A Simplified Conduction Based Modeling Scheme for Design Sensitivity Study of Thermal Solution Utilizing Heat Pipe and Vapor Chamber Technology

2003 ◽  
Vol 125 (3) ◽  
pp. 378-385 ◽  
Author(s):  
Ravi S. Prasher
Keyword(s):  
Heat Pipe ◽  
Temperature Drop ◽  
Heat Pipes ◽  
Sensitivity Study ◽  
Design Sensitivity ◽  
Thermal Design ◽  
Vapor Chamber ◽  
Modeling Tools ◽  
Heating Source ◽  
Thermal Solution

This paper introduces a simplified modeling scheme for the prediction of heat transport capability of heat pipes and vapor chambers. The modeling scheme introduced in this paper enables thermal designers to model heat pipes and vapor chambers in commercially available conduction modeling tools such as Ansys™ and IcePak™. This modeling scheme allows thermal designers to perform design sensitivity studies in terms of power dissipation of heat pipes and vapor chambers for different scenarios such as configurations, heat sink resistance for a given temperature drop between the heating source and the ambient. This paper also discusses how thermal designers can specify requirements to heat pipe/vapor chamber suppliers for their thermal design, without delving into the complete thermo-fluidic modeling of this technology.

A Simplified Modeling Scheme for Design Sensitivity Study of Thermal Solution Utilizing Heat Pipe and Vapor Chamber Technology

2001 ◽  
Author(s):  
Ravi S. Prasher ◽  
James Shipley ◽  
Amit Devpura
Keyword(s):  
Heat Pipe ◽  
Temperature Drop ◽  
Heat Pipes ◽  
Sensitivity Study ◽  
Design Sensitivity ◽  
Thermal Design ◽  
Vapor Chamber ◽  
Modeling Tools ◽  
Heating Source ◽  
Simplified Modeling

Abstract This paper introduces a simplified modeling scheme for the prediction of heat transport capability of heat pipes and vapor chambers. The modeling scheme introduced in this paper enables thermal designers to model heat pipes and vapor chambers in commercially available conduction modeling tools such as Ansys™ and IcePak™. This modeling scheme allows thermal designers to perform design sensitivity studies in terms of power dissipation of heat pipes and vapor chambers for different scenarios such as configurations, heat sink resistance for a given temperature drop between the heating source and the ambient. This paper also discusses how thermal designers can specify requirements to heat pipe/vapor chamber suppliers for their thermal design, without delving into the complete thermofluidic modeling of this technology.

Thermal Management of a 15 kV/100 kVA Intelligent Universal Transformer

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Ronald Warzoha ◽  
Amy S. Fleischer
Keyword(s):  
Heat Pipe ◽  
Power Electronics ◽  
Thermal Management ◽  
Operating Temperature ◽  
Heat Pipes ◽  
Sensitivity Study ◽  
Design Sensitivity ◽  
Thermal Dissipation ◽  
System Failure ◽  
Significant Challenge

The thermal management of power electronics presents a significant challenge to thermal engineers due to high power loads coupled with small footprints. Inadequate thermal dissipation of these loads can lead to excessively high equipment temperatures and subsequent system failure. In this study, a unique power electronics-based transformer, called the intelligent universal transformer (IUT), is thermally analyzed using the computational fluid dynamics software ICEPAK. The objective of this work is to examine the use of a finned heat pipe array for the power electronics in the IUT. A design sensitivity study was performed to determine the effect of the number of fins attached to the heat pipe array, the number of heat pipes in the heat pipe array, and the fin material on the steady-state operating temperature of the power electronics. It was determined that a set of 33 copper fins attached to an array of 36 heat pipes on each side of the containment unit is sufficient for continuous operation of the power electronics. This analysis and thermal management solution will be applicable not only to this situation but also to other high density power electronics applications.

Thermal Design and Testing of a Passive Helmet Heat Exchanger With Additively Manufactured Components

2018 ◽  
Author(s):  
Kailyn Cage ◽  
Monifa Vaughn-Cooke ◽  
Mark Fuge ◽  
Briana Lucero ◽  
Dusan Spernjak ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Thermal Management ◽  
Heat Pipes ◽  
Thermal Design ◽  
Analytical Models ◽  
Small Scale ◽  
Dimensional System ◽  
Concept Design ◽  
Environmental Chamber

