Condensation of water vapor in a vertical channel by mixed convection of humid air in the presence of a liquid film flowing down

Mohamed, A. Belhadj; Orfi, Jamel; Debissi, C.; Nasrallah, Sassi Ben

doi:10.1016/j.desal.2006.02.045

Cited by 8 publications

(3 citation statements)

References 12 publications

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“…However, these results are reversed for elevated Reynolds numbers. Mohamed et al [12] presented a model for the computational investigation of the condensation of humid air in the presence of liquid film flowing down inside a vertical channel. It was noticed that growing the quantity of water film or decreasing its inlet temperature promotes the condensation process.…”

Section: Nanoparticles Application In Convection Heat Transfermentioning

confidence: 99%

Numerical Investigation of Influence of Nanoparticles Presence on Water Vapor Condensation Process inside a Vertical Channel

Hssain

Armou

Zine-Dine

et al. 2021

Journal of Nanomaterials

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This paper is aimed at investigating the nanofluid film condensation by mixed convection in the presence of water vapor, Cu nanoparticles, and air treated as a noncondensable gas (NCG) on the inner walls of a vertical channel. In this simulation, the flow is laminar, stationary, two dimensional, and axisymmetric. The coupled governing equations for the liquid film with the nanoparticles and the mixture air-humid-nanoparticles are solved together using the finite volume method. Since the application of humid air condensation is one of the most applicable methods of phase change processes that is observed in different industrial fields such as heating, ventilation, and air conditioning (HVAC) or cooling systems, for this purpose, the influence of injecting a uniform volume fraction of nanoparticles on improving heat and mass transfer is determined as a function of the variation in relative humidity, velocity, temperature, pressure, and volume fraction of Cu nanoparticles at the channel inlet. The numerical results indicate that under the best conditions in the range of variation studied RH in = 100 % , Re in = 2000 , T in = 50 ° C , P in = 0.5 atm , and φ in = 0.1 % , the use of nanoparticles has a greater impact, and the maximum improvement in the condensation film thickness, the local Nusselt number, and the accumulated condensation rate has an effective ratio strictly greater than one compared with the case of pure humid air.

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Section: Nanoparticles Application In Convection Heat Transfermentioning

confidence: 99%

Numerical Investigation of Influence of Nanoparticles Presence on Water Vapor Condensation Process inside a Vertical Channel

Hssain

Armou

Zine-Dine

et al. 2021

Journal of Nanomaterials

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show abstract

“…Results indicate that a higher concentration of non-condensable gas caused substantial reduces in the local Nusselt number, the pressure gradient and the film thickness. Belhadj et al [6] conducted a numerical analysis to improve the condensation process of water vapour inside a vertical channel. Their results show that the phenomenon of phase change is sensitive to the inlet temperature of liquid film.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of Liquid Film Condensation with the Presence of Non-Condensable Gas in a Vertical Tube

Charef¹,

Feddaoui²,

Alla³

2018

Desalination and Water Treatment

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The main objective of this chapter is to study the liquid film condensation in a thermal desalination process, which is based on the phase change phenomenon. The external tube wall is subjected to a constant temperature. The set of the non-linear and coupled equations expressing the conservation of mass, momentum and energy in the liquid and gas mixtures is solved numerically. An implicit finite difference method is employed to solve the coupled governing equations for liquid film and gas flow together with the interfacial matching conditions. Results include radial direction profiles of axial velocity, temperature and vapour mass fraction, as well as axial variation of the liquid film thickness. Additionally, the effects of varying the inlet conditions on the phase change phenomena are examined. It was found that increasing the inlet-to-wall temperature difference improves the condensate film thickness. Decreasing the radius of the tube increased the condensation process. Additionally, non-condensable gas is a decisive factor in reducing the efficiency of the heat and mass exchanges. Overall, these parameters are relevant factors to improve the effectiveness of the thermal desalination units.

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“…The effects of the inlet parameters on the condensation process were analyzed. Belhadj et al considered a downward flow of an air‐water system in a vertical channel. They showed that increasing the water film amount benefits the condensation rate.…”

Section: Introductionmentioning

confidence: 99%

Analysis of conjugated processes of film evaporation and condensation in a tubular heat exchanger

2016

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This paper investigates coupled phase changes by forced convection from co‐current flows of liquid films and vapour‐air mixtures in a tubular heat exchanger. Evaporation occurs in the inner tube and condensation in the annulus region. Heat and mass transfers in the liquid films and the vapour‐gas mixtures are described by the conservation equations of momentum, energy, and diffusion. An appropriate change of coordinates is introduced in order to obtain a computational mesh with straight liquid‐mixture interfaces along the walls. The governing equations are discretized by an implicit finite differences method and solved using an efficient numerical methodology. The distributions of axial velocity, temperature, and vapour concentration in all regions of the tubes are determined from iterative procedures with a high convergence rate. The current analysis also provides the axial evolutions of film thicknesses, heat flux, condensation, and evaporation rates in the whole domain. In addition, the effects of the inlet parameters of Reynolds number, relative humidity, pressure, and liquid flow rate on the heat transfer characteristics, and the evaporation and condensation rates are also investigated.

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Condensation of water vapor in a vertical channel by mixed convection of humid air in the presence of a liquid film flowing down

Cited by 8 publications

References 12 publications

Numerical Investigation of Influence of Nanoparticles Presence on Water Vapor Condensation Process inside a Vertical Channel

Numerical Investigation of Influence of Nanoparticles Presence on Water Vapor Condensation Process inside a Vertical Channel

Computational Study of Liquid Film Condensation with the Presence of Non-Condensable Gas in a Vertical Tube

Analysis of conjugated processes of film evaporation and condensation in a tubular heat exchanger

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