Principle Of Heat Pipe Research Articles

Experimental Investigations of a Passive Cooling System Based on the Gravity Loop Heat Pipe Principle for an Electrical Cabinet

This paper deals with the experimental research and verification of a passive cooling system operating on the principle of a loop gravity heat pipe designed for cooling electrical cabinets. This type of cooling works automatically by changing the state of the working substance and thus saves energy consumption. Since the designed cooling system ensures heat transfer from the interior cabinet to the outdoor space, where the heat can naturally dissipate to the surroundings, it is dustproof. The heat pipe consists of an innovative evaporator concept designed to minimize liquid and vapour phase interference in the refrigeration circuit. The aim of the research was to experimentally determine the limit performance parameters of the refrigeration system for different volumes of working medium in the evaporator and decrease heat loss in the cabinet interior. The designed device was verified experimentally and by mathematical calculations as well. The greatest benefit of the work is that the cooling device was able to ensure temperature conditions inside the electrical enclosure at a heat load of 2000 W under 60 °C, 1500 W under 55 °C, 1000 W under 50 °C, 750 W under 45 °C and 500 W under 40 °C.

ТЕПЛОВЫЕ ТРУБЫ В АТОМНОЙ ЭНЕРГЕТИКЕ

The paper provides an overview of technical solutions for using of heat pipes in nuclear power plants both developed and operating. The review based on the scientific, technical and patent literature shows wide application heat pipes as heat transfer devices. Using of them for small and super-small power plants seems to be especially effective, because of high specific cost of plants with circulating coolants. A heat pipe is a device transferrind the heat by means of evaporation and condensation of a coolant circulating automatically under the action of capillar or gravitation forces. Heat pipes are used rather widely, both abroad and in Russia. The first application of a heat pipe principle in nuclear power plants was published in 1957, even before the emergence of the term "heat pipe". Now, there are about 300 patents in the world related to heat pipes application in nuclear power plants. Theare are seweral thouthands articles on the development of nuclear reactors with heat pipes have been published in the scientific and technical literature. One should expect that fifth-generation nuclear reactors cooled by heat pipes without any mechanisms and machines for the circulation of the coolant, as well as without the consumption of mechanical and electrical energy, will be appeared in this decade.

Numerical Simulation of Heat Transfer Performance of Micro-heat Pipe Array based on FLUENT

The structure and basic principle of heat pipe and plate micro heat pipe array are introduced in detail, and the application of FLUENT grid technology and numerical technique is introduced. The thermal conductivity, the phase change and the effect of the liquid filling rate on the heat transfer performance of the heat pipe were simulated by using FLUENT of CFD software. The results show that when the liquid filling rate is 20% ∼ 30%, the thermal conductivity of the micro heat pipe starts to rise, reaching 6.11 × 10-5 W · m-2 at the highest level. When the liquid filling rate of 30% to 40%, the thermal conductivity of the micro-heat pipe began to decline, which indicates that the best filling rate is when the liquid filling rate is 20 ∼ 30. When the temperature of the outer wall of the condensation section is 67.5 °C, the maximum heat flux can reach 8.1 × 105 W · m-2.

Small seawater desalination system based on loop heat pipe principle

The small seawater desalination system based on loop heat pipe principle by using plate capillary pump technology, a new type of radiator spoiler evaporator and soaking plate finned condenser to realize desktop-class solar seawater desalination system. The Venturi tube principle is used to reduce the internal pressure and energy consumption, and solar photoelectric board with electric heating board function is used to solve problems for areas where there is a shortage of electricity and fresh water resources. Full automatic control system is used to realize the full automatic operation of the equipment.Desktop-class light and small seawater desalination equipment enjoys a broad market prospect. It can not only be used in islands, fishing boats, offshore operating platforms and other complex working scenarios, but also can be used as a large ship freshwater resources emergency equipment.

베이퍼챔퍼 제조기술을 적용한 LED 투광등기구의 열 특성 비교에 관한 연구

The purpose of this paper is to analyze thermal characteristics of the heat sinks to maximize the thermal diffusivity for LED floodlight. The 2 kind of samples were prepared by vapor chamber manufacturing technology using the heat pipe principle. It was analyzed the maximum temperature reduction effect and the thermal diffusion from the heat source depending on the types of chambers with 3 kind of working fluids. As a result, it was confirmed that thermal conductivity 23% increased, GVC-R type than IVC-R type.