Additive manufacturing (AM) processes allow for complex geometries to be developed in a cost- and time-efficient manner in small-scale productions. The unique functionality of AM offers an ideal collaboration between specific applications of human variability and thermal management. This research investigates the intersection of AM, human variability and thermal management in the development of a military helmet heat exchanger. A primary aim of this research was to establish the effectiveness of AM components in thermal applications based on material composition. Using additively manufactured heat pipe holders, the thermal properties of a passive evaporative cooler are tested for performance capability with various heat pipes over two environmental conditions. This study conducted a proof-of-concept design for a passive helmet heat exchanger, incorporating AM components as both the heat pipe holders and the cushioning material targeting internal head temperatures of ≤ 35°C. Copper heat pipes from 3 manufactures with three lengths were analytically simulated and experimentally tested for their effectiveness in the helmet design. A total of 12 heat pipes were tested with 2 heat pipes per holder in a lateral configuration inside a thermal environmental chamber. Two 25-hour tests in an environmental chamber were conducted evaluating temperature (25°C, 45°C) and relative humidity (25%, 50%) for the six types of heat pipes and compared against the analytical models of the helmet heat exchangers. Many of the heat pipes tested were good conduits for moving the heat from the head to the evaporative wicking material. All heat pipes had Coefficients of Performance under 3.5 when tested with the lateral system. Comparisons of the analytical and experimental models show the need for the design to incorporate a re-wetting reservoir. This work on a 2-dimensional system establishes the basis for design improvements and integration of the heat pipes and additively manufactured parts with a 3-dimensional helmet.

Experimental Study on Applied Thin Vapor Chamber and Embedded Heat Pipe Heat Sinks

2009 ◽  
Author(s):  
Garrett A. Glover ◽  
Yongguo Chen ◽  
Annie Luo ◽  
Herman Chu
Keyword(s):  
Heat Pipe ◽  
Heat Sink ◽  
High Performance ◽  
Structural Integrity ◽  
Heat Pipes ◽  
Electronic Cooling ◽  
Working Fluid ◽  
Vapor Chamber ◽  
Trade Offs ◽  
Pipe Heat

The current work is a survey of applied applications of passive 2-phase technologies, such as heat pipe and vapor chamber, in heat sink designs with thin base for electronic cooling. The latest improvements of the technologies and manufacturing processes allow achievable heat sink base thickness of 3 mm as compared to around 5 mm previously. The key technical challenge has been on maintaining structural integrity for adequate hollow space for the working fluid vapor in order to retain high performance while reducing the thickness of the overall vapor chamber or flattened heat pipe. Several designs of thin vapor chamber base heat sink and embedded heat pipe heat sink from different vendors are presented for a moderate power density application of a 60 W, 13.2 mm square heat source. Numerous works have been published by both academia and commercial applications in studying the fundamental science of passive 2-phase flow technologies; their performance has been compared to solid materials, like aluminum and copper. These works have established the merits of using heat pipes and vapor chambers in electronic cooling. The intent of this paper is to provide a methodical approach to help to accelerate the process in evaluating the arrays of different commercial designs of these devices in our product design cycle. In this paper, the trade-offs between the different types of technologies are discussed for parameters such as performance advantages, physical attributes, and some cost considerations. This is a bake-off evaluation of the complete heat sink solutions from the various vendors and not a fundamental research of vapor chambers and heat pipes — for that, it is best left to the vendors and universities.

Characterization of the Performance of Flat Heat Pipes for Electronics Cooling

2000 ◽  
Author(s):  
Unnikrishnan Vadakkan ◽  
Suresh V. Garimella ◽  
Choondal B. Sobhan
Keyword(s):  
Heat Pipe ◽  
Heat Input ◽  
Energy Transport ◽  
Temperature Drop ◽  
Thermal Conductance ◽  
Electronics Cooling ◽  
Heat Pipes ◽  
Flow And Heat Transfer ◽  
Parametric Studies ◽  
Axial Heat

Abstract A computational model has been developed to analyze the transient and steady-state performance of flat heat pipes and assess their performance under different operating and geometric parameters, in order to arrive at optimal designs. The model assumes two-dimensional fields for flow and heat transfer and solves the governing differential equations using a finite-difference approach. The wick region of the heat pipe is analyzed using transport equations for a porous medium. The influence of axial heat conduction along the wall, as well as the energy transport in the wick, on the velocity and temperature distributions is examined. The overall performance of the heat pipe is quantified by calculating an effective thermal conductance from the heat input and the temperature drop along the heat pipe wall. Parametric studies are conducted using the model to investigate the dependence of the heat pipe performance on the heat input at the evaporator, the containing wall thickness, and the porosity of the wick.

Analysis of Heat Pipe Filled with Several Oxide Nanofluids on the Start-Up Process

2014 ◽  
Vol 490-491 ◽  
pp. 251-255 ◽  
Author(s):  
Yu Ying Gong ◽  
Zong Ming Liu ◽  
Wei Lin Zhao
Keyword(s):  
Temperature Distribution ◽  
Heat Pipe ◽  
Temperature Drop ◽  
Heat Pipes ◽  
Condenser Section ◽  
Evaporator Section ◽  
Heating Section ◽  
Start Up

Three heat pipes with nanofluids of Al2O3-water, CuO-water and SiO2-water were tested experimentally. The temperature distribution of their start-up process was analysed, and compared the heat pipe with water. The results showed that the start-up way of heat pipe filled with nanofluids was coincident, the heat pipe filled with nanofluids showed a lower start-up temperature and a shorter start-up time in evaporator section compared with heat pipe filled with water, the temperature drop between evaporator section and condenser section for the heat pipe filled with nanofluids were reduced by 2-5°C than that of the heat pipe filled with water. The effect of the length of the heating section of heat pipe filled with nanofluids on the start-up process was little.

