TOPEX Microwave Radiometer - Thermal design verification test and analytical model validation

1992 ◽  
Author(s):  
EDWARD LIN
Keyword(s):  
Model Validation ◽  
Analytical Model ◽  
Microwave Radiometer ◽  
Thermal Design ◽  
Design Verification ◽  
Verification Test

scholarly journals Novel Structure and Thermal Design and Analysis for CubeSats in Formation Flying

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 150
Author(s):  
Yeon-Kyu Park ◽  
Geuk-Nam Kim ◽  
Sang-Young Park
Keyword(s):  
Analytical Model ◽  
Formation Flying ◽  
Thermal Environment ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Analytical Models ◽  
Test Results ◽  
Solar Panels ◽  
Novel Structure ◽  
Micro Propulsion

The CANYVAL-C (CubeSat Astronomy by NASA and Yonsei using a virtual telescope alignment for coronagraph) is a space science demonstration mission that involves taking several images of the solar corona with two CubeSats—1U CubeSat (Timon) and 2U CubeSat (Pumbaa)—in formation flying. In this study, we developed and evaluated structural and thermal designs of the CubeSats Timon and Pumbaa through finite element analyses, considering the nonlinearity effects of the nylon wire of the deployable solar panels installed in Pumbaa. On-orbit thermal analyses were performed with an accurate analytical model for a visible camera on Timon and a micro propulsion system on Pumbaa, which has a narrow operating temperature range. Finally, the analytical models were correlated for enhancing the reliability of the numerical analysis. The test results indicated that the CubeSats are structurally safe with respect to the launch environment and can activate each component under the space thermal environment. The natural frequency of the nylon wire for the deployable solar panels was found to increase significantly as the wire was tightened strongly. The conditions of the thermal vacuum and cycling testing were implemented in the thermal analytical model, which reduced the differences between the analysis and testing.

Approximate Analytical Model for a First Level Package With Non-Uniformly Powered Die

2006 ◽  
Author(s):  
Abhijit Kaisare ◽  
Dereje Agonafer ◽  
A. Haji-Sheikh ◽  
Greg Chrysler ◽  
Ravi Mahajan
Keyword(s):  
Thermal Resistance ◽  
Analytical Model ◽  
Functional Integration ◽  
Thermal Design ◽  
Junction Temperature ◽  
Direct Result ◽  
Design Guideline ◽  
Functional Blocks ◽  
Distribution Of Power ◽  
Functional Components

Microprocessors continue to grow in capabilities, complexity and performance. Microprocessors typically integrate functional components such as logic and level two (L2) cache memory in their architecture. This functional integration of logic and memory results in improved performance of the microprocessor as the clock speed increases and the instruction execution time has decreased. However, the integration also introduces a layer of complexity to the thermal design and management of microprocessors. As a direct result of function integration, the power map on a microprocessor is typically highly non-uniform and the assumption of a uniform heat flux across the chip surface is not valid. The active side of the die is divided into several functional blocks with distinct power assigned to each functional block. Previous work [1,2] has been done to minimize the thermal resistance of the package by optimizing the distribution of the non-uniform powered functional blocks with different power matrices. This study further gives design guideline and key pointers to minimized thermal resistance for any number of functional blocks for a given non-uniformly powered microprocessor. In this paper, initially (Part I) temperature distribution of a typical package consisting of a uniformly powered die, heat spreader, TIM 1 & 2 and the base of the heat sink is calculated using an approximate analytical model. The results are then compared with a detailed numerical model and the agreement is within 5%. This study follows (Part II) with a thermal investigation of non-uniform powered functional blocks with a different power matrices with focus on distribution of power over die surface with an application of maximum, minimum and average uniform junction temperature over a given die area. This will help to predict the trend of the calculated distribution of power that will lead to the least thermal gradient over a given die area. This trend will further help to come up with design correlations for minimizing thermal resistance for any number of functional blocks for a given non-uniformly powered microprocessor numerically as well as analytically. The commercial finite element code ANSYS® is used for this analysis as a numerical tool.

