During heat pipe operation, heat enters the heat pipe at what is known as the evaporator. From the important results, the heat pipe heat transfer capability is directly proportional with each of the heat pipe bore, the wick cs area and the heat pipe effective length, and inversely with each of the capillary radius and the working fluid viscosity. 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. Heat pipe design guidance for heat sink integration. Figure 1 2 shows an example of such decrease for a common heat pipe employing a grooved wick. Below is a list of some of the material we have used. Heat transfer from the heat sink consists of radiation and convection from both the intrafin passages and the unshielded surfaces of two outer fins. Heat pipe performance dt vs inclination angles at various flatten thickness heat pipe tested. Design considerations when using heat pipes electronics cooling.
When the heat source is much smaller than the heat sink base, a flat heat pipe can be embedded in the base of the heat sink, or it can be attached to the base to spread the heat more uniformly on the base of the heat sink. The heat pipe is a thermal device which allows an efficient transport of thermal energy. The idea is to insert the fphp into the metallic box exactly like an electronic card. Heat pipes must be tuned to particular cooling conditions. Towards an optimal design of heat pipe equipped heat exchangers. The vapor then travels along the heat pipe to the cold interface. An introduction to operational and design principles, this book. Mathematical model for heat transfer limitations of heat pipe.
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 heat pipe is composed of a container lined with a wick that is filled with liquid near its saturation temperature. The fluid contained in the wick structure vaporizes and creates an internal pressure gradient. 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. The heat pipe flattening and or bending, ambient temperature as well as the orientation of the heat pipe will influence its performance. Traditionally, flat heat pipes have been used for this type of application. Hydronic system design manual dectra corporation march 20 6 c. These include increased surface area to volume ratio in order to maximize power density, as well as the ability to stack or layer the system with photovoltaic pv cells on both sides of the flat heat pipe to utilize available energy.
Welds which are located in positions where the metal tends to run out of the joint under the action of gravity are welded at lower currents 60180a. If you need more basic heat pipe information, please visit these two pages. For example, choice of the wick and case material eliminates many candidate working fluids often including water due to. Thanks to a stateoftheart, onsite testing process in its new heat pipe lab, ats ensures the reliability and expected thermal performance of. In cases where the amount of heat needed to be transported is too great for a single pipe, multiple pipes can be used in parallel and series to move more heat. For heat pipes the wick limit is usually the limiting factor, unless flattened. This book provides a practical study of modern heat pipe engineering, discussing how it can be optimized for use on a wider scale. Wakefield vette standard heat pipes wakefield vette part number description 121686 round heat pipe 4 x 70mm. Use features like bookmarks, note taking and highlighting while reading heat pipes. Two dimensional numerical modeling of a flat heat pipe. The design drawing of the two blocks are identical.
Heat pipe design and modeling advanced cooling technologies. Design and fabrication of a novel hybridstructure heat pipe for a. Jul 10, 2020 in this study, the development and testing of a new computational modeling and optimization tool are presented for the design of thin flat heat pipes. In this chapter, a cpu thermal design power tdp, cooling methods of electronic. Pdf investigation of a novel flat heat pipe researchgate. The characteristics of counterflow heat exchanger units, using heat pipes or twophase. Heat pipes have no moving parts and you are looking at 20 years mtbf operational. The manufacturing and testing of heat pipes needs care if long lives are to be achieved.
Flanges can be added on the outer surface for easy integration with instruments or radiators the flange is an integral part of the extrusion. Some of the options are counter sinks, offsets, card guides, embosses. This article is intended to offer design guidance when using heat pipes for the most prevalent types of electronics applications. As with any design process, many of the decisions that must be taken are interrelated and the process is iterative. Flat heat pipes vapor chambers work conceptually the same as round heat pipes. Flat finned flat tube heat exchangers, as shown in figure 5. Design, construction and analysis of a flat heat pipe defense. During the last many years, the use of heat pipes to cool the electronic devices has been rapidly increasing. Transient analysis of heat transfer and uid ow in a polymerbased micro flat heat pipe with hybrid wicks mehdi famouri a, gerardo carbajal b, chen li a, a department of mechanical engineering, university of south carolina, columbia, sc 29208, usa. New data on 3d printing of heat pipes are included. It would take twice as much 12 pex to do the same job. Temperature distribution in the condenser for flat front. There are mainly three types of heat pipes as shown in fig. As with any heat pipe heat sink design, size the heat pipe with an.
