Nanofluid Thermal Conductivity and Effective Parameters

Simpson, Sarah; Schelfhout, Austin; Golden, Chris; Vafaei, Saeid

doi:10.3390/app9010087

Cited by 85 publications

(39 citation statements)

References 85 publications

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“…The negatively charged head of SDS could change the surface charges of Al 2 O 3 and form repulsion forces among the nanoparticles. The agglomeration of nanoparticles therefore could be minimized by the act of the repulsion forces and lead to the improvements of the PDIVs for RBDPO, CO and MO [ 47 ]. Moreover, it is found that the differences on the nanoparticles dispersion between with and without SDS are not significant to cause agglomeration based on FTIR and particle size distribution [ 30 ].…”

Section: Discussionmentioning

confidence: 99%

Experimental Study on the Partial Discharge Characteristics of Palm Oil and Coconut Oil Based Al2O3 Nanofluids in the Presence of Sodium Dodecyl Sulfate

et al. 2021

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This experimental study aims to examine the partial discharge (PD) properties of palm oil and coconut oil (CO) based aluminum oxide (Al2O3) nanofluids with and without surfactants. The type of surfactant used in this study was sodium dodecyl sulfate (SDS). The volume concentrations range of Al2O3 dispersed in oil samples was varied from 0.001% to 0.05%. The ratio of surfactants to nanoparticles was set to 1:2. In total, two different types of refined, bleached and deodorized palm oil (RBDPO) and one type of CO were measured for PD. Mineral oil (MO) was also examined for comparison purpose. PDIV measurements for all samples were carried out based on rising voltage method whereby a needle-sphere electrode configuration with a gap distance of 50 mm was chosen in this study. Al2O3 improves the PDIVs of RBDPO, CO and MO whereby the highest improvements of PDIVs are 34%, 39.3% and 27%. The PD amplitude and repetition rate of RBDPO improve by 38% and 81% while for CO, it can increase up to 65% and 80% respectively. The improvement of PD amplitude and repetition rate for MO are 18% and 95%, regardless with and without SDS. Without SDS, the presence of Al2O3 could cause 26%, 75% and 65% reductions of the average emission of light signals for RBDPOA, RBDPOB and CO with the improvement of PD characteristics but both events do not correlate at the same volume concentration of Al2O3. On the other hand, the average emission of light signal levels of the oils increases with the introduction of SDS. The emission of light signal in MO does not correlate with the PD characteristics improvement either with or without SDS.

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Section: Discussionmentioning

confidence: 99%

Experimental Study on the Partial Discharge Characteristics of Palm Oil and Coconut Oil Based Al2O3 Nanofluids in the Presence of Sodium Dodecyl Sulfate

et al. 2021

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“…The thermal conductivity measurements and the thermal conductivity ratio of In an attempt to understand the phenomena that could be responsible of such thermal conductivity enhancement, some models from the literature are considered in the following [36][37][38][39][40][41][42]. Many complex and possibly coupled mechanisms shown in Figure 10have been considered in the past to use or develop theoretical models for thermal conductivity of nanofluids such as classical effective theory, nanoscale layer, agglomeration and J o u r n a l P r e -p r o o f aggregation, Brownian motion, etc [38,43].…”

Section: Thermal Conductivity Of Nanofluidsmentioning

confidence: 99%

Thermophysical properties of water ethylene glycol (WEG) mixture-based Fe3O4 nanofluids at low concentration and temperature

