Double pipe heat exchanger posted in chemical process simulation. To reduce the temperature of a hot fluid by means of a cooler fluid 3. The theories of transient heat transfer in doublepipe heat exchangers were explained and followed by literature correlations. At the hot side, the working fluid is evaporated and at the cool side it condensates again. In this chapter we will examine the basic theory of heat exchangers.
Heat exchangers 73 individual thermal resistances of the system. An exact solution of the inverse problem in heat conduction. R sekulib university of kentucky introduction a heat exchanger is a device that is used for transfer of thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a. Explore heat pipe with free download of seminar report and ppt in pdf and doc format. Hi, i need to simulate a double pipe hx with hysys. 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 pipes are highly efficient conductors of heat and can transport, in some cases, s times better than a solid copper conductor. This section covers the fundamental theory behind the heat pipe based on different research papers and books available at present time in order to open a clear path for reader to design and fabricate their required heat pipe within their applications. This new edition has been revised to include new information on the underlying. A heat pipe is a two phase heat transfer device with a very high effective thermal conductivity. A heat pipe heat exchanger is a simple device which ismade use of to transfer heat from one location to another,using an evaporationcondensation cycle. Heat pipe theory and practice, mcgrawhill, new york. A procedure for use of the equipment and the software was outlined. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.
Apr 29, 2016 this section covers the fundamental theory behind the heat pipe based on different research papers and books available at present time in order to open a clear path for reader to design and fabricate their required heat pipe within their applications. Standard heat pipe problem statement selection of working. 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. 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. 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. Through the application of thin film evaporation theory and the fundamental operating principles of heat pipes, a hybrid axial groove has been developed that can greatly enhance the performance characteristics of conventional heat pipes. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants. Kaya and goldak 5 reported the boiling limit of loop heat pipe obtained.
A heat exchanger is a component that allows the transfer of heat from one fluid liquid or gas to another fluid. When selecting the diameter and length of heat pipe it is important to consider the orientation with respect to gravity. Custom heat pipe designs act advanced cooling technologies. Jun 18, 20 a heat pipe heat exchanger is a simple device which ismade use of to transfer heat from one location to another,using an evaporationcondensation cycle. With the use5 of the space shuttle, flight testing of prototype heat pipe designs continued at a much larger scale. The transport idea will be explained in the next chapter. Heat transfer and flow analysis in loop heat pipe with. In this section we will briefly describe the basic working principle and the performance limits of heat pipes. The vapor pressure decreases as it flows from the evaporator to the condenser. Thermodynamics, heat transfer, and fluid flow volume 2 of 3 u. From heat pipe to loop heat pipefrom heat pipe to loop heat pipe and capillary pumped loop. Working fluids, wick configurations, reservoirs, and pipe materials are dealt with, and cleaning, assembly, evacuation, charging, and closure of hp are covered. The operating principles of heat pipes hp are expounded, along with a discussion of different types of hp, and the underlying theory, design, and fabrication of hp.
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. 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. Text headings in each module are linked to and f\ rom the table of contents for that module. To heat a cooler fluid by means of a hotter fluid 2. Haringx 10 modeled the bellow as the combination of annular plates connected by elastic cylinders and derived. 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. I tried with the shell and tube hx but this is not what i have to simulate.
A heat pipe is a heattransfer 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. Melted rocks and other more volatile planetary materials are transferred from the mantle to surface via. 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 pipe engineering ebook advanced thermal solutions. The liquid pressure decreases as it flows from the condenser to the evaporator. A procedures manual was created for the double pipe heat exchanger.
The basic idea of heat pipes is based on an evaporation and condensation process. A heat pipe is a selfcontained structure which achieves very high thermal conductance by means of twophase fluid flow with capillary circulation. This method has been used in the aerospace industry for about thr ee decades for supporting systemlevel design analysis. I just need a simple model, that is to said a tube inside the other. When the evaporator section le is exposed to a heat source, the liquid inside vaporizes and the pressure in that section increases. There are several limits that govern heat pipe theory, however in terrestrial applications the capillary limit is the most limiting factor.
Open, partially submerged, sintered copper wicks of varying pore size are studied. 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. Heat transfer in a buried pipe university of reading. Performance of heat pipe for different working fluids and fill ratios journal of mechanical engineering, vol. Among layman, the reason for steels dominance is usually considered to be the abundance of iron ore iron is the principal ingredient in all steels andor the ease by which it can be re. The vapor then travels along the heat pipe to the cold interface.
Heat pipes are one of the most effective procedures to. A loop heat pipe with coherent pores integrated to the heat source is considered as a calculation model in this paperfig. Heatpipe tectonics is a cooling mode of terrestrial planets in which the main heat transport mechanism in the planet is volcanism through the outer hard shell, also called the lithosphere. 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. The vacuum pump model doap707aa and 18 hp is used for evacuating the heat pipe. Heatpipe tectonics initiates when volcanism becomes the dominant surface heat transfer process. Evaporative heat transfer analysis of a heat pipe with hybrid axial groove. Assessment of the costs, performance, and characteristics. Ats engineering ebook advanced thermal solutions, inc. The modules listed in the overview are linked to the corresponding pages.
