Software Development for Satellite Thermal Design

2013 ◽  
Vol 390 ◽  
pp. 703-707
Author(s):  
Abolfazl Shirazi ◽  
Mehran Mirshams
Keyword(s):  
Thermal Analysis ◽  
Temperature Gradient ◽  
Software Development ◽  
Research Laboratory ◽  
Thermal Control ◽  
Thermal Design ◽  
Temperature Gradients ◽  
Space Research ◽  
Accurate Analysis ◽  
Control Subsystem

Accurate thermal modeling for each part in the satellite is needed for achieving temperature gradients. The result of such a modeling will be the temperature gradients of each element of the satellite as a function of time. The aim of this paper is to present a new software which has been developed recently by the author at Space Research Laboratory for thermal analyzing of the satellites that is used to characterize the gradients of subsystems temperature as a function of time in space orbit. The software accomplishes accurate analysis of internal and external thermal loads of each part of the satellite and shows temperature gradients of each element. The purpose of designing this software is to create a useful application for thermal analysis of satellites, which is a helpful manner for testing satellite thermal subsystem. The most important usages of this software are designing thermal control subsystem, choosing proper equipment for thermal control subsystem and finding optimal configuration of satellite for having an ideal temperature gradient. The outputs of this software are validated by comparing them to a different thermal analyzing application.

Structure Design for Heat Sink Based on Thermal Analysis

2011 ◽  
Vol 80-81 ◽  
pp. 767-773
Author(s):  
Hai Gang Sun ◽  
Yong Zhou
Keyword(s):  
Thermal Analysis ◽  
Thermal Performance ◽  
Heat Sink ◽  
Cfd Simulation ◽  
Thermal Control ◽  
Structure Design ◽  
Thermal Design ◽  
Structure Parameters ◽  
Igbt Module ◽  
Key Factor

Thermal design and the working temperature control have been a key factor in the design of electronic devices and system. In this paper, a sort of heat sink collocated with high-power IGBT module, which is commonly used in car-carrying motor control system, is designed based on thermal analysis by means of CFD simulation and computer-aided analyzing, also the influence relations of structure parameters with thermal performance are studied. With thermal control as the overall design objective, structure parameters of heat sink are determined according to the obtained relations. Further, thermal performance of the designed heat sink is simulated and analyzed in CFD software to examine the validity of the design result. In this way, a method of thermal analyzing and structure parameter design for heat sink, which is proved as an efficacious approach, is introduced and can be used to thermal design and analysis for similar products.

Thermal Deformation Modeling of Space Optical Systems With Variable Coefficient of Thermal Expansion

2005 ◽  
Author(s):  
Jennifer Batson ◽  
Ab Hashemi
Keyword(s):  
Thermal Expansion ◽  
Temperature Gradient ◽  
Wave Front ◽  
Thermal Deformation ◽  
Coefficient Of Thermal Expansion ◽  
Optical Element ◽  
Thermal Control ◽  
Temperature Gradients ◽  
Optical Systems ◽  
Space Optical Systems

In modeling space optical systems, an important property affecting the wave front error is the coefficient of thermal expansion (CTE) of the materials. The change of deformation that an optical element experiences due to thermal loads is proportional to both the CTE and the change in temperature gradient. This deformation affects the performance of the optical system by introducing error in the wave front. The deformation can be reduced in part by using materials with low CTE. Alternatively, using high conductivity materials to minimize temperature gradients through the mirror can also reduce deformation. Usually, a combination of these approaches is used to optimize the performance and meet the requirements of the system. Even with the utmost attention to thermal control, often the temperature gradients cannot be completely avoided. Low CTE materials have been developed to reduce thermal deformation, including ULE (Ultra-low Expansion), Zerodur, and Silicon Carbide. However, the manufacturing process can result in non-uniformities throughout the optics. For optical systems requiring highly precise performance, modeling these non-uniformities becomes important. The non-uniformity in the CTE of a material in effect compounds the deformation in the same manner as introducing additional temperature gradient through the optics. This paper describes the methodology for integrated thermal/mechanical modeling to predict the deformation response of an optical element with assumed CTE variations and thermal disturbances. A mirror with an assumed CTE variation was modeled in a changing thermal environment and using IDEAS/TMG analysis tools, thermal deformations were predicted. Results show excellent agreement with engineering predictions. Clearly knowing the CTE variation of the material is a critical step for modeling. However, measuring and specifying the material CTE is out of the scope of this paper.

