Flow and distribution of fluid phases through porous plant growth media in microgravity: Progress to date

Susan L. Steinberg, Nihad E. Daidzic, Scott Jones, Dani Or, Gerard Kluitenberg, Lakshmi Reddi, J. Iwan D. Alexander, Markus Tuller

Research output: Contribution to journalConference article

4 Scopus citations

Abstract

Results from plant growth experiments utilizing particulate growth media during space flight revealed difficulties associated with providing reliable reproducible gaseous and water supply to plant roots. These limitations were attributed to insufficient understanding of liquid configuration and growth media transport processes in reduced gravity. The objective of this NASA-funded research program is to develop a framework for modeling and quantitative characterization of physical processes associated with flow of wetting and non-wetting phases in particulate plant growth media in microgravity. This paper provides an overview of research plans and current status of research activities. Characterization and modeling of substrate water retention and transport properties in microgravity is key to management and control of gas and liquid fluxes within plant root zones. Modeling efforts will focus on both 1) a pore network model for describing discontinuous fluid phase transport (ganglia/blobs) and 2) a statistical distribution model describing water retention and hydraulic conductivity as functions of various pore configurations. Minimizing hydrostatic forces within porous media by using thin samples on earth may provide an approximation to microgravity conditions. In our preliminary study we have used Magnetic Resonance Imaging (MRI) to detect and track the evolution of liquid configuration and dynamics within thin slices of opaque porous media (Aquafoam with mean pore size of 50 μm). Both two- and three dimensional temporal MRI imaging has been performed in thin Aquafoam slices positioned vertically and horizontally (to simulate the effect of gravity). The wetting front exhibited percolation-type patterns and fingering. Preliminary results show that gravity dominates liquid flow even for low Bond numbers. Although the capillary forces are very strong the small hydrostatic pressure built in the initial liquid volume determines the subsequent evolution of the wetting front.

Original languageEnglish (US)
JournalSAE Technical Papers
DOIs
StatePublished - Jan 1 2002
Externally publishedYes
Event32nd International Conference on Environmental Systems - San Antonio, TX, United States
Duration: Jul 15 2002Jul 18 2002

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering

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