Tuesday August 18, 2020
Tuesday, August 18, 9:00 – 11:00
Dr. Eugene Ungar is a Senior Thermal and Fluids Analyst in the Crew and Thermal Systems Division of NASA/Johnson Space Center. His 30 year career has covered a wide range of thermal issues including development of the ISS active thermal system and the conceptual design of the Gateway active thermal system. He received his BS in Mechanical Engineering from the University of Cincinnati, MS in Mechanical Engineering from the University of Kentucky, and Ph. D. in Mechanical Engineering from the University of Houston.
The methods and techniques of designing spacecraft thermal control systems are presented. The critical choices and compromises made during the design process are outlined and discussed. Among the topics discussed are: single phase vs. two-phase systems, single loop vs. dual loop systems, selection of liquid flow rates and radiator design.
Tuesday, August 18, 12:00 – 13:30
Abby Zinecker, Sydney Taylor, and Brittany Spivey
Abby Zinecker received a BS in Mechanical Engineering from the University of Houston and an MS in Aerospace Engineering from the University of Colorado Boulder. She has 2 years of experience as a thermal analyst for the Space Launch System and is currently employed by Jacobs working for the Thermal Design Branch at NASA Johnson Space Center on Gateway Passive Thermal and VIPER. Abby has been researching thermal control materials and coatings and optical property degradation for the Gateway.
Sydney Taylor received a BS in Aeronautical and Astronautical Engineering from Purdue University and is currently a graduate Pathways intern in the ES3 Thermal Design Branch at NASA Johnson Space Center, where she works on VIPER, Gateway, FTRC, and BEAM. Sydney is a PhD candidate in Aerospace Engineering at Arizona State University and is supported by a NASA Space Technology Research Fellowship. Her dissertation research focuses on VO2-based nanofabricated variable emittance coatings that provide temperature-dependent heat rejection. As a member of the Gateway passive thermal control team, Sydney has been investigating the optical property degradation of thermal control materials and coatings in the NRHO environment.
Brittany Spivey received a BS in Mechanical Engineering from Texas A&M and is currently working towards her ME in Mechanical Engineering at the University of Houston. She has 2 years of experience in the oil and gas industry. In May 2020, she became employed by HX5/Jacobs working for Thermal Design Branch at NASA Johnson Space Center on Gateway Passive Thermal. Currently her role has been assisting with the research for thermal control materials and optical property degradation, analyzing the effects of specularity of Gateway thermal control surfaces and drafting a Thermal Control System Data Book for Gateway.
Passive thermal control of a spacecraft is reliant on external surface optical properties (solar absorptivity and IR emissivity), which degrade over time depending on length of mission, material or coating, and natural and induced environments. Understanding the degradation and resulting End of Life (EOL) optical properties enables optimization of the thermal performance and reduces risk. The environmental factors that affect degradation of materials and coatings include UV, solar wind, vacuum, contamination, lunar dust, atomic oxygen, and more. The Gateway will be flying in the Near Rectilinear Halo Orbit (NRHO), an environment that has not been flown before and environmental factors are different from Low Earth Orbit. There is no on orbit data for materials in this environment, and optical property data from on-orbit and ground experiments for other environments is of limited use. This 1.5 hour short course will explore optical properties and degradation in the context of the Gateway by introducing the expected environment of NRHO, types of materials and coatings that could be used, how to estimate their EOL properties, and future work. This course will focus on the NRHO environment, but it will be beneficial for anyone interested in optical property degradation in the space environment.
Wednesday August 18, 2020
Tuesday, August 18, 9:00 – 13:00
Steve Rickman joined the NASA Engineering and Safety Center in January 2009 as the NASA Technical Fellow for Passive Thermal. In this capacity, he leads a cross-agency Technical Discipline Team, leveraging expertise from within and outside of the Agency to solve high risk technical problems and foster a community of practice for the passive thermal control and thermal protection disciplines. During his 35-plus year NASA career, his primary interest has been in the area of passive thermal control of orbiting spacecraft. Recently, his interests have focused on calorimetry of lithium-ion cell thermal runaway and thermal testing and modeling of wires/wire bundles to determine ampacity. He has authored or co-authored numerous technical papers and conference presentations including public testimony given with the U.S. Air Force to the Columbia Accident Investigation Board. He authored a textbook chapter on natural and induced thermal environments. He was awarded a U.S. patent as the lead inventor for Micrometeoroid/Orbital Debris Impact Detection and Location Using Fiber Optic Strain Sensing and another as a co-inventor on an innovative space station concept. Steve has received numerous mentoring, Group Achievement, Tech Brief and Space Act Awards and has been honored with the NASA Exceptional Achievement Medal. From 2011 to 2015, he was an Adjunct Professor/Lecturer of Mechanical Engineering at Rice University. Steve earned a B.S. in Aerospace Engineering from the University of Cincinnati and a M.S. in Physical Science from the University of Houston-Clear Lake.
This course provides a theoretical background on orbital mechanics and spacecraft attitudes and applies these concepts to problems of interest to spacecraft thermal engineers. After a brief review of vector and matrix operations, the two-body problem is explored in detail. The governing differential equation is derived and conservation of specific mechanical energy and specific angular momentum are discussed. Kepler’s laws are derived and presented with illustrative examples. Orbit perturbations are introduced and the effects on the orbit are discussed. The orbit beta angle is derived and the variation of beta over time is explored. An expression for orbit eclipse is derived and examples are presented. Advanced orbit concepts are briefly discussed. Finally, spacecraft reference frames and attitudes are discussed and a mathematical framework for transforming spacecraft attitudes is presented. Calculation of heating to transformed spacecraft surfaces is demonstrated.
