Experimental Study of Flexible Electrohydrodynamic Conduction Pumping for Electronics Cooling

2018 ◽  
Author(s):  
Nicolas Vayas Tobar ◽  
Pavolas N. Christidis ◽  
Nathaniel J. O'Connor ◽  
Michal Talmor ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Flexible Electronics ◽  
Electronics Cooling ◽  
Thermal Control ◽  
Stable Operation ◽  
Space Applications ◽  
Manufacturing Method ◽  
Micro Scale ◽  
Wide Range ◽  
And Performance ◽  
And Control

As modern day electronics develop, electronic devices become smaller, more powerful, and are expected to operate in more diverse configurations. However, the thermal control systems that help these devices maintain stable operation must advance as well to meet the demands. One such demand is the advent of flexible electronics for wearable technology, medical applications, and biology-inspired mechanisms. This paper presents the design and performance characteristics of a proof of concept for a flexible Electrohydrodynamic (EHD) pump, based on EHD conduction pumping technology in macro- and meso-scales. Unlike mechanical pumps, EHD conduction pumps have no moving parts, can be easily adjusted to the micro-scale, and have been shown to generate and control the flow of refrigerants for electronics cooling applications. However, these pumping devices have only been previously tested in rigid configurations unsuitable for use with flexible electronics. In this work, for the first time, the net flow generated by flexible EHD conduction pumps is measured on a flat-plane and in various bending configurations. In this behavioral characteristics study, the results show that the flexible EHD conduction pumps are capable of generating significant flow velocities in all size scales considered in this study, with and without bending. This study also proves the viability of screen printing as a manufacturing method for these pumps. EHD conduction pumping technology shows potential for use in a wide range of terrestrial and space applications, including thermal control of rigid as well as flexible electronics, flow generation and control in micro-scale heat exchangers and other thermal devices, as well as cooling of high power electrical systems, soft robotic actuators, and medical devices.

Experimental Study of Flexible Electrohydrodynamic Conduction Pumping for Electronics Cooling

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Nathaniel J. O'Connor ◽  
Alexander J. Castaneda ◽  
Pavolas N. Christidis ◽  
Nicolas Vayas Tobar ◽  
Michal Talmor ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Electronics Cooling ◽  
Thermal Control ◽  
Working Fluid ◽  
Stable Operation ◽  
Manufacturing Method ◽  
And Performance ◽  
And Control ◽  
First Time

Abstract As modern-day electronics develop, electronic devices become smaller, more powerful, and are expected to operate in more diverse configurations. However, the thermal control systems that help these devices maintain stable operation must advance as well to meet the demands. One such demand is the advent of flexible electronics for wearable technology, medical applications, and biology-inspired mechanisms. This paper presents the design and performance characteristics of flexible electrohydrodynamic (EHD) pumps, based on EHD conduction pumping technology in macro- and mesoscales. Unlike mechanical pumps, EHD conduction pumps have no moving parts, can be easily adjusted to the microscale, and have been shown to generate and control the flow of refrigerants for electronics cooling applications. However, these pumping devices have only been previously tested in rigid configurations unsuitable for use with flexible electronics. In this work, for the first time, the net flow generated by flexible EHD conduction pumps is measured on a flat plane in various configurations. In this study, the results show that the flexible EHD conduction pumps are capable of generating significant flow velocities in all size scales considered in this study, with and without bending. This study also proves the viability of screen printing as a manufacturing method for these pumps. The selection of working fluid for EHD conduction pumping is also a topic of discussion. Novec Engineered Fluids have been a popular choice for EHD pumping; however, long-term testing has shown that some Novec fluids degrade over time.

