A novel design of pulsating heat pipe with fewer turns applicable to all orientations

Chien, Kuo Hsiang; Lin, Yur Tsai; Chen, Yi Rong; Yang, Kai; Wang, Chi-Chuan

doi:10.1016/j.ijheatmasstransfer.2012.05.068

Cited by 151 publications

(46 citation statements)

References 15 publications

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“…This start-up failure of the horizontally oriented μPHP having fewer turns occurred because of the lack of assistance from gravity [18]. Therefore, using nonuniform channels to introduce additional unbalancing capillary force and adjust the flow resistance facilitates the recover of lost gravitational force under certain operating conditions, as proposed by Chien et al [9].…”

Section: Resultsmentioning

confidence: 98%

“…The various effects of influential parameters, including internal diameter, operating inclination angle, working fluid (e.g., water, methanol, ethanol, R-123, FC-72), and number of turns, on the thermal performance of closed-loop PHPs have been experimentally investigated in studies such as Charoensawan et al [5], Zhang et al [6], Thompson et al [7], Youn and Kim [8], and Chien et al [9].…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Investigation of Micro Pulsating Heat Pipes

et al. 2014

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Two Si-based micro pulsating heat pipes (µPHPs) charged using HFE-7100 were either horizontally or vertically oriented and were tested using several heating powers. The width of each channel was 0.8 mm in one µPHP containing uniform channels, and the channel width was 1.0 mm or 0.6 mm in the other µPHP, which did not contain uniform channels. The depth of each channel was 0.25 mm. The overall size of each µPHP was 60 × 10 × 1.25 mm. Visual observation and temperature measurement of the µPHPs under various conditions were performed and the results were analyzed. The results indicated that when the µPHPs were operated horizontally at a heating power ranging from 1 to 7 W, the pulsating two-phase flow in the channels of the µPHPs could not begin, except when the µPHP containing nonuniform channels was tested at a heating power of 7 W. With a heating power less than 5 W, the frequency of the sine-like oscillating displacement of the vapor slug increased and the displacement of the vapor slug reduced in either vertically oriented μPHP, as the heating power increased With a heating power higher than 5 W, periodic "start-stop" behaviors were observed in the vertical μPHP containing nonuniform channels.

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Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

An Experimental Investigation of Micro Pulsating Heat Pipes

et al. 2014

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“…It´s generally agreed, J. Qu et al [5], H. Barua et al [6], that the thermal performance and the flow regime of OHP depends on the effects of the working fluid, filling ratio (FR), power input, operating orientation and different geometries. The working fluid is commonly the most effective parameter to improve the thermal performance of heat pipes [7] The difference between the power supplied in the evaporator zone and the heat released from the condenser part is usually less than 5% [8]. All the authors stated the same way of measuring the performance of the OHP by estimating the overall thermal resistance of the device as a simple steady state system, given by equation below:…”

Section: Introductionmentioning

confidence: 99%

Design and study of a Flat Plate Oscillating Heat Pipe. Flow Pattern analysis and Heat Transfer Performance

Cal¹,

Vishak²

2024

RE&PQJ

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Abstract. Recent and constant demands for greater power densities and smaller sizes of electronic systems have stimulated the growth of new designs of different passive heat transfer methods such as heat pipes. Particularly, Oscillating Heat Pipes (OHPs) are relatively novel devices, capable of removing high heat rates over long and short distances with not much temperature drop. Its heat transfer mechanism relies on a self-oscillating motion of a two-phase flow of a working fluid circulating through meandering channels. This study concentrates on the design, building and assembling a test rig in order to analyse the flow pattern of deionised water through a 5 turns Flat Plate Oscillating Hat Pipe under different heat inputs, which was made in the School of Engineering and Materials Science of the Queen Mary University of London by two PhD students. The filling ratio of the water is 40%. Furthermore an experimental study on the OHP thermal performance is carried out in order to examine the effects of different surface wet conditions: super hydrophilic, hydrophilic and cleaned brass. It is demonstrated the formation of liquid slugs and vapour plugs of the water along the channels. The experimental results showed that the hydrophilic surface tend to be more energy efficient. The heat transfer performance of the superhydrophilic and hydrophilic is higher than brass by 5-12% and 15-20% respectively

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“…Loop thermosiphons (LTs) [6], vapordynamic thermosiphons (VDTs) [7,8], and pulsating heat pipes (PHPs) [9] are alternative solutions to the aforementioned problems. Among these heat transfer devices, LTs are most appreciated when integrating with solar collector for the simple manufacturing process.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on a Forced-Circulation Loop Thermosiphon Solar Water Heating System

Zhang

2018

International Journal of Photoenergy

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Wickless gravity loop thermosiphons (LTs) have been widely used in heat collection for distances up to several meters. This twophase closed device, which is operating under reduced pressure, is useful in solar water heating (SWH) systems because it could address the freezing problem during winter. Compared to the normal type, forced-circulation wickless LTs have significant advantages in the long-distance heat transfer and installation freedom of condensation section. In this study, a pump-forced wickless LT-SWH system with a remolded flat-plate solar collector was put forward. Solar collector acted as the evaporation section of the wickless LT, while the spiral heat exchanger in the water tank acted as the condensation section. R600a was employed as the working fluid, and long-term outdoor experiments were carried out. Results show that the instantaneous and daily average photothermal efficiency of the proposed system can reach 69.54% and 58.22%, respectively. Temperature differences between the top and bottom and the middle and bottom of the evaporation section of the wickless LT were small, and it usually ranged between 1.1 and 3.9°C. Linear fittings of the collector and system overall performance of the pump-forced wickless LT-SWH system demonstrate the promising potential application of the system.

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A novel design of pulsating heat pipe with fewer turns applicable to all orientations

Cited by 151 publications

References 15 publications

An Experimental Investigation of Micro Pulsating Heat Pipes

An Experimental Investigation of Micro Pulsating Heat Pipes

Design and study of a Flat Plate Oscillating Heat Pipe. Flow Pattern analysis and Heat Transfer Performance

Experimental Study on a Forced-Circulation Loop Thermosiphon Solar Water Heating System

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