Novel hybrid heat pipe for space and ground applications industry demand for high heat transfer capability, efficient thermal control, flexibility and low cost has motivated our researchers to develop a new generation of passive systems mainly based on fluid phasechange. During heat pipe operation, working fluid is vaporized in the evaporator, and then condensed in the condenser, transferring heat the first step in selecting a heat pipe working fluid and envelopewick material is to determine the. One solution to remove excess heat is by utilization of heat pipes which are employed to remove the excess heat by directly attaching them to the heat source. Pulsating heat pipes are a type of system that shows great promise since it is a twophase flow passive transportation system that can, depending on the number of loops, work regardless of the orientation. Pdf embedded pulsating heat pipe radiators semantic scholar. Pulsating heat pipes, like conventional heat pipes, are closed, twophase systems capable of transporting heat without any additional power input, but they differ from conventional heat pipes in several major ways. This type of heat pipes can be used in renewable energy systems, cooling electronic devices, heat recovery systems and many other applications. Due to essential applications of pulsating heat pipes in several areas of industry, study of its mechanism, behavior and performance is crucial.
Pulsating heat pipes consist of a small diameter tube capillary tube with several bends as shown in fig. Close loop pulsating heat pipe the energy behavior of the system was characterized by high instantaneous efficiencies up to 60%. Experimental analysis on thermal performance ofclosed loop. Design and operation of a teslatype valve for pulsating heat pipes. Experimental study of flow patterns and improved configurations for. The principal of pulsating heat pipe proposed and presented by akachi h. In order to improve the thermal performance of heat pipes, nanofluids have been proposed as working fluids in. Pulsating heat pipes phps are compact cooling equipment used for various applications. Novel hybrid heat pipe for space and ground applications. In addition, there are now many new commercial applications that have helped contribute to the recent interest in heat pipes, especially related to the fields of electronic cooling and energy. Pdf advances and unsolved issues in pulsating heat pipes.
The simulation of a 2d single loop pulsating heat pipe using. Pdf experimental investigation of closed loop pulsating. Martinez prepared by sandia national laboratories albuquerque, new mexico 87185 and livermore, california 94550 sandia is a multiprogram laboratory operated by sandia corporation, a lockheed martin company, for the united states department of energys. Aug 15, 2014 the experimental result on the thermal performance of closed loop pulsating heat pipe clphp is presented. Computational model of miniature pulsating heat pipes r. Peregrine successfully demonstrated the feasibility of embedding pulsating heat pipes within the plane of a sheet. 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. The fundamentals of working of the micro pulsating heat pipes mphp are explained. The oscillating or pulsating heat pipe php is another promising heat transfer device for applications like electronic cabinet cooling.
Effect of pure and binary fluids on closed loop pulsating heat pipe. Operational limit of closed loop pulsating heat pipes. Testing was performed showing significant increases in thermal conductivity. To learn more about the ohp technology and how we innovate custom thermal solutions, click on a topic below. Pulsating or oscillating heat pipes php or ohp are new twophase heat transfer devices that rely on the oscillatory flow of liquid slug and vapor plug in a long miniature tube bent into many turns. Three typical types of pulsating heat pipes, denoted as phps later, are commonly employed including the openloop, closedloop, and closedloop with check valve phps 10. To make liquid and vapour plugs to exist diameter of tube must be small. Review of unsolved matter related to pulsating heat pipes prafull v shahare1 and k k jain1 corresponding author. High performance ultra thin heat pipe cooling module for. An experimental study on pulsating heat pipe php is presented in this work. Each of these processes has proven feasibility and used together can readily produce mephps. Thermal performance of closed loop pulsating heat pipe using. 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. 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.
Pulsating heat pipes are preferable for thermal control in different space applications due to its high thermal performance. Pdf on jan 1, 2019, viacheslav cheverda and others published water pulsating heat pipe find, read and cite all the research you need on. Experimental analysis on thermal performance ofclosed. Pulsating hpp are potentially cheaper than conventional wicked heat pipe panels.
