scholarly journals Thermal Design and Verification of Spherical Scientific Satellite Q-SAT

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yunhan He ◽  
Boxin Li ◽  
Zhaokui Wang ◽  
Yulin Zhang
Keyword(s):  
Numerical Simulations ◽  
Thermal Control ◽  
Thermal Design ◽  
Test Method ◽  
Heat Radiation ◽  
Thermal System ◽  
Thermal Tests ◽  
Output Plane ◽  
Small Satellites ◽  
Spherical Satellite

Small satellites have gradually become an important mean of space scientific exploration. The Tsinghua University developed a spherical small satellite, Q-SAT, which is aimed at detecting the Earth gravity and atmosphere parameters. In the current paper, thermal control for Q-SAT is discussed. For heat exchange between the satellite and the environment, radiation plays the main part. Different from traditional cuboid satellites, the current spherical satellite has no individual heat input and output plane which brings challenges to the thermal design of the satellite. In addition, the cost of small satellites is required to be as low as possible. A passive thermal control solution based on integrated spherical structure is employed on the Q-SAT. The combination of two integrated hemispheres is designed to facilitate the heat conduction. Different materials are utilized to control the heat transfer path. Firstly, a set of numerical simulations demonstrate that the current design can be well adapted to complex flight environment. Next, the thermal design is verified by thermal tests. As the traditional heat radiation lamps cannot meet the test requirements of the spherical satellite, an external heat flow test method which is based on distributed heaters is proposed. Results from numerical simulations agree well with the experimental test results. Both results show that the thermal system can guarantee the functions of the satellite. Q-SAT was successfully launched into orbit on August 6, 2020. The telemetry data from Q-SAT verified the effectiveness of the satellite thermal system. The thermal design and test method proposed in present paper can potentially be adopted to other small scientific satellites as well.

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.

An Insight into the Features of the OAO-C Thermal Design

1973 ◽  
Vol 95 (4) ◽  
pp. 1039-1047 ◽  
Author(s):  
H. Fine ◽  
J. Quadrini ◽  
S. Ollendorf
Keyword(s):  
Thermal Control ◽  
Astronomical Observatory ◽  
Thermal Design ◽  
Test Bed ◽  
Large Space ◽  
Flight Data ◽  
The Earth ◽  
Ground Test ◽  
Earth Observation Satellite ◽  
Insight Into

The Orbiting Astronomical Observatory (OAO)-C was successfully launched into 400-nautical mile circular orbit on August 21, 1972. For this spacecraft, a unique sensitivity approach to the thermal design was developed which resulted in a predictal design—the merits of which should be considered for application on future spacecra. The OAO-C is also serving as a test bed for the evaluation of thermal control hardware. To provide flight data for space program applications, experiments for a new coating and four different heat pipe designs are on this spacecraft. The data derived from OAO-C will be extremely valuable for such future programs as the Large Space Telescope (LST) and the Earth Observation Satellite (EOS). This paper will describe the detailed of the sensitivity design approach and thermal control hardware. For all aspects discussed, a comparison of pertinent analysis, ground test data, and flight data [1] will be given.

Compact Modeling of a Telecommunication Cabinet

2008 ◽  
Author(s):  
Aalok Trivedi ◽  
Dereje Agonafer ◽  
Deepak Sivanandan ◽  
Mark Hendrix ◽  
Akbar Sahrapour
Keyword(s):  
Heat Exchanger ◽  
Computation Time ◽  
Time Frame ◽  
Thermal Design ◽  
Compact Model ◽  
Computational Time ◽  
Compact Modeling ◽  
Thermal System ◽  
Mesh Density ◽  
Product Test

