The operational heat pipe has a capacity to spread more than 70 wcm2 with a temperature on the resistor level less than 120c. However, in an actual application when a heat pipe is soldered or epoxied to the base of a heat sink, the effective thermal conductivity of the heat pipe may be. Heat pipe engineering ebook datasheet by advanced thermal. A parametric optimization of the structural design was performed to ensure mechanical. This typically translates to dissipated heat of between 20200 watts less if power density is high and power density up to around 25 wcm 2. For example there is an analogy between micro heat pipe operation and functioning of a sweat gland 3. What is a heat pipe heat pipes basics and technology. The full range of heat pipe classifications, including rotating and revolving, micro, cryogenic, and variable conductance heat pipes, as well as thermal diodes and switches this book provides all the information and guidance you need to increase your understanding of these innovative devices and to begin to apply them to the thermal control of. This new edition has been revised to include new information on the underlying theory of heat pipes and heat transfer, and features fully updated applications, new data sections, and updated chapters on design and electronics cooling. For the pure silicon spreader only 20 wcm2 of heat flux can be achieved. The innovative design of the micro heat pipe uses sharpcornered square, triangular, or other polygonal channels that can serve as capillary arteries, see fig. However, here well just get into some of the basics to make you effective as a designer. Heat pipes are passive, twophased heat transfer devices, using liquid to vapor phase transition to.
The use of different fluids can of course, change its working ability. The bunhill 2 energy centre is designed to capture excess heat from the london underground to help warm over 1,000 buildings in the city. Micro and miniature heat pipes have received considerable attention in the past decade. Heat pipes, 6th edition, takes a highly practical approach to the design and selection of heat pipes, making it an essential guide for practicing engineers and. Heat pipe design and technology modern applications for. Maximum temperature on the dissipative component the micro heat pipe discussed by ivanova et al. Nuscale develops new micro reactor designs in fresh smr push. Cotter 1984 was the first to propose the micro heat pipe concept for coo. The triangular grooves in the copper plate allow evaporation to take place, and the vapor to. Micro heat pipe device utilizing extended nanofluidics rsc. The micro nuscale power module design is more developed, than the heat pipe reactor and builds on the smr technology being deployed at the uamps project, mundy said. A liquid trap diode has a wicked reservoir located at the evaporator end of the diode heat pipe.
A novel micro flat aluminium heat pipe array mfahpa 9 provides a. This research deals with the optimum design of the heat pipe components using matlab program, version 7, at the determined operating conditions. It is expected to provide a basis for memsbased mhp design, performance. Heat pipes, 6th edition, takes a highly practical approach to the design and selection of heat pipes, making it an essential guide for practicing engineers and an ideal text for postgraduate students. There are several limits that govern heat pipe theory, however, in terrestrial applications the capillary limit is the most limiting factor. Sep 30, 2015 hung and seng studied the effects of geometric design on thermal performance of stargroove microheat pipes. This new edition has been revised to include new information on the underlying theory of heat pipes and heat transfer, and features fully updated applications, new data sections, and updated. The micro heat pipe structure, produced using the esl 41020 tape, is based on a grooved internal cavity, which ensures the process of cooling since it guarantees the evacuation of heat, by the use.
The heat pipe makes use of the phase change of the working fluid and transports a large amount of heat from the evaporator to the condensation end with very small temperature drops. A flexible micro heat pipe array, fabricated by sintering an array of aluminum wires between two thin um sheets, was developed as part of a program velop lightweight, flexible radiator. Since that time, numerous analytical and experimental investigations have been conducted to determine the fundamental parameters that govern the operation of these devices. A plate heat pipe design with micro rectangular groove guiting yang department of mechanical and electrical engineering, shaoyang polytechnic, shaoyang, 422000, china corresponding author. Many new capillary structures have been developed for micro heat pipes. Firstly, the development history of the mathematical models of the micro flat heat pipes is chronologically. The wicks in the heat pipe and reservoir are designed so th. International heat pipe conferences have been conducted, two books on heat pipes have been authored, and numerous papers have been. The capillary condensation efficiency and the liquid transport play two important roles in the cooling performance.
