Experimental study on the effect of different surfactants on the thermophysical properties of graphene filled nanofluids

Qiao, Yu; Wen, Sheng; He, Chen; Liu, Changhui; Rao, Zhonghao

doi:10.1002/er.6497

Cited by 17 publications

(11 citation statements)

References 56 publications

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“…While many studies have concluded that adding a surfactant will increase the viscosity of the nanofluid; other studies have observed the opposite effect. Qiao et al [ 36 ] observed the change in viscosity with increasing temperature for six different surfactants added to a base fluid of water and graphene nanoparticles. The surfactants used were tested in concentrations of 0.02%, 0.04%, 0.06%, 0.08%, and 0.1% and could be classified into the following three groups: anionic (SDBS, SDS, and PAAS), nonionic (PVP), and cationic (OTAB and CTAB).…”

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

“…The surfactants used were tested in concentrations of 0.02%, 0.04%, 0.06%, 0.08%, and 0.1% and could be classified into the following three groups: anionic (SDBS, SDS, and PAAS), nonionic (PVP), and cationic (OTAB and CTAB). Qiao et al [ 36 ] found that the addition of surfactant increases the viscosity of the nanofluid. Higher concentrations of surfactant were also correlated with higher viscosity.…”

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

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Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

et al. 2022

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The focus of this paper is to investigate the effects of the addition of a connector between two serial microchannels. The idea of adding connector at the inlet of microchannels to enhance the random motion of molecules or nanoparticles in low Reynolds numbers was developed in our research group for the first time. It was experimentally determined that the shape of a connector between two microchannels has a significant impact on the enhancement of the random motion of molecules or nanoparticles. Consequently, the heat transfer coefficient is improved inside the second microchannel. The connector is large enough to refresh the memory of the fluid before entering the second channel, causing a higher maximum heat transfer coefficient in the second channel. It was also observed that the heat transfer coefficient can be increased at the end of the channel when the outlet temperature is relatively high. This may be explained by the fact that as temperature increases, the fluid viscosity tends to decrease, which generally drives an increase in the local random motion of base fluid molecules and nanoparticles. This causes an increase in the microchannel heat transfer coefficient. It was found that the addition of nanoparticles significantly modified the impact of the connector on the microchannel heat transfer coefficient. In addition, the effects of changing the Reynolds number and the shape of the connector were investigated through use of computational fluid dynamics (CFD) calculations. It was found that both factors have an important impact on the variation of velocity and enhancement of random motion of molecules and consequently significantly affect the heat transfer coefficient.

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Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

Section: Brief Review On Optimization Of Effects Of Nanoparticlesmentioning

confidence: 99%

Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

et al. 2022

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“…6,7 These nanoparticle-laden fluids are usually termed nanofluids. [8][9][10] For applications in DASCs, nanofluids, even at low concentrations, can significantly improve the collector's performance. Therefore, nanofluids are promising alternatives to the commonly used fluids in DASCs.…”

Section: Introductionmentioning

confidence: 99%

“…Incorporating nanoparticles with high light absorption capability into the fluids has been proved a practical approach to enhance the optical characteristics of the base fluids 6,7 . These nanoparticle‐laden fluids are usually termed nanofluids 8‐10 . For applications in DASCs, nanofluids, even at low concentrations, can significantly improve the collector's performance.…”

Section: Introductionmentioning

confidence: 99%

Photo‐thermal conversion performance of mono MWCNT and hybrid MWCNT‐TiN nanofluids in direct absorption solar collectors

Zheng

Yan

Long

et al. 2022

Intl J of Energy Research

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Summary Solar energy is being widely investigated due to its abundant, renewable, and clean features. Photo‐thermal conversion in solar collectors is a direct approach for harvesting solar energy. Compared to the commonly used surface‐based solar collectors (SSCs), nanofluid‐based direct absorption solar collectors (DASCs) are more efficient. In this work, water‐based mono MWCNT and hybrid MWCNT‐TiN nanofluids were prepared through a two‐step method, aiming at light absorption enhancement of nanofluids for applications in DASCs. The optical and photo‐thermal conversion performance of the MWCNT nanofluids was firstly evaluated. The results showed that the MWCNT nanofluids presented high solar absorption capability, and the highest photo‐thermal conversion efficiency was obtained at 10 ppm. The TiN nanoparticles were subsequently incorporated to form the hybrid MWCNT‐TiN nanofluids. The absorption performance of the hybrid nanofluids was further enhanced. The highest efficiency of the hybrid MWCNT‐TiN nanofluids was achieved at the TiN mass fraction of 10 ppm, which was about 6.9%, 6.0%, and 3.8% higher than that of the MWCNT nanofluid at 2000, 4000, and 6000 seconds due to the localized surface plasmon resonance (LSPR) effect of TiN nanoparticles. It was also found that the collector efficiency dropped rapidly with the prolonged irradiation time owing to the convection and radiation heat loss at the elevated temperature. Therefore, effective measures should also be taken to reduce heat loss to maintain high photo‐thermal conversion efficiency.

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“…The specific heat and thermal conductivity values were 2.37, 2.31 kJ/kg K, and .117, .119 W/mK, respectively. Stability of water‐based nanofluid was studied using UV‐visible spectrophotometer by Qiao et al 25 . The authors used different surfactants, and among them, polyvinylpyrrolidone gave better stability and a maximum absorbance of .5, whichwas almost constant even after 20 days for the mass fraction of .04%.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on low concentration nanofluids with Fresnel lens and evacuated tubes for solar applications

Kalidoss

Venkatachalapathy

Suresh

2022

Int J Applied Ceramic Tech

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Optical and thermo‐physical properties of the nanofluids play a major role in the absorption of solar energy. In the present study, photo‐thermal energy conversion of low concentration Al2O3/Deionised water (DI) water and CuO/DI water nanofluids in solar thermal collector is experimentally investigated. Properties of 50,100,150, and 200 ppm concentrations of nanofluids are reported. The absorbance results in the visible range indicate that CuO nanofluid of 200 ppm concentration is nearly three times higher compared to Al2O3 nanofluid. The extinction coefficient, optical energy band gap, and photoluminescence obtained from the absorbance data are also reported. Surfactant free nanofluids are used, and the thermal conductivity measurements show a negligible enhancement for both the nanofluids. Maximum receiver temperatures of 89 and 72°C are found with CuO and Al2O3 nanofluids, respectively, for the maximum concentration. A maximum receiver efficiency of 34.89% is obtained for CuO nanofluids.

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Experimental study on the effect of different surfactants on the thermophysical properties of graphene filled nanofluids

Cited by 17 publications

References 56 publications

Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

Heat Transfer Enhancement in the Microscale: Optimization of Fluid Flow

Photo‐thermal conversion performance of mono MWCNT and hybrid MWCNT‐TiN nanofluids in direct absorption solar collectors

Experimental investigation on low concentration nanofluids with Fresnel lens and evacuated tubes for solar applications

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