Challenges and Advances of Heat Pipes in Cooling Notebook Systems

2007 ◽  
Author(s):  
Sridhar V. Machiroutu ◽  
Himanshu Pokharna ◽  
Masahiro Kuroda
Keyword(s):  
Heat Pipe ◽  
Lower Cost ◽  
Heat Pipes ◽  
Optimum Level ◽  
Simple Design ◽  
Foreseeable Future ◽  
Design Rules ◽  
Experimental Procedure ◽  
Desktop Computers ◽  
Thermal Solution

Notebooks represent an increasing percentage of PC client market with growth surpassing that of desktop computers. Heat pipe has been an integral part of notebook computer system cooling and will remain so for the foreseeable future. Heat pipe allows for efficient transport of heat from the CPU and other high power components to a location where there is more room for accommodating motherboard cutout for a fan and a heat exchanger. The thermal resistance along this path must be minimized to enable maximum cooling. This paper first briefly describes the contributing resistance in a heat pipe and ways to measure them for a notebook thermal solution. Since there are several parameters that can affect the performance of the heat pipes, we use an experimental procedure utilizing DOE (Design of Experiments) to first understand the sensitivities of these design, manufacturing and usage parameters on performance and then to arrive at an optimum level of these parameters to minimize various resistances in a heat pipe. We show that for various different wick technologies, it is possible to optimize the heat pipes to achieve an evaporator performance of the level of 0.1 C-cm2/W. Furthermore, we show some simple design rules to minimize the condenser resistance and also results of a design study to optimize the design of heat pipe block at the CPU end to minimize the evaporator resistance. We want to encourage the heat pipe vendor community to use these methods to optimize their products for performance as well as process enhancements to produce higher performing parts, at lower cost.

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.

An Application and Investigation of Rotating Heat Pipes on Motor Rotor Cooling

2005 ◽  
Author(s):  
Qingjun Cai ◽  
Chung-Lung Chen ◽  
Jimmy Q. Dong
Keyword(s):  
Heat Pipe ◽  
Heat Dissipation ◽  
Heat Transfer Performance ◽  
Heat Pipes ◽  
Temperature Gradients ◽  
Ac Motor ◽  
Thermal Solution ◽  
Improve Heat Transfer ◽  
Fan Cooling ◽  
Rotor Losses

In some industrial AC motor applications, higher heat dissipation results in faster rotor losses than that can be accommodated with conventional shaft-mounted-fan cooling designs. In this paper, one of the heat pipe technologies - rotating heat pipe - is presented as a means of enhancing motor rotor cooling. Novel rotating heat pipes are designed to improve heat transfer performance at various rotational speeds. Preliminary experimental results indicate that this thermal solution can effectively improve motor rotor cooling. Further, the rotating heat pipes with internal wicks can reduce temperature gradients at low rotational speed.

scholarly journals Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 751-760
Author(s):  
Lei Lei
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Transfer Performance ◽  
Analysis Model ◽  
Accurate Analysis ◽  
Testing Algorithm

AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.

The Heat Transport Capacity of Micro Heat Pipes

1998 ◽  
Vol 120 (4) ◽  
pp. 1064-1071 ◽  
Author(s):  
J. M. Ha ◽  
G. P. Peterson
Keyword(s):  
Experimental Data ◽  
Heat Pipe ◽  
Heat Transport ◽  
Heat Pipes ◽  
Original Model ◽  
Semiempirical Model ◽  
Transport Capacity ◽  
Predictive Tool ◽  
Maximum Heat ◽  
Micro Heat Pipes

The original analytical model for predicting the maximum heat transport capacity in micro heat pipes, as developed by Cotter, has been re-evaluated in light of the currently available experimental data. As is the case for most models, the original model assumed a fixed evaporator region and while it yields trends that are consistent with the experimental results, it significantly overpredicts the maximum heat transport capacity. In an effort to provide a more accurate predictive tool, a semi-empirical correlation has been developed. This modified model incorporates the effects of the temporal intrusion of the evaporating region into the adiabatic section of the heat pipe, which occurs as the heat pipe approaches dryout conditions. In so doing, the current model provides a more realistic picture of the actual physical situation. In addition to incorporating these effects, Cotter’s original expression for the liquid flow shape factor has been modified. These modifications are then incorporated into the original model and the results compared with the available experimental data. The results of this comparison indicate that the new semiempirical model significantly improves the correlation between the experimental and predicted results and more accurately represents the actual physical behavior of these devices.

