With the rapid development of high-frequency, high-speed electronic devices and integrated circuit technology, the total power density of electronic components has increased significantly while the physical size is getting smaller and smaller, and the heat flow density has increased, so the high temperature environment will inevitably affect the performance of electronic components, which requires more efficient thermal control. How to solve the heat dissipation problem of electronic components is the focus at this stage. Therefore, this paper briefly analyses the heat dissipation methods of electronic components.
The problem of efficient heat dissipation of electronic components is influenced by the principles of heat transfer as well as fluid mechanics. The heat dissipation of the electrical device is to control the operating temperature of the electronic equipment, so as to ensure the temperature and safety of its work, which mainly involves the heat dissipation, materials and other aspects of the different contents. At this stage, the main way of heat dissipation is mainly natural, forced, liquid, refrigeration, evacuation, heat pipe and other ways.
1、Natural heat dissipation or cooling method
Natural heat dissipation or cooling method is in the natural condition, do not accept any external auxiliary energy, through the local heating device to the surrounding environment in order to dissipate heat for temperature control, the main way is heat conduction, convection and radiation concentration, and the main application is convection as well as natural convection several ways. Among them, natural heat dissipation and cooling methods are mainly used in electronic components with low temperature control requirements, low-power devices and components with relatively low heat flow density of device heating. It can also be used in sealed and densely assembled devices where no other cooling technology is required. In some cases, the relatively low requirements for heat dissipation capacity will also use the characteristics of the electronic device itself, appropriate to increase its heat sinks with the adjacent thermal conductive heat or radiation impact, through the optimisation of the structure to optimise the natural convection, thereby enhancing the system’s heat dissipation capacity.
2、Forced heat dissipation or cooling methods
Forced heat dissipation or cooling method is to speed up the air flow around the electronic components through the fan, a way to take away the heat. This way is relatively simple and convenient, the application effect is remarkable. In the electronic components if the space is large so that the air flow or installation of some heat dissipation facilities, you can apply this way. In practice, the main ways to enhance the convective heat transfer capacity are as follows: to appropriately increase the total area of heat dissipation, to produce a relatively large convective heat transfer coefficient on the surface of the heat sink.
In practice, the way to increase the surface heat dissipation area of the radiator is more widely used. In the project is mainly through the fins of the way to expand the surface area of the radiator, and then strengthen the heat transfer effect. The fins can be divided into different forms of heat dissipation, in some heat-consuming electronic devices on the surface as well as in the air application of the heat exchanger parts. The application of this mode can reduce the heat sink thermal resistance, but also to enhance the effect of its heat dissipation. For some relatively large power electronic period, it can be applied to the air in the way to deal with the disturbance, through the heat sink to increase the disturbance piece, in the surface flow field of the heat sink to introduce the disturbance can enhance the effect of heat transfer.
3、The liquid cooling method
The application of liquid cooling method of heat dissipation in electronic components is a heat dissipation method based on the formation of chips and chip components. Liquid cooling can be divided into direct cooling and indirect cooling two ways. Indirect liquid cooling is the application of liquid coolant and direct contact with the electronic components, through the intermediate media system, the use of liquid modules, thermal modules, spray liquid modules and liquid substrates and other auxiliary devices in the launch of the transfer between the thermal components. Direct liquid cooling method can also be called immersion cooling method, that is, the liquid and the relevant electronic components in direct contact, through the coolant to absorb heat and take away heat, mainly in some heat consumption volume density is relatively high or in the high temperature environment in the application of the device.
4、Heat dissipation or cooling method of refrigeration methods
Heat dissipation or cooling method of refrigeration methods mainly refrigerant phase change cooling and Pcltier refrigeration in two ways, in different environments the way it is also different, to integrate the actual situation of reasonable application. Refrigerant phase change cooling is a way to absorb a large amount of heat through the phase change of refrigerant, can be in some specific occasions to cool electronic devices. The general state is mainly through the refrigerant evaporation to take away the heat in the environment, which mainly includes the volume boiling and flow boiling two types. In general, deep cooling technology also has important value and influence in the cooling of electronic components. In some relatively large power computer system can apply deep cooling technology, not only can improve the cycle efficiency, its cooling quantity and temperature range is also more extensive, the structure of the whole machine and equipment is relatively more compact and the cycle of the efficiency is also relatively high. pcltier refrigeration through the semiconductor refrigeration way of heat dissipation or cooling treatment of some conventional electronic components, has a device with a small size, easy to install and strong, high quality, high efficiency, high efficiency. Pcltier refrigeration has the advantages of small size, easy installation, high quality and easy disassembly. This method is also known as thermoelectric refrigeration, is through the semiconductor material itself Pcltier effect, in the direct current through different semiconductor materials in series under the action of the formation of the electric coupling, can be in the electric coupling at both ends of the absorption of heat, heat release, so that you can achieve the effect of refrigeration. This way is a negative thermal resistance refrigeration technology and means, its stability is relatively high, but because of its relatively high cost, efficiency is relatively low, in some relatively compact volume, and for refrigeration requirements of low environmental applications. Its cooling temperature ≤ 100 ℃; cooling load ≤ 300W.
5、Heat dissipation or cooling in the energy channeling method
Through the transfer of heat transfer element will be the heat emitted by the electronic device to another environment. And in the process of integration of electronic circuits, high-power electronic devices gradually increased, the size of the electronic device is getting smaller and smaller. In this regard, this requires that the heat sink itself to have certain heat dissipation conditions, and the heat sink itself to have certain heat dissipation conditions. Because the heat pipe technology itself has a certain thermal conductivity characteristics, has a good isothermal characteristics, in the application of heat flow density variability and good thermostatic characteristics, can quickly adapt to the environment of the advantages of the heat dissipation of electrical and electronic equipment in the application of a wider range, can effectively meet the flexibility of the cooling device, high efficiency and reliability of the characteristics of the current stage in the cooling of electrical equipment, electronic components, as well as the semiconductor Component cooling is widely used in the heat dissipation of electrical equipment, electronic components and semiconductor components. Heat pipe is a high-efficiency and heat transfer mode through the phase change heat transfer mode, more widely used in electronic components heat dissipation. In practice, it is necessary to design heat pipes individually for different types of requirements, and to analyse the influence of gravity and external forces and other factors for a reasonable design. And in the heat pipe design process to analyse the production of materials, processes and cleanliness issues, to strictly control product quality, temperature monitoring and processing.
6、Heat pipe heat dissipation
Typical heat pipe by the shell, porous capillary core and work media. Work in a vacuum from the evaporation section to absorb the heat generated by the heat source after vaporisation, under the action of a small pressure difference, the rapid flow to the condensing section, and to the cold source of latent heat and condensation into a liquid condensate and then in the suction core capillary suction under the action of the condensing section to return to the evaporation section, and then absorb the heat generated by the heat source. So the cycle is repeated, and constantly transfer heat from the evaporation section to the condensing section. The biggest advantage of the heat pipe is that it can transfer a large amount of heat in the case of a small temperature difference, and its relative thermal conductivity is hundreds of times that of copper is known as the “near-superconducting body”, but there is a limit to the heat transfer of any one heat pipe, when the evaporating end of the heat more than a certain limit value, the heat pipe within the working medium will all be vaporised, resulting in the interruption of the cycle process heat pipe failure. The circulating process will be interrupted and the heat pipe will fail. Due to the current technology in China in the miniature heat pipe is still immature, so that the heat pipe in the cooling of power electronic equipment has not been widely used.