Comparative study during condensation of R152a and R134a with presence of non-condensable gas inside a vertical tube

Charef, Adil; Feddaoui, M’barek; Najim, Monssif; Meftah, Hicham

doi:10.1007/s00231-017-2205-2

Cited by 10 publications

(3 citation statements)

References 30 publications

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“…It is important to indicate that Lebedev et al [2] examined the simultaneous heat and mass transfer during humid air condensation in a vertical duct. So, to obtain the case of Lebedev et al [2], equivalent hydraulic diameter de is chosen [7,26]. Figure 4 is a plot of local condensate heat transfer coefficient compared with the study of Lebedev et al [2] for T 0 =6 0 C, P 0 =1a t m ,L = 0.6 m, T W =5 Ca n dde = 0.02 m. A good agreement between our computations and the experiment curves is found with a maximum relative error of 4.7% for both curves (u 0 =1.4m/s and u 0 = 0.7 m/s).…”

Section: Desalination and Water Treatmentmentioning

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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Section: Desalination and Water Treatmentmentioning

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

Self Cite

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“…The condensation of vapor in a porous medium has received great interest in many theoretical and experimental researches [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Shekarriz and Plumb [1] analyzed the influence of the presence of the porous medium on the condensation of a film on the external wall of a horizontal tube.…”

Section: Introductionmentioning

confidence: 99%

“…A numeric model of heat and mass transfer enhancement of liquid film condensation by covering a porous layer on one of channel vertical plates has been studied by Abdelaziz Nasr [10]. He confirmed that the heat and mass transfer performance at the liquid-gas interface when condensing the liquid film is enhanced by the presence of the porous layer.A numerical study of the liquid film condensation from vapour-gas mixtures of HFC refrigerants inside a vertical tube was carried out by Charef A. et al [11]. They performed parametric calculations to examine the effects of the Reynolds number of entry, the length of the tube and the temperature of entry of the mixtures of gases on the condensation mechanism.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Thin Film Condensation in Forced Convection in a Canal Whose Walls Are Covered with a Porous Material: Influence of ratio of form-Determination of Lengths of Entry

2022

JCBSC

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The forced convection thin film type condensation of pure saturated vapor in a channel whose walls are covered with a porous material is studied numerically. To describe the flow, in the porous medium the generalized model of Darcy-Brinkman-Forchheimer (DBF) is used while the classical equations of the boundary layer have been exploited in pure liquid. These equations thus rendered dimensionless, are solved by an implicit finite difference method and the iterative Gauss-Seidel sub-relaxation method. We note that an increase in the ratio of form (or length of the cold plate) allows better contact with the cold plate, increases the friction imposed by this porous wall and allows a decrease in velocity and temperatures in the porous medium and the pure liquid. It also causes an increase in the thickness of the liquid film (favored condensation), decreases the rate of heat transfer at the porous medium / liquid film interface and the lengths of entry. This decrease in lengths of entry is exponential and very significant when the ratio of form is between 55 and 100 (55≤L/A≤100). We conclude that the sensitivity of condensation to a change in ratio of form is very high between 55 and 100.

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The influence of plates corrugations angle on PHE thermal performance in condensing of steam with the presence of air

et al. 2023

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Comparative study during condensation of R152a and R134a with presence of non-condensable gas inside a vertical tube

Cited by 10 publications

References 30 publications

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

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

Numerical Study of Thin Film Condensation in Forced Convection in a Canal Whose Walls Are Covered with a Porous Material: Influence of ratio of form-Determination of Lengths of Entry

The influence of plates corrugations angle on PHE thermal performance in condensing of steam with the presence of air

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