Computational Fluid Dynamics (CFD) is widely used in the telecommunication industry to validate experimental data and obtain both qualitative and quantitative results during product development. A typical outdoor telecommunications cabinet requires the modeling of a large number of components in order to perform the required air flow and thermal design. Among these components, the heat exchanger is the most critical to thermal performance. The cabinet heat exchanger and other thermal components make up a complex thermal system. This thermal system must be characterized and optimized in a short time frame to support time-to-market requirements. CFD techniques allow for completing system thermal optimization long before product test data can be available. However, the computational model of the complex thermal system leads to a large mesh count and corresponding lengthy computational times. The objective of this paper is to present an overview of techniques to minimize the computational time for complex designs such as a heat exchanger used in telecommunication cabinets. The discussion herein presents the concepts which lead to developing a compact model of the heat exchanger, reducing the mesh count and thereby the computation time, without compromising the acceptability of the results. The model can be further simplified by identifying the components significantly affecting the physics of the problem and eliminating components that will not adversely affect either the fluid mechanics or heat transfer. This will further reduce the mesh density. Compact modeling, selective meshing, and replacing sub-components with simplified equivalent models all help reduce the overall model size. The model thus developed is compared to a benchmark case without the compact model. Given that the validity of compact models is not generalized, it is expected that this methodology can address this particular class of problems in telecommunications systems. The CFD code FLOTHERM™ by Flomerics is used to carry out the analysis.

Supercritical Carbon Dioxide Centripetal Compressor—Aerodynamic Design and Analysis of Off Design Conditions

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
Xuefei Du ◽  
Dengtao Yu ◽  
Dan Luo ◽  
Diangui Huang
Keyword(s):  
Carbon Dioxide ◽  
Numerical Simulation ◽  
Supercritical Carbon Dioxide ◽  
Guide Vane ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Thermal Design ◽  
Test Method ◽  
Characteristic Line ◽  
Supercritical Carbon

Abstract Based on the design of the supercritical carbon dioxide (SCO2) centripetal compressor, this paper adopts the orthogonal design test method to optimize the pear-shaped volute, designs the front guide vane with the third-order Bezier curve, and designs the outlet by the equal section method. The numerical simulation calculation and analysis of the design conditions and variable conditions of the SCO2 centripetal compressor are carried out. The results at design conditions show that the isentropic efficiency is 92%, the pressure ratio is 1.21, and the mass flow rate is 195.9 kg/s, which is close to the thermal design and level simulation results; the results of variable conditions show that the efficiency of the SCO2 centripetal compressor-flow and pressure ratio-flow characteristic line is similar to that of multistage axial flow compressor. The supercritical carbon dioxide centripetal compressor designed in this paper meets the design requirements, and its feasibility is proved through numerical simulation.

Specific Heat Capacity Measurement of Al / SiCp Composites by Differential Scanning Calorimeter

2011 ◽  
Vol 264-265 ◽  
pp. 669-674 ◽  
Author(s):  
B. Karthikeyan ◽  
S. Ramanathan ◽  
V. Ramakrishnan
Keyword(s):  
Specific Heat ◽  
Volume Fraction ◽  
Thermal Control ◽  
Stir Casting ◽  
Thermal Design ◽  
Capacity Measurement ◽  
Scanning Calorimetry ◽  
Heat Measurement ◽  
Casting Technique ◽  
Materials Used

Various materials are used to achieve a good “Thermal Control System” (TCS) of spacecraft. The performance of the TCS totally depends upon the thermal behaviour of the materials used in the elements of TCS. The measurements of the thermal properties of materials are fundamental for better understanding of the thermal design. Differential Scanning Calorimetry (DSC) is the most widely used thermal technique for obtaining a wealth of information about a material, especially for the specific heat measurement of a material. Stir casting technique was used to fabricate the 7075 aluminum alloy and 7075 Al / SiCp composites. The heat flow response is recorded as a function of actual sample temperature range from -1000 C to 4000 C. Specific heat characteristics of 7075 Al reinforced with different volume fraction of silicon carbide composites fabricated by stir casting method was analyzed.