A Numerical Analysis of Gas Turbine Disks Incorporating Rotating Heat Pipes

2000 ◽  
Author(s):  
Y. Cao ◽  
J. Ling ◽  
R. Rivir ◽  
C. MacArthur
Keyword(s):  
Heat Pipe ◽  
Gas Turbine ◽  
Heat Pipes ◽  
High Heat ◽  
Thermal Dissipation ◽  
High Heat Flux ◽  
Heating And Cooling ◽  
Turbine Disks ◽  
Higher Temperature ◽  
Lower Temperature

Abstract Radially rotating heat pipes have been proposed for cooling gas turbine disks working at high temperatures. A disk incorporating the heat pipe would have an enhanced thermal dissipation capacity and a much lower temperature at the disk rim and dovetail surface. In this paper, extensive numerical simulations have been made for heat-pipe-cooled disks. Thermal performances are compared for the disks with and without incorporating the heat pipe at different heating and cooling conditions. The numerical results presented in this paper indicate that radially rotating heat pipes can significantly reduce the maximum and average temperatures at the disk rim and dovetail surface under a high heat flux working condition. In general, the maximum and average temperatures at the disk rim and dovetail surface could be reduced by above 250 and 150 degrees, respectively, compared to those of the disk without the heat pipe. As a result, a disk incorporating radially rotating heat pipes could alleviate temperature-related problems and allow a gas turbine to work at a much higher temperature.

Theoretical Investigation of Heat Pipes Operating at Low Vapor Pressures

1968 ◽  
Vol 90 (4) ◽  
pp. 547-552 ◽  
Author(s):  
E. K. Levy
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Dimensional Analysis ◽  
Theoretical Investigation ◽  
Heat Pipes ◽  
Vapor Pressures ◽  
One Dimensional ◽  
Evaporator Section ◽  
Heat Transfer Capacity ◽  
Theoretical Results

A one-dimensional analysis of a compressible vapor flowing within the evaporator section of a heat pipe is presented. Comparisons between the theoretical results and existing heat pipe data show that the presence of gasdynamic choking can limit the heat transfer capacity of a heat pipe operating at sufficiently low vapor pressures.

Waste Heat Recovery for Powering Mobile Devices Using Thermoelectric Generators and Evaporatively-Cooled Heat Sink

2018 ◽  
Author(s):  
Michael Ozeh ◽  
A. G. Agwu Nnanna
Keyword(s):  
Heat Pipe ◽  
Mobile Devices ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Heat Pipes ◽  
Loop Heat Pipe ◽  
Thermoelectric Voltage ◽  
Voltage Generation ◽  
Alternate Source

Powering small electronics like mobile devices off-grid has remained a challenge; hence, there exists a need for an alternate source of powering these devices. This paper examines the efficacy of a novel nanoparticle-immobilized polyethylene wick in maintaining sufficient thermal gradient across a thermoelectric generator to power these devices with energy from waste heat. The work examines several other heat exchangers including heat pipes and loop heat pipe setups. The experimental evidence reveals that the nanoparticle-immobilized polyethylene wick is capable of generating sufficient thermal potential resulting in 5V, which is the minimum voltage required to power small mobile devices. In the opinion of the authors, this is the first ever recorded account of utilizing waste heat to generate enough voltage to power a mobile device. Experiment demonstrated that the nanoparticle-immobilized polyethylene wick showed over 40% thermoelectric voltage generation increment over a plain polyethylene wick and a metal wick in a loop heat pipe setup.

scholarly journals Research of Operation Factors of the of Bullerjan Stove in the Program Environmentfor 3D Simulation

2018 ◽  
Vol 7 (4.3) ◽  
pp. 350
Author(s):  
A. Kagramanyan ◽  
A. Onishchenko ◽  
J. Babichenko ◽  
A. Podoprigora
Keyword(s):  
Temperature Distribution ◽  
Heat Pipe ◽  
3D Modeling ◽  
Thermal Power ◽  
Flow Simulation ◽  
Heat Pipes ◽  
3D Simulation ◽  
Heat Output ◽  
Thermophysical Characteristics ◽  
Airflow Velocity

The article is devoted to the calculation of the thermal power of the Bullerjan stove according to a preconstructed model, which is realized in the 3D modeling environment of SolidWorks 2016. The thermophysical characteristics of the processes passing through the heat pipes of the Bullerjan stove were studied in detail. In the course of the work, the values of airflow velocity and temperature distribution, the temperature distribution of a solid, the surface of the heat pipe, that in the end allowed us to obtain the values of the heat output of the oven. The obtained data made it possible to determine the value of the heat output of the oven on the mode of smoldering wood and on the mode of flaming burning. The thermal power of a Bullerjan stove and in particular, its flow simulation module for modeling the flow of liquids and gases were obtained. 

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