Nanotechnology plays a vital role in heat transport due to its wide range of applications, significantly contributing to fields such as bioengineering, space exploration, biosensor research, semiconductor technology, and advanced electronics. The primary objective of this analysis is to examine the Casson fluid model for heat and mass transport between stretchy rotating disks, incorporating copper and titanium oxide nanoparticles into a sodium alginate base fluid. This analysis encompasses the effects of mixed convection, chemical reactions, convective conditions, activation energy, and thermal radiation. The bvp4c method is utilized to solve the resultant equations. Tables and Figures offer a clear depiction of the results. Understanding the thermal characteristics of hybrid fluids is crucial to energy systems, biological fluid dynamics, and engineering applications, where fluid flow and heat transfer are critical to system performance. At lower disk, the skin friction improved by 10.24% and 12.36% relative to the higher values of the magnetic and Cason parameters. The Schmidt number reduces mass-transfer gradients by 18.1%, whereas the activation energy decreases by 13.7%. The volume fractions of the selected nanoparticles vary from 0.02 to 0.04, and the heat transfer rates for the hybrid nanofluid increases 12% for the hybrid nanofluid as compared to the nanofluid. The hybrid nanofluid significantly affects flow distributions.

This study investigates the steady two-dimensional natural-convection flow and heat and mass transfer of a Cu–Al2O3/water thixotropic hybrid nanofluid over a vertically stretching sheet. The boundary-layer model incorporates magnetic effects, thermal radiation, heat generation, viscous dissipation, Joule heating, melting, chemical reaction, species diffusion, and motile microorganisms. By applying suitable similarity transformations, the governing partial differential equations are reduced to a system of nonlinear ordinary differential equations and solved numerically using MATLAB bvp4c. The results show that the magnetic field suppresses the velocity profile, whereas melting enhances it. Temperature increases with the heat source parameter but decreases with radiation and melting, while nanoparticle concentration declines with higher Schmidt number and chemical reaction. In addition, microorganism concentration decreases with the bioconvection Lewis number and increases with the Peclet number and microorganism concentration difference parameter.