Visualisation of subcooled pool boiling in nanofluids

Surfactants role in the enhancement of the heat transfer and stability of alumina oxide – distilled water nanofluid was introduced in this research, where there are limited studies that conjugate between the stability improvement and its effect on the heat transfer coefficients. Four weight concentrations for the experiment were used (0.1, 0.3, 0.6, and 0.9%) with 20 nm particle size under a constant wall temperature. The selection of appropriate surfactants weight was tested too by implementing three weight concentrations (0.5, 1, 1.5, and 2 %) related to each nanofluid concentration via measuring their effect on the zeta potential value. The heat transfer augmentation was tested through a double horizontal pipe under a constant wall temperature at entrance region with Reynolds number range (4000–11800). The results manifested the use of nanofluid worked on enhancement the heat transfer performance better than water, and the stable nanofluid elucidated better results.

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“…The required weight for the nano powder and the distilled water was estimated according to the mixing equation [ 4 ]:

…”

Section: Preparation Of Nanofluidmentioning

confidence: 99%

“…For both laminar and turbulent forced convective process, the temperature below 50 °C can be considered as efficient for the working fluids. The nonlinear increase of viscosity with particle concentration was due to the aggregation of particles [ 4 ]. Applicability of nanofluids in cooling and heating applications were working well.…”

Section: Introductionmentioning

confidence: 99%

The surfactants effect on the heat transfer enhancement and stability of nanofluid at constant wall temperature

Askar

Kadhim

Mshehid

2020

Heliyon

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“…where all the terms have their usual meaning, the T ave (K) is the average temperature calculated using Equation (27).…”

Section: Heat Transfermentioning

confidence: 99%

“…Furthermore, heat performance index factor shows higher value in the turbulent flow regime than laminar. Kouloulias et al experimentally studied hydrodynamic and heat transfer of Al 2 O 3 /H 2 O nanofluid under subcooled pool boiling condition. The effect of nanoparticle on bubble dynamic and nucleation site on the heated surface was presented.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, heat performance index factor shows higher value in the turbulent flow regime than laminar. Kouloulias et al 27 The authors reported that all the four input variables are statistically significant to both thermal efficiency and pumping power. In addition, the results show that more interactions were significant in pumping power than thermal efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of thermal performance of single‐walled carbon nanotube nanofluid under turbulent flow conditions

Fadodun

Amosun

Salau

et al. 2019

Engineering Reports

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In this paper, a numerical study is performed to investigate the effect of Reynolds number and nanoparticle concentration on the thermal performance of single‐walled carbon nanotubes (SWCNTs) nanofluids flowing through a straight pipe with constant heat flux in a turbulent flow regime. The governing equations (continuity, momentum, energy, rate of turbulent production, and rate of turbulent dissipation) are solved using a computational fluid dynamic approach (ie, finite volume method). In the sensitivity analysis, the Reynolds number is varied between (10 000‐200 000) and nanoparticle concentration between (0%‐0.25%). The simulation results show that convective heat transfer (average Nusselt number) increases by 7.48% while the pressure drop and pumping power increase by 119% and 199%, respectively. In addition, at low Reynolds number (104), increase in nanoparticle concentration (0%‐0.25%) decreases entropy production rate by 16.95%. However, at higher Reynolds number (2*105), the entropy production rate increases by 149.77%. Furthermore, other results such as entropy generation number, Bejan number, second thermodynamic law efficiency, and thermal performance factor, which combine the first and second law of thermodynamics, are presented as functions of Reynolds number and nanoparticle's concentration. The overall result shows that SWCNT nanofluid will only be beneficial at low Reynolds number of (10 000‐50 000).

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Experimental investigation of bubble jet flow, sweeping and rotation on horizontal or inclined micro-wire during subcooled boiling

Jiang

Zhou

Chu

et al. 2019

J Therm Anal Calorim

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Visualisation of subcooled pool boiling in nanofluids

Cited by 15 publications

References 20 publications

The surfactants effect on the heat transfer enhancement and stability of nanofluid at constant wall temperature

The surfactants effect on the heat transfer enhancement and stability of nanofluid at constant wall temperature

Numerical investigation of thermal performance of single‐walled carbon nanotube nanofluid under turbulent flow conditions

Experimental investigation of bubble jet flow, sweeping and rotation on horizontal or inclined micro-wire during subcooled boiling

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