Theory, design and applications kindle edition by reay, david, mcglen, ryan, kew, peter. These include increased surface area to volume ratio in order to maximize power density, as well as the ability to stack or layer the system with photovoltaic pv cells on both sides of the flat heat pipe to. Once the correct heat pipe s have been identified the next step is integration into the heat sink. As with any heat pipe heat sink design, size the heat pipe with an additional 25%. Remote fin stacks heat exchangers are a perfect example. Heat pipe design and selection desiggyn considerations mostl y for vendors selecting heat pipes as part of thermal control system and modeling of heat pipes for thermal analysts some practical considerationssome practical considerations some examples of flight applications other types of heat pipes 2. Thermal characterisation of micro flat aluminium heat pipe. Three fin densities were tested along with a heat pipe with no fins. 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 recognition of the heat pipe as a reliable thermal device was initially due to the preliminary theoretical results and design tools that. A novel micro flat aluminium heat pipe array mfahpa 9 provides a.
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. In this project, heat pipes are explored for use in tpv energy conversion systems. Comparative study of heat pipes performances in different. The selection of the proper heat pipe cooling solution is dependent upon the developers specifications, design constraints and budget. A loop heat pipe with coherent pores integrated to the heat source is considered as a calculation model in this paperfig. Download it once and read it on your kindle device, pc, phones or tablets.
Temperature distribution in the condenser for flat front and di ff use. Mvk160 heat and mass transfer may 7, 2012, lund, sweden heat pipe, selection of working. Indeed, with these simple capillary structures, it is possible to calculate the shape of the liquidvapor. The presence of noncondensable gases inside the heat pipe increased the overall. A compendium of analytical solutions for practically every conceivable problem. Heat transfer from the heat sink consists of radiation and convection from both the intrafin passages and. A flat plate heat pipe with screen meshes for the cooling.
This study designs a batch process and a low thermal resistance for nhsp heat pipes, which comprises a flattened copper pipe shell, a sintered. However, care must be given when designing and manufacturing the heat pipe. Effective thermal conductivity of a heat pipe digikey. Mar 15, 2005 a novel flat heat pipe has been developed to assist in meeting the high thermal design requirements in high power microelectronics, power converting systems, laptop computers and spacecraft thermal control systems. This pressure gradient moves the vapor to the cooler region known as the condenser, where it transitions back to liquid. The model predictions of the steady and transient response of the vapour and wall temperature of the heat pipes were in good agreement with the experimental results. This book also includes detailed descriptions on how an oscillating heat pipe is fabricated, tested, and utilized. Investigation of a novel flat heat pipe journal of heat. The rack is used as a radiator to dissipate heat to the ambient air. Rules of thumb for an initial estimate of equipment size the following are approximate values that may be used to estimate the size of the primary wood. There are many heat pipe shapes in the market, but the most common are either round or lat. Dec 23, 2017 home pdf heating boilers design download free pdf books 12232017 11. When heat pipes are used to move heat vs spread heat this is a twostep process.
Information for heat treatment of various carbon steels can be found in the appendix. 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. Design considerations when using heat pipes electronics. However, the smaller form factor comes with a heat transfer capacity penalty. The several components making up a heat pipe are discussed from the manufacturing and assembly viewpoint, and ways of measuring performance and carrying out life tests are discussed. It has a slightly lower temperature and pressure rating than 12 pex, but it can be spaced as far apart as 16 on center and still heat a room insulated to modern stan dards r19 walls, r27 ceilings. This book is an essential resource and learning tool for senior undergraduate, graduate students, practicing engineers, researchers, and scientists working in the area of heat pipes. A heat pipe for electronics application was introduced to cool the cpu of personal desktop computers 4. A flat plate heat pipe with screen meshes for the cooling of. Pdf with its unique ability to transfer heat over large distances with minimal loss. The computational model is described in detail and includes parameters that define properties of the liquid wick, vapor core, and structural case. Comparison of round and flat heat pipes under different orientations.