On the use of heat pipe principle for the exploitation of medium–low temperature geothermal resources

In the direct use of geothermal energy without fluid extraction, heat transfer takes place with no alteration of the natural hydrogeological balance of the basin. An interesting solution both for thermal energy and power production could be the application of heat pipe principle, in particular the Closed Loop Two Phase Thermosyphons (CLTPT). In shallow or not much deep geothermal reservoirs with temperature below 100 °C, the two phase closed loop thermosyphon can transfer heat very efficiently. In this case the most important task is the enhancement of the heat transfer mechanism between the heat exchanger and the aquifer.In the first part of the paper a review of particular applications connected to the geothermal heat pipe applications is proposed, then an analysis of the main technical elements regarding the geothermal aquifer exploitation through two phase thermosyphon systems are given. Some guidelines for power systems sizing are discussed and a proposal for the design of a single borehole heat extraction system with binary cycle utilization is provided.

Evaporative Heat Transfer Analysis of a Heat Pipe With Hybrid Axial Groove

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. This hybrid axial groove is composed of a V-shaped channel connected with a circular channel through a very narrow longitudinal slot. During the operation, the V-shaped channel can provide high capillary pressure to drive the fluid flow and still maintain a large evaporative heat transfer coefficient. The large circular channel serves as the main path for the condensate return from the condenser to the evaporator and results in a very low flow resistance. The combination of a high evaporative heat transfer coefficient and a low flow resistance results in considerable enhancement in the heat transport capability of conventional heat pipes. In the present work, a detailed mathematical model for the evaporative heat transfer of a single groove has been established based on the conservation principles for mass, momentum and energy, and the modeling results quantitatively verify that this particular configuration has an enhanced evaporative heat transfer performance compared with that of conventional rectangular groove, due to the considerable reduction in the liquid film thickness and a corresponding increase in the evaporative heat transfer area in both the evaporating liquid film region and the meniscus region.

トクデン株式会社

Tokuden Co., Ltd. was established in 1939, since then, Tokuden has been developing and manufacturing the transformer and reactor. In 1965, Tokuden developed the worlds first Induction Heated Jacket Roll using electromagnetic induction and the heat-pipe principle and it has been used in thermal processes the laminating, coating, calendering, heat stretching of films & fibers and heat setting. This article introduces an outline of Tokuden Co., Ltd. and our products.

ROTARY HEAT PUMP

An original rotary heat pump suggested by the authors is described in the presented paper. All thermodynamic processes of working fluid (evaporation – compression – condensation) based on the principle of heat pipe are provided in one volume of mushroom form closed vessel. The transportation of external heat flows is combined in the unit as well. The heat necessary for evaporation is taken from external heat sources, and heat produced by working fluid at condensation is transferred by disk type ventilators (authorship certificate No 98544, 04.01.1981). The three components of a new type are applied in the suggested heat pump: hydrodynamic pump, disk ventilator, and regeneration heat exchanger.http://dx.doi.org/10.5755/j01.mech.17.5.732

Study on Temperature Field of L-Phenylalanine Fermentation in Heat Pipe Bioreactor

L-phenylalanine fermentation (L-Phe) is produced by the preparation method of PPA-transamination using the ferment liquor, which is the production of the E.coli No.1 fermented in heat pipe bioreactor (HPBR), the technical indexes are superior. The temperature profile of ferment liquor in the period of microbe growth is well distributed, the mean difference in temperature is 0.08°C, while the maximum value is 0.4°C.Base on operational principle of heat pipe, HPBR solves many problems on heat transfer in traditional bioreactor: nonuniformity of temperature profile, inefficiency of heat transfer etc. The study in-depth on transfer process in HPBR will effectively accelerate exploitation for new-style bioreactor and advancement of biotechnology.

Characterization of cooling systems based on heat pipe principle to control operation temperature of high-tech electronic components

The use of cooling systems based on heat pipe principle to control operation temperature of electronic components is very efficient. They have an excellent miniaturizing capacity and this fact creates adaptability for more practical situations. Starting from the observation that these cooling systems are not precisely characterized from the thermal efficiency point of view, the present paper proposes a methodology of data acquisition for their thermal characterization. An experimental set-up and a data processing algorithm are shown to describe the cooling of a heat generating electronic device using heat pipes. A Thermalright SI-97 PC cooling system is employed as a case-study to determine the heat transfer characteristics of a fins cooler.

Performance of heat pipes as capillary pumps: experiments

This paper describes the development of an experimental setup to investigate the performance of heat pipes as capillary pumps. The experimental setup and the research that was performed by LFME was part of an EU funded research project called TRI-GEN EGD that aims in the overall development of a novel Tri-generation Electrogasdynamic converter system. The capillary pump will be used to pump the working fluid of the system using external waste heat. Furthermore, since the capillary pump has no moving parts it will provide the system with greater reliability. The experimental setup designed and constructed by LFME is a Capillary Pumped Loop (CPL). A CPL is a closed loop system that pumps liquid by passive means, based on the operating principles of heat pipes. Specifically capillary forces are generated on a porous structure that exists in the evaporation section and is responsible for pushing the working fluid from a high temperature source to a low temperature sink. In this paper, a brief description of the experimental setup that was constructed and a description of the experimental procedure that was followed will be given together with some results that were obtained for various configurations. Copyright , Manchester University Press.

