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Journal ArticleDOI

Increasing heat transfer of non-Newtonian nanofluid in rectangular microchannel with triangular ribs

01 Sep 2017-Physica E-low-dimensional Systems & Nanostructures (North-Holland)-Vol. 93, pp 167-178
TL;DR: In this paper, solid nanoparticles of Aluminum Oxide have been added to the non-Newtonian fluid in volume fractions of 0.2% with diameters of 25, 45 and 100nm.
Abstract: In this study, computational fluid dynamics and the laminar flow of the non-Newtonian fluid have been numerically studied. The cooling fluid includes water and 0.5 wt% Carboxy methyl cellulose (CMC) making the non-Newtonian fluid. In order to make the best of non-Newtonian nanofluid in this simulation, solid nanoparticles of Aluminum Oxide have been added to the non-Newtonian fluid in volume fractions of 0–2% with diameters of 25, 45 and 100 nm. The supposed microchannel is rectangular and two-dimensional in Cartesian coordination. The power law has been used to speculate the dynamic viscosity of the cooling nanofluid. The field of numerical solution is simulated in the Reynolds number range of 5
Citations
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TL;DR: In this paper, the effects of nanoparticles volume fraction, flow direction and Reynolds number on base fluid, nanofluid and wall temperatures, thermal efficiency, Nusselt number and convection heat transfer coefficient have been studied.

209 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of volume fraction (0.125-2%) and temperature (25-50°C) on thermal conductivity of a hybrid nanofluid was examined.

193 citations

Journal ArticleDOI
TL;DR: In this article, the authors reviewed and summarized recent investigations conducted on use of nanofluids in heat exchangers including those carried out on plate heat exchanger, double-pipe heat exchange, shell and tube heat exchange and compact heat exchange.

185 citations

Journal ArticleDOI
TL;DR: A comprehensive assessment of nanofluids' applications in various microchannel geometries and shows ever-increasing importance of nan ofluids applications in microchannels.

182 citations


Additional excerpts

  • ...[166] Numerical Rectangular Laminar 5–300 Water...

    [...]

Journal ArticleDOI
TL;DR: In this article, the effects of various weight percentages and Reynolds numbers on the laminar flow and heat transfer of water/functional multi-walled carbon nanotube nanofluid have been numerically investigated in weight percentages of 0.00, 0.12 and 0.25 by using finite volume method (FVM).
Abstract: In recent years, the study of rheological behavior and heat transfer of nanofluids in the industrial equipment has become widespread among the researchers and their results have led to great advancements in this field. In present study, the laminar flow and heat transfer of water/functional multi-walled carbon nanotube nanofluid have been numerically investigated in weight percentages of 0.00, 0.12 and 0.25 and Reynolds numbers of 1–150 by using finite volume method (FVM). The analyzed geometry is a two-dimensional backward-facing contracting channel and the effects of various weight percentages and Reynolds numbers have been studied in the supposed geometry. The results have been interpreted as the figures of Nusselt number, friction coefficient, pressure drop, velocity contours and static temperature. The results of this research indicate that, the enhancement of Reynolds number or weight percentage of nanoparticles causes the reduction of surface temperature and the enhancement of heat transfer coefficient. By increasing Reynolds number, the axial velocity enhances, causing the enhancement of momentum. By increasing fluid momentum at the beginning of channel, especially in areas close to the upper wall, the axial velocity reduces and the possibility of vortex generation increases. The mentioned behavior causes a great enhancement in velocity gradients and pressure drop at the inlet of channel. Also, in these areas, Nusselt number and local friction coefficient figures have a relative decline, which is due to the sudden reduction of velocity. In general, by increasing the mass fraction of solid nanoparticles, the average Nusselt number increases and in Reynolds number of 150, the enhancement of pumping power and pressure drop does not cause any significant changes. This behavior is an important advantage of choosing nanofluid which causes the enhancement of thermal efficiency.

165 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the effect of particle size on convective heat transfer in laminar developing region was evaluated with alumina-water nanofluids in tube flow with constant heat flux.

528 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental investigation on the effects of temperature and nanoparticles concentration on the thermal conductivity of ZnO-TiO2/EG hybrid nanofluids is presented.
Abstract: The hybrid nanofluids are novel nanofluids and can be prepared by suspending various kinds of nanoparticles in base fluid. In this paper, an experimental investigation on the effects of temperature and nanoparticles concentration on the thermal conductivity of ZnO–TiO2/EG hybrid nanofluids is presented. The experiments were implemented at temperature ranging from 25 to 50 °C and solid volume fraction range of 0–3.5 %. Experiments indicate that the thermal conductivity enhances with increasing the solid volume fraction and temperature. It was found that the variation of thermal conductivity enhancement of nanofluids with solid volume fraction at higher temperatures is greater than that at lower temperature. Moreover, it can be also seen that the variation of thermal conductivity enhancement of nanofluids with temperature at higher solid volume fraction is more than that at lower solid volume fraction. Finally, based on experimental data, in order to predict the thermal conductivity ratio of ZnO–TiO2/EG hybrid nanofluids, a correlation was proposed. Deviation analysis of the thermal conductivity ratio was also performed. Comparison between experimental data and the proposed correlation outputs revealed that this correlation has a good accuracy.

337 citations

Journal ArticleDOI
TL;DR: In this paper, the thermal conductivity of nanofluid has been determined by model proposed by Patel et al. and the fluid was considered as Newtonian as well as non-Newtonian for a wide range of Reynolds number (Re = 5 to 1500) and solid volume fraction (0.00 ⩽ ϕ⩽ 0.050 ).

322 citations

Journal ArticleDOI
TL;DR: In this article, the effects of temperature and nanoparticles concentration on the rheological behavior of Fe 3 O 4 -Ag/EG hybrid nanofluid have been experimentally investigated.

309 citations

Journal ArticleDOI
TL;DR: In this paper, an open-loop bicycle-rider model was developed in the commercial multibody dynamics software ADAMS and the effect of bicycle and rider properties on bicycle stability was analyzed.
Abstract: To work towards an advanced model of the bicycle-rider-environment system, an open-loop bicycle-rider model was developed in the commercial multibody dynamics software ADAMS. The main contribution of this article to bicycle dynamics is the analysis of tyre and rider properties that influence bicycle stability. A system identification method is used to extract linear stability properties from time domain analysis. The weave and capsize eigenmodes of the bicycle-rider system are analysed. The effect of tyre properties is studied using the tyre’s forces and torques that have been measured in several operating conditions. The main result is that extending simplified models with a realistic tyre model leads to a notable decrease in the weave stability and a stabilization of the capsize mode. This effect is mainly caused by the twisting torque. Different tyres and tyre inflation pressures have little effect on the bicycle’s stability, in the case of riding straight at a constant forward speed. On the other hand, the tyre load does have a large effect on bicycle stability. The sensitivity study of rider properties shows that body stiffness and damping have a small effect on the weave and capsize mode, whereas arm stiffness destabilizes the capsize mode and arm damping destabilizes the weave mode.

275 citations

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