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A critical unit operation used with many of the leading water reclamation
and air revitalization technologies for advanced life support systems
is the fixed packed bed reactor. Examples of systems currently under
development or in use in space that take advantage of this type of
reactor include the Volatile Removal Assembly (VRA), the Aqueous-Phase
Catalytic Oxidation (APCO) system, the Microbial Check Valve (MCV),
the Activated Carbon/Ion Exchange (ACTEX), and the IntraVenous Fluid
GENeration (IVGEN) system. However, despite the many applications,
there is very little understanding of how the reduced gravity environment
affects the performance and reliability of the reactors. This is especially
critical when the reactor involves simultaneous gas and liquid flows.
The Packed Bed Reactor Experiment (PBRE) is designed to specifically
resolve these technology gaps. The expected outcome of this research
effort is to develop a set of guidelines and tools to enable engineers
to reliably design and operate fixed packed bed reactors for microgravity
as well as the lunar and Martian environments.
The PBRE ISS flight experiment will provide critical hydrodynamic
information for a project which also includes reduced gravity aircraft
and ground-based (1-g) testing. The main objective is to develop and
validate macroscopic equations that can be used in partial and microgravity
conditions to accurately predict flow pattern transitions; pressure
drops; and chemical and biological transport rates in gas-liquid flows
through randomly packed beds. The hydrodynamic investigations will
focus on the transitions between flow regimes (i.e., bubbly-to-pulse
flow transition) and the associated pressure gradients for each flow
regime over the range of relevant test parameters (e.g., liquid flow
rates, gas flow rates, and particle sizes). These design tools will
provide important information for specific water reclamation and air
revitalization technologies for advanced life support systems.
The PBRE is being developed under the Space Flight Systems Development
and Operations Contract, through the collaboration of ZIN Technologies
and the National Aeronautics and Space Administration (NASA) Glenn
Research Center (GRC), the International Space Station (ISS), the
University of Houston, the National Center for Space Exploration Research
(NCSER) and NASA Johnson Space Center (JSC). The success of
the PBRE project is crucial to the development of technologies which
will maintain the well-being of crew members participating in extended
space missions.
Objective:
- Investigate the role and effects of gravity
on gas-liquid flow through porous media.
- Outcome will be the development of design and
operational guidelines for gas-liquid Packed Bed Reactors in partial
and microgravity conditions.
Relevance/Impact
- Directly aligns with high priorities from the
NRC Decadal survey on Biological and Physical Sciences and crosses
over to other technologies.
- AP-2: Provides a study of a critical multiphase
flowcomponent for life support systems.
- TSES-6: Provides a fundamental study in porous
media under microgravity conditions.
- Porous media are critical components in life support
systems; thermal control devices; fuel cells; and biological and
chemical reactors.
Development Approach
- Completed extensive (but time-limited) low-G
aircraft tests.
- Engineering model hardware and Proto-flight unit.
- Critical diagnostics and data collection with
the capability to add/upgrade diagnostics.
- Develop on-orbit replaceable test section to extend
experiment capabilities. Enables flexibility for future development
of two phase components/devices.
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Packed Bed
test in low-g Aircraft |
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Volatile
Reactor Assembly (VRA) on STS-89 |
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