Critical investigation of heat transfer enhancement using nanofluids in microchannels with slip and non-slip flow regimes

Abstract

The Reynolds number in nanofluids studies depends on the inlet velocity and the kinematic viscosity of nanofluid. The nanofluid kinematic viscosity increases with an increasing in nanoparticles volume fraction while the inlet velocity should be increased to keep the Reynolds number constant. Therefore, it is not clear that either increasing the nanoparticles volume fraction or increasing the inlet velocity has major role on heat transfer enhancement in nanofluids flow studies which are done at constant Reynolds numbers. In this study, forced convection Al 2 O 3 -water nanofluid flows in two-dimensional rectangular microchannels have been investigated to study heat transfer enhancement due to addition of the nanoparticles to the base fluid especially in microchannels at low Reynolds number. Three

Influence of Variable Thermal Conductivity on MHD Boundary Layer Slip Flow of Ethylene-Glycol Based Cu Nanofluids over a Stretching Sheet with Convective Boundary Condition

“…The nanofluids are more stable and have acceptable viscosity and better wetting, spreading, and dispersion properties on solid surface [3,4]. The characteristic feature of International Journal of Engineering Mathematics nanofluids is thermal conductivity enhancement, a phenomenon observed by Masuda et al [5].…”

“…As such, the Rosseland model, while limited compared with other flux models, can simulate to a reasonable degree of accuracy thermal radiation in problems ranging from thermal radiation transport via gases at low density to thermal radiation simulations associated with nuclear blast waves. If the temperature differences within the flow are sufficiently small, then (12) can be linearized by expanding 4 into the Taylor series about ∞ , which after neglecting higher-order terms takes the form…”

Effects of wall slip and nanoparticles' thermophoresis on the convective heat transfer enhancement of nanofluid in a microchannel

“…Some other researchers recognized that the boundary layer, especially the velocity-slip and temperature-jump at fluid-solid interface in a microchannel influenced heat transfer enhancement even more significantly ( Hettiarachchi, H.D.M., 2008, Vajravelu, K., 2011,Vandadi, V., 2011, Akbarinia, A., 2011, Aminreza, N., 2012. Hettiarachchi et al(2008) numerically studied 3D laminar slip-flow and heat transfer in a rectangular microchannel with constant wall temperature and found that the local Nusselt number increased with the increased slip-velocity and the decreased jump-temperature.…”

“…Vandadi et al(2011) took into account the effect of velocity slip, temperature jump and viscous dissipation term, and the results showed that the viscous dissipation effect on heat transfer in microchannels is significant and should not be neglected. Akbarinia, et al (2011) investigated forced convection of Al2O3-water nanofluid flows in two-dimensional rectangular microchannels for heat transfer enhancement. It was found that viscous dissipation is beneficial to the heat transfer enhancement.…”

Unsteady mixed convection flow through a permeable stretching flat surface with partial slip effects through MHD nanofluid using spectral relaxation method

“…For these reasons, it is prudent to combine base uids with nanoparticles to achieve both the characteristics of a base uid and the physical properties of the nanoparticles [2,3]. Suspending nanoparticles a ects the base uid's homogeneity and the randomness of molecular motion leading to higher conductive rates and better convective heat transfer performances compared to base uids [4][5][6][7]. There are however mechanisms, which include particle agglomeration, particle shape/surface area, nanoparticle size, temperature and liquid layering on the nanoparticle liquid interface that still need to be fully understood.…”