The heat pipe temperature reaches the water temperature in about 25 seconds, while the copper rod reaches just 30c after 200 seconds. Liquid flow and interface shapes in designing micro heat pipes. Thermal characterisation of micro flat aluminium heat pipe. Typically, micro heat pipes have convex but cusped cross sections e. A heat pipe is a heat transfer device that combines the principles of both thermal conductivity and phase transition to effectively transfer heat between two solid interfaces. Furukawas leading edge technology supplied over 1,000,000 micro heat pipe. During the last many years, the use of heat pipes to cool the electronic devices has been rapidly increasing. At the hot interface of a heat pipe, a liquid in contact with a thermally conductive solid surface turns into a vapor by absorbing heat from that surface. Besides, some innovative ideas and novel micro flat heat pipe designs for particular applications are also documented along with comparisons and discussion. Heat pipes for computer cooling applications intechopen. This article is intended to offer design guidance when using heat pipes for the most prevalent types of electronics applications. As with any heat pipe heat sink design, size the heat pipe with an additional 25% thermal headroom if youre interested in spreading heat to reduce hot spot andor attach to a local heat exchanger the ratio of heat spreader to heat source should be on the order of 20. The water temperature in the copper cold plate is fixed at 50c.
This chapter presents detailed accounts on variable conductance heat pipes, which have the ability to maintain a device mounted at the evaporator at a near constant temperature, independent of the amount of power being generated by the device. If you need more basic heat pipe information, please visit these two pages. The micro heat pipes excellent thermal performance accelerates the. Micro heat pipe cooled reactor power source hrp could be applied for space or underwater vehicles and it meets the future demands of them, safer structure, longer operating time, fewer mechanical moving parts than conventional power devices.
Thermal spreading resistances for different materials. Micro heat pipes ranging in size from 1 mm in diameter and 60 mm in length to 30 mum in diameter and 10 mm in length have been analyzed, modelled, and fabricated. A good description of the history of the heat pipe technology can be found in an early article published by yale eastman currently a director of act in scientific american in may 1968. By the high temperature heat pipes, the heat from the pile core is transferre d to the heat exchanger, the technology of high temperature thermal radiation is realized zhang et al, 2009.
As shown in figure 7, three different types of crosssectional shapes of microheat pipes such as square star 4 corners, hexagonal star 6 corners, and octagonal star 8 corners grooves with corner width w, were considered. Heat pipes are one of the most efficient ways to move thermal energy from one. The choice of pipe material, size, and coolant all have an effect on the optimal temperatures at which heat pipes work. When used outside of its design heat range, the heat pipes thermal conductivity is effectively reduced to the heat conduction properties of its solid metal casing alone. The vapor then travels along the heat pipe to the cold interface and condenses back into a liquid, releasing the latent heat. The kinh have the highest share 59 percent of people using hygienic toilet facilities flush toilet with septic tank or sewage pipes and the lowest share 5 percent of people without toilet.
Laboratory of advanced thermal management technologies, college of physics, university of chinese academy sciences, 19a yuquanlu road, shijingshan district, beijing 49, p. Michel, cooling of microprocessors with microevaporation. Design considerations when using heat pipes electronics. Recent developments in heat pipe technology and applications. Similar to memsbased microgrooved heat pipes, these novel memsbased mhps could be considered as small versions of corresponding conventional prototypes and work at the related mechanism. A heat pipe for electronics application was introduced to cool the cpu of personal desktop computers 4. The design of efficient micro heat pipes requires efficient heat transport capability. Micro heat pipes for cooling electronic devices were proposed in 83. Now at the computer age some changes of basic equations are performed, more powerful predicting methods are available with increasing awareness of the complexity of heat pipes and new heat pipe. Oct 01, 20 the book is a useful reference for those with experience and an accessible introduction for those approaching the topic for the first time. Contains all information required to design and manufacture a heat pipe suitable for use as a professional reference and graduate textrevised with greater coverage of key electronic cooling applications. Overall there is a 1 to2 heat pipe tofuel ratio throughout the core.
A plate heat pipe design with microrectangular groove. For the nuclear reactor cooled by the high temper ature heat pipes, the fuel bars and the high temperature heat pipes are designed to be co upled together. A micro heat pipe design by ivanova et al achieved 70 wcm2 of heat. Pdf micro flat heat pipes for microelectronics cooling. The focus of this heat pipe design guide is on sintered copper heat pipes wwater for electronics cooling applications. The interest stems from the possibility of achieving the extremely high heat fluxes near wcm 2, needed for future generation electronics cooling application. Ats engineering ebook advanced thermal solutions, inc. It is referred to as a laminar flow heat exchanger if the surface area density is above about 3000 m2m 3 914 ft2ft3, and as a micro heat exchanger if the surface area density is above about 10,000 m2m 3 3050 ft2ft3. Heat pipe design guide advanced cooling technologies. Heat pipes are an extremely effective method of reducing hot spot temperatures and increasing allowable power in a system by moving heat to an external sink or spreading heat along a surface.
