Fabrication of Heat Pipes on an Acrylic Resin Board

2013 ◽  
Author(s):  
Yasushi Koito ◽  
Hiroyuki Maehara ◽  
Toshio Tomimura
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Acrylic Resin ◽  
Working Fluid ◽  
Liquid Volume ◽  
Wiring Board ◽  
Phase Change Heat Transfer

As a first step to develop an electronic wiring board in which micro or miniature heat pipes are internally fabricated, the experimental and analytical studies are performed on a wickless gravity-assisted heat pipe, namely thermosyphon, fabricated on a surface of an acrylic resin board. This proposal aims at performing a phase-change heat transfer inside an electronic wiring board having a low thermal conductivity. In experiments, the evaporator section of the heat pipe is heated by a heater while the condenser section is water-cooled by a heat sink. Water is used as a working fluid. Changing a heat input and a liquid volume ratio inside the heat pipe, the temperature distribution is measured by thermocouples and then compared to the case where the working fluid is not charged. Moreover, the simple model of the heat pipe is made based on a thermal resistance network, and the analysis is performed on a phase-change heat transfer and a conductive heat transfer inside the resin board having the heat pipe. The effective thermal conductivity of the heat pipe is evaluated. Although this study is an initial stage, the operational and the heat transfer characteristics of the resin board having the heat pipe are confirmed.

A Capillary-Wick Heat Pipe Fabricated on a Plastic Board (Fundamental Experiments on Heat Transport Characteristics)

2015 ◽  
Author(s):  
Yasushi Koito ◽  
Hiroyuki Maehara ◽  
Daisuke Shimada ◽  
Toshio Tomimura
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Working Fluid ◽  
Experimental Investigations ◽  
Liquid Volume ◽  
Experimental Conditions ◽  
Phase Change Heat Transfer

A capillary-wick heat pipe having the dimensions of 5.0 mm × 5.0 mm × 100 mm (length) is fabricated on a surface of a plastic board, and the experimental investigations are conducted on the operational characteristics of the heat pipe. Plastics are easy to manufacturing, lightweight, low cost, flexible, and besides, the present study aims at the phase-change heat transfer inside the plastic board. A sintered copper powder and water are used as the wick structure and the working fluid of the heat pipe, respectively. In experiments, an evaporator section of the heat pipe is heated by a heater while a condenser section is water-cooled by a heat sink. A heat input and a liquid volume inside the heat pipe are changed, and the temperature distribution of the heat pipe is measured by thermocouples. Moreover, a one-dimensional thermal circuit model is made to evaluate the effective thermal conductivity of the heat pipe. From the experimental results, the continuous phase-change heat transfer inside the plastic board and its effectiveness are confirmed. It is also revealed that the effective thermal conductivity of the heat pipe is 854 W/(m·K) in maximum under the present experimental conditions.

Fabrication of a Vapor Chamber on a Plastic Board

2015 ◽  
Author(s):  
Fumihiko Hideyama ◽  
Shuto Nonoshita ◽  
Yasushi Koito ◽  
Toshio Tomimura
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Low Cost ◽  
Cooling Water ◽  
Working Fluid ◽  
Liquid Volume ◽  
Transient Temperature ◽  
Vapor Chamber ◽  
Condenser Section ◽  
Phase Change Heat Transfer

A vapor chamber is a flat-plate heat pipe, where a cooled (condenser) section is much larger than a heated (evaporator) section, and has been used as a heat spreader to enhance the cooling of electronic devices. An objective of this study is to integrate the vapor chamber into a polycarbonate board. Plastic materials are easy to manufacturing, light weight, low cost, flexible, and then the present study aims at performing a phase-change heat transfer and a heat spreading inside the polycarbonate board. A sintered copper powder and water are used as a wick structure and a working fluid, respectively. In experiments, the heat is applied by a heater while the cooling water is circulated between a thermostatic bath and a cooling jacket. The experiments are conducted changing a liquid volume and a heat input, and the transient temperature distribution of the vapor chamber is measured by thermocouples. For comparison, the experiment is also conducted where the working fluid is not charged into the vapor chamber. Moreover, based on a thermal resistance network, an analytical model of the vapor chamber is made and the analysis is performed on the phase-change heat transfer inside the vapor chamber. From the experimental and analytical results, the heat transfer characteristics of the polymer-based vapor chamber and the effectiveness of the phase-change heat transfer are confirmed.

scholarly journals Performance of a flat grooved heat pipe with a localized heat load

2021 ◽  
Vol 321 ◽  
pp. 04010
Author(s):  
Ramazan Aykut Sezmen ◽  
Barbaros Çetin ◽  
Zafer Dursunkaya
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Temperature Distribution ◽  
Phase Change ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Working Fluid ◽  
Heat Sources ◽  
High Heat Transfer ◽  
Wide Range

