Mixed Convection Heat Transfer Dynamics in Nanofluid Systems

Mixed convection in nanofluid systems arises when thermal buoyancy forces interact with externally imposed flows in fluids containing nanoscale solid particles. The presence of nanoparticles amplifies thermal conductivity and alters boundary-layer behaviour through Brownian motion and thermophoretic effects. In engineering applications such as electronic cooling, solar collectors and advanced heat exchangers, the careful balance of forced and free convection regimes enables enhanced heat removal under varying thermal loads. Numerical and experimental studies have explored two-phase models alongside effective single-phase approximations, revealing how particle volume fraction, surface geometry, rotating elements and magnetic or porous media influences the convective heat transport. Mixed regimes are commonly characterised by the Richardson and Rayleigh numbers, which govern the transition from forced-flow dominance to buoyancy-driven circulation. Recent work also highlights the role of non-Newtonian base fluids, anisotropic slip conditions and biochemical additives such as motile microorganisms in tailoring heat-transfer rates and entropy generation. Through coupled computational fluid dynamics and refined similarity transformations, researchers have mapped parameter spaces for optimising thermal performance while minimising pressure drop and irreversibility.

Research from Nature Portfolio

Recent studies have employed high-order numerical schemes to examine three-dimensional radiative nanofluid flows in the presence of gyrotactic microorganisms and anisotropic slip near stagnation regions. The interplay of Arrhenius activation energy, joule heating, viscous dissipation and binary chemical reactions has been shown to modify temperature and concentration fields significantly. It was demonstrated that increasing the bio-convection Lewis and Peclet numbers reduces microorganism distribution in the boundary layer, while modifications in thermophoretic and Brownian motion parameters yield distinct trends in local Nusselt and Sherwood numbers. These findings offer a comprehensive framework for incorporating biochemical effects into mixed-convection models and suggest pathways for active control of heat-transfer rates in micro-scale devices.

Mixed Convection Heat Transfer Dynamics in Nanofluid Systems publication trend

The graph below shows the total number of articles in mixed convection heat transfer dynamics in nanofluid systems across all publications each year (not limited to Nature Index journals).

Technical terms

Mixed convection: Combined buoyancy-driven and forced-flow heat transfer within a fluid.

Nanofluid: Suspension of nanoparticles in a base fluid to enhance thermal conductivity and heat-transfer performance.

Richardson number (Ri): Dimensionless ratio of buoyancy to inertial forces indicating the relative strength of natural versus forced convection.

Nusselt number (Nu): Dimensionless measure of convective heat transfer relative to conduction across a boundary.

Brownian motion: Random movement of nanoparticles in a fluid that contributes to enhanced thermal diffusion.

Thermophoresis: Migration of particles induced by temperature gradients, affecting distribution in nanofluids.

References

1. A numerical treatment of radiative nanofluid 3D flow containing gyrotactic microorganism with anisotropic slip, binary chemical reaction and activation energy. Scientific Reports (2017).
2. Significances of melting heat transfer and bioconvection phenomena in nanofluid flow over a three different geometries. International Journal of Thermofluids (2024).
3. The effects of heat generation absorption on boundary layer flow of a nanofluid containing gyrotactic microorganisms over an inclined stretching cylinder. Ain Shams Engineering Journal (2022).
4. Fluid flow over a vertical stretching surface within a porous medium filled by a nanofluid containing gyrotactic microorganisms. The European Physical Journal Plus (2022).