To visualize the operational mechanism dielectric working fluids novectm 649 and novectm 774 were used. The purpose of the project was to study the behaviour of a wickless pulsating heat pipe system in microgravity conditions. Jul 22, 2019 this paper describes the experimental investigations conducted on a closed loop pulsating heat pipe clphp for assessing the thermal performance. Sixty microchannel embedded pulsating heat pipes mephps of. These tubes are evacuated and partially filled with the working fluid. Heat pipe can be differentiate on the basis of wick structure as wick heat pipe and wickless heat pipes,in wickless category there are thermosyphon and pulsating heat pipes. Pulsating heat pipe pulsating heat pipe has many numbers of uturns of tube with capillary diameter. They are attractive heat transfer elements, which due to their simple design, cost effectiveness, and excellent thermal performance may find wide applications.
V minsk international seminar heat pipes, heat pumps, refrigerators minsk, belarus, september 811, 2003 on the definition of pulsating heat pipes. The inside diameter of the tube is sufficiently small critical bo. Pulsating hpp are convenient with the low pressure working fluids like water, alcohol and some hydrocarbons. Phps consist of a tube bent to form several parallel channels. Its the two phase heat transfer device suitable for low power applications such as electronic cooling. Ohps have superior performance compared to traditional heat pipes and can be used to solve the future electronic cooling problems. This cooling module consists of an ultrathin heat pipe and a metal plate. A closed loop php with a single u turn is fabricated and tested. Conclusions pulsating heat pipe panels hpp were tested to be sure they are useful for the electronic components cooling and sorption machines thermal control. A closed loop pulsating heat pipe php consists of a capillarysized tube or channel arranged in a serpentine configuration see figure 12 and joined end to end.
Computational model of miniature pulsating heat pipes. In this experiment the performance of pulsating heat pipe using ethanol and distilled water is experimented. Operational limit of closed loop pulsating heat pipes honghai yang a, s. Heat transfer enhancement of planar pulsating heat pipe.
Nov 06, 2010 a pulsating heat pipe in action at indian institute of technology kanpur, india. The heat received in the evaporator section leads to vapor generation, growth in the size of bubbles and increase in vapor pressure, which causes the motion of the fluid toward the condenser. Dec 14, 2007 heat pipes are widely used heat transfer devices in the electronic cooling area. How to make a heat pipe or solar heat collector duration.
In the present study the heat transfer capacity of the micro pulsating heat pipes. A heat pipe is simply a type of heat exchanger that is very simple in construction, easy and straight forward for use. Pulsating heat pipe, fill ratio, orientation, working fluids introduction. Thermal performance and operating regimes of a flat. The oscillating or pulsating heat pipe oph or php is a very promising heat transfer device. With the aim of exploring potential applications of pulsating heat pipe php technology for space as well as terrestrial sectors, experimental study of embedded structures in an aluminum substrate subjected to conjugate heat transfer conditions, i. Pulsating heat pipes are recently developed heat exchanging devices in which there is no need of external source for the movement of working fluid in the heat pipe. Pdf the oscillating or pulsating heat pipe oph or php is a very promising heat transfer device. The clphp is made of copper capillary tubes, having inner and outer diameters of 2.
Pdf embedded pulsating heat pipe radiators semantic. This paper presents preliminary experimental results on thermal performance of closed loop pulsating heat pipe php using copper tube having internal and. Vapour plugs and liquid slugs are formed in php due to the capillary action 1. Performance analysis of pulsating heat pipes using various. 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.
