Browsing by Author "Andish, Kambiz"
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Item Integrated Computational Fluid Dynamics and Thermal Desktop Thermal Modeling for Assessment of the EMU in Support of ISS EVA 80(2023 International Conference on Environmental Systems, 2023-07-16) Lancaster, Blain; Baukus, Abigail; Andish, Kambiz; Hanford, AnthonyFollowing the reports of water accumulation in the Extravehicular Mobility Unit (EMU) helmet during the ISS US EVA-80, various efforts for mitigation and further understanding of this phenomenon have been undertaken with the goal of prevention and to ensure crew safety in future EVAs. In support of this goal, a combination of Thermal Desktop thermal modeling and Computational Fluid Dynamics (CFD) has been performed in order to characterize the performance of the EMU components, specifically those within the ventilation/cooling water loops. This modeling effort evaluates the dry/wet gas pressure drop and flow distribution through gas and liquid flow paths using CFD, as well as a two-phase flow assessment of condensation production and water separation/removal performance using an integrated Thermal Desktop model of important EMU ventilation loop components. The models assess this overall thermal-fluid performance in comparison with previous existing models and design points, with the potential to evaluate worst case scenarios and historical EVAs.Item Performance Testing and Modeling of a Scaled Fusible Heat Sink Test Article for Exploration Vehicles(2020 International Conference on Environmental Systems, 2020-07-31) Hillstrom, Alexander; Massina, Christopher; Foley, Lauren; Abraham, Brittany; Andish, KambizA water based fusible heat sink is envisioned for use in several future human space vehicles ranging from a deep space habitable airlock to lunar rovers. This radiator concept has the potential to enable active thermal control systems with a single benign working fluid (such as propylene glycol water) as dynamic loading is buffered by the heat capacity of the integrated water layer. This paper presents the results of evaluations of a scaled test article which includes integrated coolant tubes through the radiator’s water reservoir. This testing was completed to validate analysis results and provide insight into freeze direction and control given the enclosure volume’s unique geometry and internal features. The coolant flows through the radiator in two tube bank layers. The first layer is contained within the water volume near the heat rejection interface, i.e. the radiating surface, and the second layer is submerged within the entrained water volume. The inlet temperature and flow rates of each layer can be controlled independently to better match the thermal performance expected in the full scale radiator. Results indicate that a predictable freeze direction can be obtained repeatedly and the associated water ice spike formation can be tolerated by a flexible enclosure. Implications for the next iteration of full scale hardware design are also discussed.