Coupled Heat and Mass Transfer by Mixed Convection From a Buried Pipe With Leakage

2003 ◽  
Author(s):  
C. C. Ngo ◽  
F. C. Lai
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Heat And Mass Transfer ◽  
Sherwood Number ◽  
Numerical Solutions ◽  
Lewis Number ◽  
The Body ◽  
Buried Pipe ◽  
Buoyancy Ratio

Numerical solutions are presented for combined heat and mass transfer by mixed convection induced from a buried pipe with leakage. Two locations of leakage are considered in the present study: one is on top of the pipe and the other is at the bottom of the pipe. The governing equations formulated in the body-fitted coordinates are solved via the finite difference method. A parametric study has been performed to investigate the effects of Rayleigh number, Peclet number, Lewis number, and buoyancy ratio N on the heat and mass transfer results. It is found that both the Nusselt number and Sherwood number increase for the aiding flows (N > 0) and decrease for the opposing flows (N < 0). For aiding flows, Sherwood number increases with the Lewis number but Nusselt number decreases with the Lewis number.

scholarly journals Similarity Solution of Flow, Heat and Mass Transfer of a Nanofluid Over a Porous Plate in a Darcy-Forchheimer Flow

2019 ◽  
pp. 1-14
Author(s):  
A. Falana ◽  
A. Alao Ahmed
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Sherwood Number ◽  
Similarity Solution ◽  
Porous Plate ◽  
Lewis Number ◽  
Flow Heat ◽  
Forchheimer Flow

In this work, a similarity solution of the flow, heat and mass transfer of a nanofluid over a porous plate in a Darcy-Forchheimer flow is explored. The nanofluid model includes Brownian motion and Thermophoresis diffusion effects. The governing transport equations are made dimensionless using similarity transformation technique which reduce them into ordinary differential equations with the associated boundary conditions. The equations are then solved numerically using the classical fourth order Runge-Kutta method and the results are benched marked with available results in literature and are found to be in good agreement. The results for the flow velocity, the shear stress, the temperature distribution, the nanoparticle volume concentration, the skin friction coefficient, the reduced Nusselt number, and the reduced Sherwood number, are presented graphically illustrating the effects of permeability, inertia, thermophoresis, Brownian motion, Lewis number and Prandtl number on the flow. Our analysis shows, among others, that the Nusselt number is a decreasing function, while the Sherwood number is an increasing function of the thermophoretic number

scholarly journals New exact and numerical solutions for the effect of suction or injection on flow of nanofluids past a stretching sheet

2019 ◽  
Vol 8 (1) ◽  
pp. 172-178
Author(s):  
Nader Y. Abd Elazem
Keyword(s):  
Nusselt Number ◽  
Exact Solutions ◽  
Sherwood Number ◽  
Stretching Sheet ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Lewis Number ◽  
Suction Or Injection ◽  
Wall Mass ◽  
Good Agreement

Abstract The flow of nanofluids past a stretching sheet has attracted much attention due to its wide applications in industry and engineering. Theoretical and numerical solutions have been discussed in this paper for studying the effect of suction or injection on flow of nanofluids past a stretching sheet. In the absence of thermophoresis the analytical exact solution of the stream function was obtained in terms of exponential function, while the exact solutions for temperature and nanoparticle volume fraction were obtained in terms of the generalized incomplete gamma function. In addition, in the presence of thermophoresis, the exact solutions are not available. Therefore, the numerical results, carried out by using Chebyshev collocation method (ChCM). It is found that a good agreement exists between the present results and with those published works. Useful results for temperature profile, concentration profile, reduced Nusselt number and reduced Sherwood number are discussed in details graphically. It was also demonstrated that both temperature and concentration profiles decrease by an increase from injection to suction. Finally, the present results showed that increase of the wall mass transfer from injection to suction decreased both reduced Nusselt number and the reduced Sherwood number when Brownian motion parameter and Lewis number increased.

scholarly journals Heat and Mass Transfer in Partially-Layered Cavity with Inner Square conductive Body

