Analysis of Convective Mass Transfer by Potential Relaxation: I . Steady‐State Copper Deposition with Laminar Natural Convection Stirring

1989 ◽  
Vol 136 (6) ◽  
pp. 1727-1733 ◽  
Author(s):  
V. Anantharaman ◽  
P. N. Pintauro ◽  
L Nanis
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Copper Deposition ◽  
Convective Mass Transfer ◽  
Laminar Natural Convection

A Study on the Convective Mass Transfer of Nitrogen to Water for a Gas Pressurizing System

2008 ◽  
Author(s):  
Kyoungwoo Seo ◽  
Young-In Kim ◽  
Jae-Kwang Seo ◽  
Doo-Jeong Lee
Keyword(s):  
Mass Transfer ◽  
Boundary Condition ◽  
Natural Convection ◽  
Research Work ◽  
Ideal Gas ◽  
Convective Mass Transfer ◽  
Field Function ◽  
Concentration Difference ◽  
Fluent Simulation ◽  
Fluent 6.3

Mass transfer due to a concentration difference of nitrogen can occur in a nuclear system. Our research work seeks to analyze and understand the mass transfer phenomena of nitrogen in water under the condition of a natural convection using the commercially available CFD computer model, FLUENT 6.3. The maximum solubility was employed to express the boundary condition at an interface between the nitrogen and water. First, the case that nitrogen was transferred to water by only a diffusion was simulated to verify the application of the UDS (User defined scalar) model in FLUENT 6.3 for a mass transfer. Diffusion equation, which was described as a PDE (Partial Differential Equation) with non-homogeneous boundary conditions, was solved and the solved results of the PDE showed a good agreement with those of the FLUENT simulation in the same condition. The same cylinder geometry with that of the diffusion case was used to estimate the convective mass transfer. By the natural convection caused by the thermal boundary condition, the mass transfer of nitrogen had a convection effect. The result of FLUENT 6.3 to compute the convective mass transfer showed that the nitrogen was transferred simultaneously in the entire region by the convection effect and it took about several hours until the mole fraction of nitrogen in the water side reached 50% of the maximum saturated value. The averaged mass transfer coefficient was calculated and compared with the results obtained from the heat and mass transfer analogy. The calculated coefficients showed the lower value than those obtained from the various correlations. When the steam mass transfer toward the gas side was negligible, the pressure drop of the gas side due to the reduced nitrogen caused by a mass transfer was computed using the ideal gas law and the Custom Field Function model in the FLUENT 6.3.

Numerical Study of Laminar Natural Convection From a Plate to its Cylindrical Enclosure

1991 ◽  
Vol 113 (3) ◽  
pp. 194-199 ◽  
Author(s):  
M. M. Elshamy ◽  
M. N. Ozisik
Keyword(s):  
Nusselt Number ◽  
Steady State ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Average Nusselt Number ◽  
Numerical Study ◽  
Hot Plate ◽  
Cell Pattern ◽  
Laminar Natural Convection

The steady-state laminar natural convection for air bounded by a hot plate and a cold cylindrical enclosure has been studied numerically for the case of cold isothermal cylinder and hot isothermal plate. A correlation is presented for the average Nusselt number over the range of Rayleigh number from 105 to 106 for different values of the width-aspect ratio Sw and thickness aspect-ratio St of the plate. It is found that the average Nusselt number increases with increasing Sw and Rayleigh number. A two-cell pattern is observed for Sw=1.5 and less. The effect of Sw on the average Nusselt number is found to be stronger than that of St.

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.

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