The heat dissipation mode refers to the main way in which the heat sink dissipates heat. In thermodynamics, heat dissipation is heat transfer, and there are three main ways of heat transfer: heat conduction, heat convection and heat radiation. The transfer of energy by matter itself or when matter is in contact with matter is called heat conduction, which is the most common form of heat transfer. For example, the way that the CPU heat sink base is in direct contact with the CPU to take away heat is heat conduction. Heat convection refers to the heat transfer mode of the flowing fluid (gas or liquid), and the "forced heat convection" heat dissipation mode is more common in the cooling system of the computer case. Thermal radiation refers to the transfer of heat by ray radiation, the most common daily radiation is solar radiation. These three ways of heat dissipation are not isolated, in the daily heat transfer, these three ways of heat dissipation are at the same time, work together.
In fact, any type of radiator will basically use the above three heat transfer methods at the same time, but the emphasis is different. For example, an ordinary CPU heat sink, the CPU heat sink is in direct contact with the CPU surface, and the heat on the CPU surface is transferred to the CPU heat sink through heat conduction; The heat dissipation fan generates airflow to take away heat from the surface of the CPU heat sink through heat convection. The flow of air in the chassis is also through thermal convection to take away the heat of the air around the CPU heat sink until the outside of the chassis; At the same time, all the hot parts will radiate heat to the cooler parts around them.
The heat dissipation efficiency of the radiator is related to the heat conductivity of the radiator material, the heat capacity of the radiator material and the heat dissipation medium, and the effective heat dissipation area of the radiator.
According to the way the heat is taken away from the radiator, the radiator can be divided into active heat dissipation and passive heat dissipation, the former is a common air-cooled radiator, and the latter is a common heat sink. Further subdivided heat dissipation, can be divided into air cooling, heat pipe, liquid cooling, semiconductor refrigeration and compressor refrigeration and so on.
Air-cooled heat dissipation is the most common, and it is very simple to use a fan to take away the heat absorbed by the radiator. It has the advantages of relatively low price and simple installation, but it is highly dependent on the environment, such as temperature rise and overclocking, and its heat dissipation performance will be greatly affected.
Heat pipe is a heat transfer element with very high thermal conductivity. It transfers heat through the evaporation and condensation of the liquid in the completely closed vacuum tube. It uses the fluid principle such as capillary suction to play a similar effect to the refrigeration of the refrigerator compressor. It has a series of advantages such as extremely high thermal conductivity, good isotherm, the heat transfer area on both sides of the hot and cold can be arbitrarily changed, the heat transfer can be conducted at a distance, and the temperature can be controlled, etc., and the heat exchanger composed of heat pipes has the advantages of high heat transfer efficiency, compact structure, and small fluid resistance loss. Due to its special heat transfer characteristics, the tube wall temperature can be controlled to avoid dew point corrosion.
Liquid cooling is the use of liquid forced circulation under the drive of the pump to take away the heat of the radiator, and compared with air cooling, it has the advantages of quiet, stable cooling and small dependence on the environment. However, the price of heat pipes and liquid cooling is relatively high, and the installation is relatively troublesome.
When buying a radiator, you can buy it according to your actual needs and economic conditions, and the principle is good enough.
A radiator is a device or instrument that transfers the heat generated by machinery or other appliances in the working process in time to avoid affecting their normal work. According to the heat dissipation method, the common radiator can be divided into air cooling, thermal radiation heat dissipation, heat pipe radiator, liquid cooling, semiconductor refrigeration, compressor refrigeration and other types.
There are three common ways of heat transfer in heat science: heat conduction, heat convection and heat radiation. The transfer of kinetic energy by the chemical itself or when the chemical comes into contact with the substance is called heat conduction, which is the most widespread form of heat convection. For example, the direct contact between the CPU heat sink base and the CPU to bring heat is attributed to heat conduction. Heat convection refers to the flow of liquid (vapor or liquid) will subtropical heat convection mode, in the computer host heat dissipation system software is more common is the heat dissipation fan to promote the flow of vapor "forced heat convection" heat dissipation mode. Thermal radiation refers to the transfer of heat through infrared radiation sources, and the most common daily radiation is the amount of solar radiation. These three modes of heat dissipation are not independent, in the daily heat transfer, these three modes of heat dissipation are all produced at the same time, and play a role together.
The heat dissipation efficiency of the radiator is related to the main parameters such as the thermal conductivity of the radiator raw material, the heat capacity of the radiator material and the heat dissipation substance, and the reasonable heat dissipation total area of the radiator.