Investigation of the performance of heat pipes used as capillary pumps

This paper describes the investigation being performed by the Laboratory of Fluid Mechanics and Energy (LFME) in order to test the performance of heat pipes as capillary pumps. This investigation is part of the EU funded research project TRI-GEN EGD that aims in the development of a novel Tri-generation Electrogasdynamic converter system. The capillary pump will be used to pump the working fluid of the system using external waste heat. Furthermore, since the capillary pump has no moving parts it will provide the system with greater reliability. To this end, a Capillary Pumped Loop (CPL) experimental setup was designed and constructed by LFME. A CPL is a closed loop system that pumps liquid by passive means, based on the operating principles of heat pipes. Specifically capillary forces are generated on a porous structure that exists in the evaporation section and is responsible for pushing the working fluid from a high temperature source to a low temperature sink. In this paper the experimental setup constructed as well as the experimental procedure followed are described and preliminary results are presented. Copyright , Manchester University Press.

A 2.45-GHz electron cyclotron resonance multi-mA Li+ ion gun for fusion plasma diagnostics

For the purpose of neutral-lithium beam tokamak–plasma diagnostics we have developed a compact, high current (several tens of mA/cm2) 2.45-GHz electron cyclotron resonance (ECR) Li+ plasma ion source in coaxial geometry, coupled to a helium-buffered lithium feeding system working according to the heat pipe principle. The accel–decel-type ion extraction system features either seven holes or one single aperture. First experimental results for the extractable Li+ and He+ ions in both cw and pulsed-mode operations are presented.

Convection suppression in horizontal solar collectors using density stratification

A new technique for convection suppression in solar collectors is proposed. In this method the air in the gap between the absorber and the cover is stratified by the use of a heavy vapour. The amount of vapour required to achieve convection suppression is derived. The heavy vapour which diffuses from the absorber to the cover is recirculated using the principle of heat pipe. This technique is demonstrated by a simple experiment.

Wärmerohre in der industriellen Praxis

AbstractHeat pipes in industrial practice. Heat exchangers based on single independent heat pipes have not often been used in chemical engineering processes, in spite of their numerous ad‐1 vantages. This may be because simple design rules are unavailable. After a short introduction into the working principles of heat pipes, some thermal calculation rules and design procedures are given based on dimensionless numbers for the various finned tube components of the heat pipes. A calculation example demonstrates how the design rules should be applied. Finally some practical applications illustrate the successful operation of heat pipes for the purpose of industrial heat recovery.

Heat Pipe Thermodynamic Cycle and its Applications

A new type of thermodynamic cycle originating from extended application of the heat pipe principle is proposed and its thermal cycle is discussed from the viewpoint of theoretical thermal efficiency and Coefficient of Performance (COP). An idealized structure that will meet the basic function for thermal systems is also suggested. A significant advantage of these systems is their use with low-temperature energy sources found in nature or heat rejected from industrial sites.

Development the water heater applying the heat pipe principle.

ヒートパイプの原理を応用した湯沸かし器を試作し,その性能実験を行った.その結果,設計負荷以下では,温水の流量が変化しても一定の水温が得られるなど従来の湯沸かし器にはない特長を示すことがわかった.また,簡単な作動モデルによって,始動時および定常運転時における温度挙動や燃焼器の点火時間割合などをある程度予想することができ,さらにウィックの特性や電磁弁の寿命を考慮した本形式の湯沸かし器の設計手順を示した.

The Physical Principles of Heat Pipes

"The Physical Principles of Heat Pipes." Nuclear Technology, 62(2), p. 243 Additional informationNotes on contributorsMonte V. DavisMonte V. Davis (BA, Lin field College; MA and PhD, Oregon State University) is a professor in the School of Nuclear Engineering and Health Physics at the Georgia Institute of Technology. His interests are neutron physics, high-temperature materials, direct energy conversion, and the effects of ionizing radiation on organic materials. Professor Davis is a fellow of the American Nuclear Society.

Disk-shaped heat-pipe oven used for lithium excited-state lifetime measurements

A metal-vapor spectroscopic oven based on the heat-pipe principle has been constructed in which the heated stainless steel wicks are mounted on disks spaced closely compared with their radii and in which the window is a glass spacer ring separating the disks and permitting optical access to the active volume. The device has been successfully operated using both sodium and lithium as the working fluid. The lithium 4s2S1/2 and 5s2S1/2 radiative lifetimes were measured with this device, yielding values of 56 ± 1.7 and 99 ± 9 nsec, respectively.