scholarly journals Systemic Approach Applied to Dual Pressure HRSG

1997 ◽  
Author(s):  
B. Leide ◽  
R. Gicquel
Keyword(s):  
Heat Recovery ◽  
Heat Supply ◽  
Process Integration ◽  
Thermal Design ◽  
Thermal System ◽  
Basic Process ◽  
Heat Recovery Steam Generator ◽  
Heat Exchange Surface ◽  
Design Options ◽  
Exchange Surface

Starting from a traditionally designed heat exchanger arrangement, a dual pressure and supplementary fired heat recovery steam generator (HRSG) has been examined according to a novel thermal design approach which features thermodynamic loss analyses being separately applied to individual components and to the thermal system as a whole. Basic Process Integration tools are employed in order to unveil the utility target. In addition recently developed analysis tools which are especially adapted to heat recovery equipment are introduced and then applied to the HRSG. Design modifications are identified which lead to an encouraging −8% reduction of heat exchange surface with respect to initial design while steam load and utility heat supply (by means of post-combustion) are kept unchanged. The design options are commented step by step and reflected against engineering feasibility as well as their overall economic impact.

Specific Heat Measurements of Ti6Al4V/Nano SiCp Composite

2017 ◽  
Vol 14 (1) ◽  
pp. 742-746
Author(s):  
S Krishnamohan ◽  
S Ramanathan ◽  
V Ramakrishnan
Keyword(s):  
Heat Capacity ◽  
Weight Ratio ◽  
Thermal Control ◽  
Ti6al4v Alloy ◽  
Thermal Design ◽  
Thermal Method ◽  
Scanning Calorimetry ◽  
Low Weight ◽  
Wide Range ◽  
Materials Used

The elevated strength, low weight ratio and excellent corrosion resistance intrinsic to titanium and its alloys has led to a wide range of successful applications which ensures high levels of unswerving performance in aerospace. The performance of the Thermal Control System extremely depends on the thermal behavior of the materials used in its elements. The measurements of the thermal properties of materials are necessary for better understanding of the thermal design. Differential scanning calorimetry (DSC) is the most extensively used thermal method for finding wealth of information about a material. The heat capacity (Cp) of a material was established quantitatively using DSC. The measurement was made by heating a very small quantity of the Ti6Al4V alloy and Ti6Al4V/Nano SiCp composites. Mechanical alloying (MA) and Powder metallurgy (P/M) techniques were used to fabricate the Ti6Al4V alloy and Ti6Al4V/ nano SiCp composites. The heat flow reaction was recorded as a function of definite sample temperature range from −100 °C to 375 °C. The measurements of the heat capacity of each sample in three runs were recorded by DSC. The heat capacity (Cp) of specimens is reported in this study.

The Microstructure and Thermochromic Properties of La1-XSrXMnO3 Smart Materials

2013 ◽  
Vol 690-693 ◽  
pp. 648-653 ◽  
Author(s):  
Min Xu ◽  
Zhao Hui Fu ◽  
Lin Li ◽  
Jie Bing Wang ◽  
Chun Hua Wu ◽  
...  
Keyword(s):  
Smart Materials ◽  
Thermal Control ◽  
Solid State Reaction Method ◽  
Thermal Design ◽  
Radiative Properties ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Thermal Radiative Properties ◽  
Potential Applications ◽  
Thermochromic Properties

The La1-xSrxMnO3 materials have potential applications in thermal control systems of microsatellites. The microstructure of La1-xSrxMnO3 materials is very sensitive to the compound of Sr incorporated into it. In this paper, preparation process of La1-xSrxMnO3 compounds was explored. Ceramic sintering process combined with a conventional solid state reaction method was used to prepare various components of La1-xSrxMnO3。 Annealing temperature, time and doped ratio were controlled in the experiment. X-ray diffraction and Raman spectroscopy were used to analyze phase structure and crystalline. Thermal radiative properties were measured on a Calorimetric Emissometer at 175K～375K. These investigations reveal that microstructure of La1-xSrxMnO3 compounds are affected by Sr2+doping level(x).Thermal emissivity of La0.825Sr0.175MnO3 materials vary widely from 0.68 to 0.37, which can meet requirement of future space thermal design.

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