2016 ◽  
Vol 13 (1) ◽  
Keyword(s):  
Mass Transfer ◽  
Lewis Number ◽  
Darcy Number ◽  
The Body ◽  
Thermal Conductivity Ratio ◽  
Left Wall ◽  
Conductive Body ◽  
Thermally Conductive ◽  
The Right ◽  
Buoyancy Ratio

This paper investigates the double diffusive natural convection in a partially porous layered enclosed cavity with a thermally conductive square body. The horizontal walls are thermally insulated, the left wall adds heat isothermally into the porous layer, while the right wall is cooled isothermally. The center of the square conductive body is positioned in the center of the cavity in such a way it lays on the porous-fluid interface. The governing equations have been solved using up-wind scheme finite difference method. The Parndtl number, thermal conductivity ratio of the body to fluid, Darcy number, aspect ratio of the square body to the cavity sides have fixed at 6.26, 1, 10-3, 0.5, respectively. The study has been governed by three parameters namely, Lewis number (Le = 1–50), buoyancy ratio (-10 – 10), and Rayleigh number (103 - 106 ). The results have showed that the mass diffusivity ratio, which takes into account non-unity tortuosity ratio (Deff/D = 0.53) has a significant effect on the mass transfer than the unity value. It is found also that Sherwood number is minimal when the buoyancy ratio equals to -0.5, otherwise, it increases with increasing the absolute value of the buoyancy ratio.

scholarly journals Unsteady magnetohydrodynamic mixed convection flow with heat and mass transfer over a horizontal circular cylinder embedded in a porous medium

2016 ◽  
Vol 20 (suppl. 5) ◽  
pp. 1381-1390
Author(s):  
Branko Boricic ◽  
Aleksandar Boricic
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Circular Cylinder ◽  
Mixed Convection ◽  
Heat And Mass Transfer ◽  
Thermal Parameter ◽  
Magnetic Reynolds Number ◽  
The Body ◽  
Convection Flow ◽  
Horizontal Circular Cylinder

The objective of the present study is to investigate the effect of flow parameters on the mixed convection heat and mass transfer of an unsteady magnetohydrodynamic flow of an electrically conducting, viscous, and incompressible fluid over a horizontal circular cylinder embedded in porous medium, considering effects of chemical reaction and heat source/sink, by taking into account viscous dissipation. The present magnetic field is homogenous and perpendicular to the body surface. Magnetic Reynolds number is significantly lower than one i. e. considered the problem is in approximation without induction. The governing non-linear partial differential equations and associated boundary conditions are made dimensionless using a suitable similarity transformation and similarity parameters. System of non-dimensionless equations are solved numerically by implicit finite difference three-diagonal and iteration method. Numerical results obtained for different values of porous medium, magnetic, diffusion and temperature parameters, buoyancy diffusion parameter and thermal parameter and for different values Prandtl, Echart, and Schmidt numbers. Variation of velocity, temperature and concentration and many integral and differential characteristics boundary layer are discussed and shown graphically.

Combined Heat and Mass Transfer by Natural Convection in a Vertical Enclosure

1987 ◽  
Vol 109 (1) ◽  
pp. 104-112 ◽  
Author(s):  
O. V. Trevisan ◽  
A. Bejan
Keyword(s):  
Mass Transfer ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Lewis Number ◽  
Convective Mass Transfer ◽  
Transfer Rates ◽  
Rectangular Slot ◽  
Transfer Path ◽  
Mass Fluxes ◽  
Buoyancy Ratio

The phenomenon of natural convection caused by combined temperature and concentration buoyancy effects is studied analytically and numerically in a rectangular slot with uniform heat and mass fluxes along the vertical sides. The analytical part is devoted to the boundary layer regime where the heat and mass transfer rates are ruled by convection. An Oseen-linearized solution is reported for tall spaces filled with mixtures characterized by Le = 1 and arbitrary buoyancy ratios. The effect of varying the Lewis number is documented by a similarity solution valid for Le >1 in heat-transfer-driven flows, and for Le <1 in mass-transfer-driven flows. The analytical results are validated by numerical experiments conducted in the range 1≤H/L≤4, 3.5×105≤Ra≤7×106, −11≤n≤9, 1≤Le≤40, and Pr=0.7, 7. “Massline” patterns are used to visualize the convective mass transfer path and the flow reversal observed when the buoyancy ratio n passes through the value −1.

