scholarly journals Numerical Simulation of a Thermosyphon Radiator Used in Electronic Devices

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Liang Ding ◽  
Wei Wang ◽  
Bingrui Li ◽  
Yong Shuai ◽  
Bingxi Li
Keyword(s):  
Heat Flux ◽  
Numerical Model ◽  
Thermal Resistance ◽  
Wall Temperature ◽  
Thermal Load ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
High Heat ◽  
High Heat Flux ◽  
Load Conditions

The heat dissipation of electronic devices is an important issue. The thermosyphon radiators have high heat dissipation performance, so they are gradually widely used in electronic devices. In this study, a numerical model of the thermosyphon is established. It is observed that simulated temperatures agree well with experimental data in the literature with a relative error no more than 4%. After the numerical model is validated, it is used in the simulation of the thermosyphon radiator. The wall temperature of the condensing section under different thermal load conditions is compared, and the thermal resistance of the condensing section is analyzed. The results show that with the increase of heating and condensing heat flux, the wall temperature fluctuation of the condensing section increases, but very small just about 5K, 6K, 7K, and 9K, respectively. The thermal resistance of the condensing section decreases, indicating that the thermosyphon radiator has a better performance under high heat flux conditions.

Design of Practical Liquid Metal Cooling Device for Heat Dissipation of High Performance CPUs

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Yueguang Deng ◽  
Jing Liu
Keyword(s):  
Heat Flux ◽  
Liquid Metal ◽  
Thermal Resistance ◽  
High Performance ◽  
Heat Dissipation ◽  
High Heat ◽  
High Heat Flux ◽  
Water Cooling ◽  
Cooling Device ◽  
Liquid Metal Cooling

Broad societal needs have focused attention on technologies that can effectively dissipate huge amount of heat from high power density electronic devices. Liquid metal cooling, which has been proposed in recent years, is fast emerging as a novel and promising solution to meet the requirements of high heat flux optoelectronic devices. In this paper, a design and implementation of a practical liquid metal cooling device for heat dissipation of high performance CPUs was demonstrated. GaInSn alloy with the melting point around 10°C was adopted as the coolant and a tower structure was implemented so that the lowest coolant amount was used. In order to better understand the design procedure and cooling capability, several crucial design principles and related fundamental theories were demonstrated and discussed. In the experimental study, two typical prototypes have been fabricated to evaluate the cooling performance of this liquid metal cooling device. The compared results with typical water cooling and commercially available heat pipes show that the present device could achieve excellent cooling capability. The thermal resistance could be as low as 0.13°C/W, which is competitive with most of the latest advanced CPU cooling devices in the market. Although the cost (about 70 dollars) is still relatively high, it could be significantly reduced to less than 30 dollars with the optimization of flow channel. Considering its advantages of low thermal resistance, capability to cope with extremely high heat flux, stability, durability, and energy saving characteristic when compared with heat pipe and water cooling, this liquid metal cooling device is quite practical for future application.

scholarly journals Visualization Study of Startup Modes and Operating States of a Flat Two-Phase Micro Thermosyphon

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2291 ◽  
Author(s):  
Liangyu Wu ◽  
Yingying Chen ◽  
Suchen Wu ◽  
Mengchen Zhang ◽  
Weibo Yang ◽  
...  
Keyword(s):  
Wall Temperature ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase ◽  
Interface Evolution ◽  
Visualization Experiment

The flat two-phase thermosyphon has been recognized as a promising technique to realize uniform heat dissipation for high-heat-flux electronic devices. In this paper, a visualization experiment is designed and conducted to study the startup modes and operating states in a flat two-phase thermosyphon. The dynamic wall temperatures and gas–liquid interface evolution are observed and analyzed. From the results, the sudden startup and gradual startup modes and three quasi-steady operating states are identified. As the heat load increases, the continuous large-amplitude pulsation, alternate pulsation, and continuous small-amplitude pulsation states are experienced in sequence for the evaporator wall temperature. The alternate pulsation state can be divided into two types of alternate pulsation: lengthy single-large-amplitude-pulsation alternated with short multiple-small-amplitude-pulsation, and short single-large-amplitude-pulsation alternated with lengthy multiple-small-amplitude alternate pulsation state. During the continuous large-amplitude pulsation state, the bubbles were generated intermittently and the wall temperature fluctuated cyclically with a continuous large amplitude. In the alternate pulsation state, the duration of boiling became longer compared to the continuous large-amplitude pulsation state, and the wall temperature of the evaporator section exhibited small fluctuations. In addition, there was no large-amplitude wall temperature pulsation in the continuous small-amplitude pulsation state, and the boiling occurred continuously. The thermal performance of the alternate pulsation state in a flat two-phase thermosyphon is inferior to the continuous small-amplitude pulsation state but superior to the continuous large-amplitude pulsation state.