Design and Analysis for Thermal Control System of Nanosatellite

2010 ◽  
Author(s):  
Murat Bulut ◽  
Adem Kahriman ◽  
Nedim Sozbir
Keyword(s):  
Thermal Analysis ◽  
Thermal Model ◽  
Thermal Control ◽  
Temperature Data ◽  
Thermal Design ◽  
Analysis Tool ◽  
Control Analysis ◽  
Preliminary Design ◽  
Thermal Control System ◽  
Early Phases

It is desirable to be able to turn-around thermal analysis results in a couple of minutes early phases of a satellite thermal design. Therefore, ThermXL-spreadsheet-based Thermal Analysis Tool is one of the very flexible and easy-to-use tool that is suited to preliminary design of a nanosatellite. This paper focuses on the thermal design and the results of an initial analysis of the nanosatellite by using ThermXL. The goal of this study is to take suitable measures to ensure all the components will operate in their safe range of temperatures and also a proper heat rejection. The nanosatellite such as Cube Satellite (CubeSat) is a miniaturized satellite that has dimensions of 10cm × 10cm × 10cm and weights of 1kg. The thermal model of CubeSat was modelled and the thermal analysis was performed. The thermal control analysis on this CubeSat with passive thermal control has been conducted by the ThermXL program that provided by ITP Engines. Temperature distribution of solutions was computed with ThermXL. Temperature data met the need of the mission. The results of the temperatures show that the thermal design of nanosatellite is feasible.

Study on Thermal Analysis of Main Mirror in Space Solar Telescope

2011 ◽  
Vol 328-330 ◽  
pp. 300-304 ◽  
Author(s):  
Rong Li ◽  
Hu Li Shi ◽  
Zhi Ping Chen
Keyword(s):  
Thermal Analysis ◽  
Temperature Field ◽  
Thermal Control ◽  
Thermal Design ◽  
Solar Observation ◽  
Solar Telescope ◽  
The Sun ◽  
Analysis Software ◽  
Primary Mirror ◽  
Space Solar Telescope

The proposed Chinese Space Solar Telescope (SST) is the first large aperture space telescope in China designed to observe the sun. With an effective aperture of Φ1m, the primary mirror faces the sun directly, which receives more than 1000W heat that will lead to unacceptable thermal distortion in such severe thermal condition. Therefore, the temperature field of SST, which is changing with its orbital position, is critical in its design. In this paper, an analysis of the thermal flux in the SST is presented firstly. Further more, the heat flux of orbit is calculated with the thermal softerware NEVADA (Net Energy Verification And Determination Analyzer) according to the orbit parameters of SST. The thermal design software SINDA/G (System Improved Numerical Differencing Analyzer/Gaski), the radiation analysis software NEVADA and the finite element analysis software MSC.Patran are used to simulate the temperature field of the SST. In the end, the temperature distribution of the primary mirror is calculated. The temperature level of the primary mirror indicates that the system can achieve high spatial resolution with 0.1″~0.15″. It also means that the thermal control design is effective. The optical requirements to the SST thermal control are met. The thoughts and methods of the thermal analysis are also useful for similar optical telescopes designed for solar observation.

scholarly journals Quasi-All-Passive Thermal Control System Design and On-Orbit Validation of Luojia 1-01 Satellite

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 827 ◽  
Author(s):  
Lin Yang ◽  
Qiang Li ◽  
Lin Kong ◽  
Song Gu ◽  
Lei Zhang
Keyword(s):  
Thermal Analysis ◽  
Control System ◽  
Temperature Fluctuation ◽  
Thermal Control ◽  
Temperature Data ◽  
Thermal Design ◽  
Analysis Model ◽  
Telemetry Data ◽  
Thermal Control System ◽  
Fluctuation Range

In order to resolve the large fluctuations in temperature range problem of Luojia 1-01 satellite caused by low heat inertia and poor thermal conductivity of structure, a quasi-all-passive thermal control system (TCS) design is presented under the conditions of limited resources including mass and power consumption. The effectiveness of the TCS design is verified by both ground thermal balanced test and related telemetry data of on-orbit performance. Firstly, according to the structural features and working modes of the satellite, isothermal design was implemented and the effectiveness was verified by thermal analysis using finite element method. Secondly, based on the results of the thermal analysis, thermal design was optimized and verified by the thermal balanced test. Finally, the thermal design was proved to be effective by temperature data acquired from telemetry data of on-orbit performance, and the thermal analysis model was improved and updated based on the results of thermal balanced test and temperature data of on-orbit performance. The on-orbit data indicates that temperature of optical camera stables at about 12 °C, temperature of battery stables at 19 °C, temperature of instruments inside and outside the satellite cabin is ranging from 10 °C to 25 °C. Temperature fluctuation range of optical camera is less than 2 °C when it is not imaging. Temperature fluctuation range of instruments not facing the sun is less than 4 °C. The data suggests that the temperature level of the satellite meets general design requirements, and the quasi-all-passive TCS design of the satellite is practicable.