A virtual test environment for validating spacecraft optical navigation

2013 ◽  
Vol 117 (1197) ◽  
pp. 1075-1101 ◽  
Author(s):  
S. M. Parkes ◽  
I. Martin ◽  
M. N. Dunstan ◽  
N. Rowell ◽  
O. Dubois-Matra ◽  
...  
Keyword(s):  
Small Body ◽  
European Space Agency ◽  
Ground Truth ◽  
Camera Motion ◽  
Test Environment ◽  
Space Applications ◽  
Vision Guidance ◽  
Space Agency ◽  
Wide Range ◽  
And Performance

Abstract The use of machine vision to guide robotic spacecraft is being considered for a wide range of missions, such as planetary approach and landing, asteroid and small body sampling operations and in-orbit rendezvous and docking. Numerical simulation plays an essential role in the development and testing of such systems, which in the context of vision-guidance means that realistic sequences of navigation images are required, together with knowledge of the ground-truth camera motion. Computer generated imagery (CGI) offers a variety of benefits over real images, such as availability, cost, flexibility and knowledge of the ground truth camera motion to high precision. However, standard CGI methods developed for terrestrial applications lack the realism, fidelity and performance required for engineering simulations. In this paper, we present the results of our ongoing work to develop a suitable CGI-based test environment for spacecraft vision guidance systems. We focus on the various issues involved with image simulation, including the selection of standard CGI techniques and the adaptations required for use in space applications. We also describe our approach to integration with high-fidelity end-to-end mission simulators, and summarise a variety of European Space Agency research and development projects that used our test environment.

Performance of Elastomeric Silicones in Ablative and Space Environments

1966 ◽  
Vol 39 (4) ◽  
pp. 1247-1257 ◽  
Author(s):  
Clyde L. Whipple ◽  
John A. Thorne
Keyword(s):  
High Vacuum ◽  
Thermal Control ◽  
Heat Fluxes ◽  
Space Environment ◽  
Space Applications ◽  
Wide Range ◽  
Environmental Extremes ◽  
Temperature Ranges ◽  
Space Environments ◽  
Thermal Control Coatings

Abstract Elastomeric silicones are among the best materials available for many ablative and space applications. In ablative applications, these materials protect launching equipment, safeguard various parts of vehicles and spacecraft during flight, and shield re-entering spacecraft. Generally, elastomeric silicones are used where ablative conditions involve low to moderate heat fluxes and shear forces. Ablative characteristics of materials can vary widely depending on polymer type, fillers, and applications techniques, and no one elastomeric silicone will perform in a wide range of ablative missions. A good knowledge of the ablative characteristics of silicone materials is required to select the best candidates for a given application. In the space environment, silicones are often used for seals, thermal control coatings, potting materials, and other applications because they perform well over wide temperature ranges, and because they are inherently stable to high-vacuum and ultraviolet conditions. Data given in this paper illustrate that silicones show little weight loss or loss of properties on exposure to space environmental extremes. Furthermore, these losses can be made almost negligible by proper conditioning of the finished elastomer.

scholarly journals Tailoring Thin-Film/Lacquer Coatings for Space Applications

2000 ◽  
Vol 12 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Wanda C Peters ◽  
George Harris ◽  
Grace Miller ◽  
John Petro
Keyword(s):  
Thin Film ◽  
Thermal Control ◽  
Radiative Properties ◽  
Space Applications ◽  
Solar Absorptance ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Thermal Radiative Properties ◽  
Wide Range ◽  
Specular Surfaces

Thin-film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin-film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission’s thermal control requirements, there is often a need for a variation of solar absorptance (αs), emittance (∊) and/or highly specular surfaces. The utilization of thin-film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of αs/∊ ratios. The radiative properties of thin-film coatings can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin-film application without the cost and difficulty associated with polishing.

Polymer Substrates for Flexible Electronics: Achievements and Challenges

2010 ◽  
Vol 93-94 ◽  
pp. 5-8 ◽  
Author(s):  
Iryna Yakimets ◽  
Duncan MacKerron ◽  
Peter Giesen ◽  
Keith J. Kilmartin ◽  
Marloes Goorhuis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behaviour ◽  
Flexible Electronics ◽  
Physical And Mechanical Properties ◽  
Polymer Materials ◽  
Polyethylene Naphthalate ◽  
Polymer Substrates ◽  
Micro Scale ◽  
Wide Range ◽  
Micro Deformation

Flexible electronics technology can potentially result in many compelling applications not satisfied by the rigid Si-based conventional electronics. Commercially available foils such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) have emerged as the most suitable polymer materials for wide range of flexible electronics applications. Despite the enormous progress which has been recently done on the optimization of physical and mechanical properties of PET and PEN foils, their dimensional stability at the micro-scale is still an issue during patterning of wiring by means of lithography. Consequently, the measurement of in-plane micro-deformation of foil is of great importance for understanding and predicting its thermal, hydroscopic and mechanical behaviour during processing.

