Industry information

Hot piece of the General principles of the heating tube, the use of gravity (usually divided into two phase thermosiphons) history can be traced back to the era of steam, the modern concept of capillary driven heat pipe is made by gm (General Motors) RS Gaugler first suggestion, idea patented in 1942. Using the advantage of the capillary action of independent research and development, show in los alamos national laboratory in 1963 for the first time by George gloval, then in 1964, published in the journal of applied physics. Gloval pointed out in his notebook:

 

"Heat transfer fluid through the surface tension of the capillary movement" pump ", may be enough to move the liquid from the low temperature zone to high temperature, and then return in the form of steam using difference as a driving force, in the two temperature), in the cold area to heat from heat. Such a closed system, pump, without external steam pressure can be interested in moving to the radiant heat from the reactor core is particularly interested in the space of reactor system must be under the condition of the gravity force, only as to overcome the capillary and drag will steam through the channel. "

 

Fever heat pipes in 1964 and 1966, RCA company was the first commercial application of the research and development of heat pipe (though their work is mainly funded by the U.S. government). In the late 1960 s by NASA plays a big role in the development of heat pipe money a significant amount of research on their application and reliability after space flight, from Grover's advice. NASA is the attraction of the heat pipe cooling system is understandable given the low weight, high heat flux and zero power consumption. However, their main interest is based on the fact that work under zero gravity environment, the system will not be adversely affected. In the space program in the application of heat pipe in heat balance for the first time the satellite transponder. Satellite orbit, one side is exposed to the direct radiation of the sun, but on the other side is completely dark, the exposure of the cryogenic space. This can lead to severe temperature deviation (and thus the reliability and accuracy) of the repeater. For this purpose and design of the heat pipe cooling system management of high heat flux, and the influence of gravity and don't show the flawless operation. The cooling system is the first description and use of variable
conductance heat pipe, to actively adjust the heat flow or the temperature of the evaporator.

Publication in 1967 and 1968 by feldman, Eastman, Katzoff first discuss areas of the application of heat pipe, the government's concern and classification, such as: air conditioning and engine cooling systems, electronic cooling high temperature does not drop. The documents also puts forward the first mention of elastic, artery and flat heat pipe. Publications in 1969 the introduction of the concept of the rotation of the heat pipe and its application to the turbine blade cooling and heat pipe used in the process of low temperature in the first time.

 

Fever heat pipes in the 1980 s, SONY will start heat pipe cooling scheme, some parts of the forced convection and passive fin heat sink of consumer electronics products. At first, they use the tuner and amplifier, quickly spread to other high heat flux electronics applications. In the late 1990 s of the increasingly intense microcomputer CPU to the heat pipe increased three times the number of patent applications. As a special industrial heat pipe heat transfer element from the development and production of consumer goods from America to Asia. Modern CPU heat pipe are usually made of copper and using water as working fluid.

 

Gloval and his colleagues are cells of the cooling system of nuclear power, in extreme temperature conditions. Heat pipe is widely used in the spacecraft as a means to manage the internal temperature.

 

Hot piece of heat pipe is widely used in many modern computer systems, including increasing the power requirement and the subsequent thermal radiation leads to a greater demand for cooling system. Often use of heat pipe heat from the radiator heat lost to the environment of the CPU and GPU components, such as

 

Heat pipe has been widely used in the application of solar hot water is used to heat combined with vacuum tube solar collector arrays. In these applications, the distilled water are often used as a time of glass tube, and in the face to the sun of the heat transfer fluid inside the sealing length of copper tube, individual absorption tube solar hot water heating area.the application, can provide up to 40% more efficiency than the traditional "flat solar collector. This is mainly due to slow convection and conduction heat loss of pipe, the vacuum tube. Vacuum the relative efficiency of pipeline system is reduced, because "compared to" flat "collector plate collector has a large aperture size, can absorb more solar energy, per unit area. This means that, although a single tube has better insulation (low conduction and convection losses), because in the vacuum tube, was found in the completed an array of solar battery components of tube absorb less energy per unit area, with less absorbent surface because towards the circular design of the solar glass vacuum heat-collecting tube, area is pointed out. As a result, the efficiency of the two design in the real world is about the same.

