Thermal performance of horizontal closed-loop oscillating heat pipes

Charoensawan, Piyanun; Terdtoon, Pradit

doi:10.1016/j.applthermaleng.2007.05.007

Cited by 143 publications

(67 citation statements)

References 8 publications

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“…The effects of inner diameter on the thermal performance of OHP might be the opposite for different working fluid, which is indicated by the experimental results by Rittidech et al [35,36]. Particularly, based on an experimental test on the open-loop OHPs, Saha et al [37] found that when compared with the OHP with Di = 0.9 mm, the OHP with Di = 1.5 mm demonstrated worse thermal performance, which is different from the conclusions by Charoensawan et al [32] and Yang et al [33,34].…”

Section: Introductioncontrasting

confidence: 52%

“…Charoensawan et al [32] experimentally investigated the thermal performance of the horizontal OHPs with Di = 1.0 and 2.0 mm, which indicated the better thermal performance of the OHP with bigger Di. In addition, via the comparison between the thermal resistance of two OHPs with different inner diameters, Yang et al [33,34] found that the thermal performance of the OHP with Di = 1.0 mm was decreased by about 10% relative to that with Di = 2.0 mm.…”

Section: Introductionmentioning

confidence: 99%

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High-Speed Visual Analysis of Fluid Flow and Heat Transfer in Oscillating Heat Pipes with Different Diameters

Liu¹,

Sun²,

Zhang

et al. 2016

Preprint

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Abstract:The oscillating heat pipe (OHP) is a new member in the family of heat pipes, and it has great potential applications in energy conservation. However, the fluid flow and heat transfer in the OHP as well as the fundamental effects of inner diameter on them have not been fully understood, which are essential to the design and optimization of the OHP in real applications. Therefore, by combining the high-speed visualization method and infrared thermal imaging technique, the fluid flow and thermal performance in the OHPs with inner diameters of 1, 2 and 3 mm are presented and analyzed. The results indicate that three fluid flow motions, including small oscillation, bulk oscillation and circulation, coexist or, respectively, exist alone with the increasing heating load under different inner diameters, with three flow patterns occurring in the OHPs, viz. bubbly flow, slug flow and annular flow. These fluid flow motions are closely correlated with the heat and mass transfer performance in the OHPs, which can be reflected by the characteristics of infrared thermal images of condensers. The decrease in the inner diameter increases the frictional flow resistance and capillary instability while restricting the nucleate boiling in OHPs, which leads to a smaller proportion of bubbly flow, a larger proportion of short slug flow, a poorer thermal performance, and easier dry-out of working fluid. In addition, when compared with the 2 mm OHP, the increasing role of gravity induces the thermosyphon effect and weakens the 'bubble pumping' action, which results in a little smaller and bigger thermal resistances of 3 mm OHP under small and bulk oscillation of working fluid, respectively.

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Section: Introductioncontrasting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

High-Speed Visual Analysis of Fluid Flow and Heat Transfer in Oscillating Heat Pipes with Different Diameters

Liu¹,

Sun²,

Zhang

et al. 2016

Preprint

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“…The evaporator and condenser section lengths were 50 and 100 mm, respectively (Charoensawan and Terdtoon, 2008), with a total length of 18 m. There were 15 turns. The two types of oscillating heat-pipe arrangements are shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Applied a Closed-Loop Oscillating Heat-Pipe Heat Exchanger to Increasing Oil Yield in Pyrolysis Process

Panyoyai¹

2010

Energy Research Journal

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Problem statement:A Closed-Loop Oscillating Heat-Pipe (CLOHP) heat exchanger was a heat exchanger with one of the most promising conductivity capacities because of its higher cooling and condensing potential. Therefore, the aims of this study were to design and fabricate a CLOHP to be applied to increasing oil yield in the pyrolysis process. Approach: Two types of oscillating heatpipe arrangements-parallel and perpendicular to the gas flow direction-were compared with a conventional water-to-air condenser or glass-type heat exchanger. The oscillating heat-pipe was made of four sets of copper tubes working at 90° from the horizontal plane, with an inner diameter of 2.03 mm and a total length of 18 m. The number of turns was 15. The lengths of the evaporator and condenser sections were 50 and 100 mm in total, respectively. R123 was used as a working fluid, 50% by total volume. In the experiment, an air velocity of 0.4 m sec −1 was applied to the condenser section.100 g of 5×5 mm pieces of motorcycle tire inner tubes were burned in a pyrolysis furnace of 500°C, having a heat-rate of 10°C min −1 . Result: The results showed that a CLOHP parallel to the gas flow direction was more effective, resulting in 39.08 g crude oil from the hot gas in the pyrolysis process and a maximum heat flux of 1,181.53 W m −2 . Conclusion: This study suggested that to improve the performance of a pyrolysis process which uses scrap motorcycle tire waste as a heating agent, a CLOHP should be placed in parallel to the gas flow line.

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“…The heat transport capability of heat pipe is directly related to channel density (channel/unit volume) (Charoensawan et al,2008;Sarangi et al2013). The flat plate oscillating heat pipe can increase the channel density so that increases the thermal performance of the heat pipe at higher heat flux level.…”

Section: Heat Flux Levelmentioning

confidence: 99%

Development of Flat Plate Oscillating Heat Pipe as a Heat Transfer Device

Mehta¹,

Mehta²

2017

Frontiers in Heat Pipes

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Heat transfer management is present issue which is progressively increasing importance in line with technology. Effective thermal management is needed to serve to the present trends of power & flux level of upcoming micro devices. This article describes the development of flat plate oscillating heat pipe (FP-OHP) as new entry in the family of two phase heat transfer system. As a unique heat transfer device, flat plate oscillating heat pipe has been considered have a smart prospect due to its advantages: simple fabrication methods & structure, low cost & outstanding heat transfer capability. The development of FP-OHP application is founded on the basis of experimental and theoretical research on two phase heat transfer in FP-OHP. With substantial expectation of FP-OHP application in the coming years, this article attempts to review the development of FP-OHP products. Simultaneously, some favorable and innovative applications of FP-OHP are also studied. This article is predicted to provide fundamental reference for future researcher.

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Thermal performance of horizontal closed-loop oscillating heat pipes

Cited by 143 publications

References 8 publications

High-Speed Visual Analysis of Fluid Flow and Heat Transfer in Oscillating Heat Pipes with Different Diameters

High-Speed Visual Analysis of Fluid Flow and Heat Transfer in Oscillating Heat Pipes with Different Diameters

Applied a Closed-Loop Oscillating Heat-Pipe Heat Exchanger to Increasing Oil Yield in Pyrolysis Process

Development of Flat Plate Oscillating Heat Pipe as a Heat Transfer Device

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