scholarly journals Numerical Study of Laminar Flow and Mass Transfer for In-Line Spacer-Filled Passages

2010 ◽  
Author(s):  
S. B. Beale ◽  
J. G. Pharoah ◽  
A. Kumar ◽  
S. M. Mojab
Keyword(s):  
Mass Transfer ◽  
Driving Force ◽  
Numerical Study ◽  
Mean Flow ◽  
Process Industries ◽  
Fully Developed Flow ◽  
Flow Reynolds Number ◽  
Variable Wall ◽  
Blowing Parameter ◽  
Wall Mass

Performance calculations for laminar fluid flow and mass transfer are presented for a spacer-filled passage containing cylindrical spacers configured in an inline-square arrangement, typical of those employed in the process industries. Numerical calculations are performed for fully-developed flow, based on stream-wise periodic conditions for a ‘unit cell’ and compared with those obtained for developing regime in a row of 10 such units. The method is validated for an empty passage (i.e. a plane duct). Results are presented for the normalized mass transfer coefficient and driving force, as function of mean flow Reynolds number, and also the wall mass flux, or blowing parameter. Both constant and variable wall velocities were considered, the latter being typical of those found in many practical membrane assemblies.

scholarly journals Numerical Study of Laminar Flow and Mass Transfer for In-Line Spacer-Filled Passages

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Steven B. Beale ◽  
Jon G. Pharoah ◽  
Ashwani Kumar
Keyword(s):  
Mass Transfer ◽  
Driving Force ◽  
Numerical Study ◽  
Mean Flow ◽  
Process Industries ◽  
Fully Developed Flow ◽  
Flow Reynolds Number ◽  
Variable Wall ◽  
Blowing Parameter ◽  
Wall Mass

Performance calculations for laminar fluid flow and mass transfer are presented for a passage containing cylindrical spacers configured in an inline-square arrangement, typical of those employed in the process industries. Numerical calculations are performed for fully-developed flow, based on stream-wise periodic conditions for a unit cell and compared with those obtained for developing regime in a row of ten such units. The method is validated for an empty passage, i.e., a plane duct. Results are presented for the normalized mass transfer coefficient and driving force, as a function of mean flow Reynolds number, and also the wall mass flux, or blowing parameter. Both constant and variable wall velocities were considered, the latter being typical of those found in many practical membrane modules.

Numerical Study of Effects of Wall Mass Transfer Condition for Geometry Factor

2016 ◽  
Vol 2016.21 (0) ◽  
pp. D112
Author(s):  
Tatsuya TSUNEYOSHI ◽  
Kazuaki KAMIYA ◽  
Yoichi UTANOHARA ◽  
Takahiro ITO ◽  
Yoshiyuki TSUJI
Keyword(s):  
Mass Transfer ◽  
Numerical Study ◽  
Transfer Condition ◽  
Geometry Factor ◽  
Wall Mass

scholarly journals Insight into the Significance of Hall Current and Joule Heating on the Dynamics of Darcy–Forchheimer Peristaltic Flow of Rabinowitsch Fluid

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Ji-Huan He ◽  
Doaa R. Mostapha
Keyword(s):  
Mass Transfer ◽  
Joule Heating ◽  
Hall Current ◽  
Numerical Study ◽  
Peristaltic Flow ◽  
Peristaltic Transport ◽  
Physical Parameters ◽  
Maximum Height ◽  
Mean Flow ◽  
Mild Stenosis

This paper aims to present the significance of the Hall current and Joule heating impacts on a peristaltic flow of a Rabinowitsch fluid through tapered tube. The Darcy–Forchheimer scheme is used for a porous medium; a mild stenosis is considered to study the impacts of radiative heat transfer and chemical reactions. Convective conditions are postulated for heat and mass transfer. In the meantime, the slip conditions are presumed for the velocity distribution. Soret and Dufour features bring the coupled differential systems. The hypotheses of a long wavelength and low Reynolds number are employed to approximate the governing equations of motion, and finally the homotopy perturbation method is adopted for numerical study. Pumping characteristics are revealed and the trapping procedure correlated with peristaltic transport is elucidated. The present study is very important in many medical applications, such as the gastric juice motion in the small intestine and the flow of blood in arteries. The mechanism of peristaltic transport with mild stenosis has been exploited for industrial applications like sanitary fluid transport and blood pumps in heart-lung machine. The influences of various physical parameters of the problem are debated and graphically drawn across a set of figures. It is noted that the axial velocity is reduced with the increase of the Hartmann number. However, enhancing both the Rabinowitsch parameter and the Forchheimer parameter gives rise to the fluid velocity. As well, it is debated that Rabinowitsch fluid produces a cubic term of pressure gradient. Therefore, the relation between mean flow rate and the pressure rise does not stay linear. It is recognized that the temperature rises with the enhancement of both Dufour number and Soret number. Furthermore, it is illustrated that the concentration impedes with the increase of the mass transfer Biot number. Also, it is revealed that the trapped bolus contracts in size by enlarging the maximum height of stenosis.

