Measurement of the Thermal-Conductivity Coefficient of Nanofluids by the Hot-Wire Method

Минаков, А. В.; Rudyak, V. Ya.; Guzei, D. V.; Pryazhnikov, M. I.; Lobasov, A. S.

doi:10.1007/s10891-015-1177-7

Cited by 27 publications

(7 citation statements)

References 14 publications

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“…Detailed description of the test bench and testing technique is given in [27]. Wheatstone bridge was used as the basis of the test bench instrumentation to measure an unknown electrical resistance of hot wire.…”

Section: Measurement Techniquementioning

confidence: 99%

Thermal conductivity measurements of nanofluids

Pryazhnikov

Минаков

Rudyak

et al. 2017

International Journal of Heat and Mass Transfer

214

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The paper presents the results of systematic measurements of the thermal conductivity coefficient of nanofluids at room temperature. In total, more than fifty various nanofluids based on water, ethylene glycol, and engine oil containing particles of SiO2, Al2O3, TiO2, ZrO2, CuO, and diamond were studied. The nanoparticles volume concentration ranged from 0.25 to 8% and the particles size ranged from 10 to 150 nm. It is shown that the thermal conductivity of nanofluids is not described by the classical theories (Maxwell's and so forth). The nanofluid thermal conductivity coefficient is a complicated function not only of the particle concentration, but also the particles size, their material, and type of base fluid. Measured thermal conductivity coefficients almost always exceed the values calculated by the Maxwell's formula, though nanofluids with sufficiently small particles may have thermal conductivity coefficients even lower than those predicted by the Maxwell theory. However, in all cases, the nanofluid thermal conductivity coefficient enhances with increasing particle size. It is convincingly shown that there is no direct correlation between the thermal conductivity of the nanoparticle material and the thermal conductivity of nanofluid containing these particles. The base liquid also significantly influences the effective thermal conductivity of the nanofluid. It has been confirmed that the lower the thermal conductivity of the base fluid, the higher the relative thermal conductivity coefficient of the nanofluid.

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Section: Measurement Techniquementioning

confidence: 99%

Thermal conductivity measurements of nanofluids

Pryazhnikov

Минаков

Rudyak

et al. 2017

International Journal of Heat and Mass Transfer

214

View full text Add to dashboard Cite

show abstract

“…Detailed description of the test bench and testing technique is given in [15]. The resultant relative measurement error of fluid thermal conductivity coefficient does not exceed 3%.…”

Section: Dependence Of Thermal Conductivity On Particle Concentrationmentioning

confidence: 99%

Study of transport coefficients of nanodiamond nanofluids

Pryazhnikov

Минаков

Guzei

2017

J. Phys.: Conf. Ser.

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Abstract. Experimental data on the thermal conductivity coefficient and viscosity coefficient of nanodiamond nanofluids are presented. Distilled water and ethylene glycol were used as the base fluid. Dependences of transport coefficients on concentration are obtained. It was shown that the thermal conductivity coefficient increases with increasing nanodiamonds concentration. It was shown that base fluids properties and nanodiamonds concentration affect on the rheology of nanofluids. IntroductionNanoparticle colloidal suspensions, referred to as 'nanofluids' [1], have potential application in many heat transfer areas because of their intriguing properties such as a considerable increase in thermal conductivity, long-term stability and prevention of clogging in micro-channels [2][3]. Recently extensive efforts have been made to prepare thermal performance enhanced nanofluids [4][5]. Diamond is one of the materials with very high thermal conductivity, and diamond particles are often used as filler in mixtures for upgrading the performance of a matrix [6].In some studies nanodiamonds are used as particles that improve the thermal conductivity of heat-transfer liquids, such as water, oil and ethylene glycol just as particles of metals (gold, copper), metal oxides (aluminum and copper oxides) and silicon carbide [7][8][9][10][11]. It is reasonable to expect that the addition of diamond nanoparticles would lead to thermal performance enhancement in a base fluid. However, available information about them in the open literature is very scant. Torii et al. [12] conducted experiments in nanodiamond-water nanofluids. The authors of work [12] investigated the coefficients of viscosity and thermal conductivity of nanodiamond-water nanofluids. Particle size ranged from 2 to 10 nm were used. Viscosity coefficient of nanofluid with a particle volume concentration of 2% is 55% higher the viscosity coefficient of water. Thermal conductivity coefficient of nanofluid with a particle volume concentration of 5% is 15% higher the thermal conductivity of water.In work [13], nanodiamonds were chosen to form nanofluids with mixture base fluid composed of distilled water with a volume fraction of 0.55 and ethylene glycol with a volume fraction of 0.45. The thermal transport properties, including the thermal conductivity, the viscosity and the convective heat transfer coefficient, were investigated. The thermal conductivity enhancement of nanodiamond nanofluids increases with nanodiamonds loading and the thermal conductivity enhancement is more than 18.0% for a nanofluid at a nanodiamonds volume fraction of 0.02. Viscosity measurements show that the nanodiamond nanofluids demonstrate Newtonian behaviour, and the viscosity significantly decreases with temperature.

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“…The particle size ranged from 5 to 151 nm. Thermal conductivity measurements were performed by non-stationary hot-wire method [10]. The error of fluid thermal conductivity coefficient does not exceed 3%.…”

Section: Viscosity and Thermal Conductivity Of Nanofluidsmentioning

confidence: 99%

The features of the modeling the nanofluid flows

Rudyak¹,

Минаков²

2018

AIP Conference Proceedings

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The features of the nanofluid flows modeling are analyzed. In the first part the thermophysical properties (viscosity and thermal conductivity) of nanofluids are discussed in detailed. It was shown that the transport coefficients of nanofluids depend not only on the volume concentration of the particles but also on their size and material. The viscosity increases with decreasing the particle size while the thermal conductivity increases with increasing the particle size. The heat transfer of nanofluid in cylindrical channel and laminar-turbulent transition in some flows are considered. The heat transfer coefficient is determined by the flow mode (laminar or turbulent) of the nanofluid. However it was shown that adding nanoparticles to the coolant significantly influences the heat transfer coefficient. The laminar-turbulent transition begins in all cases earlier (at smaller Reynolds numbers) than for base fluid. In conclusion the possibility of the use of traditional similarity criteria are discussed.

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Measurement of the Thermal-Conductivity Coefficient of Nanofluids by the Hot-Wire Method

Cited by 27 publications

References 14 publications

Thermal conductivity measurements of nanofluids

Thermal conductivity measurements of nanofluids

Study of transport coefficients of nanodiamond nanofluids

The features of the modeling the nanofluid flows

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