This book provides a practical study of modern heat pipe engineering, discussing how it can be optimized for use on a wider scale. Heat pipes must be tuned to particular cooling conditions. This has created interest in the application of a novel nanofluidbased ac. Development of heat pipe reactor modeling in sam technical. Cotter defined it as a pipe so small that the mean curvature of the liquidvapor. The expanded author team consolidate and update the theoretical background included in previous editions, and include new sections on recent developments in.
Micro heat pipe phenomena available in the capillary porous structure, the. Your complete resource on heat pipe operation, behavior, performance characteristics, and limitations this book is designed to help students, operations engineers, and mechanical and electrical engineers in the electronic packaging industry grasp the principles of operation for a wide range of heat pipes. You go through all the formulas in the book and determine what the flow will be. So there are many lengthy books and articles on heat pipe theory and operation. This book introduces operational and design principles for heat pipes. Nuclear reactor 2 mw for remote operating bases and microgrids.
In this work steadyliquid flow and heat transfer in a micro heat pipe with. Analysis of the applicability of different grooved mhps show, that there are some advantages of this heat pipe design simple geometry of the micro channel, low cost of fabrication, using etching. Microelectromechanical systems memsbased microheat pipes, as a novel heat pipe technology, is considered as one of the most promising options for. Studies ebooks product brochures patents published articles technical papers. Acts expertise with heat pipe technology can find a thermal solution for. Each fuel pin in the core is adjacent to three heat pipes for efficiency and redundancy. At present, micro groove flat heat pipe has become the focus of study and development of heat pipe. Micro flat heat pipes for microelectronics cooling. Overview of micro heat pipe research and development. Types of heat pipes thermosyphon leading edge rotating and revolving cryogenic pumped loop heat pipe flat plate micro heat pipes variable conductance capillary pumped loop heat pipe 16. Design, working fluid, and experimental apparatus of the mfahpa. Many novel heat pipes have been developed over recent years. Nuclear reactor 2 mw for remote operating bases and. Theory, design and applications, seventh edition, takes a highly practical approach to the design and selection of heat pipes, making it an essential guide for practicing engineers and an ideal text for postgraduate students.
The heat pipe is used to transfer maximum available thermal energy to heat the feed water entering steam boiler. A novel threelayer silicon waferstacking fabrication process was employed to. A micro heat pipe is defined as a heat pipe in which the mean curvature of the liquidvapor interface is comparable in magnitude to the reciprocal of the hydraulic radius of the total flow channel. The concept of a micro heat pipe was first proposed in 1984. The future of electronic substrates by navdeep singh dhillon.
The key feature of the heat pipe reactors is the use of heat pipes for heat removal from the reactor core. Progress works of high and super high temperature heat pipes. Ats engineer greg is in the lab today to discuss the ways to attach heat pipes to an assembly and the processes needed for each option. Persistent malnutrition in ethnic minority communities of. Design considerations when using heat pipes electronics cooling. Liquid salt heat sink for emergencyshutdown cooling 9. The heat pipe is a device that utilizes evaporation heat transfer in the evaporator and condensation heat transfer in the condenser, in which the vapor flow from the evaporator to the condenser is caused by the vapor pressure difference and the liquid flow from the condenser to the evaporator is produced by capillary force, gravitational force, electrostatic force, or other forces directly. This book is designed to help students, operations engineers, and mechanical and electrical engineers in the electronic packaging industry grasp the principles of operation for a wide range of heat pipes.
A micro loop heat pipe or mlhp is a miniature loop heat pipe in which the radius of curvature of the liquid meniscus in the evaporator is in the same order of magnitude of the micro grooves dimensions. Apr 17, 2019 nuscale is developing the conceptual design for a 10 to 50 mw micro nuscale power module and a smaller 1 to 10 mw heat pipe reactor, tom mundy, chief commercial officer of nuscale power, told the conference in atlanta on april 2. Where heat pipe types have been omitted from the discussion in this chapter, but were present in earlier editions, some suggestions for further reading are retained in the bibliography section in the appendices. Electronics cooling, high heat flux, micro flat heat pipe, modeling, novel designs, wick structure. Heat pipe design guide thermal management solutions heat. The affecting parameters on heat pipe performance were detailed as well as the. Open type mini micro heat pipes are suggested in 4, 5, as a system of thermal control of. Nuscale develops new micro reactor designs in fresh smr. Micro and miniature heat pipes electronic component. Overview of micro heat pipe research and development journal. The actual test results of heat pipe with different wick structure athorizontal and vertical gravity assist orientations. In this paper, a 50kwe potassium heat pipe cooled reactor power source system is proposed. The perkins tube design closest to the present heat pipe was patented by jacob.
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