Mass Transfer Cooling of Laminar Flow Between Parallel Porous Plates

1974 ◽  
Vol 96 (3) ◽  
pp. 343-347 ◽  
Author(s):  
G. Walker ◽  
R. M. Terrill
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Mass Concentration ◽  
Energy Equation ◽  
Analytic Solutions ◽  
Thermal Capacity ◽  
Injection Velocity ◽  
Concentration Profiles ◽  
Nonisothermal Flow ◽  
Two Dimensional

The limiting temperature and mass concentration profiles and the limiting wall Nusselt number are obtained for the laminar nonisothermal flow in a two-dimensional porous channel. Results are reported for a uniform rate of injection at the wall of a foreign component of higher thermal capacity than the fluid in the channel. An exact solution of the diffusion equation is found while numerical and analytic solutions of the energy equation are discussed for small injection rates. It is shown that the enthalpy transport resulting from the diffusion process has an effect equivalent to increasing the Prandtl number. It is also found that for a given injection velocity at the wall, the limiting Nusselt number is significantly reduced by the injection of a foreign component of high thermal capacity.

Viscous Dissipation and Variable Properties Effect on Two Dimensional Conjugate Heat Transfer of Nanofluids in Microchannels

2011 ◽  
Author(s):  
A. Ramiar ◽  
A. A. Ranjbar
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Viscous Dissipation ◽  
Conjugate Heat Transfer ◽  
Energy Equation ◽  
Critical Reynolds Number ◽  
Two Dimensional ◽  
Variable Properties ◽  
Enhance Heat Transfer

Laminar two dimensional forced convective heat transfer of Al2O3–water nanofluid in a horizontal microchannel has been studied numerically, considering axial conduction, viscous dissipation and variable properties effects. The existing criteria in the literature for considering viscous dissipation in energy equation are compared for different cases and the most proper one is applied for the rest of the paper. The results showed that nanoparticles enhance heat transfer characteristics of the channel and inversely, viscous dissipation causes the Nusselt number and friction factor to decrease. The viscous dissipation effect may be emphasized by increasing Reynolds number and decreased by raising the exerted heat flux. Also, it was found that there is a critical Reynolds number below which the average Nusselt number of the nanofluid changes abnormally with Reynolds number as a result of variable properties effect.

scholarly journals Dufour and Soret Effects on Square Porous Annulus

2014 ◽  
Vol 6 ◽  
pp. 209753 ◽  
Author(s):  
N. Nik-Ghazali ◽  
Irfan Anjum Badruddin ◽  
A. Badarudin ◽  
S. Tabatabaeikia
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Heat And Mass Transfer ◽  
Significant Contribution ◽  
Soret Effect ◽  
Physical Parameters ◽  
Concentration Profiles ◽  
Cool Temperature ◽  
Dufour Effect ◽  
Inner Surface

A study on heat and mass transfer behaviour on porous medium embedded in a square annulus is conducted. The inner surface wall is considered to have a cool temperature T c while the outer surface is exposed to a hot temperature T h. Finite element method (FEM) is used to solve the governing partial differential equations. The results present the influences of the Dufour and Soret effects on the heat and mass transfer of a square annulus. The effects of various physical parameters on the temperature and concentration profiles together with the local Nusselt and Sherwood numbers are presented graphically. It is found that when Dufour parameter is increased, Nusselt number increases. Dufour effect has more influences on velocity profile, while it has no significant effect on the concentration and can be deemed negligible. It is observed that the local Nusselt number is highest at the bottom wall for low values of Dufour parameter; however, the top wall Nusselt number is highest for higher values of Dufour parameter. Soret effect tends to make more significant contribution to the concentration profile than Dufour effect.

scholarly journals Dual DTM-Padé approximations on free convection MHD mass transfer flow of nanofluid through a stretching sheet in presence of Soret and Dufour Phenomena

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Nusselt Number ◽  
Sherwood Number ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Concentration Profiles ◽  
Temperature Profiles ◽  
Padé Approximations ◽  
Pade Approximations

A theoretical study is made to investigate heat and mass transfer analysis on the single phase flow of an electrically conducting, Al2O3-Water nanofluid over a linearly stretching sheet in presence of Soret and Dufour effects. An applied magnetic field is considered normal to the flow, while the effect of induced magnetic field got neglected for small magnetic Reynolds number’s value of the flow field relative to the applied field. Since voltage difference at the lateral ends of the sheet is very small, the influence of the electric field is thus omitted. The governing equations representing the physical model of the fluid flow is solved by means of DTM-Padé approximations. The acquired results show that an increase in the Soret number (Dufour number) decreases (increases) the temperature profiles but increases (decreases) the concentration profiles. The axial velocity profiles found decreasing with increasing values of the magnetic parameter. Both chemical reaction and thermal radiation parameters maximize the temperature profiles whereas a reverse phenomenon is seen on concentration profiles. The obtained tables show that increasing nanoparticle volume fraction escalates skin-friction coefficient, Nusselt number and Sherwood number whereas an increase in Richardson number decreases the Nusselt number but increases the Sherwood number.

