Three-Dimensional Study of Heat and Mass Transfer in a Partially Porous Elongated Cavity

2010 ◽  
Vol 297-301 ◽  
pp. 728-732
Author(s):  
N. Mimouni ◽  
Salahs Chikh ◽  
Rachid Bennacer
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Cooling System ◽  
Mass Transfer Rate ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Geometrical Parameters ◽  
Computational Domain ◽  
Adsorption Cooling System

A 3D numerical analysis is carried out to investigate heat and mass transfer in a partly porous cavity of high aspect ratio. The goal is to determine the best physical and geometrical parameters that allow optimal heat and mass transfer rate in such domain used in a solar adsorption cooling system. The computational domain consists of a tall cavity heated on the left vertical wall and cooled on the opposing wall. The SIMPLE algorithm is used to handle the velocity pressure coupling. Simulation results allow determining the optimal configuration of the used porous substrate and plain fluid position in the cavity in order to optimize the performance of such solar adsorption cooling installation.

Characteristics of Flow and Heat-and-Mass Transfer in a Falling Liquid Film With Three-Dimensional Interfacial Waves

2002 ◽  
Author(s):  
Takao Nagasaki ◽  
Hirokuni Akiyama ◽  
Hiroshi Nakagawa ◽  
Yutaka Ito
Keyword(s):  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Mass Transfer Rate ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Large Wave ◽  
Calculated Mass ◽  
Dimensional Wave

Numerical simulations have been made on the flow and heat-and-mass transfer in a laminar liquid film falling down along a vertical wall by using a boundary-fitted coordinate system. The development of a two-dimensional wave was successfully predicted, which consists of a large solitary wave and ripple waves in front of it. In the large wave a circulating flow exists, and the heat and mass transfer is enhanced by the wave. Further, it was shown by a three-dimensional calculation that a two-dimensional wave becomes unstable with the increase of Re number, resulting in U-shaped three-dimensional wave. The mass transfer rate increases with the transition from two-dimensional to three-dimensional waves. The calculated mass transfer coefficient roughly agrees with empirical correlations.

A Review on Working Pair Used in Adsorption Cooling System

2015 ◽  
Vol 23 (02) ◽  
pp. 1530001 ◽  
Author(s):  
Vinayak D. Ugale ◽  
Amol D. Pitale
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Cooling System ◽  
Physical Adsorption ◽  
Vital Role ◽  
Transfer Performance ◽  
Adsorption System ◽  
Adsorption Cooling System ◽  
Adsorber Bed

Adsorption cooling system find its application in refrigeration, air conditioning, chiller, Ice making, etc. It uses thermal energy as driving force. Adsorption systems are environmental friendly (zero global warming potential and ozone depleting potential) and also eliminates use of compressor and minimize vibration problem. So it can be used as substitute for conventional vapor compression refrigeration system or vapor absorption system. The adsorption generally classified in two types as physical adsorption (due to weak van der waal forces) and chemical adsorption (chemical reaction between adsorbent and adsorbate form new molecules). The working pair of adsorber and adsorbate play vital role in the performance of adsorption system. Activated carbon, zeolite, silica gel are commonly used adsorber and water, ammonia, methanol and ethanol can be used as adsorbate. The poor heat and mass transfer performance of adsorption is major challenge for researchers. The heat transfer performance of adsorption system can be increased by increasing heat transfer area of adsorber bed i.e., design of new adsorber bed, while mass transfer performance is improved by use of new adsorbent with higher sorption rate. Composite adsorber solve the problem of heat and mass transfer performance of chemical adsorbents and adsorption quantity of physical adsorbents by combination of chemical and physical adsorbent but it can add some limitation with it. In this paper, various adsorption pair, their selection, design of adsorber bed, methods to improve thermal performance of adsorber bed is reviewed with their properties, advantages and limitations.

Unsteady flow of three-dimensional Maxwell nanofluid with variables properties over a stretching surface

2021 ◽  
pp. 095440892110390
Author(s):  
Muhammad N Khan ◽  
Shafiq Ahmad ◽  
Sohail Nadeem ◽  
El-Sayed M. Sherif ◽  
Hijaz Ahmad ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Variable Viscosity ◽  
Fluid Velocity ◽  
Mass Transfer Rate ◽  
Three Dimensional ◽  
Maxwell Fluid ◽  
Convective Boundary Condition ◽  
Convective Boundary ◽  
Viscosity Parameter

The present article focuses on the time-dependent three-dimensional Maxwell fluid flow with temperature-dependent fluid properties along the stretching sheet. The heat and mass transfer analysis are presented in the occurrence of activation energy, convective boundary condition, and non-uniform heat source/sink effect. The flow model is converted into a system of coupled ODEs with the help of a similarity transformation. The numerical built-in technique Bvp4c is employed to solve the obtained coupled ODEs. The graphical outcomes are obtained against the various parameters and discussed. It is seen from the graphs that fluid velocity diminishes for stronger values of relaxation parameter and shows an opposite trend for the variable viscosity parameter. Moreover, it is noted from the tabulated data that the heat and mass transfer rate reduces for the stronger values of unsteadiness and the variable viscosity parameter.

Heat and Mass Transfer Characteristics in Consolidated Silica Gel/Water Adsorption–Cooling System

1997 ◽  
Author(s):  
Hideharu Yanagi ◽  
Nobumi Ino
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Silica Gel ◽  
Cooling System ◽  
Adsorption Heat ◽  
Overall Heat Transfer Coefficient ◽  
Operational Characteristics ◽  
Adsorption Cooling System ◽  
Desorption Cycle

The heat and mass transfer on adsorption beds is decisive for the operational characteristics of adsorption refrigerators. To overcome its heat and mass transfer limitations a consolidated silica gel adsorption heat exchanger has been designed and successfully developed. It was made of composite as 4.3 wt% graphite, 86.4 wt% silica gel and binders, which was pressed into a heat exchanger module and then dried under a temperature of 90°C for 24 hours. With use of this adsorption heat exchanger, we measured an overall heat transfer coefficient of 62.2 W/m2K at the beginning of desorption cycle and 61.5 W/m2K during desorption, respectively. Whereas corresponding values of a granular silica gel bed were 44.8 W/m2K and 25.9 W/m2K, respectively. This paper presents the operational characteristics of consolidated silica gel adsorption heat exchanger in refrigeration cycles, in addition to its isoster measurements for silica gel-water pair compared to that of the granular heat exchanger.

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