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

2020 ◽  
Vol 307 ◽  
pp. 01034 ◽  
Author(s):  
Monssif Najim ◽  
M’barek Feddaoui ◽  
Abderrahman Nait Alla ◽  
Adil Charef
Keyword(s):  
Mass Transfer ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Difference Method ◽  
Single Phase ◽  
Vertical Channel ◽  
Two Phase ◽  
Phase Models

The main purpose of this study is to survey numerically comparison of two-phase and single-phase models of heat and mass transfer of Al2O3-water nanofluid liquid film flowing downward a vertical channel. A finite difference method is developed to produce the computational predictions for heat and mass transfer during the evaporation of the liquid film approached by the single-phase and two-phase models. The model solves the coupled governing equations in both nanofluid and gas phases together with the boundary and interfacial conditions. The systems of equations obtained by using an implicit finite difference method are solved by Tridiagonal Matrix Algorithm. The results show that the two-phase model is more realistic since it takes into account the thermophoresis and Brownian effects.

Modelling of a desiccant rotor by using the collocation method

2013 ◽  
Vol 24 (1) ◽  
pp. 201-220 ◽  
Author(s):  
Marcello Aprile ◽  
Mario Motta
Keyword(s):  
Mass Transfer ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Heat And Mass Transfer ◽  
Collocation Method ◽  
Difference Method ◽  
Transfer Problem ◽  
Operating Conditions ◽  
Content Type ◽  
The Finite Difference Method

Purpose – This article aims to develop a fast numerical method for solving the one-dimensional heat and mass transfer problem within a desiccant rotor. Design/methodology/approach – The collocation method is used for discretizing the axial dimension and reducing the number of dependent variables. The resulting system of equation is then solved through backward differentiation formulas. Findings – The numerical results obtained here focus on verifying the accuracy and the computation time of the proposed method with respect to the finite difference method. The proposed numerical solution method resulted faster than, and as much accurate as, the finite difference method, over a large range of operating conditions that are of interest in desiccant cooling applications. Research limitations/implications – For heat and mass transfer analysis, constant average transfer coefficients are used. The results are calculated for NTU between 2 and 15 and for Le number between 0.5 and 2. Practical implications – The results can be used in designing desiccant heat exchangers and desiccant cooling systems including complex rotor arrangements. Originality/value – Different from other simplified solution techniques, the proposed method relies on few parameters that retain physical meaning and applies also to complex rotor configurations.

scholarly journals Computational Study of Liquid Film Evaporation along a Wavy Wall of a Vertical Channel

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Monssif Najim ◽  
M’barek Feddaoui ◽  
Abderrahman Nait Alla ◽  
Adil Charef
Keyword(s):  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Numerical Study ◽  
Computational Study ◽  
Vertical Channel ◽  
Wavy Wall ◽  
Gas Phases ◽  
Multiple Parameters ◽  
Film Evaporation

A numerical study of mixed convection heat and mass transfer along a vertical channel with a wavy wall is performed. The wavy wall is heated by a constant flux, while the other is adiabatic. The discretisation of equations in both liquid and gas phases is realised using an implicit finite difference scheme. Results of simulation compare the effect of multiple parameters, especially amplitude and characteristic length of the curve, on the liquid film evaporation process. The results indicate that heat and mass transfer is enhanced by increasing the amplitude and number of wall waves. Moreover, a very small value of waves amplitude of the wall may reduce the sensible heat and mass transfer.

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