Transient Analysis of a Flat Heat Pipe Working as a Passive Air Conditioning System in Residential Buildings

2004 ◽  
Author(s):  
Gustavo Gutierrez ◽  
Juan Catan˜o
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Sink ◽  
Transient Analysis ◽  
Residential Buildings ◽  
Temperature Drop ◽  
Heat Pipes ◽  
External Irradiation ◽  
Actual Performance ◽  
Flat Heat Pipe

In this study, a flat heat pipe is proposed to use the enormous heat capacity of the soil as a heat sink to remove heat from the ambient and a the same time provides a heat pathway for the external irradiation so that the thermal insulation of the construction is significantly improved. Heat pipes offer an effective and attractive alternative since they work with a small temperature budget. Heat pipes use the latent heat of vaporization as a heat transfer mechanism and provide a very high effective conductivity. Heat pipes are not thermodynamics cycles then do not suffer from the Carnot limitation. Temperature drop in the vapor core is very small and the vapor provides an almost isothermal condition. The operational temperature of a heat pipe is controlled by the conditions in the condenser (in this case, the soil). So, providing an effective heat transfer pathway in the condenser, the vapor temperature will be closed to the temperature of the soil. Soil temperature does not fluctuate bellow certain distance from the surface and in a tropical climate is always cooler that the ambient and can function as a heat sink. As part of this research, a full transient analysis of the operation of a flat heat pipe is carried out. With the insight of numerical results, a flat heat pipe thermal panel can be constructed and tested to verify the feasibility and actual performance of the flat heat pipe panel.

An integrated heat pipe coupling the vapor chamber and two cylindrical heat pipes with high anti-gravity thermal performance

2019 ◽  
Vol 159 ◽  
pp. 113816 ◽  
Author(s):  
Huawei Wang ◽  
Pengfei Bai ◽  
Honglin Zhou ◽  
Reinder Coehoorn ◽  
Nan Li ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Pipes ◽  
Vapor Chamber ◽  
Pipe Coupling

scholarly journals A Brief Review of Heat Sink, Heat Pipe, and Vapor Chamber as a Key Function of Thermal Solution for Electronic Devices

2020 ◽  
Vol 5 (11) ◽  
pp. 1297-1300
Author(s):  
Mohamed Elnaggar ◽  
Mohammed Abu Hatab ◽  
Ezzaldeen Edwan
Keyword(s):  
Heat Pipe ◽  
Heat Sink ◽  
Electronic Devices ◽  
High Heat ◽  
Design Guidelines ◽  
Thermal Design ◽  
High Heat Flux ◽  
Efficient Design ◽  
Vapor Chamber ◽  
Working Process

Electronics industry requires efficient design that can handle fast mathematical operations to compensate for the growing development and demand for processing power. These days, there are numerous equipment or parts inside machines called heating elements particularly with electrical or electronic devices and they should be cooled during the working process. However, with respect to their size, manufacturers are minifying day by day to satisfy requirements of users but the power should be maintained. Hence, elements withstand a high amount of heat and high heat flux (transition/mutability) is being generated during the working process. The main contribution of this study is to investigate thermal solutions using four cooling tools and to compare to each other and consider thermal design guidelines and factors as well. Furthermore, we review the appropriate thermal solutions for the produced heat from the electronic equipment and we present the effective and suitable tools which used to dissipate this heat. A heat sink, heat pipe, and vapor chamber are reviewed and compared depending on the previous studies that have implemented them.

Computational Modeling of Vapor Chambers With Nanostructured Wicks

2009 ◽  
Author(s):  
E. Bozorg-Grayeli ◽  
C. Fang ◽  
A. Rogacs ◽  
K. Goodson
Keyword(s):  
Finite Difference ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Heat Fluxes ◽  
Heat Output ◽  
Simulation Tool ◽  
Vapor Chamber ◽  
Future Studies ◽  
Variable Porosity ◽  
Spatially Varying

As the power and heat output of modern CPUs climb ever higher and the interest in compact, passively cooled devices grows, there is an urgent need for thinner and more effective vapor chamber technologies. Nanostructured wick technologies based on oxide and organic nanowires have been proposed as a method of improving heat pipe performance in such applications. This work performs finite difference simulations of a 2D heat pipe accounting for variable porosity in the wick. For heat fluxes of 10 and 100 W/cm2, we find that temperature difference between the evaporator and condenser regions decreases by 10%, which is promising for spreading thermal energy. We find that spatially varying porosity yields improvements in spreading heat throughout the entire wick region. Finally, we observe that boiling is depressed in the evaporator region. These results verify the benefits of nanostructured wicks. This simulation tool provides the groundwork for future studies of 3D flat package heat pipes.

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