Experimental and Computational Characterization of a Heat Sink Tester

Author(s):  
Aalok Trivedi ◽  
Nikhil Lakhkar ◽  
Madhusudhan Iyengar ◽  
Michael Ellsworth ◽  
Roger Schmidt ◽  
...  

With the continuing industry trends towards smaller, faster and higher power devices, thermal management continues to be extremely important in the development of electronics. In this era of high heat fluxes, air cooling still remains the primary cooling solution in desktops mainly due to its cost. The primary goal of a good thermal design is to ensure that the chip can function at its rated frequency or speed while maintaining the junction temperature within the specified limit. The first and foremost step in measurement of thermal resistance and hence thermal characterization is accurate determination of junction temperature. Use of heat sinks as a thermal solution is well documented in the literature. Previously, the liquid cooled cold plate tester was studied using a different approach and it was concluded that the uncertainty in heat transfer coefficient was within 8% with errors in appropriate parameters, this result was supported by detailed uncertainty analysis based on Monte-Carlo simulations. However, in that study the tester was tested computationally. In this paper, testing and characterization of a heat sink tester is presented. Heat sinks were tested according to JEDEC JESD 16.1 standard for forced convection. It was observed that the error between computational and experimental values of thermal resistances was 10% for the cases considered.

Author(s):  
M. Zugic ◽  
J. R. Culham ◽  
P. Teertstra ◽  
Y. Muzychka ◽  
K. Horne ◽  
...  

Compact, liquid cooled heat sinks are used in applications where high heat fluxes and boundary resistance preclude the use of more traditional air cooling techniques. Four different liquid cooled heat sink designs, whose core geometry is formed by overlapped ribbed plates, are examined. The objective of this analysis is to develop models that can be used as design tools for the prediction of overall heat transfer and pressure drop of heat sinks. Models are validated for Reynolds numbers between 300 and 5000 using experimental tests. The agreement between the experiments and the models ranges from 2.35% to 15.3% RMS.


Author(s):  
Tunc Icoz ◽  
Mehmet Arik ◽  
John T. Dardis

Thermal management of electronics is a critical part of maintaining high efficiency and reliability. Adequate cooling must be balanced with weight and volumetric requirements, especially for passive air-cooling solutions in electronics applications where space and weight are at a premium. It should be noted that there are systems where thermal solution takes more than 95% of the total weight of the system. Therefore, it is necessary to investigate and utilize advanced materials to design low weight and compact systems. Many of the advanced materials have anisotropic thermal properties and their performances depend strongly on taking advantage of superior properties in the desired directions. Therefore, control of thermal conductivity plays an important role in utilization of such materials for cooling applications. Because of the complexity introduced by anisotropic properties, thermal performances of advanced materials are yet to be fully understood. Present study is an experimental and computational study on characterization of thermal performances of advanced materials for heat sink applications. Numerical simulations and experiments are performed to characterize thermal performances of four different materials. An estimated weight savings in excess of 75% with lightweight materials are observed compared to the traditionally used heat sinks.


Author(s):  
Devdatta P. Kulkarni ◽  
Priyanka Tunuguntla ◽  
Guixiang Tan ◽  
Casey Carte

Abstract In recent years, rapid growth is seen in computer and server processors in terms of thermal design power (TDP) envelope. This is mainly due to increase in processor core count, increase in package thermal resistance, challenges in multi-chip integration and maintaining generational performance CAGR. At the same time, several other platform level components such as PCIe cards, graphics cards, SSDs and high power DIMMs are being added in the same chassis which increases the server level power density. To mitigate cooling challenges of high TDP processors, mainly two cooling technologies are deployed: Liquid cooling and advanced air cooling. To deploy liquid cooling technology for servers in data centers, huge initial capital investment is needed. Hence advanced air-cooling thermal solutions are being sought that can be used to cool higher TDP processors as well as high power non-CPU components using same server level airflow boundary conditions. Current air-cooling solutions like heat pipe heat sinks, vapor chamber heat sinks are limited by the heat transfer area, heat carrying capacity and would need significantly more area to cool higher TDP than they could handle. Passive two-phase thermosiphon (gravity dependent) heat sinks may provide intermediate level cooling between traditional air-cooled heat pipe heat sinks and liquid cooling with higher reliability, lower weight and lower cost of maintenance. This paper illustrates the experimental results of a 2U thermosiphon heat sink used in Intel reference 2U, 2 node system and compare thermal performance using traditional heat sinks solutions. The objective of this study was to showcase the increased cooling capability of the CPU by at least 20% over traditional heat sinks while maintaining cooling capability of high-power non-CPU components such as Intel’s DIMMs. This paper will also describe the methodology that will be used for DIMMs serviceability without removing CPU thermal solution, which is critical requirement from data center use perspective.


2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Craig Green ◽  
Peter Kottke ◽  
Xuefei Han ◽  
Casey Woodrum ◽  
Thomas Sarvey ◽  
...  