It is a vacuum tight device consisting of an envelope, a working fluid, and a wick structure. The liquid refrigerant in the tubes boils off to a vapor removing heat from the water and conveying the heat to the compressor and then to the condenser. Introduction heat pipe is a capillary twophase heat transfer device. The theories of transient heat transfer in double pipe heat exchangers were explained and followed by literature correlations. Selecting heat pipes as part of thermal control system and. Heat pipes are referred to as the superconductors of heatdue to their fast transfer capability with low heat loss. Heat pipes a novel cooling principle for generator circuit. Heat pipes a novel cooling principle for generator.
Evaporative heat transfer analysis of a heat pipe with hybrid. This portable document format \ pdf \ file contains bookmarks, thumbnails, and hyperlinks to help you navigate through the document. Fundamentals of the heat treating of steel 11 steel, however, is by far the most widely used alloy and for averygood reason. In theory they can be used to construct hypothetical heat networks based.
Pdf the heat pipe is one of the remarkable achievements of thermal physics and heat transfer engineering in this century because of its. Heat pipes do not actually dissipate the heat to the environment, but serve to move heat efficiently within a thermal system. 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. An inverse problem in unsteady heat conduction is one for which boundary conditions are prescribed internally, the surface conditions being unknown. The basic heat pipe is a closed container whfch contains a capillary wick structure. Polasek stated that for the successful operation of an oscillating heat pipe, liquid plugs and vapor bubbles must coexist inside the capillary tube along its length. A rule of thumb for the effective thermal conductivity of a heat pipe is 4000 wmk. Transports heat from a heat source to a heat sink works as an isothermalizer why twophase thermal system. Various works on the heat transfer performance of loop heat pipes have been reported. Hence, other than thermal design of the heat pipe, mechanical design of the.
The total heat load a heat pipe can carry is a function of total length, evaporator and condenser length, diameter, and orientation with respect to gravity. Journals pdf frontiers in heat pipes fhp effect of. While there are many types of heat pipes, a grounding in the basic theory of the operation of wicked heat pipes is highly desirable. Assessment of the costs, performance, and characteristics of uk heat networks final report. 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. Double pipe heat exchanger chemical process simulation. At any cross section of the heat pipe, a pressure differential exists between the vapor and liquid phases. 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. For proper heat pipe operation, the total pressure drop must not exceed its capillary pressure head. Furthermore, even if the size, shape, temperature and materials of a heat pipe are specified, the mass, vapor volume fraction, thermal conductance and maximum heat flux are individually through not independently under the control of the designer. A heat exchanger is a device that is used to transfer thermal energy enthalpy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. 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. Loop heat pipe with multiple evaporators has the advantage of design flexibility for the cooling systems of many heating devices and it has been used for spacecraft applications 3, 4. The basic idea behind a heat pipe is the circular process shown.
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. For the convenience of the users of the present theory, complete listings of two computer programs for high and lowtemperature heat pipes respectively are. Heat pipes and its applications lunds tekniska hogskola. Thermal conductivity of the heat pipe according to the circuitbreaker standards the maximum acceptable temperature rise at the main contacts is 65 k. Beginning with a definition of the problem, including the temperature. Thermomechanical design and characterization of flexible. There are many types of heat exchangers applied in the process industry. Subscripts h and c refer to the hot and cold fluids, respectively, and subscripts i and o refer to the inlet and outlet of the heat exchanger, respectively. A heat exchanger is a device used to transfer heat between a solid object and a fluid, or between two or more fluids. Remote fin stacks heat exchangers are a perfect example 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.
Unit operations lab heat exchanger 12 theory notes 1. Efficient heat transferefficient heat transfer boiling and condensationboiling and condensation small temperature difference between the heat source and. Heat exchangers are devices used to transfer heat between two or more. Heat pipe theory and practice 1976 edition open library. As shown in figure 1, the heat input vaporizes the liquid working fluid inside the wick in the evaporator section. Heat pipe design handbook, volume 1 internet archive. Heat transfer in curved pipes christian carlsson may 2014 1 introduction heat transfer in pipes has important applications in many areas, such as for e. Design, analysis and testing, warrendale, pa, sae paper no. Heat pipes are even cooling satellites electronics in zero gravity orbit.
Pdf basic principles of heat pipes and history researchgate. In heat pipe tectonics, volcanism is the major heat transport mechanism in which melts of rock are transferred to the surface by localised vents. Heat exchanger and its types engineering solutions. Heat pipe is a capillary twophase heat transfer device. This formulation leads to some unphysical heat transfer properties at the surface when both pipe and surface boundary temperatures are constant. Monogroove heat pipe radiator shuttle flight experiment. The interior of the pipe is covered with a wick, and the pipe is partially filled with a liquid such as water.
The evaporator is a heat exchanger that allows heat from the chwr to flow by conduction into the refrigerant tubes. Combining each of these resistances in series gives. How to model a heat pipe a brief explanation is provided of a networkbased method that is suitable for modeling constant conductance heat pipes cchps, also called fixed conductance heat pipes or fchps and vapor chamber fins. This book provides a practical study of modern heat pipe engineering, discussing how it can be optimized for use on a wider scale.
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