scholarly journals Dynamic manipulation of droplets using mechanically tunable microtextured chemical gradients

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ali J. Mazaltarim ◽  
John J. Bowen ◽  
Jay M. Taylor ◽  
Stephen A. Morin

AbstractMaterials and strategies applicable to the dynamic transport of microdroplets are relevant to surface fluidics, self-cleaning materials, thermal management systems, and analytical devices. Techniques based on electrowetting, topographic micropatterns, and thermal/chemical gradients have advanced considerably, but dynamic microdroplet transport remains a challenge. This manuscript reports the fabrication of mechano-tunable, microtextured chemical gradients on elastomer films and their use in controlled microdroplet transport. Specifically, discreet mechanical deformations of these films enabled dynamic tuning of the microtextures and thus transport along surface-chemical gradients. The interplay between the driving force of the chemical gradient and the microtopography was characterized, facilitating accurate prediction of the conditions (droplet radius and roughness) which supported transport. In this work, the use of microtextured surface chemical gradients in mechano-adaptive materials with microdroplet manipulation functionality was highlighted.

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1357
Author(s):  
Wei Li ◽  
Shusheng Xiong ◽  
Xiaojun Zhou ◽  
Wei Shi ◽  
Chongming Wang ◽  
...  

This paper aims to design thermal dummy cells (TDCs) that can be used in the development of lithium-ion battery thermal management systems. Based on physical property and geometry of real 18,650 cylindrical cells, a three-dimensional model of TDCs was designed, and it is used to numerically simulate the thermal performance of TDCs. Simulations show that the TDC can mimic the temperature change on the surface of a real cell both at static and dynamic current load. Experimental results show that the rate of heating resistance of TDC is less than 0.43% for temperatures between 27.5 °C and 90.5 °C. Powered by a two-step voltage source of 12 V, the temperature difference of TDCs is 1 °C and 1.6 °C along the circumference and the axial directions, respectively. Powered by a constant voltage source of 6 V, the temperature rising rates on the surface and in the core are higher than 1.9 °C/min. Afterwards, the proposed TDC was used to simulate a real cell for investigating its thermal performance under the New European Driving Cycle (NEDC), and the same tests were conducted using real cells. The test indicates that the TDC surface temperature matches well with that of the real battery during the NEDC test, while the temperature rise of TDC exceeds that of the real battery during the suburban cycle. This paper demonstrates the feasibility of using TDCs to replace real cells, which can greatly improve safety and efficiency for the development of lithium-ion battery thermal management systems.


Author(s):  
Giulia Righetti ◽  
Claudio Zilio ◽  
Luca Doretti ◽  
Giovanni A. Longo ◽  
Simone Mancin

2021 ◽  
Vol 198 ◽  
pp. 117503 ◽  
Author(s):  
Mohsen Akbarzadeh ◽  
Theodoros Kalogiannis ◽  
Joris Jaguemont ◽  
Lu Jin ◽  
Hamidreza Behi ◽  
...  

Author(s):  
Amip J. Shah ◽  
Van P. Carey ◽  
Cullen E. Bash ◽  
Chandrakant D. Patel

Data centers today contain more computing and networking equipment than ever before. As a result, a higher amount of cooling is required to maintain facilities within operable temperature ranges. Increasing amounts of resources are spent to achieve thermal control, and tremendous potential benefit lies in the optimization of the cooling process. This paper describes a study performed on data center thermal management systems using the thermodynamic concept of exergy. Specifically, an exergy analysis has been performed on sample data centers in an attempt to identify local and overall inefficiencies within thermal management systems. The development of a model using finite volume analysis has been described, and potential applications to real-world systems have been illustrated. Preliminary results suggest that such an exergy-based analysis can be a useful tool in the design and enhancement of thermal management systems.


Langmuir ◽  
2014 ◽  
Vol 30 (39) ◽  
pp. 11591-11598 ◽  
Author(s):  
Giulia Fioravanti ◽  
Francesca Lugli ◽  
Denis Gentili ◽  
Vittoria Mucciante ◽  
Francesca Leonardi ◽  
...  

Author(s):  
Herschel C. Pangborn ◽  
Justin P. Koeln ◽  
Matthew A. Williams ◽  
Andrew G. Alleyne

This paper proposes and experimentally validates a hierarchical control framework for fluid flow systems performing thermal management in mobile energy platforms. A graph-based modeling approach derived from the conservation of mass and energy inherently captures coupling within and between physical domains. Hydrodynamic and thermodynamic graph-based models are experimentally validated on a thermal-fluid testbed. A scalable hierarchical control framework using the graph-based models with model predictive control (MPC) is proposed to manage the multidomain and multi-timescale dynamics of thermal management systems. The proposed hierarchical control framework is compared to decentralized and centralized benchmark controllers and found to maintain temperature bounds better while using less electrical energy for actuation.


2020 ◽  
Author(s):  
Foo Shen Hwang ◽  
Thomas Confrey ◽  
Stephen Scully ◽  
Dean Callaghan ◽  
Cathal Nolan ◽  
...  

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