Three-dimensional (3D) stacked electronics present significant advantages from an electrical design perspective, ranging from shorter interconnect lengths to enabling heterogeneous integration. However, multitier stacking exacerbates an already difficult thermal problem. Localized hotspots within individual tiers can provide an additional challenge when the high heat flux region is buried within the stack. Numerous investigations have been launched in the previous decade seeking to develop cooling solutions that can be integrated within the 3D stack, allowing the cooling to scale with the number of tiers in the system. Two-phase cooling is of particular interest, because the associated reduced flow rates may allow reduction in pumping power, and the saturated temperature condition of the coolant may offer enhanced device temperature uniformity. This paper presents a review of the advances in two-phase forced cooling in the past decade, with a focus on the challenges of integrating the technology in high heat flux 3D systems. A holistic approach is applied, considering not only the thermal performance of standalone cooling strategies but also coolant selection, fluidic routing, packaging, and system reliability. Finally, a cohesive approach to thermal design of an evaporative cooling based heat sink developed by the authors is presented, taking into account all of the integration considerations discussed previously. The thermal design seeks to achieve the dissipation of very large (in excess of 500 W/cm2) background heat fluxes over a large 1 cm × 1 cm chip area, as well as extreme (in excess of 2 kW/cm2) hotspot heat fluxes over small 200 μm × 200 μm areas, employing a hybrid design strategy that combines a micropin–fin heat sink for background cooling as well as localized, ultrathin microgaps for hotspot cooling.


2021 ◽  
Vol 2116 (1) ◽  
pp. 012052
Author(s):  
David Olugbenga Ariyo ◽  
Tunde Bello-Ochende

Abstract Deionized water at a temperature of 25 °C was used as the cooling fluid and aluminium as the heat sink material in the geometric optimization and parameter modelling of subcooled flow boiling in horizontal equilateral triangular microchannel heat sinks. The thermal resistances of the microchannels were minimized subject to fixed volume constraints of the heat sinks and microchannels. A computational fluid dynamics (CFD) ANSYS code used for both the simulations and the optimizations was validated by the available experimental data in the literature and the agreement was good. Fixed heat fluxes between 100 and 500 W/cm2 and velocities between 0.1 and 7.0 m/s were used in the study. Despite the relatively high heat fluxes in this study, the base temperatures of the optimal microchannel heat sinks were within the acceptable operating range for modern electronics. The pumping power requirements for the optimal microchannels are low, indicating that they can be used in the cooling of electronic devices.


Author(s):  
H. Chiba ◽  
T. Ogushi ◽  
H. Nakajima

In recent years, since heat dissipation rates and high frequency electronic devices have been increasing, a heat sink with high heat transfer performance is required to cool these devices. Heat sink utilizing micro-channels with several ten microns are expected to provide an excellent cooling performance because of their high heat transfer capacities due to small channel. Therefore, various porous materials such as cellular metals have been investigated for heat sink applications. However, heat sink using conventional porous materials has a high pressure drop because the cooling fluid flow through the pores is complex. Among the described porous materials, a lotus-type porous metal with straight pores is preferable for heat sinks due to the small pressured drop. In present work, cooling performance of the lotus copper heat sink for air cooling and water cooling is introduced. The experimental data for air cooling show 13.2 times higher than that for the conventional groove fins. And, the data for the water cooling show 1.7 times higher than that for the micro-channels. It is concluded that lotus copper heat sink is the most prospective candidate for high power electronics devices.


Author(s):  
Matt Connors

Current blade processors need air cooling solutions that dissipate 100–300 watts with heat sinks that are less than 30 mm high. In order to cool these processors, the heat sink base has to grow in length and width to compensate for the lack of available height. As these dimensions grow, decreasing the base spreading of the heat sink becomes an important factor is decreasing the overall resistance of the heat sink. A vapor chamber used as a substitute to common copper or aluminum as the base of the heat sink can increase performance by 20–25%. A vapor chamber is a two phase heat transport system that significantly reduces the spreading resistance in applications where there is a high heat flux processor coupled with a large heat sink. In this paper, a CFD model will be constructed to predict the performance gains realized by using a vapor chamber base in lieu of a copper or aluminum base. These predictions will then be experimentally tested to confirm the modeling parameters and the actual measured thermal performance of the heat sink. By utilizing vapor chambers in heat sink design, thermal engineers will gain valuable heat sink performance within the constraints imposed by the blade system architecture.


2007 ◽  
Vol 129 (4) ◽  
pp. 512-517
Author(s):  
Thomas E. Salem ◽  
Stephen B. Bayne ◽  
Don Porschet

As power electronic applications continue to switch higher levels of voltage and current in smaller-sized component packages, the resulting increase in power density requires efficient thermal management. This paper compares the thermal performance for operating a metal-oxide-semiconductor field-effect transistor on a water-cooled pole-arrayed heat sink versus a novel water-cooled microchannel heat sink. Details are presented on an innovative technique using Fourier analysis techniques for determining the thermal capacitance modeling parameter for the heat sinks from experimental data.


Author(s):  
Robert A. Taylor ◽  
Gary L. Solbrekken

The electronics industry has relied heavily on air cooling to dissipate waste heat. Each new generation of technology is smaller and more powerful, pushing the limits of air-cooled heat sinks. A competing constraint is that the thermal solutions need to be smaller and lighter, particularly for portable devices. A viable strategy to extend the limits of air-cooled heat sinks in a mass effective way is thermoelectric (TE) cooling. In general, the limiting COP of currently available TE materials requires that TE modules be operated at near optimum conditions. The conventional approach for optimizing TE modules ignores external irreversibilities, such as the heat sink temperature drop between the TE hot side and the ambient. The current study reviews two schemes for optimizing the operating current and compares their performance. The comparison between the COP maximizing current and the junction temperature minimizing current identifies where the two approaches yield the exact same performance. Performance regimes are then identified where the junction temperature minimizing approach provides an advantage over the COP maximizing approach. A significant extension of the current modeling activity over previous studies is allowing the TE module geometry to be optimized in addition to the operating current. When the TE module geometry is allowed to be optimized, it is found that using TE refrigeration operating at the junction temperature minimizing current will always have a performance benefit relative to a heat sink alone. The way this performance is achieved at higher heat loads is that the TE module elements must be made very thin.


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