A heat sink integrating fins within high thermal conductivity phase change material to cool high heat-flux heat sources

2022 ◽  
Vol 172 ◽  
pp. 107190
Author(s):  
Salah Addin Burhan Al-Omari ◽  
Zahid Ahmed Qureshi ◽  
Emad Elnajjar ◽  
Farooq Mahmoud
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Sink ◽  
High Heat ◽  
High Thermal Conductivity ◽  
High Heat Flux ◽  
Heat Sources ◽  
Change Material

Wickability and Transient Cooling Capacity of Binary Mixtures

2007 ◽  
Author(s):  
Mauricio A. Salinas ◽  
S. M. You ◽  
B. Elliott Short ◽  
Donald C. Price
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Metal Matrix ◽  
Solid Phase ◽  
High Heat ◽  
Cooling Capacity ◽  
Working Fluid ◽  
High Heat Flux ◽  
Testing Procedures ◽  
Change Material

Previously, aerospace and military, high heat-flux, electronics have been cooled with phase-change-modules composed of a metal-matrix saturated with a solid phase-change-material. This method requires the heat to be transferred from the source location, through the metal matrix, to the available phase-change-material. Empirical evaluations indicate that wick-based coldplates including non-metallic porous media, saturated with fluid may be much more effective. This wick-based method allows the capillary action of the wick to passively transport liquid from liquid-rich areas to the point of need; a much more efficient process. The optimization of a wick-based coldplate involves a careful balance between the wickability of the working fluid and its heat of vaporization (i.e. cooling capacity). The wickability and transient cooling capacity of both ethanol-water and methanol-water mixtures were empirically evaluated for the full mass fraction range. Testing procedures and results will be described in detail.

Effective Thermal Conductivity of Phase Change Material-Based Composites for High Heat Flux Electronic Cooling

2020 ◽  
Author(s):  
Ayushman Singh ◽  
Srikanth Rangarajan ◽  
Leila Choobineh ◽  
Bahgat Sammakia
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Material ◽  
Heat Sink ◽  
Volume Fraction ◽  
Electronic Cooling ◽  
Metal Volume ◽  
Metal Volume Fraction ◽  
Change Material

Abstract This work presents a simplified approach to optimally designing a heat sink with metallic thermal conductivity enhancers infiltrated with phase change material for electronic cooling. In present study, thermal conductivity enhancers are in the form of a honeycomb structure. A benchmarked two-dimensional computational fluid dynamics model was employed to investigate the thermal performance of the phase change material-metallic thermal conductivity enhancer composite heat sinks. Metallic thermal conductivity enhancers are often used in conjunction with phase change material to enhance the conductivity of the composite heat sink. Under constrained heat sink volume, the higher volume fraction of thermal conductivity enhancers improves the effective thermal conductivity of the composite, while it reduces the amount of latent heat storage simultaneously. The present work arrives at the optimal design of heat sink for electronic cooling by resolving the stated tradeoff. In this study, the total volume of the heat sink and the interfacial heat transfer area between the phase change material and thermal conductivity enhancers are constrained for all design points. Furthermore, assuming conduction-dominated heat transfer, an effective numerical model that solves the single energy equation with the effective properties of the phase change material- metallic thermal conductivity enhancer composite has been developed. The temperature gradient-time history is compared and matched for both the models to arrive at the accurate effective thermal conductivity value. The relationship of effective thermal conductivity as a function of metal volume fraction and thermal conductivity of metallic thermal conductivity enhancer is obtained. The figure of merit (FOM) is used to define the balance between effective thermal conductivity and energy storage capacity. The FOM is maximized to find the optimal volume fraction for the present design. The results from the study reveals that there exists an optimal metal volume fraction that maximizes the thermal performance of the composite.

A Vapor Chamber Using Graphite Foams as Wicks for Cooling High Heat Flux Electronics

2005 ◽  
Author(s):  
Minhua Lu ◽  
Larry Mok ◽  
R. J. Bezama
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
High Heat ◽  
High Thermal Conductivity ◽  
Working Fluid ◽  
High Heat Flux ◽  
Vapor Chamber ◽  
Capillary Limit ◽  
Wick Structure ◽  
Graphite Foam

A vapor chamber using high thermal conductivity and permeability graphite foam as a wick has been designed, built and tested. With ethanol as the working fluid, the vapor chamber has been demonstrated at a heat flux of 80 W/cm2. The effects of the capillary limit, the boiling limit, and the thermal resistance in restricting the overall performance of a vapor chamber have been analyzed. Because of the high thermal conductivity of the graphite foams, the modeling results show that the performance of a vapor chamber using a graphite foam is about twice that of one using a copper wick structure. Furthermore, if water is used as the working fluid instead of ethanol, the performance of the vapor chamber will be increased further. Graphite foam vapor chambers with water as the working fluid can be made by treating the graphite foam with an oxygen plasma to improve the wetting of the graphite by the water.

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