The simulation of a 2d single loop pulsating heat pipe using. The thesis titled thermal characteristics of an alumunum closedloop pulsating heat pipe charged with ammonia submitted by md shahidul haque, roll no. It has excellent features, such as high thermal performance, rapid response to high heat load, simple design and low cost 3. Paper open access design and operation of a cryogenic. The oscillating or pulsating heat pipe oph or php is a very promising heat transfer device. Adjacent liquid slugs are shown to merge in the vicinity of the condenser. The thermal and response time of the heat pipe with agdi water nanofluids decreased up to 30% and 20% respectively, compared to a heat pipe with di water. What is a heat pipe heat pipes basics and technology. Pulsating heat pipe, fill ratio, orientation, working fluids introduction. The pulsating heat pipe according to claim 2, wherein the tubes contain at least one porous insert with the azimuth and axial channels and heater. Pdf pulsating heat pipes php have created a newer arena and promising possibilities as passive devices for heat transfer applications. Modeling of pulsating heat pipes sandia national laboratories.
Heat transfer performance of a pulsating heat pipe charged. For any custom solutions contact our team of engineers today. Oscillating heat pipes offer elegant thermal management. In the present paper, the characteristics and working principles of the phps.
Peregrine successfully demonstrated the feasibility of embedding pulsating heat pipes within the plane of a sheet. Thermomhydrodynamics of closed loop pulsating heat pipes. Operational limit of closed loop pulsating heat pipes. 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. Startup heat load, maximum heat load and optimum fill ratio of pulsating heat pipe php of 16 turn, 1 mm id, 2 mm od and 9. Closed loop pulsating heat pipe php is a twophase passive heat transfer device proposed and patented by akachi 1990. Pdf cfd simulation of a pulsating heat pipe using ansys. An overview of the different types of heat pipes, including vapor chambers, variable conductance heat pipes, thermal diodes thermosyphons, and heat pipe heat exchanger. When heated, the vapor and liquid begin a varied pulsating flow that transfers heat more efficiently due to the. Groll c a college of environmental science and engineering, donghua university, shanghai 200051, pr china b mechanical engineering department, indian institute of technology kanpur, kanpur 208016, india c institute of nuclear technology and energy systems, university of stuttgart. Keywords pulsating heat pipe, heat pipe panel, sorption technology introduction. Indian institute of technology kanpur, kanpur up 208016 india. In this paper, a novel study on full visualization and startup performances of pulsating heat pipe using ammonia as working fluid are experimented. This functionality has been implemented combining a digital controller.
Pulsating heat pipes phps are used as high efficiency heat exchangers, and the selection of working fluids in phps has a great impact on the heat transfer performance. Nano fluid an alternative fluid in pulsating heat pipe. Sixty microchannel embedded pulsating heat pipes mephps of. The vapor then travels along the heat pipe to the cold.
Pictures relating to the experimental setups are shown in fig. It is a member of wickless heat pipes the oscillation of working fluid and phase change phenomina in capillary tube is basic principle. The tested pulsating heat pipe, consisting of 6 turns, is fully made of quartz glass tubes with 6 mm outer diameter and 2 mm inner diameter. Experimental analysis of solar water heater using pulsating heat pipe 1d. A php is a simple in structure with a small diameter coil partially filled with certain working fluid in it and extended from the heat source to sink. Heat inputs are supplied to the evaporator side of the pulsating heat pipe varied from 80 to 180 w. Testing was performed showing significant increases in thermal. The basic structure of a typical pulsating heat pipe consists of meandering capillary tubes having no internal wick structure, as shown in figure 1a. Analysis of pulsating heat pipe with capillary wick and varying channel diameter, int. A closed loop pulsating heat pipe php consists of a capillarysized tube or channel arranged in. Pdf pulsating or oscillating heat pipes php or ohp are new twophase heat transfer devices that rely on the oscillatory flow of liquid slug. It is made from a long continuous capillary tube bent into many turns, and it contains more working fluid. Introduction akachi proposed and patented pulsating or loop type heat pipein 1990s 1. Factor affecting closed loop pulsating heat pipe it can be seen that six major thermomechanical parameters have emerged as the primary design parameters affecting the php system dynamics.
Operational limit of closed loop pulsating heat pipes honghai yang a, s. Thermal performance of closed loop pulsating heat pipe. 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. Pulsating heat pipe php, or oscillating heat pipe ohp, a novel type of highly efficient heat transfer component, has been widely applied in many fields, such as in spaceborne twophase thermal control systems, in the cooling of electronic devices and in energysaving technology, etc. Ats engineering ebook advanced thermal solutions, inc. Experimental investigation of the thermal characteristics. Riehl characteristics of an open loop pulsating heat pipe. April 2009 has been accepted as satisfactory in partial fulfillment of the requirements for the degree of master of science in mechanical engineering on. Pulsating heat pipes, apparently simple and very promising cooling devices, are very intriguing for theoretical and experimental investigations alike. A pulsating heat pipe in action at indian institute of technology kanpur, india.
