Flow and Distribution of Fluid Phases through Porous Plant Growth Media in Microgravity: Progress to Date

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Conference Proceeding

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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 (AquafoamTM with mean pore size of 50 μm). Both two- and three dimensional temporal MRI imaging has been performed in thin AquafoamTM 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.



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Conference Name

32nd International Conference on Environmental Systems

Conference Place

San Antonio, TX