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Coupled radiative thermal and nonlinear stress analysis for thermal deformation in large space structures
Large space structures are capable of large thermal deformations in the space environment. A case of large-scale thermal deformation was observed in the analysis of the Near Earth Asteroid Scout solar sail, with predicted tip displacements of more than one meter in seven-meter booms. Experimental data supports the broad conclusions of the analysis, but shows poor agreement on the details of the thermal deformation. Prediction that is precise enough to drive engineering decisions will require coupled thermal-stress analysis with features that are not found in current multiphysics codes.
This paper describes a simple method for stepwise coupling between commercial nonlinear stress analysis software and radiative thermal analysis software. Results are presented for a round stainless steel tube, which is a common case in existing literature.
Author: Olive R. Stohlman
Extending the Capabilities of Thermal Desktop with the OpenTD Application Programming Interface
With the release of Thermal Desktop 6.0, users now had the ability to interface with some of the many elements and constructs of a Thermal Desktop model through external applications developed using the TD API (Application Programming Interface). This file allows applications to be developed in the .NET framework and interface to a number of object types within a Thermal Desktop model. The release of 6.1 expands the subset of objects able to be manipulated and now includes the raw geometrical information of surfaces. With the release of 6.1, the API was now referred to as OpenTD. This paper discusses some of the utilities and capabilities developed using the OpenTD API at the NASA Goddard Space Flight Center. These include utilities to help with configuration control of models and case sets, addition of logic to better process heater performance, and a methodology implemented to allow for submodel level processing of radiation couplings to include smaller radks where needed in a cryogenic region without using the same criteria for the warmer portions of the model. This last utility is targeting a reduction in run time without sacrificing accuracy. Lastly, some lessons learned, work-arounds, and wishes for the next release of the OpenTD API are also presented.
Author: Hume L. Peabody
Content Tags: third-party software, OpenTD, heater, Monte Carlo, ray tracing, orbital heating, surface properties, parametric, parameterize, optical properties, thermophysical properties, symbols, absorptivity, mli, multi-layer insulation, case set manager, API
Passive Thermal Control Design Methods, Analysis, Comparison, and Evaluation for Micro and Nanosatellites Carrying Infrared Imager
Advancements in satellite technologies are increasing the power density of electronics and payloads. When the power consumption increases within a limited volume, waste heat generation also increases and this necessitates a proper and efficient thermal management system. Mostly, micro and nanosatellites use passive thermal control methods because of the low cost, no additional power requirement, ease of implementation, and better thermal performance. Passive methods lack the ability to meet certain thermal requirements on larger and smaller satellite platforms. This work numerically studies the performance of some of the passive thermal control techniques such as thermal straps, surface coatings, multi-layer insulation (MLI), and radiators for a 6U small satellite configuration carrying a mid-wave infrared (MWIR) payload whose temperature needs to be cooled down to 100K. Infrared (IR) imagers require low temperature, and the level of cooling is entirely dependent on the infrared wavelengths. These instruments are used for various applications including Earth observations, defence, and imaging at IR wavelengths. To achieve these low temperatures on such instruments, a micro-cryocooler is considered in this study. Most of the higher heat dissipating elements in the satellite are mounted to a heat exchanger plate, which is thermally coupled to an external radiator using thermal straps and heat pipes. The effects of the radiator size, orbital inclinations, space environments, satellite attitude with respect to the sun, and surface coatings are discussed elaborately for a 6U satellite configuration.
Source: Applied Sciences, 2022, 12(6), 2858
Author: Shanmugasundaram Selvadurai, Amal Chandran, David Valentini, and Bret Lamprecht
Content Tags: mli, multi-layer insulation, surface elements, surface coating a mesh, radiator, phase change material, thermocouples, finite element, finite elements, convergence, material properties, properties, CCHP
Integrated Analysis of Thermal/Structural/Optical Systems
Productivity bottlenecks for integrated thermal, structural, and optical design activities were identified and systematically eliminated, making possible automated exchange of design information between different engineering specialties.
The problems with prior approaches are summarized, then the implementation of the corresponding solutions is documented. Although the goal of this project was the automated evaluation of coupled thermal/optical/structural designs, significant process improvements were achieved for subset activities such as stand-alone thermal, thermal/ structural, and structural/optical design analysis.
Author: B. Cullimore, T. Panczak, J. Baumann, Dr. Victor Genberg, Mark Kahan
Content Tags: finite element, finite elements, finite difference, parametric, conductance, contact conductance, design optimization, robust design, optical, registers, radiation, dynamic SINDA, dynamic mode
Automated Multidisciplinary Optimization of a Space-based Telescope
Automated design space exploration was implemented and demonstrated in the form of the multidisciplinary optimization of the design of a space-based telescope.
