Mass Transfer Phenomena (mass + transfer_phenomenon)

Distribution by Scientific Domains


Selected Abstracts


Hybrid Simulation of Miscible Mixing with Viscous Fingering

COMPUTER GRAPHICS FORUM, Issue 2 2010
Seung-Ho Shiny
Abstract By modeling mass transfer phenomena, we simulate solids and liquids dissolving or changing to other substances. We also deal with the very small-scale phenomena that occur when a fluid spreads out at the interface of another fluid. We model the pressure at the interfaces between fluids with Darcy's Law and represent the viscous fingering phenomenon in which a fluid interface spreads out with a fractal-like shape. We use hybrid grid-based simulation and smoothed particle hydrodynamics (SPH) to simulate intermolecular diffusion and attraction using particles at a computable scale. We have produced animations showing fluids mixing and objects dissolving. [source]


Heat and mass transfer phenomena in magnetic fluids

GAMM - MITTEILUNGEN, Issue 1 2007
Th. Völker
Abstract In this article the influence of a magnetic field on heat and mass transport phenomena in magnetic fluids (ferrofluids) will be discussed. The first section is dealing with a magnetically driven convection, the so called thermomagnetic convection while in the second section the influence of a temperature gradient on the mass transport, the Soret effect in ferrofluids, is reviewed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Carbothermal synthesis of vanadium nitride: Kinetics and mechanism

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 6 2006
A. Ortega
Constant rate thermal analysis (CRTA) has been used for the first time to study the kinetics of the carbothermal reduction of V2O5 in nitrogen to obtain vanadium nitride. It is noteworthy to point out that CRTA method allows both a good control of pressure in the sample surroundings and the use of reaction rates low enough to keep temperatures gradients at a negligible level to avoid any heat or mass transfer phenomena. This method allows one to control the texture and the structure of many materials through kinetic control of the thermal treatment of the precursors. The precise control of the external parameters of the reaction shows that CRTA is an attractive method for kinetic studies and leads to more reliable kinetic data. It has been shown that the carbothermal synthesis of vanadium nitride is best described by a three-dimensional diffusion kinetic model (the Jander equation) with an activation energy which falls in the range of 520,540 kJ/mol. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 369,375, 2006 [source]


The impact of flow field pattern on concentration and performance in PEMFC

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2005
A. Su
Abstract In this study, we present a rigorous mathematical model, to treat prediction and analysis of proton exchange membrane fuel cells gas concentration and current density distribution in mass transfer area and chemical reaction area performed in 3-D geometry. The model is based on the solution of the conservation equations of mass, momentum, species, and electric current in a fully integrated finite-volume solver using the CFDRC commercial code. The influences of fuel cell performance with two kinds of flow channel pattern design are studied. The gas concentration of the straight flow pattern appears excessively non-uniform, resulting in a local concentration polarization. On the other hand, the gas concentration is well distributed for the serpentine flow pattern, creating a better mass transfer phenomena. The performance curves (polarization curves) are also well correlated with experimental data. Copyright © 2005 John Wiley & Sons, Ltd. [source]


MASS TRANSFER IN PACIFIC HAKE (Merluccius australis) PACKED IN REFRIGERATED MODIFIED ATMOSPHERE

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2001
R. SIMPSON
ABSTRACT The objective of this research was to develop, and experimentally validate a fully mathematical model, to predict mass transfer phenomena in Pacific Hake (Merluccius australis) packed in refrigerated modified atmosphere. A mathematical model to predict mass transfer of CO2, O2, N2 and water vapor was developed and validated. The diffusion model was developed utilizing Fick's second law, considering fish fillet as an infinite slab and applied to Pacific Hake (lean fish species) under refrigeration conditions. CO2 diffusivity of Pacific Hake was determined by an inverse procedure at OC and resulted in a value of 5.19 × 10,10 [m2/s] that is in accordance with values reported in the literature. However, postmortem variations of pH could affect solubility and diffusivity of CO2 in fish muscle. [source]