Document Detail


Dynamical evolution of volume fractions in multipressure multiphase flow models.
MedLine Citation:
PMID:  18643369     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
Compared to single-pressure models, multipressure multiphase flow models require additional closure relations to determine the individual pressures of the different phases. These relations are often taken to be evolution equations for the volume fractions. We present a rigorous theoretical framework for constructing such equations for compressible multiphase mixtures in terms of submodels for the relative volumetric expansion rates DeltaE_{i} of the phases. These quantities are essentially the rates at which the phases dynamically expand or contract in response to pressure differences, and represent the general tendency of the volume fractions to relax toward values that produce local pressure equilibrium. We present a simple provisional model of this type in which DeltaE_{i} is proportional to pressure differences divided by the time required for sound waves to traverse an appropriate characteristic length. It is shown that the resulting approach to pressure equilibrium is monotonic rather than oscillatory, and occurs instantaneously in the incompressible limit.
Authors:
C H Chang; J D Ramshaw
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Publication Detail:
Type:  Journal Article     Date:  2008-06-10
Journal Detail:
Title:  Physical review. E, Statistical, nonlinear, and soft matter physics     Volume:  77     ISSN:  1539-3755     ISO Abbreviation:  Phys Rev E Stat Nonlin Soft Matter Phys     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-07-22     Completed Date:  2008-08-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101136452     Medline TA:  Phys Rev E Stat Nonlin Soft Matter Phys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  066305     Citation Subset:  -    
Affiliation:
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA. chc@lanl.gov
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