Tuesday, August 18, 14:30 – 16:30
Jeffrey Feller received his PhD in experimental low temperature physics at the University of Wisconsin. He has been with the Cryogenics Group at NASA Ames Research Center since 2000. There he has worked on designing, building, and testing cryogenic refrigerators and components. More recently he has played a large role in the design and analysis of passive and active cryogenic propellant management systems.
SOFIA, the Stratospheric Observatory For Infrared Astronomy, is a Boeing 747SP aircraft modified to carry a 2.7-meter (106-inch) reflecting telescope. SOFIA’s science instruments (SIs) operate in the infrared, and for that reason most of them need to be cooled to liquid helium temperatures or below. This presentation examines the many types of cryogenic refrigerators and other thermal control components, including their principles of operation, operating constraints, potential capabilities, flight heritage (SOFIA or otherwise), and their overall applicability to SOFIA SIs.
An overview of SIs that have been developed, emphasizing the various cryogenic components used, will also be presented.
Thursday August 20, 2020
Monday, August 4, 9:00 – 11:30
Session Moderator: William Walker, Ph.D.
Presentation 1 Title: Practical Battery Thermal Modeling Techniques
Presentation 1 Speaker: Kylie Cooper (USRA) and Jonathan London (USRA)
Presentation 1 Abstract: Lithium-ion batteries are thermo-electrochemical devices, whereby nearly every facet of their functionality and performance are thermally driven. As a result, it is important to have thermal modeling techniques that effectively capture the intricacies of both the electrochemical nature of the battery and also the complex thermal network that typically results from the design of the battery thermal management system. Here we present a thermal modeling workflow and a set of general assumptions for how to construct a thermal model of a Li-ion battery pack. We use a 14-cell bank of 18650-format Li-ion cells, loosely based on a proposed alternative battery design for Orion, as the example. Although the workflow is performed with Thermal Desktop and related utilities, the focus of this presentation is less about software specific techniques, but rather is focused on the assumptions and conditions that should be used in a model (regardless of the tool used to build the model). Example cases and results will be presented for charge, discharge, and thermal runaway.
Presentation 2 Title: Simulation of Abuse tolerance of Battery Packs
Presentation 2 Speaker: Kaushik Illa (Siemens)
Presentation 2 Abstract: Physically developing and performing trials on new battery compositions and cooling strategies is an expensive and resource intensive process that only large funded organization and laboratories have the facilities to perform successfully. In this paper we would like to address how simulation would assist in minimizing the research, analysis, and experiments to analyze the behavior of battery systems undergoing thermal runaway where there is a need for strongly coupled resolution of flow, heat transfer, electrochemistry, stress and combustion to provide the best possible prediction to maintain the integrity of the system and identifying potential problems at an early stage. Thermal runaway is a key safety concern during the use of battery systems. They need to be designed in a way to minimize the impact of thermal runaway.
This paper presents case study for an abuse of an 18650 battery module where the failure is initiated by a heater attached to the central cell to study the gas evolution, propagation and mitigation. Finally performing a full system level simulation to capture various interactions such as control on pack level integration. At system level we use advanced equivalent circuit models, making it possible to simulate thermal runaway inside a battery system to optimize its design.
In all, it is becoming more vital to analyze packs and modules through simulation to capture the complexity of a thermal management at component and system level.
Presentation 3 Title: Lithium-ion Battery Combined Electrochemical and Thermal Modeling Techniques and Assumptions
Presentation 3 Speaker: Jonathan Harrison (GT Suite)
Presentation 3 Abstract: Lithium-ion batteries are energy storage devices which operate on thermo-electrochemistry principles for power. These batteries must be temperature controlled to operate at maximum performance, and thus it is important to analyze the design of the thermal management system for these battery packs. Additionally, the chemical reactions occurring in the cells can lead to catastrophic failure via thermal runaway if not properly designed. Since thermal runaway testing is costly and dangerous, modeling batteries from an electrochemical and thermal perspective is an important method to achieving proper battery thermal management system design. In this paper we present a thermal and electrochemistry modeling workflow along with a set of assumptions and apply it to a Li-ion battery pack of 14 cells of cylindrical 18650 design, loosely based on a battery design for the Orion spacecraft. The workflow will be presented with GT-SUITE simulation software, but the principles and modeling techniques can be applied to any modeling tool. Examples will be demonstrated for charge, discharge, thermal runaway, predictive state of charge, and aging characterization.
Presentation 4 Title: Battery Thermal Analysis Techniques with Thermal Desktop
Presentation 4 Speaker: Douglas Bell (CR Technologies)
Presentation 4 Abstract: While modeling the electrochemical phenomena is important at some level, approximations of the exothermic and endothermic heating in the cells allow evaluating the thermal behavior in a cell-, subsystem-, or system-level model using CRTech’s Thermal Desktop. We will present the modeling procedure for creating a 14-cell block of 18650-format Li-ion cells along with a separation material and capture plates above and below the cells using the Thermal Desktop suite of tools. The results presented will show the thermal behavior of the system while charging and discharging and the thermal behavior during thermal runaway events in an exterior and an interior cell. Features of the tool suite that benefit the analysis of battery packs will be highlighted.