What is heat dc cooling fan inherent defects

What is heat dc cooling fan inherent defects? A wide range of form is to use axis diaspora heat fan ( Is very common that the cooling fan) Drum wind down, was so popular because wrapped it in a comprehensive effect and low cost. If the diaspora thermal fan of axial direction, in turn, becomes upward convulsions, in some special types of radiator will use this form. Two kinds of air distribution in the form of the difference lies in the form of air blast is turbulent flow, when the wind pressure big but susceptible to resistance losses; Convulsions is laminar flow, when the wind pressure small but stable airflow. In theory, the turbulence of the cooling efficiency is much bigger than laminar flow, thus become the mainstream design form. Axial flow fan, although widely used, but also has inherent defects. Axial flow fan is block by motor position, air could not flow smooth blast area of central, which is referred to as a 'dead zone'. Low noise dc cooling fan air pressure and air volume are two relative concepts. Heat dissipation dc cooling fan under the manufacturer's cost considerations, to design the cooling fan air volume is big, have to sacrifice some wind pressure. If the cooling fan can bring a lot of air flow, but the wind pressure is small, the wind is less than the bottom of the radiator ( That is why some cooling fan speed is high, volume is very big, but is the cooling effect in not good) , on the contrary, wind pressure is often means that the air volume is small, there is not enough air and heat sink for heat exchange, also causes the cooling effect in bad. All types of radiator is inseparable from the following three kinds of basic heat transfer way, just different needs. 1. Heat conduction, convection and radiation. Substance itself or when in contact with the material, the energy transfer is called a heat conduction, this is a very common way of a kind of heat transfer. For example, direct contact heat dissipation fin base and the cooling fan take away heat is heat conduction. 2. Heat convection: refers to the flow of fluid ( Gas or liquid) Will go tropical way of heat transfer in the cooling system of automobile chassis is common radiator cooling fan drive gas flow 'forced heat convection cooling way. 3. Thermal radiation: refers to rely on the radiation heat transfer, the daily common is solar radiation. The three thermal radiation are not isolated, in daily heat transfer, the three thermal radiation is happening at the same time, work together. Such as ordinary cooling fan cooling cooling fan, radiator surface direct contact heat sink and cooling fan and heat by conduction of heat transfer on the surface of the cooling fan for cooling fan, radiator; Heat dissipation dc cooling fan to produce air through heat convection heat away on the surface of the cooling fan, radiator; And the flow of the air inside the case is also through the heat convection cooling fan cooling fin heat of the surrounding air away, until the case outside; At the same time all around the part of high temperature on low temperature part of the thermal radiation. Radiator heat radiator thermal conductivity of materials, materials and the heat capacity of heat medium radiator and radiator area of effective heat dissipation and so on related parameters.