Heat pipes are phase change heat transfer devices used in wide range of heat transport applications due to their high thermal transport capacities with low temperature differences. Heat pipes are especially preferred for electronic cooling applications and aerospace avionics to satisfy high heat transfer rate requirements. In this study, heat transfer and phase change mechanisms of working fluid are investigated and modeled using a 3-D thermal resistance network for multichannel flat grooved heat pipes. First, heat transfer and fluid flow are modeled in half of a single grooved structure due to symmetry, and is subjected to uniform heat flux. Radius of meniscus curvature and temperature distribution along the groove are calculated. Results are compared with experiments in the literature and show good agreement. The validated heat transfer and fluid flow models are extended to a multichannel model to observe performance of grooved heat pipes with localized heat sources, not covering the entire width, a vital feature for realistic simulation of operational devices. Predictions of the temperature distribution along the multichannel of the heat pipe are provided and the effect of the distribution of heat sources on the heat pipe is discussed.

scholarly journals The effect of operating parameters on the heat transfer in the heat pipe

2021 ◽  
Vol 2119 (1) ◽  
pp. 012088
Author(s):  
A. A. Litvintceva ◽  
N. I. Volkov ◽  
N. I. Vorogushina ◽  
V. A. Moskovskikh ◽  
V. V. Cheverda
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Pipe ◽  
Temperature Difference ◽  
Heat Pipes ◽  
Working Fluid ◽  
Operating Parameters ◽  
Temperature Stabilization ◽  
Ir Camera ◽  
Fluid Properties

Abstract Heat pipes are a good solution for temperature stabilization, for example, of microelectronics, because these kinds of systems are without any moving parts. Experimental research of the effect of operating parameters on the heat transfer in a cylindrical heat pipe has been conducted. The effect of the working fluid properties and the porous layer thickness on the heat flux and temperature difference in the heat pipe has been investigated. The temperature field of the heat pipe has been investigated using the IR-camera and K-type thermocouples. The data obtained by IR-camera and K-type thermocouples have been compared. It is demonstrated the power transferred from the evaporator to the condenser is a linear function of the temperature difference between them.

scholarly journals An investigation on effect of EDL on heat transfer of micro heat pipe with square and triangular cross section

2020 ◽  
Vol 21 (3) ◽  
pp. 309
Author(s):  
Maryam Fallah Abbasi ◽  
Hossein Shokouhmand ◽  
Morteza Khayat
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Double Layer ◽  
Electric Double Layer ◽  
Heat Pipes ◽  
The Body ◽  
Working Fluid ◽  
Two Phase ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

Electronic industries have always been trying to improve the efficiency of electronic devices with small dimensions through thermal management of this equipment, thus increasing the use of small thermal sinks. In this study micro heat pipes with triangular and square cross sections have been manufactured and tested. One of the main objectives is to obtain an understanding of micro heat pipes and their role in energy transmission with electrical double layer (EDL). Micro heat pipes are highly efficient heat transfer devices, which use the continuous evaporation/condensation of a suitable working fluid for two-phase heat transport in a closed system. Since the latent heat of vaporization is very large, heat pipes transport heat at small temperature difference, with high rates. Because of variety of advantage features these devices have found a number of applications both in space and terrestrial technologies. The theory of operation micro heat pipes with EDL is described and the micro heat pipe has been studied. The temperature distribution have achieved through five thermocouples installed on the body. Water and different solution mixture of water and ethanol have used to investigate effect of the electric double layer heat transfer. It was noticed that the electric double layer of ionized fluid has caused reduction of heat transfer.

Effects of Surface Coating of Nanoparticles on Thermal Performance of Open Loop Pulsating Heat Pipes

2012 ◽  
Author(s):  
Mehdi Taslimifar ◽  
Maziar Mohammadi ◽  
Ali Adibnia ◽  
Hossein Afshin ◽  
Mohammad Hassan Saidi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Surface Coating ◽  
Heat Pipes ◽  
Open Loop ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Performance Of Heat Transfer

Homogenous dispersing of nanoparticles in a base fluid is an excellent way to increase the thermal performance of heat transfer devices especially Heat Pipes (HPs). As a wickless, cheap and efficient heat pipe, Pulsating Heat Pipes (PHPs) are important candidates for thermal application considerations. In the present research an Open Loop Pulsating Heat Pipe (OLPHP) is fabricated and tested experimentally. The effects of working fluid namely, water, Silica Coated ferrofluid (SC ferrofluid), and ferrofluid without surface coating of nanoparticles (ferrofluid), charging ratio, heat input, and application of magnetic field on the overall thermal performance of the OLPHPs are investigated. Experimental results show that ferrofluid has better heat transport capability relative to SC ferrofluid. Furthermore, application of magnetic field improves the heat transfer performance of OLPHPs charged with both ferrofluids.