According to the way to bring heat from the radiator, the radiator can be divided into active heat dissipation and passive heat dissipation, the front is a common air-cooled radiator, and the back is a common heat sink. Further differentiated heat dissipation methods can be divided into air-cooled, heat pipe, heat radiation, liquid cooling, electronic refrigeration and refrigeration compressor cooling.
1, air-cooled radiator is the most common, and relatively simple, is the application of the fan to the heat absorbed by the radiator. It has the advantages of relatively low price and easy installation and operation, but it depends on the natural environment very high, such as the heat dissipation characteristics will be greatly affected when the temperature rises and the CPU overclocking.
2, the heat pipe is a kind of heat exchange components with high heat transfer performance, it uses the volatilization and solidification of the liquid in the fully closed vacuum solenoid valve to transfer heat, it uses the basic principle of liquid such as wool absorption effect, with similar to the actual effect of refrigerator compressor cooling. It has a series of advantages such as high heat transfer, excellent isostatic temperature, the total area of heat conduction on both sides of hot and cold can be changed at will, long distance heat conduction, adjustable temperature, etc., and the heat exchanger composed of heat pipes has advantages such as high efficiency of heat conduction, compact structure, and small liquid resistance loss. Because of its unique heat conduction characteristics, the wall thickness temperature can be manipulated to prevent leakage point erosion.
3, thermal radiation is a kind of coating with high radiation heat dissipation, coating the heat dissipation body of microcrystalline technology graphene heat dissipation coating, because of its high thermal radiation coefficient, it can make the heat radiation more quickly distributed, and can be used in the environment above 500 ° C for a long time without falling off, yellowing, cracking and other phenomena. At the same time, it can also improve the heat dissipation performance of the parts after painting, and make the corrosion resistance and high temperature resistance of the parts have been significantly improved.
4. Liquid cooling is the heat brought to the radiator by the mandatory circulation system driven by the pump, which has the advantages of quiet, stable temperature reduction and small dependence on the natural environment compared with the air-cooled type. However, the price of heat pipes and liquid cooling is higher than that, and the assembly is relatively inconvenient.
Heat sink material refers to the specific material used by the heat sink. The thermal conductivity of each material is different, and the thermal conductivity is arranged from high to low, respectively, silver, copper, aluminum, steel. However, if silver is used as a heat sink, it is too expensive, so the best solution is to use copper. Although aluminum is much cheaper, it obviously does not conduct heat as well as copper. The commonly used heat sink materials are copper and aluminum alloy, both of which have their advantages and disadvantages. Copper has good thermal conductivity, but the price is expensive, the processing is difficult, the weight is too large, the heat capacity is small, and it is easy to oxidize. The pure aluminum is too soft, can not be used directly, is the use of aluminum alloy to provide enough hardness, the advantages of aluminum alloy is low price, light weight, but the thermal conductivity is much worse than copper. Some radiators take their strengths and embed a copper plate in the base of the aluminum alloy radiator. For ordinary users, the aluminum heat sink is enough to meet the heat dissipation needs.
The heat dissipation mode refers to the main way in which the heat sink dissipates heat. In thermodynamics, heat dissipation is heat transfer, and there are three main ways of heat transfer: heat conduction, heat convection and heat radiation. The transfer of energy by matter itself or when matter is in contact with matter is called heat conduction, which is the most common form of heat transfer. Heat convection refers to the heat transfer mode of the flowing fluid (gas or liquid), and the "forced heat convection" heat dissipation mode of the cooling fan driving the gas flow. Thermal radiation refers to the transfer of heat by ray radiation, the most common daily radiation is solar radiation. These three ways of heat dissipation are not isolated, in the daily heat transfer, these three ways of heat dissipation are at the same time, work together.
The heat dissipation efficiency of the heat sink is related to the heat conductivity of the heat sink material, the heat capacity of the heat sink material and the heat dissipation medium, and the effective heat dissipation area of the heat sink.
According to the way the heat is taken away from the heat sink, the heat sink can be divided into active heat dissipation and passive heat dissipation, the former is commonly air-cooled heat sink, and the latter is commonly heat sink. Further subdivided heat dissipation, can be divided into air cooling, heat pipe, liquid cooling, semiconductor refrigeration and compressor refrigeration and so on.
Air-cooled heat dissipation is the most common, and it is very simple to use the fan to take away the heat absorbed by the heat sink. It has the advantages of relatively low price and simple installation, but it is highly dependent on the environment, such as temperature rise and overclocking, and its heat dissipation performance will be greatly affected.
