Investigations of nanofluid flow and heat transfer in a rotating microchannel using single- and two-phase approaches

Abstract

The impacts of single- (SPM) and two-phase models (TPMs), including Euler-Lagrange (ELM) and Eulerian-Eulerian models (EEM), on a laminar forced convection heat transfer and fluid flow of the ${\mathrm{Al}}_2{\mathrm{O}}_3/\mathrm{water}$ nanofluid are evaluated in a rotating U-shape microchannel with a square cross-section and constant wall temperature. The effects of Reynolds numbers, rotational speed, volume fraction, Brownian motion, and implementation of no-slip and slip conditions are investigated. The slip velocity and heat transfer increase by increasing the volume fraction and rotational speed. The EEM and ELM provide a higher total Nusselt number than the SPM. The maximum heat transfer augmentations of 53.3%, 45.7%, and 41% are achieved for the EEM, ELM, and SPM by increasing the rotational speed from zero to 600 at ϕ = 5%. The predictions of pressure drop by TPMs are essentially the same but considerably lower than SPM. Unlike the ELM, the nanoparticle concentrations of EEM and SPM are uniform.

Keywords:

• Brownian motion
• Euler-lagrange model
• nanofluid
• rotating U-type microchannel
• slip flow
• two-phase models