Experimental study on thermal performance of an anti-gravity pulsating heat pipe and its application on heat recovery utilization

Deng, Zilong; Yi, Zheng; Liu, Xiangdong; Zhu, Bingpeng; Chen, Yongping

doi:10.1016/j.applthermaleng.2017.07.107

Cited by 80 publications

(14 citation statements)

References 29 publications

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“…While for traditional heat pipes, the antigravity capability is very weak, i.e., typically on the level of millimeter or centimeter, and a small increase in the adverse elevation will cause an obvious performance degradation. In some particular applications, the heat pipes have to be designed to operate at an antigravity orientation [33][34][35]. Under this condition, the normal operation of the heat pipes will be at the expense of significantly reduced heat transfer capacity, where the limited capillary pressure has to overcome both the liquid frictional pressure drop and the gravitational pressure drop.…”

Section: Operation With Adverse Elevationmentioning

confidence: 99%

Quiet power-free cooling system enabled by loop heat pipe

Bai

Lin

et al. 2019

Applied Thermal Engineering

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Loop heat pipe (LHP) is a quite promising two-phase heat transfer device, holding significant application potential in the modern electronics cooling. In this work, a LHP-based cooling system has been developed, which features no power consumption and no noise, taking full advantage of LHP's efficient longdistance heat transport capability. The heat source was simulated by a film electric resistance heater, which was connected to the cylindrical evaporator of the LHP through an aluminum saddle. The condenser line was embedded into the bottom surface of a fin radiator with a relatively large volume, where heat dissipation to the ambient was completely in the form of air natural convection. Extensive experiments on this cooling system were conducted, mainly focusing on its startup and system thermal resistance. Experimental results show that this cooling system can successfully realize the startup with a very small heat load. With the film heater temperature not exceeding 80 , this cooling system can dissipate a heat load up to 150 W to the ambient at a temperature about 24 , corresponding to a system thermal resistance about 0.30 /W. In addition, this cooling system exhibited very strong anti-gravity capability. With an adverse elevation of 0.5 m, the cooling system can realize normal operation, and no obvious performance decay was observed except an increased operating temperature at small heat loads.

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Section: Operation With Adverse Elevationmentioning

confidence: 99%

Quiet power-free cooling system enabled by loop heat pipe

Bai

Lin

et al. 2019

Applied Thermal Engineering

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“…Aiming to achieve highly efficient heat dissipation of high-heat-flux electronics, several advanced cooling technologies, including boiling cooling [1][2][3], liquid cooling [4,5], functional surface [6,7], microchannels heat sink [8][9][10], heat pipes [11][12][13], microfluidic engineering [14,15], metal foam [16], etc., have been introduced and applied in every field. Among these advanced cooling technologies, the heat pipes (such as grooved heat pipes [17], pulsation heat pipes [18], thermosyphons, etc.) are most widely used for the heat dissipation of microelectronic devices under high heat flux density due to high heat transfer capacity, good temperature uniformity, and no power consumption [19].…”

Section: Introductionmentioning

confidence: 99%

Visualization Study on Thermo-Hydrodynamic Behaviors of a Flat Two-Phase Thermosyphon

et al. 2018

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The coupled effect of boiling and condensation inside a flat two-phase thermosyphon has a non-negligible influence on the two-phase fluid flow behavior and heat transfer process. Therefore, a flat two-phase thermosyphon with transparent wall was manufactured. Based on this device, a visualization experiment system was developed to study the vapor–liquid two-phase behaviors and thermal performance of the flat two-phase thermosyphon. A cross-shaped wick using copper mesh was embedded into the cavity of two-phase thermosyphon to improve the heat transfer performance. The effects of heat flux density, working medium, and wick structure on the thermal performance are examined and analyzed. The results indicated that a strong liquid disturbance is caused by the bubble motions, leading to the enhancement of both convective boiling and condensation heat transfer. More bubbles are generated as the heat flux increases; therefore, the disturbance of bubble motion on liquid pool and condensation film becomes stronger, resulting in better thermal performance of the flat two-phase thermosyphon. The addition of the wick inside the cavity effectively reduces the temperature oscillation of the evaporator wall. In addition, the wick structure provides backflow paths for the condensate owing to the effect of capillary force and enhances the vapor–liquid phase change heat transfer, resulting in the improvement of thermal performance for the flat two-phase thermosyphon.

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“…Along with high development of electronic systems, the continuous increase in heat dissipation at components, module and system levels (the peak local heat flux of these electronic equipments may reach 10 6~1 0 7 W/m 2 ) leads to an increasing demand for highly efficient electronic cooling technologies Chen (2013, 2014), Chen et al (2012)), so the traditional ways of air cooling technologies cannot meet the requirements of heat dissipation. Among the available heat transfer techniques for electronic cooling including heat pipe , Deng et al (2017)), phase change materials (Ashraf et al (2017)) et al, the microchannel heat sink has been proven to be a high performance cooling method (Mudawar (2001)).…”

Section: Introductionmentioning

confidence: 99%

Effect of axial conduction on heat transfer in a rectangular microchannel with local heat flux

Wang

Zhang

2018

JTST

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Based on the continuum assumption and Navier-Stokes equation, three-dimensional fluid flow and conjugate heat transfer in heat sinks with rectangle microchannels have been studied by numerical simulation. The validation of this approach has been demonstrated by comparisons with analytical solutions. Results were obtained for the detailed description of the local and average heat transfer characteristics including wall and fluid temperatures, heat flux, Nusselt number (Nu). Effects of the Peclet number (Pe), the relative conductivity (k w /k f ) and the relative thickness (W/D) of solid substrate were presented and discussed. At low Pe flow, axial conduction dominates the heat transfer, which results in a large upstream region which is pre-warmed by axial conduction, so axial conduction cannot be neglected at small Pe. The increase of Pe induces an enhancement of convection, the heat exchange mainly happens on heat region by convection under this condition. A more uniform streamwise temperature distribution at fluid-solid interface indicates the enhancement of the pre-warmed effect along with the increase of k w /k f . The study also reveals that the Nu x of low k w /k f material is higher than the Nu x of high k w /k f material. The increase of wall thickness has an effect on axial distribution of the Nu x , the trend is similar to that of an increase of the wall thermal conductivity k w /k f . It was concluded that the average Nusselt number is proportional to thermal conductivity of the wall. For low Pe, the fluid is heated by the wall by means of convection on heat region, when Pe ≤ 1, a slight increase of the Nu on heat region is shown as the increase of Pe. When Pe > 10, the convection is the dominant factor in heat transfer, an obvious increase of Nu is shown with increase of Pe. For high Pe flow, the heat transfer enhancement as increase of Pe is weak. KeywordsNomenclature a thermal diffusivity, m 2 .s A wall cross-sectional area of the microchannel, m 2

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Experimental study on thermal performance of an anti-gravity pulsating heat pipe and its application on heat recovery utilization

Cited by 80 publications

References 29 publications

Quiet power-free cooling system enabled by loop heat pipe

Quiet power-free cooling system enabled by loop heat pipe

Visualization Study on Thermo-Hydrodynamic Behaviors of a Flat Two-Phase Thermosyphon

Effect of axial conduction on heat transfer in a rectangular microchannel with local heat flux

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