Thermal Design, Analysis and Experimental Verification of Electronic Equipment of a Satellite Borne Microwave Radiometer

2013 ◽  
Vol 655-657 ◽  
pp. 84-87 ◽  
Author(s):  
Bo Chen
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Microwave Radiometer ◽  
Engineering Application ◽  
Element Model ◽  
Thermal Design ◽  
Electronic Equipment ◽  
Element Analysis ◽  
Experiment Verification ◽  
Experimental Values

Thermal design, finite element analysis and experiment verification of electronic equipment of a satellite borne microwave radiometer are introduced. Some methods were adopted to help heat conduct and a finite element model was built. The analysis results show that the temperature scopes of the main structures are from 45°C to63.9°C in the digital control equipment and 45°C to 68.7°C in the receiver equipment and all of junction temperatures of the components are lower than the derated maximum junction temperatures themselves and leave enough design margins, which match the requirements of thermal analysis. The experimental results show that the computing values are close to experimental values and the largest error is 10.1°C, which is allowed for engineering application.

scholarly journals An Analytical Model for Transient Heat Transfer with a Time-Dependent Boundary in Solar- and Waste-Heat-Assisted Geothermal Borehole Systems: From Single to Multiple Boreholes

2021 ◽  
Vol 11 (21) ◽  
pp. 10338
Author(s):  
Mohammed A. Hefni ◽  
Minghan Xu ◽  
Ferri Hassani ◽  
Seyed Ali Ghoreishi-Madiseh ◽  
Haitham M. Ahmed ◽  
...  
Keyword(s):  
Heat Flux ◽  
Energy Storage ◽  
Analytical Model ◽  
Thermal Performance ◽  
Closed Loop ◽  
Waste Heat ◽  
Analytical Framework ◽  
Thermal Design ◽  
Time Dependent ◽  
Borehole Wall

With the increasing engineering applications of geothermal borehole heat exchangers (BHEs), accurate and reliable mathematical models can help advance their thermal design and operations. In this study, an analytical model with a time-dependent heat flux boundary condition on the borehole wall is developed, capable of predicting the thermal performance of single, double, and multiple closed-loop BHEs, with an emphasis on solar- and waste-heat-assisted geothermal borehole systems (S-GBS and W-GBS) for energy storage. This analytical framework begins with a one-dimensional transient heat conduction problem subjected to a time-dependent heat flux for a single borehole. The single borehole scenario is then extended to multiple boreholes by exploiting lines of symmetry (or thermal superposition). A final expression of the temperature distribution along the center line is attained for single, double, and multiple boreholes, which is verified with a two-dimensional finite-element numerical model (less than 0.7% mean absolute deviation) and uses much lesser computational power and time. The analytical solution is also validated against a field-scale experiment from the literature regarding the borehole and ground temperatures at different time frames, with an absolute error below 6.3%. Further, the thermal performance of S-GBS and W-GBS is compared for a 3-by-3 borehole configuration using the analytical model to ensure its versatility in thermal energy storage. It is concluded that our proposed analytical framework can rapidly evaluate closed-loop geothermal BHEs, regardless of the numbers of boreholes and the type of the heat flux on the borehole wall.

Thermal design of Earth-to-air heat exchanger. Part II a new transient semi-analytical model and experimental validation for estimating air temperature

2018 ◽  
Vol 198 ◽  
pp. 1536-1544 ◽  
Author(s):  
Charaf-Eddine Mehdid ◽  
Adel Benchabane ◽  
Amar Rouag ◽  
Noureddine Moummi ◽  
Mohammed-Amin Melhegueg ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Analytical Model ◽  
Air Temperature ◽  
Experimental Validation ◽  
Thermal Design

Thermal design verification of a large deployable antenna for a communications satellite

1992 ◽  
Vol 29 (2) ◽  
pp. 271-278 ◽  
Author(s):  
H. Tsunoda ◽  
K. Nakajima ◽  
A. Miyasaka
Keyword(s):  
Thermal Design ◽  
Design Verification
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