Transient free convection heat and mass transfer of Casson nanofluid over a vertical porous plate subjected to magnetic field and thermal radiation

2020 ◽  
Vol 3 (4) ◽  
pp. 35-54 ◽  
Author(s):  
M. G. Sobamowo ◽  
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Free Convection ◽  
Thermal Radiation ◽  
Heat And Mass Transfer ◽  
Schmidt Number ◽  
Casson Fluid ◽  
Local Skin ◽  
Local Skin Friction ◽  
Buoyancy Ratio

In this present study, the transient magnetohydrodynamics free convection heat and mass transfer of Casson nanofluid past an isothermal vertical flat plate embedded in a porous media under the influence of thermal radiation is studied. The governing systems of nonlinear partial differential equations of the flow, heat and mass transfer processes are solved using implicit finite difference scheme of Crank-Nicolson type. The numerical solutions are used to carry out parametric studies. The temperature as well as the concentration of the fluid increase as the Casson fluid and radiation parameters as well as Prandtl and Schmidt numbers increase. The increase in the Grashof number, radiation, buoyancy ratio and flow medium porosity parameters causes the velocity of the fluid to increase. However, the Casson fluid parameter, buoyancy ratio parameter, the Hartmann (magnetic field parameter), Schmidt and Prandtl numbers decrease as the velocity of the flow increases. The time to reach the steady state concentration, the transient velocity, Nusselt number and the local skin-friction decrease as the buoyancy ratio parameter and Schmidt number increase. Also, the steady-state temperature and velocity decrease as the buoyancy ratio parameter and Schmidt number increase. Also, the local skin friction, Nusselt and Sherwood numbers decrease as the Schmidt number increases. However, the local Nusselt number increases as the buoyancy ratio parameter increases. It was established that near the leading edge of the plate), the local Nusselt number is not affected by both buoyancy ratio parameter and Schmidt number. It could be stated that the present study will enhance the understanding of transient free convection flow problems under the influence of thermal radiation and mass transfer as applied in various engineering processes.

scholarly journals UNSTEADY MHD HEAT AND MASS TRANSFER FLOW OF A RADIATING FLUID PAST AN ACCELERATED INCLINED POROUS PLATE WITH HALL CURRENT

2017 ◽  
Vol 5 (7) ◽  
pp. 42-59
Author(s):  
G. Sivaiah ◽  
K. Jayarami Reddy
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Skin Friction ◽  
Heat And Mass Transfer ◽  
Sherwood Number ◽  
Hall Current ◽  
Porous Plate ◽  
Physical Parameters ◽  
Laplace Transform Technique ◽  
Transfer Flow

In this paper an analysis has been performed to study the effects of Hall current and radiation of MHD free convective heat and mass transfer flow of a radiating fluid past an accelerated inclined porous plate with hall current in presence of thermal diffusion and heat source. The solutions for velocity, temperature and concentration distributions are obtained by using Laplace transform technique. The expressions for skin friction, Nusselt number and Sherwood number are also derived. The variations in fluid velocity, temperature and species concentration are shown graphically, whereas numerical values of skin friction, Nusselt number and Sherwood number are presented in tabular form for various values of physical parameters.

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 Heat and mass transfer of an unsteady mhd peristaltic flow in a porous medium with cross diffusion effect

2020 ◽  
Vol 7 (2) ◽  
pp. 130-142
Author(s):  
Panneerselvi R ◽  
Selvameena N ◽  
Sheebarani N
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Skin Friction ◽  
Heat And Mass Transfer ◽  
Stream Function ◽  
Sherwood Number ◽  
Peristaltic Flow ◽  
Diffusion Effect ◽  
Cross Diffusion

In this work the significance of Cross Diffusion effect on unsteady MHD peristaltic flow in a porous medium with heat and mass transfer is investigated. The governing partial differentialequations are transformed into dimensionless equations by using dimensionless quantities. Stream function, velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number are obtained. The results are discussed for various emerging parameters encountered in the problem under investigation. The importance of main parameters on the present study is explained graphically

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