Off-the-shelf software representing the industry standards for thermal, structural, and optical analysis were employed. The integrated thermal/structural/optical models were collected and tasked with finding an optimum design using yet another off-the-shelf program. Using this integrated tool, the minimum mass thermal/structural design was found that directly satisfied optical performance requirements without relying on derived requirements such as isothermality and mechanical stability. Overdesign was therefore avoided, and engineering productivity was greatly improved.
This ambitious project was intended to be a pathfinder for integrated design activities. Therefore, difficulties and lessons learned are presented, along with recommendations for future investigations.
Author: B. Cullimore, T. Panczak, J. Baumann
Margin Determination in the Design and Development of a Thermal Control System
A method for determining margins in conceptual-level design via probabilistic methods is described. The goal of this research is to develop a rigorous foundation for determining design margins in complex multidisciplinary systems. As an example application, the investigated method is applied to conceptual-level design of the Mars Exploration Rover (MER) cruise stage thermal control system. The method begins with identifying a set oftradable system-level parameters. Models that determine each of these tradable parameters are then created. The variables of the design are classified and assigned appropriate probability density functions. To characterize the resulting system, a Monte Carlo simulation is used. Probabilistic methods can then be used to represent uncertainties in the relevant models. Lastly, results of this simulation are combined with the risk tolerance of thermal engineers to guide in the determination of margin levels. The method is repeated until the thermal engineers are satisfied with the balance of system-level parameter values. For the thermal control example presented, margins for maximum component temperatures, dry mass, power required, schedule, and cost form the set of tradable system-level parameters. Use of this approach for the example presented yielded significant differences between the calculated design margins and the values assumed in the conceptual design of the MER cruise stage thermal control system.
Author: D. Thunnissen, G. Tsuyuki
Analysis and Design of the Mechanical Systems Onboard a Microsatellite in Low-Earth Orbit: an Assessment Study
A study of the mechanical systems contributing to the design and performance of a picosatellite’s mission in low-Earth orbit (LEO) was performed through design and analysis. The unique architecture of this satellite stems from a form factor established by the internationally recognized CubeSat Program. This CubeSat-Plus architecture limits the satellite’s size to be no larger than a 10 x 10 x 15 cm cube with an overall mass not exceeding 2 kg. This satellite would then be launch into LEO and conduct on-orbit GPS measurements while remaining tethered to the second stage booster of a Boeing Delta II Launch Vehicle (LV). To ensure the structural integrity of the satellite, Finite Element Analysis (FEA) was conducted on all primary, secondary, and tertiary structural constituents to determine the maximum stresses experienced by the satellite during launch, deployment, and while in orbit around Earth. All space deliverable platforms must be designed in strength to satisfy a predetermined standard as set forth by the LV provider. Theoretical characterization of the dynamic environment coupled with the equation of motion, and static failure modes were the primary constituents of this assessment study. Consequential data sets piloted the assessment criterion and a means of implementing conclusive remarks. The design of this satellite will reveal evidence of system level design philosophies that were required given the extremely small form factor. The satellite’s on-orbit thermal environment was quantified and characterized using finite difference techniques and solar simulation software. The extremely dynamic behavior of a LEO satellite required a fundamental understanding of both long wave and shortwave thermal radiation along with creative strategies to ensure on-orbit thermal stability for the satellite’s electrical components. Thermal Desktop was employed to develop an accurate thermal model by which to assess incident radiation, conductive and radiative heat management, and temperature-dependent mechanical responses of the satellite’s structure and working systems. Conclusions from both the design efforts and model analyses show that this picosatellite is both sufficiently strong to survive the expected launch loads, and provides a thermally stable environment for the components housed within its interior.
Publication: SolomonD0506 (3).pdf
Source: TFAWS Short Course
Author: Dylan Raymond Solomon
Non-grey Radiation Modeling using Thermal Desktop/SINDAWORKS
This paper provides an overview of the non-grey radiation modeling capabilities of Cullimore and Ring’s Thermal Desktop® Version 4.8 SindaWorks software. The non-grey radiation analysis theory implemented by Sindaworks and the methodology used by the software are outlined. Representative results from a parametric trade study of a radiation shield comprised of a series of v-grooved shaped deployable panels is used to illustrate the capabilities of the SindaWorks non-grey radiation thermal analysis software using emissivities with temperature and wavelength dependency modeled via a Hagen-Rubens relationship.
