Simultaneous Heat and Mass Transfer in Film Absorption With the Presence of Non-Absorbable Gases

2000 ◽  
Vol 123 (5) ◽  
pp. 984-989 ◽  
Author(s):  
Hamza M. Habib ◽  
Byard D. Wood
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Lithium Chloride ◽  
Numerical Solutions ◽  
Adiabatic Wall ◽  
Average Mass ◽  
Mass Fluxes ◽  
Wide Range ◽  
Aqueous Lithium Bromide

Numerical solutions are presented for the effect of a non-absorbable gas on the heat and mass transfer rates during the absorption of water vapor by a falling laminar smooth film of an aqueous lithium bromide or aqueous lithium chloride solution (absorbent). The geometry consists of a vertical channel with two walls, one of which is isothermal and the other adiabatic. The liquid film of an absorbent flows down over the isothermal wall, while a mixture of water vapor and air flows between the liquid free-surface and the adiabatic wall. The whole system is kept under vacuum pressure. Water vapor is absorbed by the film and air is the non-absorbable gas. The momentum, energy, and concentration equations are written with a set of interfacial and boundary conditions and solved numerically for the two phases. Variable property effects are included, as well as the interfacial shear. Heat and mass transfer results are presented over a wide range of inlet air concentrations. The average mass fluxes showed a continuous reduction with an increase in the amount of air for a concentration of air as high as 40 percent by weight. But the local mass fluxes showed a different behavior from the absorption of a pure vapor case. The decrease was much higher at the entrance than in a pure vapor case. The numerical results are in good agreement with the experimental data available for lithium chloride. The model has promise as means of predicting the heat and mass transfer characteristics of falling film absorber.

Effects of a Nonabsorbable Gas on Interfacial Heat and Mass Transfer for the Entrance Region of a Falling Film Absorber

1996 ◽  
Vol 118 (1) ◽  
pp. 45-49 ◽  
Author(s):  
T. A. Ameel ◽  
H. M. Habib ◽  
B. D. Wood
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Analytical Solution ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Vertical Wall ◽  
Lithium Bromide ◽  
Entrance Region ◽  
Falling Film ◽  
Aqueous Lithium Bromide

An analytical solution is presented for the effect of air (nonabsorbable gas) on the heat and mass transfer rates during the absorption of water vapor (absorbate) by a falling laminar film of aqueous lithium bromide (absorbent), an important process in a proposed open-cycle solar absorption cooling system. The analysis was restricted to the entrance region where an analytical solution is possible. The model consists of a falling film of aqueous lithium bromide flowing down a vertical wall which is kept at uniform temperature. The liquid film is in contact with a gas consisting of a mixture of water vapor and air. The gas phase is moving under the influence of the drag from the falling liquid film. The governing equations are written with a set of interfacial and boundary conditions and solved analytically for the two phases. Heat and mass transfer results are presented for a range of uniform inlet air concentrations. It was found that the concentration of the nonabsorbable gas increases sharply at the liquid gas interface. The absorption of the absorbate in the entrance region showed a continuous reduction with an increase in the amount of air.

Combined Heat and Mass Transfer by Natural Convection With Opposing Buoyancies

1993 ◽  
Vol 115 (3) ◽  
pp. 606-612 ◽  
Author(s):  
R. L. Mahajan ◽  
D. Angirasa
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Numerical Solutions ◽  
Boundary Layer Analysis ◽  
Layer Analysis ◽  
Wide Range ◽  
Schmidt Numbers ◽  
Buoyancy Ratio

A numerical study is presented for combined heat and mass transfer by natural convection from a vertical surface with opposing buoyancy effects. A comparison with similarity solutions shows that boundary layer analysis is suitable only when the two buoyant forces aid each other. For opposing flows the boundary layer analysis does not predict the transport rates accurately. A detailed comparison with experimental data with opposing buoyancies shows good agreement between the data and the numerical solutions. The heat and mass transfer rates follow complex trends depending on the buoyancy ratio and the Prandtl and Schmidt numbers. Comprehensive Nusselt and Sherwood number data are presented for a wide range of thermal Grashof number, buoyancy ratio, and Prandtl and Schmidt numbers.

scholarly journals Influence of Couple Stresses and Thermophoresis on Free Convective Heat and Mass Transfer of Viscoelastic Fluid.

