Fabrication and Thermal Characterization of Novel Copper-CNT Micropillars for Electronics Cooling Applications

2017 ◽  
Author(s):  
Siavash Ghanbari ◽  
Jeff Darabi
Keyword(s):  
Experimental Investigation ◽  
Capillary Pressure ◽  
Thermal Performance ◽  
Material Characterization ◽  
Electronics Cooling ◽  
Thermal Characterization ◽  
Two Phase ◽  
Cooling Systems ◽  
Two Phase Cooling

This paper presents an experimental investigation to study the thermal and material characterization of an array of composite copper-carbon nanotubes (CNT) micropillars for applications in passive two-phase cooling systems. These novel micropillar structures have a larger spacing at the base of the micropillars to provide a higher liquid permeability and mushroom-like structures on the top surface of the micropillars with a smaller spacing to provide a greater capillary pressure. First, composite copper-CNT micropillars are fabricated by an electrodeposition method on a patterned copper template. Then, cauliflower-like nanostructures are grown on the top surface of the micropillars using chronoamperometry technique to improve the capillary pressure and thermal performance of the micropillars. Finally, a series of tests are conducted to quantify the thermal performance of the fabricated micropillars. The results indicate that the performance of mushroom-like composite copper-CNT micropillars is significantly higher than those of copper micropillar arrays.

Model Predictive Control of a Pumped Two-Phase Cooling System With Microchannel Heat Exchangers

2018 ◽  
Author(s):  
Oyuna Angatkina ◽  
Andrew Alleyne
Keyword(s):  
Heat Flux ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Heat Exchangers ◽  
Cooling System ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase ◽  
Cooling Systems ◽  
Two Phase Cooling

Two-phase cooling systems provide a viable technology for high–heat flux rejection in electronic systems. They provide high cooling capacity and uniform surface temperature. However, a major restriction of their application is the critical heat flux condition (CHF). This work presents model predictive control (MPC) design for CHF avoidance in two-phase pump driven cooling systems. The system under study includes multiple microchannel heat exchangers in series. The MPC controller performance is compared to the performance of a baseline PI controller. Simulation results show that while both controllers are able to maintain the two-phase cooling system below CHF, MPC has significant reduction in power consumption compared to the baseline controller.

Experimental Validation and Design Simulations of a Passive Two-Phase Cooling System for Datacenters

2020 ◽  
Author(s):  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Raffaele L. Amalfi ◽  
Filippo Cataldo
Keyword(s):  
Thermal Performance ◽  
Experimental Validation ◽  
Cooling System ◽  
Electronics Cooling ◽  
Operating Conditions ◽  
Two Phase ◽  
Data Set ◽  
Pressure Drops ◽  
Wide Range ◽  
Important Challenge

Abstract Thermosyphon cooling systems represent the future of datacenter cooling, and electronics cooling in general, as they provide high thermal performance, reliability and energy efficiency, as well as capture the heat at high temperatures suitable for many heat reuse applications. On the other hand, the design of passive two-phase thermosyphons is extremely challenging because of the complex physics involved in the boiling and condensation processes; in particular, the most important challenge is to accurately predict the flow rate in the thermosyphon and thus the thermal performance. This paper presents an experimental validation to assess the predictive capabilities of JJ Cooling Innovation’s thermosyphon simulator against one independent data set that includes a wide range of operating conditions and system sizes, i.e. thermosyphon data for server-level cooling gathered at Nokia Bell Labs. Comparison between test data and simulated results show good agreement, confirming that the simulator accurately predicts heat transfer performance and pressure drops in each individual component of a thermosyphon cooling system (cold plate, riser, evaporator, downcomer (with no fitting parameters), and eventually a liquid accumulator) coupled with operational characteristics and flow regimes. In addition, the simulator is able to design a single loop thermosyphon (e.g. for cooling a single server’s processor), as shown in this study, but also able to model more complex cooling architectures, where many thermosyphons at server-level and rack-level have to operate in parallel (e.g. for cooling an entire server rack). This task will be performed as future work.

scholarly journals Thermal Characterization of Low-Dimensional Materials by Resistance Thermometers

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1740 ◽  
Author(s):  
Yifeng Fu ◽  
Guofeng Cui ◽  
Kjell Jeppson
Keyword(s):  
Thermal Performance ◽  
Three Dimensional ◽  
Thermal Characterization ◽  
Resistance Thermometer ◽  
Light Emitting ◽  
Resistance Thermometers ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
Boron Nitride Films

The design, fabrication, and use of a hotspot-producing and temperature-sensing resistance thermometer for evaluating the thermal properties of low-dimensional materials are described in this paper. The materials that are characterized include one-dimensional (1D) carbon nanotubes, and two-dimensional (2D) graphene and boron nitride films. The excellent thermal performance of these materials shows great potential for cooling electronic devices and systems such as in three-dimensional (3D) integrated chip-stacks, power amplifiers, and light-emitting diodes. The thermometers are designed to be serpentine-shaped platinum resistors serving both as hotspots and temperature sensors. By using these thermometers, the thermal performance of the abovementioned emerging low-dimensional materials was evaluated with high accuracy.

Mechanical, Electrical and Thermal Characterization of Commercially Available LTCC Dielectric Tapes

2013 ◽  
Vol 543 ◽  
pp. 212-215
Author(s):  
Goran Radosavljević ◽  
Nelu Blaž ◽  
Andrea Marić ◽  
W. Smetana ◽  
Ljiljana Živanov
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Electrical Properties ◽  
Material Characterization ◽  
Mechanical Characterization ◽  
Thermal Characterization ◽  
Material Parameters ◽  
Mechanical And Electrical Properties

Presented paper deals with mechanical and electrical properties of several commercially available LTCC (Low Temperature Co-fired Technology) tapes, as well as their thermal characterization. Three commercially available dielectric tape materials provided by Heraeus (CT700, CT707 and CT800) are investigated. The samples for determination of significant material parameters are prepared using the standard LTCC fabrication process. Results of the material characterization (chemical analysis, surface roughness electrical and mechanical properties) are presented. In addition thermo-electrical and-mechanical characterization of investigated tapes analysis is performed.

Experimental investigation on startup of a novel two-phase cooling loop

2008 ◽  
Vol 32 (4) ◽  
pp. 939-946 ◽  
Author(s):  
Liu Jie ◽  
Nian-qiang Pei ◽  
Kai-hua Guo ◽  
Zhen-hui He ◽  
Ting-xuen Li ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Two Phase ◽  
Cooling Loop ◽  
Two Phase Cooling
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