Banisharif

Aghajani

Vaerenbergh

et al. 2020

Journal of Molecular Liquids

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In the present work, Fe 3 O 4 nanoparticles produced by the ultrasonic precipitation method and characterized by XRD, SEM, and BET methods are used to produce nanofluids using a mixture of water and ethylene glycol (WEG 50:50) as a base fluid and both sodium dodecyl sulfonate and oleic acid as surfactants. The thermal conductivity, dynamic viscosity and surface tension of these Fe 3 O 4 nanofluids are experimentally evaluated for temperatures ranging from 253.15 to 293.15K and different volume concentrations of nanoparticles, 0.01, 0.05 and 0.1% respectively. Experiments indicate that the thermophysical properties of nanofluids are strongly dependant on concentrations of nanoparticles and temperatures, particularly at sub-zero temperatures. Actually, it is shown that the thermal conductivity of nanofluids increases with almost 9.5%, and 14.3%, at 263.15K and 293.15K respectively, with 0.1 vol%. The thermal conductivity enhancement of nanofluids with concentration and temperature is compared to some relevant theoretical models. A good agreement is achieved with a comprehensive model taking into consideration effective medium theory, the nanolayer effect of molecules around the solid particle, Brownian motion of nanoparticles encompassing aggregation and nano-convection. It is also found that the dynamic viscosity of nanofluids decreases with nanoparticle content in particular below Journal Pre-proof J o u r n a l P r e -p r o o f 2 273.15K, up to 40% at 0.1% in volume. Surface tension decreases by adding the surfactant to the base fluid and then increases with Fe 3 O 4 concentration with nearly 38% and 33% with 0.1% in nanoparticle volume fraction at 253.15 and 293.15K, respectively. Finally, these results are promising in view of Fe 3 O 4 nanofluids use in cooling applications.

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“…Apart from the apparent dynamic viscosity, the strain oscillation already displayed the viscoelastic nature of NFs. Therefore, to estimate the yield stress Herschel Bulkley (H-B) 64 and Bingham models 65 were fitted to the shear flow experimental data as shown in Equations (1) and 2, respectively.…”

Section: Shear Flow Behaviourmentioning

confidence: 99%

“…For the conventional heat transfer fluids (HTFs), thermal conductivity and the rheology are key parameters which can affect the FTSs efficiency. Since the development of nanofluids (NFs), a variety of nanoparticles (NPs) with a wide range of size, morphology and exotic thermal properties have been used as the dispersed phase in conventional HTFs 1 . Additionally, the researchers have also exploited the potential of nanocomposites materials to improve the heat transfer (HT) performance of carrier fluids 2 .…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity, rheology and stability analysis of 2D tungsten disulphide‐doped polyaniline‐based nanofluids: An experimental investigation

et al. 2020

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Summary In this study, polyaniline (PANI) nanocomposite‐based nanofluids (NFs) in ethylene glycol were obtained with a two‐step method by varying volume concentrations from 0.005% to 0.02%. Tungsten disulphide (WS2) nanoparticles were doped in PANI having different weight percentage (1%, 2% and 5%) via oxidative in situ polymerization employing ammonium persulphate oxidant in an acidic environment. The nanocomposites were comprehensively characterised using various techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy and high‐resolution transmission electron microscopy. The formulated NFs were extensively investigated with zeta‐sizer, particle size analyzer, thermal property analyzer and rheometer in a temperature range of 25°C to 70°C. The zeta potential results (up to 54.5 mV) were evident of extraordinary stability of NFs at all targeted temperatures along with polydispersity index <30% and mean particle/agglomerate size in the range of 335.8 to 489 nm. Additionally, a remarkable thermal conductivity improvement (~20.7%) was achieved with intrinsic PANI‐based NFs at an operating temperature of 50°C. Subsequently, it varied substantially with WS2 doping within PANI matrix and reached to 117.9%. Furthermore, the rheological measurements have revealed the viscoelastic nature of NFs along with a remarkable reduction in apparent viscosity (up to 8.4%). The temperature sweep viscosity indicated the transition of relative viscosity from high to low at a critical temperature of about 55°C. The NF10 (WS2 + PANI 5, at 0.005 vol%) was found to be the best candidate with 63.8% thermal conductivity enhancement and 6.4% viscosity reduction as compared with the base fluid at an operating temperature of 50°C. Thus, WS2 doping within PANI has proved to be crucial in the proliferation of thermal conductivity and mitigation of viscosity.

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Nanofluid Thermal Conductivity and Effective Parameters

Cited by 85 publications

References 85 publications

Experimental Study on the Partial Discharge Characteristics of Palm Oil and Coconut Oil Based Al2O3 Nanofluids in the Presence of Sodium Dodecyl Sulfate

Experimental Study on the Partial Discharge Characteristics of Palm Oil and Coconut Oil Based Al2O3 Nanofluids in the Presence of Sodium Dodecyl Sulfate

Thermophysical properties of water ethylene glycol (WEG) mixture-based Fe3O4 nanofluids at low concentration and temperature

Thermal conductivity, rheology and stability analysis of 2D tungsten disulphide‐doped polyaniline‐based nanofluids: An experimental investigation

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