Wick structure problem description a heat pipe with minimum heat transport of 25 w is going to be used for cooling electronic components. Heat pipes are highly efficient conductors of heat and can transport, in some cases, s times better than a solid copper conductor. 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. Thermomechanical design and characterization of flexible. 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. The working principle, the fluid flow and heat transfer mechanism are similar in any heat pipe irrespective of the shape. It is a twophase heat transfer device that utilizes the evaporation and condensation of a working fluid to transfer heat, and the capillary forces developed in fine porous wicks to circulate the fluid. Furnaces and refractories fusion dust and slag or by the action of alkalies on fireclay refractories, to form alkalialumina silicates. This section introduces furnaces and refractories and explains the various design and operation aspects.
The most important heat pipe design consideration is the amount of power theheat pipe is capable of transferring. Heat pipe 1piece vapor chamber 2piece vapor chamber 20 heat pipes bend radius 3x diameter of heat pipe. A heat exchanger involves two flowing fluids separated by a solid wall. Since then, heat pipes have been used in such diverse applications as laptop computers, spacecraft, plastic injection molders, medical devices, and lighting systems. Advanced cooling technologies yale eastman currently a director of act, a few years later describes the theory and history of the heat pipe technology in an article published in scientific american, may 1968. Heat exchangers are used in both cooling and heating processes. The heat pipe is a highperformance heat transfer device, able to transfer heat at high rates, over considerable distances, with almost no temperature drop. The history and origins of modern heat pipe technology. A rule of thumb for the effective thermal conductivity of a heat pipe is 4000 wmk.
Amir faghri written to cover simple, intermediate, and advanced approaches to the theoretical and experimental analysis of heat pipes, this second edition emphasizes the physics and mathematics of heat pipes as well as the related technological and experimental issues. Heat pipes hardware m t l l i t b ith th i fmetal aluminum tube with grooves on the inner surface cold t ild extrusion grooves are filled with the working fluid water, ammonia, propylene, etc. The vapor then travels along the heat pipe to the cold. In the short heat pipe extreme 34 length, this effect is nearly zero, so please consult with wakefieldvette engineers to find the right solution for your application.
Determination of surface convective heat transfer coefficients by cfd adam neale1 dominique derome1, bert blocken2 and jan carmeliet2,3 1 building envelope performance laboratory, dep. Also heat pipe experiments were conducted aboard the applications technology satellite6, in which an ammonia heat pipe with a spiral artery wick was used as a thermal diode. Heat pipes employ phase change to transfer thermal energy from one point to another by the vaporization and condensation of a working fluid or coolant. A heat pipe or heatpipe is a heat transfer mechanism that can transport large quantities of heat with a very small difference in temperature between the hotter and colder interfaces. Heat pipe design handbook, volume 1 internet archive. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.
If a heat pipe length is less than 150 mm, at 40c it passes. Haringx 10 modeled the bellow as the combination of annular plates connected by elastic cylinders and derived. A furnace is an equipment used to melt metals for casting or to heat materials to change their shape e. Flanges can be added on the outer surface for easy integration with instruments or radiators the flange is an integral part of the extrusion. History of heat pipe technology the history of the heat pipe can be traced back to angier march am perkins 1 who in 1831 took out a patent on a hermetic boiler tube. With the use5 of the space shuttle, flight testing of prototype heat pipe designs continued at a much larger scale. Heat pipe is a capillary twophase heat transfer device. If a heat pipe length is larger than 150 mm, at 5 oc it passes. Recent experimental study on the fundamental aspects of the dowtherma heat. Qmax customer requirement then heat pipe is passed test frequency. Heat pipe is one of the most efficient tools for heat dissipation in electronics and power systems. The loop heat pipe lhp was invented in russia in the early 1980s. 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 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. Heat pipes can be designed to carry a fewwatts or several kilowatts, depending on the application.
