ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Role of base fluids in heat and mass transport of TiO₂ nanofluids under annular mixed convection

D. Ravinder, T. Kiran Kumar, P. Chandrakala, and Amitosh Tiwari

Jyothishmathi Institute of Technology and Science, Karimanagar, India

E-mail: ravinderdasari76@gmail.com

Received: 20 November 2025  Accepted: 31 December 2025

Abstract:

This study investigates the mixed convection flow, heat, and mass transfer characteristics of TiO₂ nanofluids within a vertically stretching cylindrical annulus, a configuration relevant to energy, cooling, and chemical processing systems. The objective is to assess how the choice of base fluid influences nanofluid performance when multiple physical mechanisms act simultaneously. The analysis incorporates the combined effects of variable viscosity and electrical conductivity, Arrhenius activation energy, viscous dissipation, homogeneous chemical reactions, magnetic field forces, and Darcy–Forchheimer porous-medium resistance for three base fluids: ethylene glycol, engine oil, and kerosene. The governing equations are solved numerically using the finite element method. The results reveal that magnetic forces, Forchheimer drag, viscous dissipation, and increased nanoparticle volume fraction suppress axial velocity, whereas buoyancy and permeability enhance it. Enhanced electrical conductivity improves thermal transport, while higher viscosity, Prandtl number, and radiative cooling reduce heat transfer. Among the nanofluids examined, kerosene-TiO₂ exhibits the highest axial transport, engine oil-TiO₂ shows moderate enhancement, and ethylene glycol-TiO₂ provides the most pronounced improvement in heat and mass transfer. These findings highlight the critical role of base fluid selection in optimising nanofluid-based thermal systems, particularly in porous and magnetised environments.

Keywords: Porous medium; Variable viscosity; Variable electrical conductivity; Activation energy; Viscous dissipation; Thermodiffusion

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04638-9

Chemical Papers 80 (4) 3613–3639 (2026)