Mathematical model for heat transfer limitations of heat pipe. Numerical analysis of thermal performance of flat heat pipe d. A heat pipe is a passive device that enhances the transfer of heat from a region of higher temperature i. Simulation and optimization of pulsating heat pipe flat. Loop heat pipes lhps are very versatile heat transfer devices that have been used for thermal control of many commercial communications satellites and. This research study presents an investigation on the behavior of a pulsating heat pipe flatplate solar collector phpfpsc by artificial neural network method and an optimization of the parameters of the collector by genetic algorithm. Thermal resistance of heat pipe with nanofluid was found to be less. Review of solar, heat pipe and thermoelectric hybrid. Such a design step was intended to bring at least two other sides of a heat pipe into thermal contact with the module heat sink. Pulsating heat pipe, phase, passive, flow pattern corresponding author email. Nasa glenn steadystate heat pipe code users manual version 2, dos input leonard k. Thermomechanical design and characterization of flexible. What is a heat pipe heat pipes basics and technology.
A heat pipe is a metallic pipe that is sealed at both ends and is. It describes the variety of complex and coupled processes of heat and mass transfer in heat pipes. The vapor rises to the tip condenser of the heat pipe where. A novel analytical modeling of a loop heat pipe employing the. Design and technology of heat pipes for cooling and heat. This entry was posted in heat pipe and tagged advanced thermal solutions, air flow, ats, electronics cooling, engineering, heat pipe, heat transfer, loop heat pipes, thermal design, thermal management. 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. Numerical analysis of thermal performance of flat heat pipe.
The book consists of fourteen chapters, two appendices, and over 400 illustrations, along with numerous references and a wide. Tower national aeronautics and space administration glenn research center cleveland, ohio 445 abstract the heat pipe code lerchp has been revised, corrected, and extended. A solar heat pipe collector performs well at high temperatures. Modelling and performance of heat pipes with long evaporator. Qmax customer requirement then heat pipe is passed test frequency. In a second program, a heat pipe solar receiver was designed to accept, isothermalize and transfer the solar thermal energy to reactors for oxygen production from lunar regolith. A study on the heat transfer of nanofluids in pipes. When selecting the diameter and length of heat pipe it is important to consider the orientation with respect to gravity. Use of heat pipe cooling systems in the electronics industry. 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. Beginning with a definition of the problem, including the temperature.
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. How to model a heat pipe heat transfer and fluid flow. Experimental analysis on thermal performance ofclosed loop. 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. 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. Pulsating hea t pipes phps a few connected tubes or minichannels in the material, partiall y filled with liquid. Research paper thermomechanical design and characterization of.
The heat pipe was 5 mm in diameter and 150 mm long with a thermal capacity of 10 w. The present work aims at obtaining mass flow rate measurements in heat pipe wick structures under conditions that simulate the operation of a heat pipe, and builds on the work initiated by fields. Adiabatic temperature of heat pipe, measurement on heat pipe top side. 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. Journals pdf frontiers in heat pipes fhp effect of. A loop heat pipe with coherent pores integrated to the heat source is considered as a calculation model in this paperfig. In many engineering applications it is desirable to. I introduction gears are the most common means of transmitting power in the modern mechanical engineering world. Kamaraj b indian institute of technology madras, a refrigeration and airconditioning laboratory, department of mechanical engineering, b department of metallurgical and.
Computational model of miniature pulsating heat pipes. It emphasizes the physical aspects of heat pipe behavior and develops design formulas on the basis of mathematical models and empirical observation. Nam nguyen who developed the heat pipe fluid properties. Efficient heat transferefficient heat transfer boiling and condensationboiling and condensation small temperature difference between the heat source and. Computational modelling, heat transfer limitations, mathematical and mechanical and surface modifications. 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. Heat loss and temperature profile along an insulated pipe.
They can be implemented as heat exchangers inside sorption and vapourcompression heat pumps, refrigerators and other types of heat transfer devices. Evaporator temperature of heat pipe, measurement on heat pipe top side. 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. Design considerations when using heat pipes electronics. This method has been used in the aerospace industry for about thr ee decades for supporting systemlevel design analysis. Introduction closed loop pulsating heat pipe php is a twophase passive heat transfer device proposed and patented by akachi 1990. 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. Energy is an important part of most aspects of daily life. 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 loss and temperature profile along an insulated pipe simulated with mathematica 9 and floefd 11. 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 up the heating end of the heat pipe emperature 700c and dissipate 5 6. This book provides a practical study of modern heat pipe engineering, discussing how it can be optimized for use on a wider scale.
Heat exchanger, any of several devices that transfer heat from a hot to a cold fluid. Design and manufacturing of wickless heat pipe in this chapter, design and manufacturing of wickless heat pipe is discussed. Characteristics of heat transfer for heat pipe and its. Design calculation and heat transfer analysis of heat pipe.
