Views:60 Author:Site Editor Publish Time: 2021-04-29 Origin:Site
The heat pipe is a heat transfer element with extremely high transient performance. It was invented at Los Alamos National Laboratory (Los Alamos National Laboratory) in the United States in 1964 and reached the peak of theoretical research in the late 1960s. It has been widely used in the industrial field since the 1970s.
It transfers and transforms through the vapor and liquid phase changes of the working fluid in a fully enclosed vacuum tube. It has extremely high resonance, which is hundreds of times the variable capacity of pure copper. It is known as the "thermal superconductor". The CPU heat sink will have a strong performance that ordinary air-cooled heat sinks without heat pipes cannot achieve.
1. Basic introduction
When the volume of solid aluminum or copper heat sink reaches 0.006m3, increasing its volume and area will not significantly increase the thermal resistance. For discrete semiconductor devices with double-sided heat dissipation, the thermal resistance of air-cooled all-copper or all-aluminum heat sinks can only reach 0.04°C/W. The heat pipe heat sink can reach 0.01℃/W. Under the condition of natural convection cooling, the performance of the heat pipe heat sink can be increased by more than ten times than that of the physical heat sink.
2. The principle of the heat pipe
The heat pipe is an artificial component with excellent heat transfer. The commonly used heat pipe consists of three parts: the main body is a closed metal pipe with a small amount of working medium and capillary structure inside, and the air and other sundries in the pipe must be excluded. Three physical principles are used when the heat pipe works:
⑴ In the vacuum state, the boiling point of the liquid decreases;
(2) The latent heat of vaporization of the same substance is much higher than the sensible heat;
(3) The injection force of the porous capillary structure on the liquid alternates with the liquid flow.
3. The advantages of the heat pipe
Since the advent of heat pipes, the heat dissipation system of power electronic devices has undergone new development. No matter how the heat is dissipated, the heat-dissipating medium is air, and the rest are loop connections. The scope of application is rapidly expanding. Because the heat pipe self-cooling heat dissipation system does not require a fan, no noise, maintenance-free, safe and reliable, the heat pipe air-cooling or even self-cooling can replace the water-cooling system, saving volume and related auxiliary equipment investment. The heating elements can be concentrated or even sealed, and the heat dissipation part can be moved to the outside or far away, which can prevent dust, moisture, and explosion, and improve the safety, reliability and application scope of electrical equipment.