The micro heat pipe offers increased downsizing and improved performance for all electronic devices. Since then, heat pipe technology has progressed from cooling vacuum tubes to being applied on the cpu chip of modern lap top computers. In its basic form, the heat pipe consists of a sealed tube, lined. Transports heat from a heat source to a heat sink works as an isothermalizer why twophase thermal system. Furnaces and refractories break free from excessive. The heat pipe temperature reaches the water temperature in about 25 seconds, while the copper rod reaches just 30c after 200 seconds. These tubes are enclosed in a shell with provisions for the other fluid to flow through the spaces between the tubes.
Effective thermal conductivity of copperwater groove in the calculation of a heat pipe thermal resistance or effective thermal conductivity, one needs to calculate the effective thermal conductivity of the wick fluid combination. It utilizes a bundle of tubes through which one of the fluids flows. Nov 25, 2016 heat pipe science and technology, second edition by dr. Heat pipe design and technology modern applications for. Combining each of these resistances in series gives. The manifold header pipe is mounted within the manifold casing and is made of 28mm diameter, 1 mm thick copper pipe rated for a maximum pressure of 10 kgcm2, the standard operational maximum being 6kgcm2. Two pipe originated 50 or 60 years ago as a costeffective way to add air conditioning. Although gaugler patented a very lightweight heat transfer device. The original idea of heat pipe was considered in 1944 by gaugler 1 and in 1962 by trefethen 2. Currently, a popular application to use heat pipes is cooling intels pentium processors in notebook computers. The most common type of heat exchanger is the shellandtube type illustrated in figure 2. Heat pipes are used in many applications all from cooling of the cpu in a computer, space application, energy storage for some solar thermal applications, air conditions etc.
Traditionally, heat pipes are cylindrical in shape. Currently, heat pipes are usually made of copper, aluminum or stainless steel. Hence, other than thermal design of the heat pipe, mechanical design of the. Determination of convective heat transfer coefficients for.
Loop heat pipe with coherent porous wick since the porous material used for current heat pipes is usually stochastic structure, it is hard to apply analytical or numerical methods for design optimization. An environment capable of absorbing heat from an object with which it is in thermal contact without a phase change or an appreciable change in. It is a common practice to include a slight excess of working fluid over and above that required to saturate 147. Heat pipe science and technology 1995 edition open library. Heat pipes are even cooling satellites electronics in zero gravity orbit. Heatpipe article about heatpipe by the free dictionary. Furnaces and refractories break free from excessive melting. Heat up the heating end of the heat pipe emperature 700c and dissipate 5 6.
Hence, majority of the investigations are done in the area of circular heat pipe. Advection, referring to the transfer of mass and heat, occurs when a moving fluid carries substances or heat to or away from a source and through a surrounding solid along channels. In heat pipe tectonics, volcanism is the major heat transport mechanism in which melts of rock are transferred to the surface by localised vents. The history and origins of modern heat pipe technologya heat pipe heat exchanger is a straightforward device which is utilized to move heat fromone place to another, using an evaporationcondensation cycle. The principle of the heat pipe is an amazingly sim ple one.
Heat pipe science and technology, an international journal is encompassed on publishing i fundamental studies of heat and mass transfer in heat pipes and twophase thermosyphons, ii new streams of technology development, iii industrial innovation in electronic thermal control, air conditioning, heating and cooling, aerospace thermal control. Tepelna trubice anglicky heatpipe, nebo heat pipe dokaze prenaset velke tepelne vykony pri zachovani maleho rozdilu teplot. The tubes and pipe dimensions are according to steel pipe dimensions aisi schedule 40. 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. Project description by means of knowledge about the theory of heat pipes, one is now able to carry out a basic calculation of a heat pipe. Heat exchangers 73 individual thermal resistances of the system. Research paper thermomechanical design and characterization of. In this article we look at some common wick structures used in heat pipe construction. Dec 15, 2012 the history and origins of modern heat pipe technology 1.