Design and operation of a teslatype valve for pulsating heat pipes citation for published version apa. Experimental investigations on the thermal performance of. When the diameter of the tube is so small, preferably pulsating heat pipe olphp to investigate the possible application of such heat pipes in low voltage power electronic devices. The experimental result on the thermal performance of closed loop pulsating heat pipe clphp is presented. Design and operation of a teslatype valve for pulsating. Also pachghare 8, kandekar 9 has deep studied on the pulsating heat pipe. A closed loop pulsating or oscillating heat pipe consists of a metallic tube of capillary dimensions wound in a serpentine manner and joined end to end as shown. The european space agency partnered with the european design engineering team of aavid, thermal division of boyd corporation, for its inwip project. By changing the width, the flattened thickness and the effective length of the ultrathin heat pipe, several experiments have been conducted to characterize the thermal properties of the developed cooling module.
Pulsating heat pipes are a new type of heat exchanger that can be useful in the context of the thermal management of electronic components khandekar, m. Groll c a college of environmental science and engineering, donghua university, shanghai 200051, pr china. Evaporation and condensation of the working fluid is what gives heat pipes their high effective thermal conductivity, which can be as high as 100,000 wm k. Ats engineering ebook advanced thermal solutions, inc.
Pdf startup, heat transfer and flow characteristics of. Thermohydrodynamics of closed loop pulsating heat pipe. Improvements have been done over time in heat pipes used for heat transfer. The micro pulsating heat pipes having channel diameter 800m and different number. Startup, heat transfer and flow characteristics of siliconbased micro pulsating heat pipes. This gives many advantages like, good thermal performance than that of conventional heat exchangers. A copperwater closed flat pulsating heat pipe php, 3. Introduction pulsating heat pipe php is a heat exchanger device which absorbs heat from evaporator region and transfers it to the. A typical php is a small meandering tube that is partially. 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. Pdf pulsating or oscillating heat pipes php or ohp are new twophase heat transfer devices that rely on the oscillatory flow of liquid slug. The basic structure of a typical pulsating heat pipe consists of meandering capillary tubes having no internal wick structure, as shown in figure 1a. Pdf cfd simulation of a pulsating heat pipe using ansys.
Pulsating heat pipe php is a special type of heat pipe where the driving force is the slugplug motion of the working fluid in the tube, generated by the evaporation. Oscillating heat pipes ohp, also referred to as pulsating heat pipes php, are a relatively new development in the field of heat pipe technology. Optical visualization results indicated that there might exist three flow patterns, i. Martinez prepared by sandia national laboratories albuquerque, new mexico 87185 and livermore, california 94550 sandia national laboratories is a multiprogram laboratory managed. 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. Case study pulsating heat pipes by the peregrine falcon. Two closed loop pulsating heat pipes clphps are tested on board rexus 18 sounding rocket in order to obtain data over a relatively long microgravity period. Closed loop pulsating heat pipe has a great prospect in the upcoming days for an effective cooling solution due to its excellent characteristics. A pulsating heat pipe php 1 is a passive and extremely efficient way of exchanging heat between a hot source and a cold one.
Ashutosh kr singh in partial fulfillment of the requirements for the award of master of technology degree in mechanical engineering with specialization in thermal engineering at the. Among the novel methods for thermal management of the high heat transfer rate found in microelectronic devices, pulsating heat pipes are the most effective heat removal device. Pdf cfd simulation of a pulsating heat pipe using ansys fluent. Aug 17, 2011 pulsating heat pipes, apparently simple and very promising cooling devices, are very intriguing for theoretical and experimental investigations alike. Development of efficient cooling system is a challenging task in electronics.
