New evaporator structure for micro loop heat pipes

Fukushima, Kazuki; Nagano, Hosei

doi:10.1016/j.ijheatmasstransfer.2016.10.116

Cited by 47 publications

(8 citation statements)

References 10 publications

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“…The maximum heat load obtained by this LHP was 11 W and the minimum thermal resistance was 1.21 °C/W. This LHP could work under natural convection without any active cooling implemented; start-up stable at a heat load of 2 W. The LHP was made of aluminum and the working fluid was ethanol [68]. The photo of this miniature LHP is presented in Figure 19.…”

Section: Miniature Flat Lhpmentioning

confidence: 99%

Recent Advances in Loop Heat Pipes with Flat Evaporator

Szymański

Law

McGlen

et al. 2021

Entropy

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The focus of this review is to present the current advances in Loop Heat Pipes (LHP) with flat evaporators, which address the current challenges to the wide implementation of the technology. A recent advance in LHP is the design of flat-shaped evaporators, which is better suited to the geometry of discretely mounted electronics components (microprocessors) and therefore negate the need for an additional transfer surface (saddle) between component and evaporator. However, various challenges exist in the implementation of flat-evaporator, including (1) deformation of the evaporator due to high internal pressure and uneven stress distribution in the non-circular casing; (2) heat leak from evaporator heating zone and sidewall into the compensation chamber; (3) poor performance at start-up; (4) reverse flow through the wick; or (5) difficulties in sealing, and hence frequent leakage. This paper presents and reviews state-of-the-art LHP technologies; this includes an (a) review of novel manufacturing methods; (b) LHP evaporator designs; (c) working fluids; and (d) construction materials. The work presents solutions that are used to develop or improve the LHP construction, overall thermal performance, heat transfer distance, start-up time (especially at low heat loads), manufacturing cost, weight, possibilities of miniaturization and how they affect the solution on the above-presented problems and challenges in flat shape LHP development to take advantage in the passive cooling systems for electronic devices in multiple applications.

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Section: Miniature Flat Lhpmentioning

confidence: 99%

Recent Advances in Loop Heat Pipes with Flat Evaporator

Szymański

Law

McGlen

et al. 2021

Entropy

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“…This LHP does not require electric power and features a large heat transfer distance, high heat transfer capacity, and flexible configuration [15,16]. In addition, the ground uses of LHPs for cooling engines and central processing units (CPU) have been proposed [17][18][19]. However, it is difficult for the LHP to cool intense heat sources, such as the electric aircraft's motor, as a result of the insufficient driving force.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Wick-Type Two-Phase Mechanically Pumped Fluid Loop for Thermal Control of Electric Aircraft Motors

2022

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The development of thermal control systems has become an important issue in next-generation electric aircraft design due to the increase in heat exhausted with electrification. In this paper, a wick-type two-phase mechanically pumped fluid loop system for future electric aircraft was proposed through the investigation of current two-phase flow cooling technology. Taking the experimental electric aircraft X-57 as an example, a wick-type two-phase mechanically pumped fluid loop with four evaporators for transporting 12 kW of waste heat within an 80 °C temperature limit was proposed and its feasibility was confirmed. A numerical model was constructed and validated to predict the operating characteristics of a two-phase mechanically pumped fluid loop. The optimal pump outputs under-even and uneven heat load conditions and was investigated for the first time by considering the vapor-liquid separation conditions in each flow path and the power consumption of the pump. Under the optimal pump output condition, the operating characteristics of the wick-type two-phase mechanically pumped fluid loop system were calculated. The calculation results indicate that the proposed wick-type two-phase mechanically pumped fluid loop is suitable as the thermal control system for an X-57 electric aircraft motor, as the calculation results satisfied the operational requirements of the motor.

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“…Microelectronics technology, which plays a key role in the national economy, military construction, and other fields, is at the core of today's information industry. 1 In recent years, the rapid development of this technology has increasingly tended towards high-frequency, high-speed, miniaturized, and integrated devices. However, this high integration has the unwanted side effect of causing the electronic components to rapidly heat up, which leads to a rise in the working temperature of the equipment.…”

mentioning

confidence: 99%

Superhydrophobic/Superhydrophilic Hybrid Copper Surface Enhanced Micro Heat Pipe by Using Laser Selective Texturing

Lou¹,

Li²,

Liang³

et al. 2021

ECS J. Solid State Sci. Technol.

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The heat transfer performance of Flat micro heat pipe (FMHP) is mainly determined by liquid absorption capacity of the wick. A chemical-free laser selective micro-texture technology is proposed for the fabrication of FMHP. Series of samples with different widths of the superhydrophobic-superhydrophilic spacing stripes were prepared by laser micro texturing, and their transport capacity was tested. Scanning electron microscope, three-dimensional optical profiling, and X-ray photoelectron spectroscope techniques were used to characterize the surfaces, and the mechanism of accelerating liquid reflux was investigated. Two samples with the same spacing width were used to make FMHPs. The heat transfer performance of each group of FMHPs was tested, including the start-up time, steady state temperature, and axial maximum temperature difference, and the corresponding thermal resistances were calculated. The results show that the width of superhydrophobic-superhydrophilic spacing stripes can affect the capillary force and hysteresis force during droplet transport, thereby affecting the droplet transport velocity, and in turn, influencing the heat transfer performance of the FMHP. Compared with most current flat micro heat pipes, the laser selective textured heat pipe with superhydrophobic-superhydrophilic stripes can significantly improve the heat transfer performance, and is promising for heat transfer applications in microelectronic equipment.

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New evaporator structure for micro loop heat pipes

Cited by 47 publications

References 10 publications

Recent Advances in Loop Heat Pipes with Flat Evaporator

Recent Advances in Loop Heat Pipes with Flat Evaporator

Numerical Analysis of Wick-Type Two-Phase Mechanically Pumped Fluid Loop for Thermal Control of Electric Aircraft Motors

Superhydrophobic/Superhydrophilic Hybrid Copper Surface Enhanced Micro Heat Pipe by Using Laser Selective Texturing

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