2020 ◽  
Vol 17 ◽  
pp. 50-63
Author(s):  
N. T. M. Eldabe ◽  
Ahmed Refaie Ali ◽  
Gamil Ali Shalaby
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Newtonian Fluid ◽  
Numerical Solutions ◽  
Viscoelastic Model ◽  
Skin Friction Coefficient ◽  
Physical Parameters ◽  
Couple Stresses ◽  
Linear Differential

A theoretical study has been developed to investigate the influence of thermophoresis and couple stresses on the steady flow of non-Newtonian fluid with free convective heat and mass transfer over a channel bounded by two permeable plates. The considered non-Newtonian fluid follows a viscoelastic model. The problem is modulated mathematically by a system of non-linear differential equations pertaining to describe the continuity, momentum, energy, and concentration. These equations involve the effects of viscous dissipation and chemical reaction. The numerical solutions of the dimensionless equations are found as a function of the physical parameters of this problem. The numerical formulas of the velocity (u), temperature Φ and concentration Θ as well as skin friction coefficient T*, Nusselt number(Nu) and Sherwood number(Sh) are computed. The physical parameter's effects of the problem on these formulas are described and illustrated graphically through some figures and tables. It is observed that any increase in the thermophoretic parameter T leads to reduce in velocity profiles as well as concentration layers. In contrast, the velocity increases with increasing the couple stresses inverse parameter.

Effect of Thermophoresis and Brownian Moment on 2D MHD Nanofluid Flow over an Elongated Sheet

2017 ◽  
Vol 377 ◽  
pp. 111-126 ◽  
Author(s):  
C. Sulochana ◽  
G.P Ashwinkumar ◽  
Naramgari Sandeep
Keyword(s):  
Mass Transfer ◽  
Heat Source ◽  
Heat And Mass Transfer ◽  
Newtonian Fluid ◽  
Numerical Solutions ◽  
Frictional Heating ◽  
Mass Transfer Rate ◽  
Dual Nature ◽  
Source Sink ◽  
The Impact

In this study, we investigated the 2D MHD flow of a dissipative Maxwell nanofluid past an elongated sheet with uneven heat source/sink, Brownian moment and thermophoresis effects. The flow governing PDEs are transmuted into nonlinear ODEs adopting the suitable similarity transmissions. Further, the RK-4 technique is employed to acquire the numerical solutions. The impact of pertinent parameters such as thermal radiation, frictional heating, irregular heat source/sink, biot number, Brownian moment and thermophoresis on the flow quantities such as velocity, thermal and concentration fields likewise friction factor, heat and mass transfer rates are bestowed with the succour of graphs and tables. Dual nature is witnessed for Newtonian and non-Newtonian fluid cases. It is noticed that the heat and mass transfer rate in Newtonian fluid larger as compared with non-Newtonian fluid.

scholarly journals Unsteady Hydromagnetic Heat and Mass Transfer Flow of a Heat Radiating and Chemically Reactive Fluid Past a Flat Porous Plate with Ramped Wall Temperature

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
R. Nandkeolyar ◽  
M. Das ◽  
P. Sibanda
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Wall Temperature ◽  
Numerical Solutions ◽  
Porous Plate ◽  
Transfer Coefficients ◽  
Electrically Conducting ◽  
Fluid Properties ◽  
Parameter Values ◽  
Transfer Flow

Unsteady hydromagnetic free convective flow of a viscous, incompressible, electrically conducting, and heat radiating fluid past a flat plate with ramped wall temperature and suction/blowing is studied. The governing equations are first subjected to Laplace transformation and then inverted numerically usingINVLAProutine of Matlab. The numerical solutions of the fluid properties are presented graphically while the skin friction and heat and mass transfer coefficients are presented in tabular form. The results are verified by a careful comparison with results in the literature for certain parameter values.