Source: TFAWS Short Course
Author: Dr. Kevin R. Anderson, Dr. Chris Paine
WPI Nanosat-3 Final Report, PANSAT - Powder Metallurgy and Navigation Satellite
This document summarizes the activities of the WPI Nanosat-3 (N3) program proposed in response to a BAA by the AFOSR and AIAA (University Nanosat Program, AFOSR BAA 2003-02) . Specifically, we proposed to have WPI undergraduate and graduate student teams under the direct guidance of WPI faculty, develop a nanosat that would be used as a vehicle to investigate:
- A GPS based navigation and orientation determination system
- the use of a powder metallurgy (P/M) component design methods to develop the primary satellite bus structure
Program highlights include the successful development of; i) a high quality satellite tracking and communications system, ii) powder metallurgy components of the satellite bus structure, iii) the sensor and communications subsystem, iv) the triple modular redundant processor system, v) the GPS navigation and orientation system, vi) a very high reliability and efficiency solar cell power system using custom designed switching power supplies, and vii) the satellite navigation/stability system. Also completed in conjunction with this NS3 program was a detailed MATLAB/Simulink model of the orbital mission. Finally, completed in parallel with the NS3 program but not supported by it was a prototype Picosat that built upon technology developed as part of the NANOSAT 3 program.
Source: Electrical and Computer Engineering, Worcester Polytechnic Institute
Author: Fred J Looft
Thermal Analysis on Plume Heating of the Main Engine on the Crew Exploration Vehicle Service Module
The crew exploration vehicle (CEV) service module (SM) main engine plume heating is analyzed using multiple numerical tools. The chemical equilibrium compositions and applications (CEA) code is used to compute the flow field inside the engine nozzle. The plume expansion into ambient atmosphere is simulated using an axisymmetric space-time conservation element and solution element (CE/SE) Euler code, a computational fluid dynamics (CFD) software. The thermal analysis including both convection and radiation heat transfers from the hot gas inside the engine nozzle and gas radiation from the plume is performed using Thermal Desktop. Three SM configurations, Lockheed Martin (LM) designed 604, 605, and 606 configurations, are considered. Design of multilayer insulation (MLI) for the stowed solar arrays, which is subject to plume heating from the main engine, among the passive thermal control system (PTCS), are proposed and validated.
Author: Xiao-Yen J. Wang and James R.Yuko
Ground Plane and Near-Surface Thermal Analysis for NASA’s Constellation Programs
Crew Exploration Vehicle Composite Pressure Vessel Thermal Assessment
The Crew Exploration Vehicle (CEV) is the next generation space vehicle to follow the Space Shuttle. A design with the inclusion of a Composite Pressure Vessel (CPV) has been assessed for its thermal response. The temperature distribution on the CPV that results from the heat produced by internal spacecraft systems and external space environments was calculated as part of a project-level assessment to understand thermomechanical stresses. A finite element translation of the crew module CPV was integrated into an existing CEV Thermal Math Model (TMM) based on the 605 baseline configuration and analyzed for four orbital cases. Steady state temperature profiles were generated based on orbit average heating. Preliminary thermal analysis results suggest that the CPV requires less make-up energy when compared to the baseline aluminum pressure vessel. It is emphasized that only local make-up energy was considered in the study. The make-up energy did not include the zoning configuration that occurs with heaters. This document presents the approach and assumptions used for this thermal assessment.
Author: Laurie Y. Carrillo, Ángel R. Álvarez-Hernández, Steven L. Rickman
Improvements to a Response Surface Thermal Model for Orion
Thermal Modeling of Nanosat
Advances in computer technologies and manufacturing processes allow creation of highly sophisticated components in compact platform. For example, a small scale satellite, such as the CubeSat, can now be used for scientific research in space rather than big scale project like the International Space Station (ISS). Recently a team of undergraduate and graduate students at SJSU has the opportunity to collaborate on designing and building a miniature size CubeSat with the dimension of 10x10x10 cm. Although the integration of compact electronics allows sophisticated scientific experiments and missions to be carried out in space, the thermal control options for such small spacecraft are limited. For example, because of its small size there is no room for dedicated radiator or insulation panels. To minimize mass of the thermal control system while keeping the electronics at safe operating conditions, this thesis aims at studying the external orbital radiation heat flux the CubeSat is expected to expose to and the steady state heat conduction of the internal electronics. If the operating temperature from these heating conditions causes issue, appropriate thermal control solutions will be presented.