scholarly journals GRADIENT-BASED OPTIMIZATION OF SPACECRAFT AND AIRCRAFT THERMAL DESIGN

Aviation ◽  
2020 ◽  
Vol 24 (3) ◽  
pp. 105-116
Author(s):  
Laurynas Mačiulis ◽  
Rimantas Belevičius
Keyword(s):  
Thermal Analysis ◽  
Thermal Control ◽  
Multidisciplinary Optimization ◽  
Thermal Design ◽  
Thermal Models ◽  
Computational Overhead ◽  
Gradient Based ◽  
Multidisciplinary System ◽  
Initial Starting ◽  
Derivatives Of

Steady-case thermal analysis plays an important role in dimensioning thermal control systems for spacecrafts and aircrafts. Usually a trial and error approach is used based on engineering judgement and experience. When thermal models become complex or there are conflicting thermal requirements, however, it becomes harder for an engineer to gain insight as to which design decisions will lead to better results. Numerical optimization, on the other hand, could provide a more robust approach for the thermal design of complex spacecraft or aircraft models. In this paper, we suggest a gradient-based multidisciplinary optimization of thermal models where the coupled derivatives of the multidisciplinary system are obtained with the adjoint method. We show that in the case of steady-state thermal analysis, there is an analytic solution of a partial derivatives of implicit heat-transfer equation that can be used to derive total derivatives of the system. We present a practical application of this method by solving a small interplanetary spacecraft thermal optimization problem consisting of one objective, 15 design variables, and 10 constraints. We found that by using gradient-based optimization with exact derivatives, the best results can be achieved by exploring the design space at multiple initial starting points without major computational overhead.

Transient Thermal Analysis of Electrical Machine

2009 ◽  
Author(s):  
Ahmad K. Sleiti
Keyword(s):  
Thermal Analysis ◽  
Temperature Gradient ◽  
Thermal Stresses ◽  
Electric Machines ◽  
Temperature Gradients ◽  
Electrical Machine ◽  
Transient Thermal Analysis ◽  
Operation Conditions ◽  
Severe Reduction ◽  
Transient Thermal

Transient thermal analysis of electric machine under realistic operation conditions and thermal losses is studied. A symmetrical portion of the stator and rotor is modeled and all thermal losses and cooling boundary conditions are applied according to operational duty cycle. It is found that there is a temperature gradient across the stator of more than 30 °C, across the rotor of more than 70 °C and across the whole machine of more than 100 °C. These temperature gradients could cause high thermal stresses and lead to severe reduction in the machine life. It is extremely important in future designs to consider reducing the temperature gradients by optimizing the design of the electric machines through advanced cooling techniques and strategies.

scholarly journals The principle of minimum entropy production and snow structure

2004 ◽  
Vol 50 (170) ◽  
pp. 342-352 ◽  
Author(s):  
Perry Bartelt ◽  
Othmar Buser
Keyword(s):  
Mass Transfer ◽  
Temperature Gradient ◽  
Entropy Production ◽  
Surface Curvature ◽  
The State ◽  
Temperature Gradients ◽  
Curvature Radius ◽  
Minimum Entropy ◽  
Snow Layer ◽  
Minimum Entropy Production

AbstractAn essential problem in snow science is to predict the changing form of ice grains within a snow layer. Present theories are based on the idea that form changes are driven by mass diffusion induced by temperature gradients within the snow cover. This leads to the well-established theory of isothermal- and temperature-gradient metamorphism. Although diffusion theory treats mass transfer, it does not treat the influence of this mass transfer on the form — the curvature radius of the grains and bonds — directly. Empirical relations, based on observations, are additionally required to predict flat or rounded surfaces. In the following, we postulate that metamorphism, the change of ice surface curvature and size, is a process of thermodynamic optimization in which entropy production is minimized. That is, there exists an optimal surface curvature of the ice grains for a given thermodynamic state at which entropy production is stationary. This state is defined by differences in ice and air temperature and vapor pressure across the interfacial boundary layer. The optimal form corresponds to the state of least wasted work, the state of minimum entropy production. We show that temperature gradients produce a thermal non-equilibrium between the ice and air such that, depending on the temperature, flat surfaces are required to mimimize entropy production. When the temperatures of the ice and air are equal, larger curvature radii are found at low temperatures than at high temperatures. Thus, what is known as isothermal metamorphism corresponds to minimum entropy production at equilibrium temperatures, and so-called temperature-gradient metamorphism corresponds to minimum entropy production at none-quilibrium temperatures. The theory is in good agreement with general observations of crystal form development in dry seasonal alpine snow.

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