Dual DTM-Padé approximations on free convection MHD mass transfer flow of nanofluid through a stretching sheet in presence of Soret and Dufour Phenomena

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Nusselt Number ◽  
Sherwood Number ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Concentration Profiles ◽  
Temperature Profiles ◽  
Padé Approximations ◽  
Pade Approximations

A theoretical study is made to investigate heat and mass transfer analysis on the single phase flow of an electrically conducting, Al2O3-Water nanofluid over a linearly stretching sheet in presence of Soret and Dufour effects. An applied magnetic field is considered normal to the flow, while the effect of induced magnetic field got neglected for small magnetic Reynolds number’s value of the flow field relative to the applied field. Since voltage difference at the lateral ends of the sheet is very small, the influence of the electric field is thus omitted. The governing equations representing the physical model of the fluid flow is solved by means of DTM-Padé approximations. The acquired results show that an increase in the Soret number (Dufour number) decreases (increases) the temperature profiles but increases (decreases) the concentration profiles. The axial velocity profiles found decreasing with increasing values of the magnetic parameter. Both chemical reaction and thermal radiation parameters maximize the temperature profiles whereas a reverse phenomenon is seen on concentration profiles. The obtained tables show that increasing nanoparticle volume fraction escalates skin-friction coefficient, Nusselt number and Sherwood number whereas an increase in Richardson number decreases the Nusselt number but increases the Sherwood number.

Modeling mass transfer and substrate utilization in the boundary layer of biofilm systems

1998 ◽  
Vol 37 (4-5) ◽  
pp. 139-147 ◽  
Author(s):  
Harald Horn ◽  
Dietmar C. Hempel
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Film Theory ◽  
Substrate Utilization ◽  
The Other ◽  
Concentration Profiles ◽  
Hydrodynamic Conditions ◽  
Time Axis ◽  
Transfer Coefficients

The use of microelectrodes in biofilm research allows a better understanding of intrinsic biofilm processes. Little is known about mass transfer and substrate utilization in the boundary layer of biofilm systems. One possible description of mass transfer can be obtained by mass transfer coefficients, both on the basis of the stagnant film theory or with the Sherwood number. This approach is rather formal and not quite correct when the heterogeneity of the biofilm surface structure is taken into account. It could be shown that substrate loading is a major factor in the description of the development of the density. On the other hand, the time axis is an important factor which has to be considered when concentration profiles in biofilm systems are discussed. Finally, hydrodynamic conditions become important for the development of the biofilm surface when the Reynolds number increases above the range of 3000-4000.

scholarly journals A high accurate scheme for numerical simulation of two-dimensional mass transfer processes in food engineering

2021 ◽  
Vol 60 (2) ◽  
pp. 2629-2639
Author(s):  
Yin Yang ◽  
Grzegorz Rządkowski ◽  
Atena Pasban ◽  
Emran Tohidi ◽  
Stanford Shateyi
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Two Dimensional ◽  
Food Engineering ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Accurate Scheme

scholarly journals Dynamics with Cattaneo–Christov heat and mass flux theory of bioconvection Oldroyd-B nanofluid

2020 ◽  
Vol 12 (8) ◽  
pp. 168781402093046 ◽  
Author(s):  
Noor Saeed Khan ◽  
Qayyum Shah ◽  
Arif Sohail
Keyword(s):  
Mass Transfer ◽  
Porous Media ◽  
Differential Equations ◽  
Mass Flux ◽  
Homotopy Analysis Method ◽  
Two Dimensional ◽  
Analysis Method ◽  
Homotopy Analysis ◽  
Transfer Flow ◽  
Insight Into

Entropy generation in bioconvection two-dimensional steady incompressible non-Newtonian Oldroyd-B nanofluid with Cattaneo–Christov heat and mass flux theory is investigated. The Darcy–Forchheimer law is used to study heat and mass transfer flow and microorganisms motion in porous media. Using appropriate similarity variables, the partial differential equations are transformed into ordinary differential equations which are then solved by homotopy analysis method. For an insight into the problem, the effects of various parameters on different profiles are shown in different graphs.

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