Heat pipe is a heat transfer element with very high thermal conductivity. It transfers heat through the evaporation and condensation of the liquid in the completely closed vacuum tube. It uses the fluid principle such as capillary suction to play a similar effect to the refrigeration of the refrigerator compressor. It has a series of advantages such as extremely high thermal conductivity, good isotherm, the heat transfer area on both sides of the hot and cold can be arbitrarily changed, the heat transfer can be conducted at a distance, and the temperature can be controlled, etc., and the heat exchanger composed of heat pipes has the advantages of high heat transfer efficiency, compact structure, and small fluid resistance loss. Due to its special heat transfer characteristics, the tube wall temperature can be controlled to avoid dew point corrosion.
Liquid cooling is the use of liquid forced circulation under the drive of the pump to take away the heat of the radiator, and compared with air cooling, it has the advantages of quiet, stable cooling and small dependence on the environment. However, the price of heat pipes and liquid cooling is relatively high, and the installation is relatively troublesome.
Generally speaking, according to the method of bringing heat from the radiator, the radiator can be divided into active heat dissipation and passive heat dissipation.
In short, passive heat dissipation, heat is naturally released into the air according to the radiator, the actual effect of heat dissipation is proportional to the size of the radiator, but because the heat dissipation is naturally released, the actual effect will naturally be greatly affected, usually used in these machines and equipment that have no provisions for indoor space, or for cooling parts with low calorific value. For example, some popular computer motherboards also use active cooling on the North Bridge. Most of them use active heat dissipation, that is, according to the cooling machine and cooling fan and other equipment, forced to take away the heat of the heat sink. It is characterized by high heat dissipation efficiency and small machine size.
Active heat dissipation, from the heat dissipation method, can be divided into air-cooled heat dissipation, water-cooled heat dissipation, heat dissipation pipe heat dissipation, semiconductor refrigeration, organic chemical cooling.
1, air cooling
Air-cooled heat dissipation is the most common method of heat dissipation, and relatively speaking, it is also a cheaper method. Air-cooled heat dissipation is essentially the heat absorbed by the heat dissipation fan to the radiator. It has the advantages of relatively low price and convenient installation.
2, water cooling heat
Water cooling heat dissipation is based on the heat brought to the radiator by the forced circulation system of the liquid driven by the pump, which has the advantages of quiet, stable temperature reduction and small dependence on the natural environment compared with air cooling. The price of water-cooled heat dissipation is relatively high, and the installation is relatively inconvenient. In addition, when installing, as far as possible, follow the specific instructions in the way of installation to achieve the best heat dissipation effect. Due to the cost and convenience considerations, water-cooled heat dissipation generally uses water as a heat transfer liquid, so water-cooled heat dissipation radiator is often called water-cooled heat dissipation radiator.
3, heat dissipation pipe
The heat dissipation tube belongs to a heat conduction component, which makes full use of the basic principle of heat conduction and the rapid heat convection characteristics of refrigerating substances, and transmits heat according to the volatilization and solidification of the liquid in the fully enclosed vacuum solenoid valve. It has a series of advantages such as very high heat transfer, excellent isostatic temperature, the total area of heat conduction on both sides of hot and cold can be changed at will, long distance heat conduction, and controllable temperature, etc., and the heat exchanger composed of heat dissipation tube has advantages such as high efficiency of heat conduction, compact structure, and small fluid mechanical resistance loss. Its heat transfer capacity has far exceeded the heat transfer capacity of all known metal materials.
4, semiconductor refrigeration
Semiconductor refrigeration is the use of a specially made semiconductor refrigeration sheet to cause a temperature difference when connected to the power supply to cool, if the heat at the high temperature end can be reasonably released, the ultra-low temperature end will continue to be cooled. A temperature difference is caused on each semiconductor material particle, and a cooling sheet is composed of dozens of such particles, which in turn produces a temperature difference on the two surface layers of the cooling sheet. Using this kind of temperature difference, and cooperating with air cooling/water cooling to reduce the temperature of the high temperature end, excellent heat dissipation can be obtained. Semiconductor refrigeration has the advantages of low cooling temperature and high credibility, and the cold surface temperature can be below minus 10 ° C, but the cost is too high, and will cause short circuit failure because the temperature is too low, and now the processing technology of semiconductor refrigeration pieces is not perfect, not easy to use.
5, organic chemical cooling
To put it bluntly, organic chemical cooling is the application of some low-temperature compounds, using them to digest and absorb a lot of heat in the case of melting to reduce the temperature. These aspects are more common in the application of liquid nitrogen and liquid nitrogen. For example, the application of liquid nitrogen can reduce the temperature to below minus 20 ° C, there are some more "super abnormal" game players use liquid nitrogen to reduce the CPU temperature to below minus 100 ° C (in theory), naturally because the price is relatively expensive and the delay time is too short, this method is common in the laboratory or extreme CPU overclocking enthusiasts.