 

Vacuum tube collector reduces the need to add antifreeze additive vacuum help slow heat loss. However, long time exposure to the freezing point temperature of the heat transfer fluid can still frozen, must take preventive measures, to ensure that the design of frozen liquid will not damage the vacuum tube. Design of solar hot water heater can frost protection down to more than 3 ° C, special additives, and is used to heat water in Antarctica.

 

Permafrost building is difficult, because from the structure of the thermal thawing of the permafrost. In order to avoid the risk of instability, in some cases, the use of heat pipe. Across Alaska, for example, the remaining heat the remaining oil in the pipeline system, as well as in the mobile oil can be produced by friction and turbulence of the pipe support legs and melting permafrost on the support of the anchor. This will lead to pipe sinking, and may be damaged. In order to prevent this kind of circumstance of each vertical supporting member has been fitted with four vertical heat pipe.

 

Along the qinghai-tibet railway parts, also can be used in the heat pipe radiator. Subgrade and track absorbs the heat of the sun. The formation of either side of the vertical tube to prevent any further, thermal diffusion into the surrounding ground.

 

"Hot magic cooking needle", through the energy conversion systems, the company developed the first commercial heat pipe products, and sold for the first time in 1966. Cooking pin using water as working fluid. The envelope have stainless steel, the compatibility of internal copper layer. In the process of operation, heat pipe by stamp. One end of the pipe to it in the middle of heat absorption baking ovens. The effective thermal conductivity of heat pipe high cut large pieces of meat cooking time half a normal period.

 

This principle has been applied to the camping stoves, such as camping, will be a lot of heat, at low temperatures, the baked goods and other dishes to cook. An example of this is Bakepacker system.

 

In heating, ventilation and air conditioning systems, air conditioning, heat pipe is positioned in the air supply and exhaust air flow processing system, or an industrial process of exhaust gas range, with recovery of heat energy.

 

The device by more rows of finned tube of heat pipe in gas supply and exhaust air flow inside the battery. The exhaust air side heat pipe, its heat of refrigerant evaporation, at the same time in the extract air. The refrigerant vapor to move to the cold end of the tube, supply air side equipment, where condensation, and its heat is presented. By gravity and capillary condensation of the refrigerant in the burning core actions of portfolio returns. Therefore, the heat from exhaust air flow transferred to the refrigerant through the wall, and then from the refrigerant supply air flow through the pipe wall.

 

Due to the nature of the device, get a higher efficiency, when the unit is installed on the exhaust side with air supply side upright position, this allows the rapid flow of liquid refrigerant is returned to the evaporator under gravity. In general, the total heat transfer efficiency is as high as 75% of the manufacturers claim

 

Since the early 1990 s, many nuclear reactor power system is put forward using heat pipe heat transfer between the hot reactor cores and power conversion system [13] of the first nuclear reactors generate electricity using heat pipe, demo using flat fission first operation in September 13201.

 

Heat pipe must be tuned to a specific cooling conditions. Tube material, size and the choice of coolant in heat pipe work, in the best temperature effect.

 

When heated above a certain temperature, all of the working fluid in the tube will no longer occur, the evaporation and condensation process in such conditions, the thermal conductivity of the heat pipe are effectively to reduce the heat transfer performance of solid metal shell separately. As most of the heat pipe made of copper (metal) with high thermal conductivity, overheating tube usually will continue, in about 1/80 of the original heat conductivity.

 

In addition, under a certain temperature, the working fluid will not change phase, and the thermal conductivity will reduce the solid metal shell. Of the choice of working fluid is one of the key criteria of the required operating temperature range for this application. The lower limit of temperature, the working fluid usually happened a few degrees above freezing point.

 

Most manufacturers can make traditional heat pipe not less than 3 mm in diameter, as a result of the limitation of material (though can make 1.6 mm wafer). Experiment has carried on the micro heat pipe, the use of pipeline, sharp edges, such as triangle or lozenge tube. In these cases, the sharp edges by capillary action transmission fluid, no burning core is necessary.