Flow behaviour of suspensions of functionalized graphene nanoplatelets in propylene glycol–water mixtures

Vallejo, Javier P.; Gómez-Barreiro, S.; Cabaleiro, David; Gracia-Fernández, Carlos; Fernández-Seara, José; Lugo, Luis

doi:10.1016/j.icheatmasstransfer.2017.12.001

Cited by 45 publications

(31 citation statements)

References 54 publications

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“…The dynamic viscosity values in the second plateau for the fGnP nafluid set were modelled by means of Vallejo et al’s equation [33], which includes, in the same expression, the concentration and temperature dependences of viscosity: η=η0·eA·T0T−T0+B·eCT· ϕv −D·ϕv2 with B , C , and D as the fitting parameters; η 0 , A , and T 0 as the previously fitted parameters from the VFT equation, Equation (3), for the corresponding base fluid; and ϕ v as the volume fraction. This equation was tested in previous works [33,34,66] for experimental viscosities of GnP-water dispersions [34,39], GnP-propylene glycol water 10:90 wt% dispersions [33], GnP-propylene glycol water 30:70 wt% dispersions [33,34,66], and GnP-propylene glycol water 50:50 wt% dispersions [34], obtaining very good results. Table 5 and Figure 7 show the goodness of Equation (4) for the fGnP nanofluids of this study, the reached AAD being lower than 0.9%.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, other structures, like graphene nanoplatelets (GnP) and nanodiamonds, have become more widespread [27,28,29,30,31,32]. In our previous work [33], a comprehensive study on the dynamic viscosity of propylene glycol-water-based nanofluids containing sulfonic acid-functionalized GnP was presented. Newtonian behavior at higher shear rates with dynamic viscosity dependences on nanoadditive fraction and temperature was reported, as well as pseudoplasticity at lower shear rates.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Six Carbon-Based Nanomaterials on the Rheological Properties of Nanofluids

et al. 2019

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Nanofluids, dispersions of nanosized solid particles in liquids, have been conceived as thermally-improved heat transfer fluids from their conception. More recently, they have also been considered as alternative working fluids to improve the performance of direct absorption solar thermal collectors, even at low nanoadditive concentrations. Carbon-based nanomaterials have been breaking ground in both applications as nanoadditives during the last decade due to their high thermal conductivities and the huge transformation of optical properties that their addition involves. In any application field, rheological behavior became a central concern because of its implications in the pumping power consumption. In this work, the rheological behavior of four different loaded dispersions (0.25, 0.50, 1.0, and 2.0 wt%) of six carbon-based nanomaterials (carbon black, two different phase content nanodiamonds, two different purity graphite/diamond mixtures, and sulfonic acid-functionalized graphene nanoplatelets) in ethylene glycol:water mixture 50:50 vol% have been analysed. For this purpose, a rotational rheometer with double cone geometry was employed, which included a special cover to avoid mass losses due to evaporation at elevated temperatures. The flow curves of the twenty-four nanofluids and the base fluid were obtained by varying the shear rate between 1 and 1000 s−1 for seven different temperatures in the range from 283.15 to 353.15 K. The shear-thinning behaviors identified, as well as their dependences on carbon-based nanomaterial, concentration, and temperature, were analyzed. In addition, oscillatory tests were performed for samples with the clearest Non-Newtonian response, varying the deformation from 0.1 to 1000% with constant frequency and temperature. The dependence of the behaviors identified on the employed carbon-based nanomaterial was described.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Six Carbon-Based Nanomaterials on the Rheological Properties of Nanofluids

et al. 2019

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“…The rheological behavior of nanofluids is diverse, as presented in recent review papers in this field [ 145 , 146 , 147 , 148 ]. From the application point of view, nanofluids considered as potential heat transfer fluids should preferably exhibit low viscosity and Newtonian behavior.…”

Section: Properties Of Carbon-based Nanofluidsmentioning

confidence: 99%

Carbon Nanomaterial-Based Nanofluids for Direct Thermal Solar Absorption

et al. 2020

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Recently, many scientists have been making remarkable efforts to enhance the efficiency of direct solar thermal absorption collectors that depends on working fluids. There are a number of heat transfer fluids being investigated and developed. Among these fluids, carbon nanomaterial-based nanofluids have become the candidates with the most potential by the heat absorbing and transfer properties of the carbon nanomaterials. This paper provides an overview of the current achievements in preparing and exploiting carbon nanomaterial-based nanofluids to direct thermal solar absorption. In addition, a brief discussion of challenges and recommendations for future work is presented.

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“…Vallejo et al [7] studied experimentally the rheological behaviour of different dispersions of functionalized graphene nanoplatelets, f-GnPs (from 0.25-1 wt.%) in two propylene-glycol-water mixtures (10:90 and 30:70) within the temperature range [5-50 • C]. They reported also a Newtonian behaviour over all the concentrations, temperatures and shear rate ranges they considered.…”

Section: Propylene-glycol-based Nanofluidsmentioning

confidence: 99%

“…As shown in Tables 1 and 2, EG-W solutions exhibit lower freezing points and higher boiling points compared to PG-W solutions. However, it is strongly recommended to use PG-W mixtures especially in human interaction applications such as heating residential buildings because propylene-glycol is non-toxic and easily decomposes in the environment, contrary to ethylene-glycol, which is toxic and takes a longer time to degrade [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Ethylene- and Propylene-Glycol Based Nanofluids: A Litterature Review on Their Thermophysical Properties and Thermal Performances

Sekrani

Poncet

2018

Applied Sciences

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Nanofluids are considered a promising way to improve the heat transfer capability of base fluids. Water is the most commonly-used heat transfer fluid. However, in refrigeration systems, it may be necessary to mix water with either ethylene- or propylene-glycol to lower its freezing point and prevent from ice formation. In the same way, for car radiators or industrial heat exchangers, the boiling point of water can be pushed up by mixing it with glycol-based fluids. The increasing awareness of energy saving and industrial energy efficiency improvement results in the growing interest in ethylene- or propylene-glycol-based nanofluids for applications in various thermal systems. The present paper proposes an extensive review of the most recent and relevant experimental and numerical works on the thermophysical properties and performances of ethylene- or propylene-glycol-based nanofluids. Research perspectives are also provided with the long-term objective that these nanofluids be more widely considered in real industrial applications.

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Flow behaviour of suspensions of functionalized graphene nanoplatelets in propylene glycol–water mixtures

Cited by 45 publications

References 54 publications

Influence of Six Carbon-Based Nanomaterials on the Rheological Properties of Nanofluids

Influence of Six Carbon-Based Nanomaterials on the Rheological Properties of Nanofluids

Carbon Nanomaterial-Based Nanofluids for Direct Thermal Solar Absorption

Ethylene- and Propylene-Glycol Based Nanofluids: A Litterature Review on Their Thermophysical Properties and Thermal Performances

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