Exploration of Chemical Reaction Effects on Entropy Generation in Heat and Mass Transfer of Magneto-Jeffery Liquid

2018 ◽  
Vol 16 (9) ◽  
Author(s):  
R. Mohapatra ◽  
B. Mahanthesh ◽  
B.J. Gireesha ◽  
S.R. Mishra
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Chemical Reaction ◽  
Chemical Engineering ◽  
Numerical Solutions ◽  
Ceramic Materials ◽  
Transverse Magnetic ◽  
Cross Diffusion ◽  
Order Chemical Reaction ◽  
First Order Chemical Reaction

AbstractIn many chemical engineering processes, a chemical reaction between a foreign mass and the fluid does occur. These processes find relevance in polymer production, oxidation of solid materials, ceramics or glassware manufacturing, tubular reactors, food processing, and synthesis of ceramic materials. Therefore, an exploration of homogeneous first-order chemical reaction effects on heat and mass transfer along with entropy analysis of Jeffrey liquid flow towards a stretched isothermal porous sheet is performed. Fluid is conducting electrically in the company of transverse magnetic field. Variations in heat and mass transfer mechanisms are accounted in the presence of viscous dissipation, heat source/sink and cross-diffusion aspects. The partial differential equations system governing the heat transfer of Jeffery liquid is reformed to the ordinary differential system through relevant transformations. Numerical solutions based on Runge-Kutta shooting method are obtained for the subsequent nonlinear problem. A parametric exploration is conducted to reveal the tendency of the solutions. The present study reveals that the Lorentz force due to magnetism can be used as a key parameter to control the flow fields. Entropy number is larger for higher values of Deborah and Brinkman numbers. It is also established that the concentration species field and its layer thickness of the Jeffery liquid decreases for a stronger chemical reaction aspect. To comprehend the legitimacy of numerical results a comparison with the existing results is made in this exploration and alleged an admirable agreement.

Geometrical Effects of Cabinet Size and Aspect Ratio on Heat and Mass Transfer During Open Door Conditions

2005 ◽  
Author(s):  
W. Terrell
Keyword(s):  
Mass Transfer ◽  
Aspect Ratio ◽  
Heat And Mass Transfer ◽  
Ambient Air ◽  
Open Door ◽  
Nusselt Numbers ◽  
Aspect Ratios ◽  
Mass Fluxes ◽  
Geometrical Effects ◽  
Aluminum Plates

The goal of this paper is to examine the effects of size and aspect ratio (H/L) of open cavities on heat and mass transfer during open door conditions of refrigerator cabinets. An experimental investigation was conducted using test cavities constructed from foam board insulation and interior covered with aluminum plates acting as calorimeters. Various size cavities with heights of 15.24 cm, 30.48 cm, and 45.72 cm along with aspect ratios of 0.5, 1.0, and 2.0 were tested. Cavities were heated to an initial temperature of 50°C, 60°C, 70°C, and 80°C before being exposed to the ambient air. In addition, tests were conducted in which the cavities were cooled before being exposed to the ambient. The relative humidity was varied from 60% to 75% and initial temperatures varied from 5°C, 1°C, and −5°C. The cavity mass fluxes were measured to validate the heat/mass transfer analogy for the tests. Experimental results were also presented for Rayleigh numbers from 5.88 × 106 to 2.21 × 108 with Nusselt numbers ranging from 15.48 to 53.51. The Nusselt numbers for cavities with an aspect ratio of one and two were in good agreement with each other. The Nusselt numbers for the cavity with an aspect ratio of 0.5 were slightly lower than the other cavities at given Rayleigh values.

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