Source: San José State University
Author: Dai Q. Dinh
Upper Stage Tank Thermodynamic Modeling Using SINDA/FLUINT
Modeling to predict the condition of cryogenic propellants in an upper stage of a launch vehicle is necessary for mission planning and successful execution. Traditionally, this effort was performed using custom, in-house proprietary codes, limiting accessibility and application. Phenomena responsible for influencing the thermodynamic state of the propellant have been characterized as distinct events whose sequence defines a mission. These events include thermal stratification, passive thermal control roll (rotation), slosh, and engine firing. This paper demonstrates the use of an off the shelf, commercially available, thermal/fluid-network code to predict the thermodynamic state of propellant during the coast phase between engine firings, i.e. the first three of the above identified events. Results of this effort will also be presented.
Author: P. Schallhorn, D. Michael Campbell, Sukhdeep Chase, Jorge Piquero, Cindy Fortenberry, Xiaoyi Li, Lisa Grob
Content Tags: Optimization, parametric, radiation, radiation analysis groups, conduction, evaporation, CFD, convergence, structural, heat flux, thermal stratification, register, two-phase, slosh, wall, splash
Upper Stage Tank Thermodynamic Modeling Using SINDA/FLUINT (Presentation)
Source: TFAWS Short Course
Author: Paul Schallhorn, D. Michael Campbell, Sukhdeep Chase, Jorge Piquero, Cindy Fortenberry, Xiaoyi Li, Lisa Grob
The Finite Element Method and Thermal Desktop
Despite recent advances in computer aided design (CAD) based tools, spacecraft thermal analysis remains outside the realm of finite element method (FEM) based analysis. The primary complaints against FEM often cited are:
- FEM is not based on physical principles.
- FEM codes do not provide procedural modeling for heaters, heat pipes, or other abstract thermal control components.
- Inadequate radiation analysis capabilities.
- FEM codes generate inappropriately large thermal models.
However, a failure on the part of existing FEM based codes does not invalidate the advantages of the Finite Element Method. Properly implemented, FEM based systems can have significant advantages.
A simple first law interpretation of FEM is presented, and shows that finite difference (FD) and FEM meshes may co-exist in the same thermal model, and solved using traditional analyzers such as SINDA/FLUINT.
A description of an integrated FD/FEM based system that efficiently satisfies all areas of spacecraft thermal analysis, including thermal radiation, is also presented.
Source: CRTech White Paper
Author: Tim Panczak
Highlights in thermal engineering at Carlo Gavazzi Space
Non-Grey and Temperature Dependent Radiation Analysis Methods
Most radiation analysis tools in use in the aerospace industry assume that grey conditions hold. That is, over the range of temperatures considered, optical properties are assumed to have a constant value with respect to wavelength. This reasonable approximation for systems that are near room temperature may show significant error at temperature extremes, particulary for conductive materials at cryogenic temperatures. Other areas where non-grey analysis may be appropriate is in furnace and lamp design, and in systems with specialized optical filters such as thermalphotovoltaics.
This short course reviews the definitions of optical properties and discusses the conditions for which greyness holds. A number of approaches to modeling non-grey radiation are discussed, and the approach used by Thermal Desktop is described. Non-grey analysis with materials that have temperature dependent properties at a given wavelength is also discussed. The new methodology is reviewed, in particular its dynamic integration with the thermal analyzer. Example cases are presented to highlight appropriate areas for non-grey radiation analysis.
Source: TFAWS Short Course 2005
Author: Tim Panczak
A CAD-based Tool for FDM and FEM Radiation and Conduction Modeling
Thermal engineering has long been left out of the concurrent engineering environment dominated by CAD (computer aided design) and FEM (finite element method) software. Current tools attempt to force the thermal design process into an environment primarily created to support structural analysis, which results in inappropriate thermal models. As a result, many thermal engineers either build models “by hand” or use geometric user interfaces that are separate from and have little useful connection, if any, to CAD and FEM systems.
This paper describes the development of a new thermal design environment called the Thermal Desktop. This system, while fully integrated into a neutral, low-cost CAD system, and which utilizes both FEM and FD methods, does not compromise the needs of the thermal engineer. Rather, the features needed for concurrent thermal analysis are specifically addressed by combining traditional parametric surface-based radiation and FD based conduction modeling with CAD and FEM methods. The use of flexible and familiar temperature solvers such as SINDA/FLUINT is retained.
Author: Tim Panczak, Steve Ring, Mark Welch
Content Tags: finite element, finite difference, concurrent engineering, heater, heatpipe, heat pipe, radiation analysis groups, optical properties, Phenomena, refraction, scaffolding, CAD geometry, layers, expression editor, solver, mesh, mesher, structural mesh, ray tracing, boundary conditions, thermal stress, radiator, conductance, batteries, orbital heating, mli, multi-layer insulation, radks, articulation, articulating