Jan 01, 20 the heat pipe is a vaporliquid phasechange device that transfers heat from a hot reservoir to a cold reservoir using capillary forces generated by a wick or porous material and a working fluid. The focus of this heat pipe design guide is on sintered copper heat pipes wwater for electronics cooling applications. Cross section of a flat plate solar collector that uses. Round heat pipes will be available in lengths of 70600 mm and diameters of 410 mm, while flat heat pipes will be available in lengths of 70500 mm, widths of 4. Development and application of a thin flat heat pipe design.
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. A flat heat pipe offers many advantages over the conventional. Ats engineering ebook advanced thermal solutions, inc. Heat pipe design handbook nasa technical reports server. Heat pipes can be bent and flattened in order to move the heat where needed or to fit into smaller spaces, but these types of modifications impact the total heat that can be transported.
It is best to test flammable or heat sensitive materials before releasing a production part. Fluid engine oil sea water inlet temperature, c 65 20 outlet temperature, c 55 25 heat load, kw 117. Involve us during design stage to optimize cost and performance in component design. Double pipe heat exchanger consists of two concentric pipes as shown in figure 5. Transient analysis of heat transfer and fluid flow in a. C 0 5 10 15 20 25 30 35 4090 60 30 0 30 60 90 inclination angle deg dt evc d. The design of a heat pipe or thermosyphon to fulfil a particular duty involves four. Background s ome basic information about phase diagrams and timetemperaturetransformation ttt diagrams of steels is presented first as background material for the heat treatment part of this lab. A flat plate heat pipe offers many advantages over the conventional cylindrical design, such as increased surface area to volume ratio and the ability to stack or layer the energy conversion system on both sides of the flat heat pipe to utilize available energy. Consider a 2,000 square foot well insulated home with a design heat loss of 18,000 btuhr. Both experimental and analytical investigations were conducted to examine the maximum heat transport capacity and optimize the design. The perkins tube design closest to the present heat pipe was patented by jacob perkins 1836. However, here well just get into some of the basics to make you effective as a designer. Naturally, a heat pipe has a maximum heat transfer capacity when its cross section is round.
The following reference texts were used to prepare the notes. The choice of pipe material, size, and coolant all have an effect on the optimal temperatures at which heat pipes work. Floor to floor height is 3m water supply from city main is irregular and we have to rely on two well pumps for water. Typical application of transverse flat plate heat pipe. The term spray transfer is used to describe this type of operation. Heat pipes are passive, twophased heat transfer devices, using liquid to vapor phase transition to provide minimal temperature rise across their length.
Unit 571 new smyrna beach, fl 32128 386882ezce3923. Lots of theoretical works have been published on flat plate heat pipes with rectangular grooves or also on micro heat pipes arrays. Transient analysis of heat transfer and uid ow in a polymerbased micro flat heat pipe with hybrid wicks mehdi famouri a, gerardo carbajal b, chen li a, a department of mechanical engineering, university of south carolina, columbia, sc 29208, usa b department of mechanical engineering, universidad del turabo, p. Each flat consist of one master bedroom, three bedrooms, one living room, one dining room, one kitchen, maid room and six bathrooms. A flat heat pipe offers many advantages over the conventional cylindrical design. Temperature difference between the evaporator and the condenser in a heat pipe 2. Design, working fluid, and experimental apparatus of the mfahpa. Design a double pipe heat exchanger with bare inner multitubes that can be used to cool engine oil with cold sea water. Figure 7 shows a flat pipe design, they can be used as heat spreaders. 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. Chapter 4 presents a first step towards numerical simulation of the flow in a thermosyphon, to gain more understanding of the experimental results obtained in chapter 2 especially with respect to the operating limit in a single heat pipe. A feature of heat pipe design, which is important when considering small heat pipes. Precision ground flat 01 metric drill rod 01 a2 plate alloy steels 4140 h. So there are many lengthy books and articles on heat pipe theory and operation.
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