Heat pipes are very effective and passive heat transfer devices. The widespread and fastpaced adoption of notebook computers in the home, workplace and ontheroad owes part of its success to space shuttle and space station technology. As heat is applied to the surface of the heat pipe, the working fluid is vaporized. Ats engineering ebook advanced thermal solutions, inc.
Pulsating heat pipe php cooling is the new and emerging technique in the field of thermal management of electronics. Heat pipes are great thermal energy transporters that use an evaporator and condenser in place of a solid conductor. As reported in chapter 2, modification in the crosssectional area of a heat pipe. Presents basic and advanced techniques in the analytical and numerical modeling of various heat pipe systems under a variety of operating conditions and limitations. The heat pipe is composed of a container lined with a wick that is filled with liquid near its saturation temperature. Pdf cfd analysis of pulsating heat pipe using different. In this paper a computer simulation was developed by matlab to design the heat pipe heat exchangers. The heat pipe transfers the heat to the manifold by a very simple method. 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 study of a nitrogen heat pipe by jay dudheker, 1932a thesis submitted to the faculty of the university of missourirolla in partial fulfillment of the requirements for the degree of master of science in mechanical engineering rolla, missouri 1971. In the present work, transient and steady state experiments are conducted on a single turn closed loop php. I am descended from 5,000 generations of toolusing primates. It has to therefore be leakproof, maintain the pressure differen tial across its walls, and enable transfer of heat to.
Understanding loop heat pipes advanced thermal solutions. A novel single loop pulsating heat pipe slphp filled at 60% filling ratio with pure ethanol, with an inner diameter of 2mm is tested in bottom heated mode varying the heating power. A heat pipe is simply a type of heat exchanger that is very simple in construction, easy and straight forward for use. Heat pipes are referred to as the superconductors of heatdue to their fast transfer capability with low heat loss. A study on the heat transfer of nanofluids in pipes koh kai liang peter dept. Heat pipe with nanofluid found to operate at higher heat loads.
New features include provisions for pipes with curvature and bends in g fields. Finally, the thermal model is used for the design of a 1 kw planar systemlevel elec tronics cooling infrastructure featuring six 1 m heat pipes in. Miniature loop heat pipe with multiple evaporators for. Introduction heat pipe is a capillary twophase heat transfer device. Thermoelectricity could be utilized for power generation and provide cooling and heating. Nasa glenn steadystate heat pipe code users manual. An experimental investigation of heat transfer performance of a heat pipe for dry condition and with three different liquids as acetone, methanol, and water having four fill ratios, for each liquid has been conducted in the present study. For a heat pipe to function properly, the net capillary pressure difference between evaporator heat source and condenser heat sink must be greater than the sum of all pressures losses occurring throughout the liquid and vapor flow paths.
The application of heat pipes should be considered when the thermal design is either conduction limited or when nonthermal goals such as weight cannot be achieved with other materials such as solid aluminum andor copper. Heat and mass transport in heat pipe wick structures. Improvements have been done over time in heat pipes used for heat transfer. Heat pipes and two phase thermosyphons are heat transfer devices whose operating principles are based on the evaporationcondensation of a. Modeling of the heat pipe heat exchangers for heat recovery. Design and technology of heat pipes for cooling and heat exchange crc press book this book describes the characteristics of heat pipes under steadystate and transient operating conditions. Originally developed and patented by hisateru akachi in 1990, ohps consist of a long meandering tube which is heated and cooled at various points along its length. Flanges can be added on the outer surface for easy integration with instruments or radiators the flange is an integral part of the extrusion. This program can be considered as a simple tool for modeling and designing heat pipe heat exchangers. Ideal when heat needs to be moved more than 3050mm 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. This work deals with cfd analysis on the performance of pulsating heat pipe with 560 mm length and 1. Solar energy is a renewable energy heat source freely and widely available everywhere throughout the year. 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 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.
Transports heat from a heat source to a heat sink works as an isothermalizer why twophase thermal system. The heat pipe temperature reaches the water temperature in about 25 seconds, while the copper rod reaches just 30c after 200 seconds. Oscillating heat pipes ohp, also referred to as pulsating heat pipes php, are a relatively new development in the field of heat pipe technology. A model to analyse the heat transfer of nanofluids was. Heat pipes are very stretchy systems with regard to the effective thermal control. In this study, several experiments were performed to study the effects of various evaporator lengths, filling ratios, inclination angles, solar radiation, and. Contact our experienced engineering team to learn how to recover and save energy with heat pipe technology. A php is a simple in structure with a small diameter coil partially filled with. The copper heat pipe is hollow and contains a small amount of working fluid. Condenser temperature, sensor is embedded between hp and condenser section of heat pipe. Heat pipes for high temperature thermal management advanced. Typically, a heat pipe employs a working fluid confined within a sealed channelcompartment, in which the. A loop heat pipe lhp shares with conventional heat pipes fundamental physics including phase change of a working fluid and capillary force.
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