Speciality pipe and tube for boiler and petrochemical plant 0810r04031 jtr printed in japan notice while every effort has been made to ensure the accuracy of the information contained within this publication, the use of the information is at. A loop heat pipe with coherent pores integrated to the heat source is considered as a calculation model in this paperfig. Search the history of over 431 billion web pages on the internet. The gas goes through various cleanup and pipe delivery processes to get to our stoves. As with any design process, many of the decisions that must be taken are interrelated and the process is iterative. Aug 14, 2015 heat pipes are a type of cooling with a large heat flux transport capability. The history of the heat pipe can be traced back to angier march am perkins 1 who in 1831 took out a patent on a hermetic boiler tube. D o l and u is the overall heat transfer coefficient. When selecting the diameter and length of heat pipe it is important to consider the orientation with respect to gravity. Heat is transferred from the hot fluid to the wall by convection, through the wall by conduction and from the wall to the cold fluid by convection. Heat pipe definition of heat pipe by the free dictionary. Basic principles of heat pipes and history springerlink. In most designs of this type, the free fluid flows roughly. Allows direct contact with heat source 1piece vapor chamber 10mm bend radius along.
They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum. Grovers suggestion was taken up by nasa, which played a large role in heat pipe. A heat exchanger is a system used to transfer heat between two or more fluids. Heat pipes rely on a temperature difference between the ends of the pipe, and cannot lower temperatures at either end below the ambient temperature hence they tend to equalize the temperature within the pipe. The maximum thermal load was 1 kw and the operating temperature of the heat pipe was around 250 the liquid fill charge was adjusted so that the first condenser section may work as an evaporator when the original evaporator was inactive in a vertical configuration. A 2 pipe hvac system is one that uses the same piping alternately for hot water heating and chilled water cooling, as opposed to a 4 pipe system that uses separate lines for hot and chilled water. 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.
Pipes of this type are used in a wide range of machinery and appliances, including air conditioning equipment and any type of machines that involve the use of heat exchangers. They concluded that the start up behavior of a liquid metal heat pipe. Heat pipes do not actually dissipate the heat to the environment, but serve to move heat efficiently within a thermal system. Therefore, it is meaningful to investigate the performance characteristics of a dowtherma heat pipe for various configurations and operating conditions. Heat pipe article about heat pipe by the free dictionary.
A heat pipe is a copper tube with an internal wick structure that is sealed on both ends with a small amount of water inside. A variety of highintensity heat transfer processes are involved with combustion and chemical reaction in the gasi. Beginning with a definition of the problem, including the temperature. Heat pipes cantransfer much higher powers for a given temperature gradient than even the bestmetallic conductors. This book provides a practical study of modern heat pipe engineering, discussing how it can be optimized for use on a wider scale. What is a heat pipe heat pipes basics and technology. Ats engineering ebook advanced thermal solutions, inc. Explore heat pipe with free download of seminar report and ppt in pdf and doc format. Efficient heat transferefficient heat transfer boiling and condensationboiling and condensation small temperature difference between the heat source and. For example, choice of the wick and case material eliminates many candidate working fluids often including water due to compatibility constraints. Any material expands when heat ed, and contracts when cooled.
Also explore the seminar topics paper on heat pipe with abstract or synopsis, documentation on advantages and disadvantages, base paper presentation slides for ieee final year mechanical engineering me or production automobile students for the year 2019 2020. They concluded that the start up behavior of a liquid metal heat pipe from the. The history and origins of modern heat pipe technology 1. Heat pipes consist of an evaporator, an adiabatic section, and a condenser section. The heat pipe is made of stainless steel, and the working fluid used was sodium. The lhp was first developed in the former soviet union in the early 1980s 1, about the same time that the capillary. The history and origins of modern heat pipe technologya heat pipe heat exchanger is a straightforward device which is utilized to move heat fromone place to another, using an. 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 drastically reduced due to the extra thermal resistances added by the bonding. As heat is generated, the pressure also helps to move the heat through the structure of the pipe, ultimately delivering that heat to a point of destination. The fouling factors are to be taken according to tema standards. The effective heat conductivity of a heat pipethe ratio of the density of the heat flow through the pipe to the drop in temperature per unit of length of pipeis tens of thousands of times greater than the conductivity of copper, silver, or aluminum and can reach 10 7 watts per meter per degree kelvin. Heat exchanger design exampled standards to be used. Before studying the details of how a heat pipe functions, it might be best to understand the history of heat pipes and the progress of heat pipe technology.
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