Conjugate Mass Transfer in Gas Channels and Diffusion Layers of Fuel Cells

2005 ◽  
Author(s):  
S. B. Beale
Keyword(s):  
Mass Transfer ◽  
Driving Force ◽  
Transfer Problem ◽  
Computational Procedure ◽  
Diffusion Layers ◽  
Blockage Factor ◽  
Mass Transfer Problem ◽  
Blowing Parameter ◽  
Mathematical Foundations ◽  
And Diffusion

An analysis is performed for mass transfer in a rectangular gas passage, porous diffusion layer, and the combination of the two. The results of detailed calculations are presented and correlated in terms of the mass transfer driving force as a function of the blowing parameter and geometry, as characterized by the aspect ratio and blockage factor. It is shown that a simple solution for the overall driving force may be obtained for the conjugate mass transfer problem. This solution is quite general in its nature. The mathematical foundations are presented together with the details of the computational procedure used to obtain the results.

scholarly journals Conjugate Mass Transfer in Gas Channels and Diffusion Layers of Fuel Cells

2006 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
S. B. Beale
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Diffusion Layer ◽  
Driving Force ◽  
Transfer Problem ◽  
Analytical Methodology ◽  
Diffusion Layers ◽  
Wide Range ◽  
Simple Mass ◽  
Blowing Parameter

Prediction of mass transfer effects is a key element in fuel cell design. In this paper, the results of a generalized analysis appropriate to a wide range of designs and flow conditions are presented. Mass transfer in a rectangular gas passage, diffusion layer, and the combination of the two is considered. Fully developed viscous flow is presumed to occur within the passage, while the incompressible form of Darcy’s law is prescribed for the diffusion layer. The mathematical foundations for a simple mass transfer analysis are presented. Detailed calculations are then performed by means of a computational fluid dynamics code. These results are then correlated according to the analytical methodology in terms of nondimensional numbers appropriate to mass transfer analysis; namely, the overall mass transfer driving force as a function of the blowing parameter. Parametric studies are performed for a range of geometries, as characterized by the aspect ratio and blockage factor. It is shown that a simple solution for the overall driving force may readily be obtained from the two individual solutions for the conjugate mass transfer problem. This solution is quite general in its nature, and may readily be used to predict concentration polarization effects for a variety of fuel cells.

Numerical Study of the Combined Free-Forced Convection and Mass Transfer Flow Past a Vertical Porous Plate in a Porous Medium with Heat Generation and Thermal Diffusion

2006 ◽  
Vol 11 (4) ◽  
pp. 331-343 ◽  
Author(s):  
M. S. Alam ◽  
M. M. Rahman ◽  
M. A. Samad
Keyword(s):  
Mass Transfer ◽  
Flow Field ◽  
Differential Equations ◽  
Forced Convection ◽  
Heat Generation ◽  
Numerical Study ◽  
Porous Plate ◽  
Integration Scheme ◽  
Suction Parameter ◽  
Transfer Flow

The problem of combined free-forced convection and mass transfer flow over a vertical porous flat plate, in presence of heat generation and thermaldiffusion, is studied numerically. The non-linear partial differential equations and their boundary conditions, describing the problem under consideration, are transformed into a system of ordinary differential equations by using usual similarity transformations. This system is solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with Runge-Kutta sixth order integration scheme. The effects of suction parameter, heat generation parameter and Soret number are examined on the flow field of a hydrogen-air mixture as a non-chemical reacting fluid pair. The analysis of the obtained results showed that the flow field is significantly influenced by these parameters.

scholarly journals Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3634
Author(s):  
Grzegorz Czerwiński ◽  
Jerzy Wołoszyn
Keyword(s):  
Mass Transfer ◽  
Phase Change ◽  
Heat Dissipation ◽  
Cooling System ◽  
Numerical Study ◽  
Relaxation Parameter ◽  
Phase Changes ◽  
Transfer Time ◽  
Two Phase ◽  
Time Relaxation

With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation rc depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation re = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient re should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time.

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