Fast Transient and Intensified Heat Dissipation Applicable to High Heat Flux Density

2011 ◽  
Author(s):  
Jing Li ◽  
Shuanshi Fan ◽  
Zemin Yao ◽  
Jing Li ◽  
Xinli Wei
Keyword(s):  
Heat Flux ◽  
Flux Density ◽  
Heat Flux Density ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
Spray Cooling ◽  
High Heat ◽  
High Heat Flux ◽  
Power Electronic ◽  
Fast Transient

In this paper, in order to solve the problem of intensified heat dissipation in high power electronic devices, a fast transient and intensified heat dissipation technology was put forward by comparing many heat transfer modes based on the analytical study on the existing technologies about heat dissipation at high heat flux density and about fast heat transport. This technology combined spray cooling technology with fast endothermic chemical reaction processes; we summarized the characteristics of media applicable to an environment with transient high heat flux density by comparing various parameters of many sprayed media in the spray cooling process. According to the energy balance of endothermic chemical reactions of relevant media, we determined the media (mainly carbon dioxide hydrate) applicable to the fast transient and intensified heat dissipation technology and presented the conditions for the chemical reactions. We analyzed the methods controlling the instantaneous chemical reaction rate and proposed the structural characteristics of the chemical reactor so as to ensure that the time for heat removal will be control to around 0.01 second. Thus, the problem of fast transient heat dissipation in high power electronic devices, etc. would be radically solved.

Experimental Investigation of Boiling Heat Transfer in a Liquid Chamber With Partially Soluble Nanofluids

2021 ◽  
Author(s):  
Noriyuki Unno ◽  
Kazuhisa Yuki ◽  
Risako Kibushi ◽  
Rika Nogita ◽  
Atsuyuki Mitani
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Electronic Devices ◽  
High Heat ◽  
Experimental Result ◽  
High Heat Flux ◽  
Promising Technique ◽  
Cooling Device ◽  
Cooling Devices

Abstract Boiling heat transfer (BHT) is a promising technique to remove a high heat flux emitted from next-generation electronic devices. However, critical heat flux (CHF) is a big problem in BHT because it restricts the maximum performance of the cooling devices using BHT. Nanofluid has been widely used to improve the CHF. In this study, the authors investigated the BHT of a compact cooling device at low pressure using a special nanofluid: that is made with partially soluble particles in water. The experimental result found that the CHF with the special nanofluid is 170 W/cm2 and is higher than that with nanofluid made with an insoluble nanoparticle.

Thermal Analysis of Cold Plate for Direct Liquid Cooling of High Performance Servers

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Bharath Ramakrishnan ◽  
Yaser Hadad ◽  
Sami Alkharabsheh ◽  
Paul R. Chiarot ◽  
Bahgat Sammakia
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Resistance ◽  
High Heat ◽  
High Heat Flux ◽  
Cold Plate ◽  
Liquid Cooling ◽  
Maximum Heat ◽  
Effective Heat ◽  
Cold Plates

Data center energy usage keeps growing every year and will continue to increase with rising demand for ecommerce, scientific research, social networking, and use of streaming video services. The miniaturization of microelectronic devices and an increasing demand for clock speed result in high heat flux systems. By adopting direct liquid cooling, the high heat flux and high power demands can be met, while the reliability of the electronic devices is greatly improved. Cold plates which are mounted directly on to the chips facilitate a lower thermal resistance path originating from the chip to the incoming coolant. An attempt was made in the current study to characterize a commercially available cold plate which uses warm water in carrying the heat away from the chip. A mock package mimicking a processor chip with an effective heat transfer area of 6.45 cm2 was developed for this study using a copper block heater arrangement. The thermo-hydraulic performance of the cold plates was investigated by conducting experiments at varying chip power, coolant flow rates, and coolant temperature. The pressure drop (ΔP) and the temperature rise (ΔT) across the cold plates were measured, and the results were presented as flow resistance and thermal resistance curves. A maximum heat flux of 31 W/cm2 was dissipated at a flow rate of 13 cm3/s. A resistance network model was used to calculate an effective heat transfer coefficient by revealing different elements contributing to the total resistance. The study extended to different coolant temperatures ranging from 25 °C to 45 °C addresses the effect of coolant viscosity on the overall performance of the cold plate, and the results were presented as coefficient of performance (COP) curves. A numerical model developed using 6SigmaET was validated against the experimental findings for the flow and thermal performance with minimal percentage difference.

