A model for thermal conductivity of carbon nanotubes with ethylene glycol/water based nanofluids

A model reported by the present investigators has earlier shown that the extent of heat pick up by a nanoparticle during its collision with the heat source in a given nanofluid would depend on the thermal conductivity (kp, unit W/m.K), density (ρ, unit kg/m3), elastic modulus (E, unit GPa) and Poissons ratio (μ) of the nanoparticle and heat source. Considering the expression for collision period and thermal conductivity of nanoparticle, a factor χ =kp(ρ/E)0.4 is proposed here and examined for the preliminary identification of the potential of a dispersoid in enhancing the thermal conductivity of a nanofluid. The χ-factor for Ag, Cu, CuO, Al2O3 and SiO2 are 2960, 2247, 116, 14.1 and 5.5, respectively. The higher χ-factor of CuO compared to that of Al2O3 can explain why water and ethylene glycol (EG) based CuO-nanofluid is reported to show higher enhancement in the thermal conductivity, when compared to similar Al2O3-nanofluid. The χ for SiO2 is much smaller than that for Ag, which also corroborates well with the marginal enhancement in thermal conductivity of water based nanofluid containing SiO2 nanoparticles. Therefore, a high value of χ of the nanodispersoid can serve as a parameter for the design of nanofluids for heat transfer applications.

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Experimental study on density, thermal conductivity, specific heat, and viscosity of water-ethylene glycol mixture dispersed with carbon nanotubes

Thermal Science ◽

10.2298/tsci141015028g ◽

2017 ◽

Vol 21 (1 Part A) ◽

pp. 255-265 ◽

Cited By ~ 10

Author(s):

Jayabalan Ganeshkumar ◽

Durai Kathirkaman ◽

Kandhaswamy Raja ◽

Vellisamy Kumaresan ◽

Ramalingam Velraj

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Ethylene Glycol ◽

Specific Heat ◽

Fold Increase ◽

Modified Model ◽

Multi Wall Carbon Nanotubes ◽

Conductivity Enhancement ◽

Mwcnt Concentration ◽

Nanoparticle Aggregates

This article presents the effect of adding multi wall carbon nanotubes (MWCNT) in water ? ethylene glycol mixture on density and various thermophysical properties such as thermal conductivity, specific heat and viscosity. Density of nanofluids was measured using standard volumetric flask method and the data showed a good agreement with the mixing theory. The maximum thermal conductivity enhancement of 11 % was noticed for the nanofluids with 0.9 wt. %. Due to lower specific heat of the MWCNT, the specific heat of the nanofluids decreased in proportion with the MWCNT concentration. The rheological analysis showed that the transition region from shear thinning to Newtonian extended to the higher shear stress range compared to that of base fluids. Viscosity ratio of the nanofluids augmented anomalously with respect to increase in temperature and about 2.25 fold increase was observed in the temperature range of 30 ? 40 ?C. The modified model of Maron and Pierce predicted the viscosity of the nanofluids with the inclusion of effect of aspect ratio of MWCNT and nanoparticle aggregates.

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COMPARISON OF THERMAL CONDUCTIVITY FOR HHT-24-CNF-BASED NANOFLUID USING DEIONIZED WATER AND ETHYLENE GLYCOL

Jurnal Teknologi ◽

10.11113/jt.v77.6612 ◽

2015 ◽

Vol 77 (21) ◽

Author(s):

Syarifah Norfatin Syed Idrus ◽

Nor Salihah Zaini ◽

Imran Syakir Mohamad ◽

Norli Abdullah ◽

Mohd Haizal Mohd Husin

Keyword(s):

Thermal Conductivity ◽

Thermal Properties ◽

Ethylene Glycol ◽

Carbon Nanofibers ◽

Deionized Water ◽

Water Based

Carbon nanofibers (CNF) is one of potential nanoparticles that possess superior thermal conductivity. In this study, nanofluids with suspension of CNF in deionized water (DI water) and ethylene glycol (EG) are prepare. Thermal conductivity (TC) of the nanofluids are measured at 6°C, 25°C and 40°C using KD2 Pro Thermal Properties Analyser. The results show that, TC increases with increasing of temperature and CNF loading. Best TC is recorded by 36.7 % enhancement at 40 °C for EG based fluid with 0.9 wt% CNF loading. Meanwhile, for DI water based fluid, best TC enhancement (39.6 %) can be achieved with CNF loading of 0.7 wt% at 40°C. Overall, both based fluid show a promising enhancement in thermal conductivity. However, DI water based fluid show higher TC in comparison to EG based fluid due to the higher TC in standard DI water itself.

