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System Modeling of Metabolic Heat Regenerated Temperature Swing Adsorption (MTSA) Subassembly for Prototype DesignThis paper describes modeling methods for the three core components of a Metabolic heat regenerated Temperature Swing Adsorption (MTSA) subassembly: the sorbent bed, a sublimation (cooling) heat exchanger (SHX), and a condensing icing (warming) heat exchanger (CIHX). The primary function of the MTSA, removing carbon dioxide from a ventilation loop, is performed via the sorbent bed. The CIHX is used to heat the sorbent bed for desorption and to remove moisture from the ventilation loop while the SHX is alternately employed to cool the sorbent bed via sublimation of a spray of water at low pressure to prepare the reconditioned bed for the next cycle. This paper describes a system level model of the MTSA as developed in Thermal Desktop and SINDA/FLUINT including assumptions on geometry and physical phenomena, modeling methodology and relevant pa ra mete rizatio ns. Several areas of particular modeling interest are discussed. In the sorbent bed, capture of the translating CO2 saturation front and associated local energy and mass balance in both adsorbing and desorbing modes is covered. The CIHX poses particular challenges for modeling in SINDA/FLUINT as accounting for solids states in fluid submodels are not a native capability. Methods for capturing phase change and latent heat of ice as well as the transport properties across a layer of low density accreted frost are developed. This extended modeling capacity is applicable to temperatures greater than 258 K. To extend applicability to the minimum device temperature of 235 K, a method for a mapped transformation of temperatures from below the limit temperatures to some value above is given along with descriptions for associated material property transformations and the resulting impacts to total heat and mass transfer. Similar considerations are shown for the SHX along with assumptions for flow mechanics and resulting model methods for sublimation in a flow.
Document ID
20090038924
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Bower, Chad
(Paragon Space Development Corp. Tucson, AZ, United States)
Padilla, Sebastian
(Paragon Space Development Corp. Tucson, AZ, United States)
Iacomini, Christie
(Paragon Space Development Corp. Tucson, AZ, United States)
Paul, Heather L.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2009
Subject Category
Man/System Technology And Life Support
Report/Patent Number
JSC-CN-19036
Meeting Information
Meeting: 40th International Conference on Environmental Systems
Location: Barcelona
Country: Spain
Start Date: July 11, 2010
End Date: July 15, 2010
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 903184.04.02.03.03
Distribution Limits
Public
Copyright
Other

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