Comparative numerical study of single and two-phase models of nanofluid liquid film evaporation in a vertical channel

Najim, Monssif; Feddaoui, M’barek; Alla, Abderrahman Nait; Charef, Adil

doi:10.1051/matecconf/202030701034

Cited by 2 publications

(2 citation statements)

References 12 publications

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“…Subsequently, comparison of heat and mass transfer between single and two phase models was drawn via numerical study for nanofluid liquid film which was flowing downward a vertical channel. It was deduced that two phase model was more practical as it accounts for thermophoresis and Brownian effects [13]. Latterly, Ambreen et al, [14] carried out very comprehensive research on single phase and the multiphase models where they noticed that at low Reynolds number, single and multiphase models can precisely predict the thermal fields of diluted nanofluids but at denser concentration and higher Reynold number the results are overestimated.…”

Section: Introductionmentioning

confidence: 99%

Multiphase CFD Investigation on Convective Heat Transfer Enhancement for Turbulent Flow of Water-Al2O3 Nanofluid

Mahmud

Ismail

2021

CFDL

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Because of extraordinary heat transfer capability, nanofluids have become a potential interest in engineering sectors. Despite being a multiphase fluid, nanofluids were treated as single phase fluids in many previous studies and comparison between single and two phase models was drawn. Examining nanofluids capability to augment heat transfer is one of the keys to utilize them properly in the field of thermofluids. However, the optimal multiphase model to simulate nanofluids heat transfer enhancement is yet to be found out. In this study, the method of computational fluid dynamics has been used to simulate flow of water-Al2O3 nanofluid in a circular pipe in the purpose of identifying the best multiphase model to simulate heat transfer enhancement of nanofluids. Two multiphase models have been taken into account: Volume of Fluid and Mixture model. Three different volume fractions of nanoparticles in nanofluid have been tested for each of these models such as 1%,4% and 6% for highly turbulent flows where Reynolds number was ranged between 20000 to 80000. The standard k-ɛ turbulence model has been employed to model the flow of nanofluid with the mentioned multiphase models in the present study. The results have been carried out in forms of correlation between Re and Nu and have been compared with existing experimental results. The results showed that the heat transfer enhancement of nanofluid is mostly dominated by concentration of nanoparticles present in the fluid and suggested that Mixture model is suitable for predicting convective heat transfer enhancement of nanofluid for cases with high particle concentration though the necessity of further experimental study in some scopes has been detected.

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Section: Introductionmentioning

confidence: 99%

Multiphase CFD Investigation on Convective Heat Transfer Enhancement for Turbulent Flow of Water-Al2O3 Nanofluid

Mahmud

Ismail

2021

CFDL

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“…According to the obtained results, the increase in the amplitude and number of waves of the wall causes an enhancement in heat and mass transfer. Recently, Najim et al [25][26][27] have conducted numerical studies on nanofluid liquid film evaporation in vertical channels.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of effective parameters of falling film evaporation in a vertical‐tube evaporator

Haghsheno

Kouhikamali

2020

Heat Trans

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Wastewater treatment is one of the most effective solutions to manage the problem of water scarcity. Falling film evaporators are excellent technology in wastewater treatment plants. These wastewater evaporators provide high heat transfer, short residence time in the heating zone, and high‐purity distilled water. In the present study, the mechanism of turbulent falling film evaporation in a vertical tube has been investigated. A model has been developed for symmetrical two‐dimensional pure and saline water flow in a vertical tube under constant wall heat flux. The numerical simulation has been carried out by a commercial computational fluid dynamics code. The evaporation of saturated liquid film is simulated utilizing a two‐phase volume of fluid method and Tanasawa phase‐change model. The main objective of this study is to evaluate the effects of water salinity, liquid Reynolds number, wall heat flux, and liquid film thickness on the two‐phase heat transfer coefficient and vapor volume fraction. The numerical heat transfer coefficients are compared with the obtained results by Chen's empirical correlation. With a MAPE ≤ 11%, this study proves that the numerical method is highly effective at predicting the heat transfer coefficient. Moreover, the empirical coefficient of the Tanasawa model and the minimum thickness of the falling film are determined.

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Comparative numerical study of single and two-phase models of nanofluid liquid film evaporation in a vertical channel

Cited by 2 publications

References 12 publications

Multiphase CFD Investigation on Convective Heat Transfer Enhancement for Turbulent Flow of Water-Al2O3 Nanofluid

Multiphase CFD Investigation on Convective Heat Transfer Enhancement for Turbulent Flow of Water-Al2O3 Nanofluid

Numerical investigation of effective parameters of falling film evaporation in a vertical‐tube evaporator

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