composition of dc dc fan:
Fan frame, fan blade, bearing, PCB control circuit, drive motor
Speed:
Speed refers to the speed at which the electric fan rotates, usually measured by the number of turns rolled in 1 minute, that is, rpm. The rotating speed is related to the number of turns of electromechanical winding, wire diameter, outer diameter and bottom diameter of fan blade impeller, blade shape and bearing used, etc. The rotating speed increases and the air volume increases accordingly.
The size of the speed value represents the size of the air volume to a certain extent. When the conditions are punctual, the greater the speed, the noise and oscillation will increase accordingly. Therefore, when the air volume satisfies the heat dissipation requirements, you should try to use Low-speed fans.
The general speed is very small (taking DC axial fan as an example):2510 fan 7000~12000rpm;3010 electric fan 5000~9000rpm;4010 electric fan 5000~7000rpm;5010 electric fan 3500~5000rpm;6025 electric fan 2600~4500rpm;7025 electric fan 2400~3600rpm;8025 electric fan 2000~3500rpm;9225 electric fan 1600~3100rpm;12025 electric fan 1500~2500rpm;12038 2000~3200000 fan.
The speed of DC cooling fan can be tested by BIOS when starting the computer, or by monitoring software provided by other motherboards. It can also be tested by speed tester. Note: The first two methods must be electric fans that support the speed measurement function.
1. DC DC fan air volume and air pressure:
There are two kinds of test methods of air volume and wind pressure, one is to use the wind tunnel test, the other is to use the double box method. But for the average user, there is no such device. Can only be based on the data supplied by the manufacturer as a reference, and ultimately depends on the cooling effect.
2. DC DC fan air volume:
The air volume refers to the product of the plane speed of the ventilation area of the electric fan. The ventilation area is the exit area minus the projected area at the vortex tongue. The plane velocity is the velocity of the gas moving through the entire plane, in m3/s. When the plane speed is punctual, the larger the outer diameter of the fan blade impeller, the larger the ventilation area and the greater the air volume. The plane speed is determined by the rotational speed of the rotor and the wind pressure. When the ventilation area is punctual, the greater the plane speed, the greater the air volume. The greater the air volume, the greater the heat absorption of the air, the more heat can be taken away when the air is moving, and the more significant the fan heat effect.
3. DC DC fan wind pressure:
In order to carry out normal ventilation and overcome the resistance in the ventilation stroke, the electric fan must generate pressure to overcome the resistance of air supply. The measured change value of pressure is called static pressure, that is, the differential pressure between zui large static pressure and atmospheric pressure. It is the pressure of the gas acting parallel to the surface of the object, and the static pressure is measured through a hole perpendicular to its surface. The kinetic energy required in the gas activity is converted into a form of pressure called dynamic pressure.
In order to complete the purpose of air supply, static pressure and dynamic pressure are required. The total pressure is the algebraic sum of static pressure and dynamic pressure. The total pressure refers to the total pressure increase given by the electric fan, that is, the difference between the total pressure between the outlet and the inlet. In practice, the nominal zui wind value is not the air supply volume obtained by the practical fan heat plate. Large air volume does not mean strong ventilation capacity. When the air is active, the air flow will encounter the obstruction of the fan heat plate or element in its active path, and its impedance will restrict the air to flow freely. That is, when the air volume increases, the wind pressure will decrease. Therefore, there must be a zui good operating point, that is, the intersection of the fan performance curve and the wind resistance curve. At the operating point, the slope of the fan characteristic curve is the smallest, and the rate of change of the system characteristic curve is the lowest. Pay attention to the static efficiency of the electric fan (air volume × air pressure ÷ power consumption) at this moment. Of course, sometimes in order to reduce the impedance of the system, and even choose a smaller size of the fan, you can also get the same air volume.
Main performance parameters:
The main parameters of the cooling fan include flow, pressure, speed, power, etc...