Parametric Control of a Two-Phase Thermal Management System for Space Applications

2008 ◽  
Author(s):  
M. J. Brooks ◽  
L. C. Nortje ◽  
W. E. Lear ◽  
S. A. Sherif
Keyword(s):  
Time Pressure ◽  
Waste Heat ◽  
Thermal Control ◽  
Pulse Frequency ◽  
Working Fluid ◽  
Absolute Pressure ◽  
Stable Operation ◽  
Two Phase ◽  
Space Applications ◽  
R 134A

As spacecraft increase in complexity, greater power is required to drive their onboard systems. The resulting generation of waste heat demands efficient thermal control, especially for electrical components emitting heat at high flux densities. Weislogel proposed a passive two-phase heat transport system for space application, driven by constant volume boilers, called the pulse thermal loop (PTL). This paper describes four methods of operating a PTL using real-time pressure data as the control parameter. Preliminary results are presented from an experimental loop using R-134a as the working fluid. Control is exercised through algorithm-based schemes implemented in LabVIEW. Results suggest that stable operation of the loop is best achieved by actuating flow control valves in response to a preset pressure difference between the boilers. Control schemes based on absolute pressure, set pulse frequency, and a combination of absolute and differential pressures are also described. Performance data are presented, and some of the challenges faced during PTL operation are discussed, including start-up and asymmetrical pressurization of the boilers.

Flexible electronics for space applications

2004 ◽  
Vol 814 ◽  
Author(s):  
Erik Brandon ◽  
William West ◽  
Lisong Zhou ◽  
Tom Jackson ◽  
Greg Theriot ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Large Area ◽  
Sensors And Actuators ◽  
Solar Sails ◽  
Space Applications ◽  
Distributed Sensor ◽  
Wide Range ◽  
Control Electronics ◽  
Low Mass ◽  
Space Environments

AbstractNASA is currently developing a host of deployable structures for the exploration of space. These include balloons, solar sails, space-borne telescopes and membrane-based synthetic aperture radar. Each of these applications is driven by the need for a thin, low mass, large area structure (e.g., polymer-based) which could not be implemented using conventional engineering materials such as metals and alloys. In each case, there is also the need to integrate sensing and control electronics within the structure. However, conventional silicon-based electronics are difficult to integrate with such large, thin structures, due to a variety of concerns including mass, reliability and manufacturing issues. Flexible electronics, particularly thin film transistors (TFTs), are a potentially key enabling technology that may allow the integration of a wide range of sensors and actuators into these types of structures. There are numerous challenges, however, regarding the survivability of such devices during stowage and deployment of the structure, as well as during operation in the harsh environments of space. We have fabricated TFTs on polyimide substrates, and are investigating the durability of these devices with respect to relevant space environments. We are also developing flexible sensor technologies for the integration of distributed sensor networks on large area structures.

scholarly journals Robust scalable reversible strong adhesion by gecko-inspired composite design

Friction ◽  
2021 ◽  
Author(s):  
Xiaosong Li ◽  
Pengpeng Bai ◽  
Xinxin Li ◽  
Lvzhou Li ◽  
Yuanzhe Li ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Natural State ◽  
Large Area ◽  
High Adhesion ◽  
Wide Range ◽  
Grasping And Manipulation ◽  
Strong Adhesion ◽  
Strong Attachment ◽  
And Control ◽  
Intelligent Robotics

