Numerical Simulations of Heat and Mass Transfer Process of a Direct Evaporative Cooler From a Porous Layer

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Karima Sellami ◽  
M'barek Feddaoui ◽  
Nabila Labsi ◽  
Monssif Najim ◽  
Youb Khaled Benkahla
Keyword(s):  
Porous Medium ◽  
Porous Layer ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Mass Transfer Process ◽  
High Porosity ◽  
Ambient Conditions ◽  
Cooling Performance ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler

This paper deals with the numerical study of the combined heat and mass exchanges in the process of direct evaporative cooler, from a porous media of laminar air flow between two parallel insulated walls. The numerical model implements momentum, energy, and mass conservation equations of humid air and water flow incorporating non-Darcian model in the porous region. The finite volume method is used for the mathematical model resolution, and the velocity–pressure coupling is treated with the SIMPLE algorithm. The main objective of this study is to examine the influences of ambient conditions and the porous medium properties (porosity and porous layer thickness) on the direct evaporative cooling performance from a porous layer. The major results of this study demonstrate that the porous evaporative wall could, in a satisfying manner, reduce the bulk air temperature. The better cooling performance can be achieved for lower air mass flow at the entrance and relative humidity. Additionally, the evaporative cooler is more effective for a high porosity and a thick porous medium, with an improvement achieving 23% for high porosity.

Advanced Cooling Tower Concept for Commercial and Industrial Applications

2014 ◽  
Author(s):  
Sergey Anisimov ◽  
Aleksandr Kozlov ◽  
Paul Glanville ◽  
Mark Khinkis ◽  
Valeriy Maisotsenko ◽  
...  
Keyword(s):  
Cooling Tower ◽  
Industrial Applications ◽  
Process Efficiency ◽  
Limiting Factor ◽  
Cooling Towers ◽  
Water Stream ◽  
Cooling Performance ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler ◽  
The U.S

For the majority of cooling towers installed, of which there are greater than half a million installed in the U.S., tower design uses direct evaporative cooler technology where an ideally enthalpy-neutral process cools the process water stream to a temperature above the ambient wet bulb. This ambient wet bulb temperature is the limiting factor for the process cooling. As such the energy-water connection is clear, these cooling towers are direct consumers of treated water and their cooling performance is intimately tied to the process efficiency.

Numerical study of interaction of compression waves with a layer of a porous medium in the linear approximation

2007 ◽  
Vol 5 ◽  
pp. 151-156
Author(s):  
A.A. Gubaidullin ◽  
O.Yu. Boldyreva ◽  
D.N. Dudko
Keyword(s):  
Porous Medium ◽  
Linear Approximation ◽  
Porous Layer ◽  
Numerical Study ◽  
Fourier Method ◽  
Rigid Wall ◽  
Method Of Calculation ◽  
Compression Waves

The interaction of compression waves with a porous layer shielding a rigid wall is investigated. The cases of the presence or absence of the gap between the porous layer and the rigid wall are considered. On the basis of the Fourier method, method of calculation of pressure and stress in the porous layer, the gap and at the obstacle with the passage of the compression waves from the fluid into the porous layer and the subsequent reflection from obstacles, in linear approximation is proposed.

Numerical Study of Premixed Combustion of Methane Stabilized on Porous Medium

2016 ◽  
Author(s):  
Valerio Giovannoni ◽  
Rajnish N. Sharma ◽  
Robert R. Raine
Keyword(s):  
Porous Medium ◽  
Numerical Study ◽  
Burning Velocity ◽  
Combustion Process ◽  
Heat Losses ◽  
Low Flow ◽  
Small Scale ◽  
High Porosity ◽  
Flow Rates ◽  
Flame Holder

The present study focuses on the numerical analysis of the combustion process occurring in a small scale cylindrical combustion chamber using a commercial computational code. The chosen diameter is 18 mm, being the same as the flat flame regenerative combustor currently under experimental investigation by the author (Giovannoni), and it includes a 10 mm thick porous flame holder and a 1 mm thick stainless steel outer wall. A 17 species and 73 reactions skeletal mechanism related to methane oxidation is employed for the simulations. A parametric study is performed and results in terms of temperature profiles, major species’ concentrations and flow velocities are presented. Results show that the flame holder can considerably affect combustion and heat losses from the combustor. In particular at low flow rates, when the laminar burning velocity is much higher than the flow velocity, heat is lost mainly through the flame holder to the walls and to the surroundings. At high flow rates the flame appears to be slightly lifted from the porous medium and heat is mainly dispersed to the walls. This causes preheating of the mixture upstream of the combustion through axial conduction in the wall, achieving superadiabatic temperature. It is also clear from the simulations that employing a flame holder with low thermal conductivity and high porosity yields benefits in limiting heat losses and in widening flammability limits.

Effect of Viscous Dissipation on MHD Williamson Nanofluid Flow in a Porous Medium

2019 ◽  
Vol 8 (3) ◽  
pp. 5795-5802 ◽  
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Numerical Solution ◽  
Viscous Dissipation ◽  
Flow Problem ◽  
Numerical Study ◽  
Steady State Flow ◽  
Nanofluid Flow ◽  
Shooting Technique ◽  
Order Four

The main objective of this paper is to focus on a numerical study of viscous dissipation effect on the steady state flow of MHD Williamson nanofluid. A mathematical modeled which resembles the physical flow problem has been developed. By using an appropriate transformation, we converted the system of dimensional PDEs (nonlinear) into coupled dimensionless ODEs. The numerical solution of these modeled ordinary differential equations (ODEs) is achieved by utilizing shooting technique together with Adams-Bashforth Moulton method of order four. Finally, the results of discussed for different parameters through graphs and tables.

Simulation of volumetric heating of a moist medium with allowance for fluid mobility

2012 ◽  
Vol 9 (1) ◽  
pp. 91-93
Author(s):  
U.R. Ilyasov ◽  
A.V. Dolgushev
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Numerical Solution ◽  
Heat And Mass Transfer ◽  
Transfer Process ◽  
Thermal Action ◽  
Mass Transfer Process ◽  
Low Permeability ◽  
Volumetric Heating ◽  
Drying Regime

The problem of volumetric thermal action on a moist porous medium is considered. Numerical solution, the influence of fluid mobility on the dynamics of the heat and mass transfer process is analyzed. It is established that fluid mobility leads to a softer drying regime. It is shown that in low-permeability media, the fluid can be assumed to be stationary.

Numerical study of the flow of a mixture of reacting gases in an inhomogeneous catalyst layer

2003 ◽  
Vol 3 ◽  
pp. 246-254
Author(s):  
C.I. Mikhaylenko ◽  
S.F. Urmancheev
Keyword(s):  
Velocity Field ◽  
Chemical Reactions ◽  
Porous Layer ◽  
Computational Experiment ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Catalyst Layer ◽  
Granular Catalyst ◽  
Fluid Velocity Field

The behavior of a liquid flowing through a fixed bulk porous layer of a granular catalyst is considered. The effects of the nonuniformity of the fluid velocity field, which arise when the surface of the layer is curved, and the effect of the resulting inhomogeneity on the speed and nature of the course of chemical reactions are investigated by the methods of a computational experiment.

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