Among the many heat transfer elements, heat pipes are known as one of the most efficient heat transfer elements, which can transfer a large amount of heat over long distances through its small cross-sectional area without additional power.
The principle of heat pipe was first proposed by R. S. Gaugler of General Engine Company of Ohio in the United States patent (No. 2350348) in 1944.
He was studying the problem of freezing at the time, and he envisioned a device consisting of a closed tube, in which the liquid in the tube was heated and evaporated after the heat absorption and condensation was released at a certain location below, and without any additional power, the condensed liquid returned to the top with the capillary force generated by the capillary core in the tube to continue the heat absorption and evaporation, and so on, to achieve the purpose of heat transfer from one place to another.
However, his ideas were not adopted by General Motors at the time.
In 1962 L. Trefethenf again proposed a heat transfer element similar to Gaugler for use in spacecraft, but because this proposal was not experimentally proven, it could not be implemented.
1963 G. Alamos National Laboratory in the United States M. Grover independently invented a heat transfer element similar to Thatghler's proposal, and conducted performance test experiments, published the first paper in the American journal "Applied Physics", and officially named this heat transfer element Heat Pipe, pointing out that its thermal conductivity has far exceeded any known metal, giving the experimental results of the heat pipe with sodium as the working liquid, stainless steel as the shell, and the inner wire mesh suction core.
Los Alamos National Laboratory in the United States has been in a leading position in thermal management theory and the application of heat pipes in space technology.
In 1965, Cotter first proposed a relatively complete thermal management theory, which laid the foundation for the future research work of thermal management theory.
In 1967, a stainless steel-hydrothermal tube was first sent into the orbit of the Earth satellite and successfully operated, which has attracted many scientific and technological personnel to engage in heat pipe research, and the former West Germany, Italy, the Netherlands, the United Kingdom, the former Soviet Union, France and Japan have carried out a lot of research work, so that heat pipe technology can be developed rapidly.
Katzow invented heat pipes with arterials in 1966. The role of the arterial road is to provide a channel with a small pressure drop for the liquid returning from the condensation section back to the evaporation section, which greatly improves the transmission capacity of the heat pipe.
In 1969, the relevant magazines of the former Soviet Union and Japan published articles on the application of heat pipes. Air heaters with finned heat pipe bundles have been described in Articles in Japan, which can be used to recover heat from industrial exhaust in the face of increasing energy constraints.
At the same time, Turner and Bienert proposed to use variable thermal heat pipes to achieve constant temperature control.
Gray has studied a new type of heat pipe, the rotating heat pipe, which is a major advance in heat pipe technology.
In 1970, a division of supplier heat pipes appeared in the United States, and the application of heat pipes expanded from aerospace to the ground.
In the history of heat pipe development, it is worth mentioning that in the project of crossing the Alaska oil pipeline, the heat pipe is used as the support of the pipeline to protect the permafrost layer on the ground to meet the needs of the project. A total of more than 112,000 heat pipes were used in the project, and the length of a single heat pipe was 9 to 23m.
After 1974, the research of heat pipes in energy conservation and new energy development has received full attention, and heat pipes are used to form heat exchangers to recover waste heat and use them in industry to save energy. The United States and Japan have made the most significant progress in this regard.
In 1980, the American Q・Dot Company produced a heat pipe waste heat boiler, and the Japanese Teijin Engineering Company also successfully used heat pipes to make boiler feed water preheaters, which solved the problem of dew point corrosion of smoke exhaust. After that, the development of heat pipe heat exchangers in various countries has been carried out rapidly, and new structural forms such as rotary type and separation type have emerged one after another, and they have become increasingly industrialized and large-scale.
In 1984, Cotter put forward the theory and prospect of micro heat pipe more completely, laying a theoretical foundation for the research and application of micro heat pipe.
Capillary pump circuit CPL (Capillary pumped loops) and loop heat pipe system LHP (Loop heat pipe systems) with its flexible structure, wide application scope and can transfer more heat than conventional heat pipes over a long distance under a small temperature difference, which has attracted the general attention of the entire heat pipe community and become a hot spot in theoretical research and application research.
Since the 1970s, heat pipe technology has developed rapidly, scientific research institutions, colleges and universities, companies and factories and mines in various countries have carried out multi-faceted development and application research, and international and national heat pipe technology exchange activities have become increasingly frequent.
From 1985 to 1994, China and Japan held four bilateral and multilateral heat pipe technology seminars, and the multilateral conference held in Melbourne, Australia in 1996 was officially developed into an international heat pipe technology seminar.
Since the 1970s, China has carried out research on the heat transfer performance of heat pipes and the application of heat pipes in the cooling of electronic devices and space vehicles.
Since China is a developing country, the comprehensive utilization level of energy is low, so since the early 1980s, the focus of China's heat pipe research and development has shifted to energy conservation and rational utilization of energy, and various heat pipe products such as heat pipe gas-gas heat exchangers, heat pipe waste heat boilers, high temperature heat pipe steam generators, high temperature heat pipe hot air furnaces and other types of heat pipe products have been developed successively.
Due to the simple structure, low price, convenient manufacturing and easy application of carbon steel-water two-phase closed thermosiphon pipes, the basic solution of carbon steel-water compatibility makes such heat pipes widely used.
The development and research of the industrial application of heat pipe technology in China has developed rapidly, and the academic exchange activities are also very active, and six national heat pipe conferences have been held since 1983.
With the continuous improvement of the level of science and technology, the field of heat pipe research and application will continue to expand. The development of new energy, the cooling of electronic device chips, the cooling of notebook computers CPU, and the cooling of high-power transistors, thyristor components, circuit control boards, etc., and the development of efficient heat and mass transfer equipment in the fields of chemical, power, metallurgy, glass, light industry, ceramics, etc., will promote the further development of heat pipe technology.