Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems
The Maxwell-Stefan (MS) approach is commonly used for describing mass transport by diffusion in gases and liquids since it correctly accounts for the chemical potential gradient as driving force. It is well known that MS diffusivities are concentration dependent which should be taken into account in...
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ndltd-DRESDEN-oai-qucosa.de-bsz-15-qucosa-1857822015-10-30T03:25:31Z Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems Liu, Xin Bardow, André Vlugt, Thijs, J.H. Diffusion Transport diffusion transport ddc:530 The Maxwell-Stefan (MS) approach is commonly used for describing mass transport by diffusion in gases and liquids since it correctly accounts for the chemical potential gradient as driving force. It is well known that MS diffusivities are concentration dependent which should be taken into account in practical applications. Unfortunately, it is difficult to obtain MS diffusivities both from experiments and molecular simulations. Therefore, there is a considerable interest in predictive models describing the concentration dependence of MS diffusivities. MS diffusivities can be expressed as functions of (1) easily obtainable self- diffusivities, and (2) the integrals of velocity cross-correlations. By assuming that the latter terms are small, we recently derived the multicomponent Darken equation. The objectives of the present study are twofold: First, we present a validation of the multicomponent Darken equation in ternary systems. Second, we investigate the dependence of velocity crosscorrelations on concentration and system size. A linear relation between the velocity cross-correlations and 1/N is found (“N” being the total number of molecules in the system). Two types of systems are studied: (1) Weeks-Chandler-Andersen (WCA) fluids in which only repulsive interactions are considered; (2) the ternary system water-DMSO-methanol in which atoms are interacting using both Lennard-Jones and electrostatic potentials. Universitätsbibliothek Leipzig RWTH Aachen University, Lehrstuhl für Technische Thermodynamik Universität Leipzig, Fakultät für Physik und Geowissenschaften Delft University of Technology, Process & Energy Laboratory 2015-10-29 doc-type:article application/pdf http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-185782 urn:nbn:de:bsz:15-qucosa-185782 issn:1862-4138 http://www.qucosa.de/fileadmin/data/qucosa/documents/18578/diff_fund_16%282011%2981.pdf Diffusion fundamentals 16 (2011) 81, S. 1-11 eng |
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English |
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Diffusion Transport diffusion transport ddc:530 |
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Diffusion Transport diffusion transport ddc:530 Liu, Xin Bardow, André Vlugt, Thijs, J.H. Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems |
description |
The Maxwell-Stefan (MS) approach is commonly used for describing mass transport by diffusion in gases and liquids since it correctly accounts for the chemical potential gradient as driving force. It is well known that MS diffusivities are concentration dependent which should be taken into account in practical applications. Unfortunately, it is difficult to obtain MS diffusivities both from experiments and molecular simulations. Therefore, there is a considerable interest in predictive models describing the concentration dependence of MS diffusivities. MS diffusivities can be expressed as functions of (1) easily obtainable self- diffusivities, and (2) the integrals of velocity cross-correlations. By assuming that the latter terms are small, we recently derived the multicomponent Darken equation. The objectives of the present study are twofold: First, we present a validation of the multicomponent Darken equation in ternary systems. Second, we investigate the dependence of velocity crosscorrelations on concentration and system size. A linear relation between the velocity cross-correlations and 1/N is found (“N” being the total number of molecules in the system). Two types of systems are studied: (1) Weeks-Chandler-Andersen (WCA) fluids in which only repulsive interactions are considered; (2) the ternary system water-DMSO-methanol in which atoms are interacting using both Lennard-Jones and electrostatic potentials. |
author2 |
RWTH Aachen University, Lehrstuhl für Technische Thermodynamik |
author_facet |
RWTH Aachen University, Lehrstuhl für Technische Thermodynamik Liu, Xin Bardow, André Vlugt, Thijs, J.H. |
author |
Liu, Xin Bardow, André Vlugt, Thijs, J.H. |
author_sort |
Liu, Xin |
title |
Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems |
title_short |
Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems |
title_full |
Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems |
title_fullStr |
Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems |
title_full_unstemmed |
Maxwell-Stefan diffusivities and velocity cross-correlations in dilute ternary systems |
title_sort |
maxwell-stefan diffusivities and velocity cross-correlations in dilute ternary systems |
publisher |
Universitätsbibliothek Leipzig |
publishDate |
2015 |
url |
http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-185782 http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-185782 http://www.qucosa.de/fileadmin/data/qucosa/documents/18578/diff_fund_16%282011%2981.pdf |
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