A Numerical Model of a Reciprocating-Mechanism Driven Heat Loop for Two-Phase High Heat Flux Cooling

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Olubunmi Popoola ◽  
Ayobami Bamgbade ◽  
Yiding Cao
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Model ◽  
Performance Optimization ◽  
Numerical Study ◽  
High Heat ◽  
Working Fluid ◽  
High Heat Flux ◽  
Two Phase ◽  
Transfer Device

An effective design option for a cooling system is to use a two-phase pumped cooling loop to simultaneously satisfy the temperature uniformity and high heat flux requirements. A reciprocating-mechanism driven heat loop (RMDHL) is a novel heat transfer device that could attain a high heat transfer rate through a reciprocating flow of the two-phase working fluid inside the heat transfer device. Although the device has been tested and validated experimentally, analytical or numerical study has not been undertaken to understand its working mechanism and provide guidance for the device design. The objective of this paper is to develop a numerical model for the RMDHL to predict its operational performance under different working conditions. The developed numerical model has been successfully validated by the existing experimental data and will provide a powerful tool for the design and performance optimization of future RMDHLs. The study also reveals that the maximum velocity in the flow occurs near the wall rather than at the center of the pipe, as in the case of unidirectional steady flow. This higher velocity near the wall may help to explain the enhanced heat transfer of an RMDHL.

Cooling of high heat flux electronic devices using ultra-thin multiport minichannel thermosyphon

2020 ◽  
Vol 169 ◽  
pp. 114669 ◽  
Author(s):  
Stephen Manova ◽  
Lazarus Godson Asirvatham ◽  
Rajesh Nimmagadda ◽  
Jefferson Raja Bose ◽  
Somchai Wongwises
Keyword(s):  
Heat Flux ◽  
Electronic Devices ◽  
High Heat ◽  
High Heat Flux

E219 High Heat Flux Cooling for Electronic Devices by Subcooled Flow Boiling : Cooing performance of small channel

2001 ◽  
Vol 2001 (0) ◽  
pp. 553-554
Author(s):  
Koichi SUZUKI ◽  
Hiroki SAITO ◽  
Hiroshi KAWAMURA ◽  
Hideo IWASAKI ◽  
Koichiro KAWANO ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flow Boiling ◽  
Electronic Devices ◽  
High Heat ◽  
High Heat Flux ◽  
Subcooled Flow Boiling ◽  
Small Channel ◽  
Subcooled Flow

Integrated Vapor Chamber Heat Spreader for Power Module Applications

2017 ◽  
Author(s):  
Clayton L. Hose ◽  
Dimeji Ibitayo ◽  
Lauren M. Boteler ◽  
Jens Weyant ◽  
Bradley Richard
Keyword(s):  
Heat Flux ◽  
Thermal Resistance ◽  
Power Electronics ◽  
Coefficient Of Thermal Expansion ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Vapor Chamber ◽  
Power Module ◽  
Heat Spreader

This work presents a demonstration of a coefficient of thermal expansion (CTE) matched, high heat flux vapor chamber directly integrated onto the backside of a direct bond copper (DBC) substrate to improve heat spreading and reduce thermal resistance of power electronics modules. Typical vapor chambers are designed to operate at heat fluxes > 25 W/cm2 with overall thermal resistances < 0.20 °C/W. Due to the rising demands for increased thermal performance in high power electronics modules, this vapor chamber has been designed as a passive, drop-in replacement for a standard heat spreader. In order to operate with device heat fluxes >500 W/cm2 while maintaining low thermal resistance, a planar vapor chamber is positioned onto the backside of the power substrate, which incorporates a specially designed wick directly beneath the active heat dissipating components to balance liquid return and vapor mass flow. In addition to the high heat flux capability, the vapor chamber is designed to be CTE matched to reduce thermally induced stresses. Modeling results showed effective thermal conductivities of up to 950 W/m-K, which is 5 times better than standard copper-molybdenum (CuMo) heat spreaders. Experimental results show a 43°C reduction in device temperature compared to a standard solid CuMo heat spreader at a heat flux of 520 W/cm2.

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