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Thermophysical Properties of Nanofluids Composed of Ethylene Glycol and Long Multi-Walled Carbon Nanotubes

Fluids ◽

10.3390/fluids5040241 ◽

2020 ◽

Vol 5 (4) ◽

pp. 241

Author(s):

Karolina Brzóska ◽

Bertrand Jóźwiak ◽

Adrian Golba ◽

Marzena Dzida ◽

Sławomir Boncel

Keyword(s):

Thermal Conductivity ◽

Carbon Nanotubes ◽

Ethylene Glycol ◽

Chemical Vapor ◽

Step Method ◽

Mwcnt Content ◽

Multi Walled Carbon Nanotubes ◽

The Stability ◽

Walled Carbon Nanotubes ◽

Rotary Viscometer

In this work, thermal conductivity, viscosity, isobaric heat capacity, and density of stable carbon-based nanofluids are presented. The nanofluids under study are composed of 1,2-ethanediol (ethylene glycol, EG) and long multi-walled carbon nanotubes (MWCNTs), so-called ‘in-house 16h’ (synthesized in our laboratory via catalytic chemical vapor deposition during 16 h with a diameter of 60–80 nm and length of 770 μm). Poly(N-vinylpyrrolidone) (PVP) was used to increase the stability of nanofluids. The nanofluids were prepared via an ultrasonication-assisted, three-step method while their key thermophysical characteristics were obtained using the hot-wire technique and rotary viscometer. As a result, the addition of MWCNTs significantly improved the thermal conductivity of nanofluids by 31.5% for the highest 1.0 wt% (0.498 vol%) long MWCNT content, leaving the Newtonian character of the nanofluids practically intact.

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Designing an artificial neural network using radial basis function (RBF-ANN) to model thermal conductivity of ethylene glycol–water-based TiO2 nanofluids

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-016-5725-y ◽

2016 ◽

Vol 127 (3) ◽

pp. 2125-2131 ◽

Cited By ~ 38

Author(s):

Mohammad Hemmat Esfe

Keyword(s):

Neural Network ◽

Thermal Conductivity ◽

Artificial Neural Network ◽

Ethylene Glycol ◽

Radial Basis Function ◽

Basis Function ◽

Water Based ◽

Radial Basis ◽

Artificial Neural ◽

Tio2 Nanofluids

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Intertube Falling-Film Heat Transfer Behavior of Multiwall Carbon Nanotube Suspensions (MWCNT Nanofluids)

ASME/JSME 2011 8th Thermal Engineering Joint Conference ◽

10.1115/ajtec2011-44542 ◽

2011 ◽

Cited By ~ 2

Author(s):

Binglu Ruan ◽

Anthony M. Jacobi

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Heat Transfer Coefficient ◽

Ethylene Glycol ◽

Multiwall Carbon Nanotube ◽

Falling Film ◽

Water Based ◽

Film Heat Transfer ◽

The Heat Transfer Coefficient ◽

Multiwall Carbon

The thermal conductivity and viscosity of water-based and ethylene-glycol-based multiwall carbon nanotube (MWCNT) suspensions are measured for MWCNT volume concentrations up to 0.24%. The thermal conductivity is found to increase up to 8.6% and 9.3% for water-based and ethylene-glycol-based nanofluids, respectively. The viscosity of the nanofluids increases compared to that of their base fluids, with larger increases for the ethylene-glycol-based nanofluids. Intertube falling-film heat transfer characteristics of these nanofluids are measured and compared to data for the base fluids. The heat transfer coefficient of the water-based nanofluids decreases at low MWCNT concentrations but increases as the concentration increases. The heat transfer coefficient of the ethylene-glycol-based nanofluids decreases with an increase in MWCNT concentration, with a maximum deviation of 30%.

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