconvection Lewis and Peclet numbers. The comparative analysis confirms agreement with existing literature. Moreover, as thermophoresis rises from 1.0 to 4.0, the heat transfer rate increases from 1.9057 to 2.3332, while Brownian motion causes a larger rise from 2.0057 to 3.4968. The percentage heat transfer rate varies from 2.30% to 12.27% for thermophoresis and from 3.20% to 14.46% for Brownian motion, indicating a stronger influence of Brownian motion.