Circulation Effectiveness of Working Fluid in Inclined Micro Heat Pipes

2015 ◽  
Vol 789-790 ◽  
pp. 422-425
Author(s):  
Fun Liang Chang ◽  
Yew Mun Hung
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Pipes ◽  
Operating Conditions ◽  
Circulation Rate ◽  
Working Fluid ◽  
High Heat Flux ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

Micro heat pipe is a two-phase heat transfer device offering effective high heat-flux removal in electronics cooling. Essentially, micro heat pipe relies on the phase change processes, namely evaporation and condensation, and the circulation of working fluid to function as heat transfer equipment. The vast applications of micro heat pipe in portable appliances necessitate its functionality under different orientations with respect to gravity. Therefore, its thermal performance is strongly related to its orientation. By incorporating solid wall conduction, together with the continuity, momentum, and energy equations of the working fluid, a mathematical model is developed to investigate the heat and fluid flow characteristics of inclined micro heat pipes. We investigate both the favorable and adverse effects of gravity on the circulation rate which is intimately related to the thermal performance of micro heat pipes. The effects of gravity, through the angle of inclination, on the circulation strength and heat transport capacity are analysed. This study serves as a useful analytical tool in the micro heat pipe design and performance analysis, associated with different inclinations and operating conditions.

Use of an Inorganic Aqueous Solution to Prevent Non-Condensable Gas Formation in Aluminum Heat Pipes

2013 ◽  
Author(s):  
Michael Stubblebine ◽  
Sean Reilly ◽  
Qi Yao ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Aqueous Solution ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Solid Metal ◽  
Aluminum Surface ◽  
Working Fluid ◽  
Water Based ◽  
Inorganic Aqueous Solution ◽  
Over Time

Heat pipes are used in many applications as an effective means for transferring heat from a source to a sink. The basic heat pipe typically consists of a solid metal casing within which a working fluid is sealed inside at a given pressure. The latent heat transfer via the heat pipe’s working fluid allows it to carry a larger amount of heat energy than would normally be possible with an identically dimensioned solid metal rod. Water is often used as a working fluid due to its high heat of vaporization and suitable operating range for electronics cooling. For many applications, especially space, aluminum is desired as a casing material for its high thermal conductivity, low weight, and low cost. However, water is incompatible for use with aluminum heat pipes because it forms a non-condensable gas (NCG), hydrogen, when they contact. In this work, an inorganic aqueous solution (IAS), which has thermophysical properties similar to water, has been used as the working fluid with an aluminum alloy 5052-H2 casing. The prepared thermosiphon underwent long-term lifetime testing and the results indicate no tube failure or significant NCG formation for the duration of the 9 week study. Furthermore, the data indicate that the IAS fluid not only inhibited NCG production but also led to a reduction in heat pipe thermal resistance over time. It is believed that the chemicals in IAS react with the aluminum surface to create a compact oxide layer and electrochemical reaction which prevents hydrogen generation. A secondary, hydrophilic surface coating is also generated by the fluid on top of the first oxide (passivation) layer. This hydrophilic layer is believed to be responsible for the heat transfer enhancement which was observed during testing and the reduction in ΔT (defined as Tevap−Tcond) over time. Aluminum heat pipes used currently in practice utilize ammonia, or other non-water based working fluids, which have inferior latent heats of vaporization compared to water or an aqueous-based fluid such as IAS. The use of aluminum heat pipe casings in combination with a water-based fluid such as IAS has the potential to provide a significant increase in heat transport capability per device unit mass over traditional ammonia charged aluminum heat pipes.

Fabrication and Testing of SOG Structure Flat Heat Pipes with Triangle Grooves

2011 ◽  
Vol 483 ◽  
pp. 58-61 ◽  
Author(s):  
Xiao Wei Liu ◽  
Chao Wang ◽  
Tian Han ◽  
Tian Dong
Keyword(s):  
Thermal Conductivity ◽  
Heat Pipe ◽  
Glass Structure ◽  
Heat Pipes ◽  
Experimental Results ◽  
Working Fluid ◽  
Micro Heat Pipe ◽  
Vacuum Atmosphere

A new kind of charging and sealing method for SOG (silicon on glass) structure micro heat pipe with triangular grooves is investigated. MHP (micro heat pipe) is fully charged in a vacuum atmosphere which is useful for preventing air intermingle. Experimental results shows that when the fill ration of working fluid is about 35%, thermal conductivity of MHP with ethanol as its working fluid has an improvement of 19% compared to empty MHP.

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