Nano fluid an alternative fluid in pulsating heat pipe oscillating heat pipe, iosr journal of electronics and communication engineering, sepoct 2012. The working fluids employed are water, ethanol, methanol and acetone also binary mixture 1. Heat pipes are referred to as the superconductors of heatdue to their fast transfer capability with low heat loss. An introduction to pulsating heat pipes electronics cooling. A volume of fluid in a vacuum is introduced into a microchannel which will become slugs of liquid. The working fluids used are water and titanium dioxide nanofluids with varying concentrations of tio 2 nanoparticles 1. The methodology involves investigation of the effect of different orientations vertical, horizontal and inclined at an angle 45 of a closed loop pulsating heat pipe clphp with particular. Introduction akachi proposed and patented pulsating or loop type heat pipein 1990s 1. Pdf comparison of heat transfer rate of closed loop micro. Even the name is heat pipe,but working is very much different than the conventional heat pipes. Pulsating heat pipes are different from conventional. It is a member of wickless heat pipes the oscillation of working fluid and phase change phenomina in capillary tube is basic principle. Numerical analysis of performance of closed loop pulsating. Modeling of pulsating heat pipes sandia national laboratories.
The pulsating heat pipes php, also called oscillating heat pipes, belong to the thermal system category of heat pipes, twophase passive thermal devices used to transfer heat from a hot source toa coldregion, withvery highequivalent thermal conductivity, higher thanany usual metallicmaterial,light,and abletomanage high heat. Pulsating heat pipe php is a heat exchanger device which absorbs heat from evaporator region and transfers it to the condenser region. Experimental analysis of close loop pulsating heat pipe at. Pulsating heat pipes phps are becoming a popular technology to address passive thermal management of nuclear, defence and space applications 57. In this paper, a novel pulsating heat pipe php design, which combines features of php and capillary microstructures, is presented to enhance heat transfer of electronic printed circuit boards pcb. Martinez prepared by sandia national laboratories albuquerque, new mexico 87185 and livermore, california 94550 sandia national laboratories is a multiprogram laboratory managed and operated by sandia corporation.
Several theoretical, numerical and experimental investigations have been carried out to get better understanding and solving of the issues in pulsating heat pipes. The development of such systems, however, is hindered by the rate of. Peregrine embeds pulsating heat pipes within the plane of flat sheetsplates by using printed circuit board technology to micromachine the channels. Since phps have superior thermal performance, by applying them in energy systems enhance their efficiency. 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 is to certify that the thesis entitled, numerical analysis of performance of closed loop pulsating heat pipe submitted by mr. 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. 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. Recent advances in electronics design and manufacturing have resulted in significant increases in heat flux density through a miniaturization of components and a simultaneous increase in power requirements associated with improved product. The transient and steady state experiments are conducted and operating temperatures are measured. Experimental investigations on the thermal performance of a. Pulsating heat pipes are made from long capillary tubes shaped with several turns at the top and bottom. Vapor thermodynamics and fluid merit for pulsating heat pipe. Modeling of pulsating heat pipes sandia national laboratories prodng. In addition to its excellent heat transfer performance, it has a simple structure. Recent advances in electronics design and manufacturing have resulted in significant increases in heat flux density through a miniaturization of components and a. Understanding effect of operating parameters on thermal. And they gives the pulsating heat pipe is efficient and fast. In this literature focus is on pulsating heat pipes phps.
Advances and unsolved issues in pulsating heat pipes. Ohp has wide range of applications in modern electronics systems due to its capability of dissipating high heat flux. As with most heat pipes, no external power source is needed to either initiate or sustain the fluid motion or the transfer of heat. On the design fundamentals of pulsating heat pipes. A series of experiments were performed on three types of closed loop pulsating heat pipes phps, intending to investigate various kinds of flow patterns, and to develop some improved configurations for the phps. Performance analysis of pulsating heat pipes using various fluids. The pulsating heat pipe has a single closed loop made of copper. Our proprietary diffusion bonding technology is then applied to assemble the mephps. The experiments are carried out for different working fluids, heat input and for different evacuation levels. Pulsating heat pipes, a novel research topic in heat pipe science, are new twophase heat transfer devices that rely on the oscillatory flow of liquid slug and vapor plug in a long miniature tube. A heat pipe device and a corresponding method in which microchannel embedded pulsating heat pipes are incorporated into a substrate. Oscillating heat pipes ohps use thermally driven, twophase fluid flow to rapidly transfer heat between heat sources and heat sinks.
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