Oscillating heat pipes ohps use thermally driven, twophase fluid flow to rapidly transfer heat between heat sources and heat sinks. An introduction to pulsating heat pipes electronics cooling. The pulsating heat pipe according to claim 2, wherein at least some of the internal surface of the tubes of the branches in the heating section has rough coatings alternating with smooth parts. The pulsating heat pipe php, invented by akachi in 1990 4, has shown great promise to manage and transfer heat for microelectronic system cooling. Oscillating heat pipes ohp, also referred to as pulsating heat pipes php, are a relatively new development in the field of heat pipe technology. Heat pipes are referred to as the superconductors of heatdue to their fast transfer capability with. The result is less pumping of the wick with reduced heat transfer. Recent advances in electronics design and manufacturing have resulted in significant increases in heat flux density through a miniaturization of components and a. This study investigates the thermal resistance characteristics of the php charged with acetonebased binary mixtures, where deionized water, methanol and ethanol were added to and mixed with. The phpohp has a number of unique features as follows. It is different from the conventional heat pipe in design and working principle. Tech 2nd year thermal engineering, 2assistant professor, 1,2mechanical department, government college of engineering, amravati m.
Introduction as the advancement is taking place in all fields of engineering, especially in making components compact and efficient. The amount of heat transfer decrease depends on the particular heat pipe. In this experiment the performance of pulsating heat pipe using ethanol and distilled water is experimented. The experimental results demonstrate the heat transfer characteristics, lower thermal resistance and higher heat transfer coefficient of php are found to be better at a fill ratio of 60% for various heat input. A sorption panel system for cooling buildings was developed, working with an adsorptionrefrigeration unit, the evaporator of which is the panel itself. The closed loop pulsating heat pipe of inner diameter 2mm is filled with one of the fluid with a filling ratio of 50% and the variation of temperature is observed for every 2 minutes interval of time at 100 watts, 120 watts 1nd 140 watts. 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. 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. Culham microelectronics heat transfer laboratory department of mechanical engineering university of waterloo waterloo, ontario, canada, n2l 3g1 phone. We explore and scrutinize two possible configurations of pulsating heat pipe php based heat exchangers for process waste heat exchange as well as high heat flux. Includes an explanation for each heat pipe type, as well as examples.
Full visualization and startup performance of an ammonia. The experimental results proved that methanol serves as a better working fluid compared to acetone and ethanol with fill ratio of 60%. 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. Performance analysis of pulsating heat pipes using various.
How to make a heat pipe or solar heat collector duration. There are mainly two types of pulsating heat pipe, open loop and closed loop. Even the name is heat pipe,but working is very much different than the conventional heat pipes. Schematic of a typical pulsating heat pipe with design variations. Its the two phase heat transfer device suitable for low power applications such as electronic cooling. An introduction to pulsating heat pipes may 1, 2003 sameer khandekar heat pipes design, liquid cooling, number 2, php, pulsating heat pipe, volume 9 modern electronics thermal management faces considerable challenges in the wake of component miniaturization, which has led to higher demands on net heat flux dissipation. For various reasons a closed loop pulsating heat pipe clphp is thermally a better option than an open loop device. A typical php is a small and long meandering tube that is filled with liquid slugs and vapor plugs of a working fluid, and it allows phps to be potentially.
Schematics of the phps, dimensions and thermocouple locations for both types of the pulsating heat pipes are depicted in fig. Two closed loop pulsating heat pipes clphps are tested on board rexus 18. A loop heat pipe with coherent pores integrated to the heat source is considered as a calculation model in this paperfig. To make liquid and vapour plugs to exist diameter of tube must be small. Pulsating heat pipe, taylor bubble flow, oscillating and uniform contact line motion corresponding author. They are attractive heat transfer elements, which due to their simple design, cost effectiveness, and excellent thermal performance may find wide applications. Khandekar closed and open loop pulsating heat pipe. A pulsating heat pipe php 1 is a passive and extremely efficient way of exchanging heat between a hot source and a cold one. S, india abstractsolar energy is used for solar water heater in domestic and industrial purpose. A part of an expanding bubble breaks away from it and travels further to merge with another bubble. Smallsized pulsating heat pipesoscillating heat pipes with. In addition to its excellent heat transfer performance, it has a simple structure. The geometrical features of the module are given in the rocket manual. The inside diameter of the tube is sufficiently small critical bo.
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. An experimental investigation of micro pulsating heat pipes. Pdf advances and unsolved issues in pulsating heat pipes. To learn more about the ohp technology and how we innovate custom thermal solutions, click on a topic below. The graph also shows that if the heat pipe is operated against the force of gravity, the liquid undergoes a larger pressure drop. Nano fluid an alternative fluid in pulsating heat pipeoscillating heat pipe. Beginning with a definition of the problem, including the temperature. Presently such systems have found niche applications in micropower electronics cooling and the future prospects seem quite promising. The experimental investigation of thermal performance of. Kumaresan et al conducted a study to investigate the enhancement in heat transfer characteristics of a copper sintered wick heat pipe with surfactant free cuo. High speed flow visualization of a closed loop pulsating heat pipe, proceeding of the 11th international heat pipe conference, tokyo, japan, 1999, pp. Development of a large diameter pulsating heat pipe.
Parameters affecting the functioning of close loop. Introduction with the advances in minimicro fabrication techniques, many applications have emerged which utilize singlephase or twophase flows in such minimicro geometries to achieve specific goals. Multiple quasisteady states in a closed loop pulsating. 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. Journals pdf frontiers in heat pipes fhp effect of. One of which is the conventional php created only in a singleturn configuration fig. Experimental analysis on thermal performance ofclosed. Internal diameter of the php tube, input heat flux to the device. The principal of pulsating heat pipe proposed and presented by akachi h. This paper presents an experimental study of pulsating heat pipes php. These features are in vogue today and this elation has especially gripped the electronics and allied industries. Pulsating heat pipe php can be used for the cooling of power electronics such as the diodes, thyristors, power modules, igbts.
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