AbstractBio-inspired reversible adhesion has significant potential in many fields requiring flexible grasping and manipulation, such as precision manufacturing, flexible electronics, and intelligent robotics. Despite extensive efforts for adhesive synthesis with a high adhesion strength at the interface, an effective strategy to actively tune the adhesion capacity between a strong attachment and an easy detachment spanning a wide range of scales has been lagged. Herein, we report a novel soft-hard-soft sandwiched composite design to achieve a stable, repeatable, and reversible strong adhesion with an easily scalable performance for a large area ranging from ∼1.5 to 150 cm2 and a high load ranging from ∼20 to 700 N. Theoretical studies indicate that this design can enhance the uniform loading for attachment by restraining the lateral shrinkage in the natural state, while facilitate a flexible peeling for detachment by causing stress concentration in the bending state, yielding an adhesion switching ratio of ∼54 and a switching time of less than ∼0.2 s. This design is further integrated into versatile grippers, climbing robots, and human climbing grippers, demonstrating its robust scalability for a reversible strong adhesion. This biomimetic design bridges microscopic interfacial interactions with macroscopic controllable applications, providing a universal and feasible paradigm for adhesion design and control.

scholarly journals Architectural approach to cope with network-induced problems in network control systems design

2018 ◽  
Vol 69 (4) ◽  
pp. 270-278
Author(s):  
Ivan Popović ◽  
Aleksandar Rakić
Keyword(s):  
Process Control ◽  
Systems Design ◽  
Network Control ◽  
Data Transport ◽  
Architectural Styles ◽  
Wide Range ◽  
Automation And Control ◽  
And Performance ◽  
The Stability ◽  
And Control

Abstract In the field of process control engineering, network-based systems enable extensive, flexible and scalable applications in industrial automation and control. However, network-induced problems are influencing the stability and performance and they are introducing constraints in the system design and operation. While most of the existing design methodologies are searching for the specific solution within the domain of the control theory, we propose the comprehensive architectural approach that addresses wide range of the network-related issues and copes with them in the effective way. Presented solution combines several architectural styles encapsulating the actuating, sensing and control functionality into the unified service-oriented components, while the data transport is supported through event-triggered distributed middleware components. Given architectural approach decouples the design of process control functionality from the properties of the control network infrastructure. The effectiveness of the proposed solution is verified through the analysis of the system operation in the given case-study.

Development and Experimental Demonstration of a Shape Memory Alloy-Based Adaptive Two-Phase Radiator for Space Applications

2020 ◽  
Author(s):  
Jared Lilly ◽  
Bethany Hansen ◽  
Ryan Lotz ◽  
Darren Hartl ◽  
Thomas Cognata ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Single Phase ◽  
Thermal Control ◽  
Working Fluid ◽  
Two Phase ◽  
Space Applications ◽  
Regenerative Heat ◽  
Heat Rejection ◽  
Wide Range

Abstract Future space exploration, such as the Artemis program, journeys to Mars, and future lander missions will require thermal control systems (TCSs) with the ability to adapt to a wide range of thermal loads due to vastly fluctuating external temperatures. Current TCSs employ radiators that can achieve a turndown ratio (defined as the ratio of the maximum to minimum heat rejection rates) of 12:1 by utilizing regenerative heat exchangers and a two-fluid-loop system, both of which are heavy and complex. However, future missions will demand radiators that can provide turndown ratios of 12:1 while remaining light, functionally passive, and simply designed. Previous work has investigated using shape memory alloy (SMA) components in single phase radiator prototypes to achieve efficient heat rejection. Preliminary analysis shows that SMA-based radiators can enable turndown ratios as high as 37:1. In this paper, the design, fabrication, and testing of an SMA torque tube driven radiator prototype is discussed. The SMA torque tube is attached to a heat rejecting panel that resembles flat radiator panels currently installed on the International Space Station. As the temperature of the working fluid in the TCS increases, the SMA torque tube actuates and rotates the panel, allowing for more radiative heat rejection to occur. This new design matures the concept past a previous prototype that merely demonstrated actuation under single-phase (e.g., liquid water) flow. The current radiator prototype has been designed to function not only with closed-loop, single-phase fluid flow, but also in conjunction with a two-phase TCS and even as a heat pipe. Both approaches take advantage of phase transformation of the working fluid to improve overall TCS efficiency and decrease complexity. During testing, a heated two-phase working fluid was circulated through the system, resulting in a maximum angular actuation of 67 degrees, thus demonstrating two-phase operation for the first time. These results give confidence that an SMA torque tube-driven radiator can outperform current radiators as development continues.

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