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Modeling of two-phase flow in membranes and porous media in microgravity as applied to plant irrigation in spaceIn traditional applications in soil physics it is convention to scale porous media properties, such as hydraulic conductivity, soil water diffusivity, and capillary head, with the gravitational acceleration. In addition, the Richards equation for water flux in partially saturated porous media also contains a gravity term. With the plans to develop plant habitats in space, such as in the International Space Station, it becomes necessary to evaluate these properties and this equation under conditions of microgravitational acceleration. This article develops models for microgravity steady state two-phase flow, as found in irrigation systems, that addresses critical design issues. Conventional dimensionless groups in two-phase mathematical models are scaled with gravity, which must be assigned a value of zero for microgravity modeling. The use of these conventional solutions in microgravity, therefore, is not possible. This article therefore introduces new dimensionless groups for two-phase models. The microgravity models introduced here determined that in addition to porous media properties, important design factors for microgravity systems include applied water potential and the ratio of inner to outer radii for cylindrical and spherical porous media systems.
Document ID
20040107217
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Scovazzo, P. (University of Colorado Boulder, Colorado, United States)
Illangasekare, T. H.
Hoehn, A.
Todd, P.
Date Acquired
August 21, 2013
Publication Date
May 1, 2001
Publication Information
Publication: Water resources research
Volume: 37
Issue: 5
ISSN: 0043-1397
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAGW-1197
Distribution Limits
Public
Copyright
Other