Centrifugal fans rely on input mechanical energy to increase gas pressure and send gas to side by side. It is a driven fluid machinery. Centrifugal fans are widely used for ventilation, dust discharge and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings; ventilation and draught of boilers and industrial furnaces; cooling and ventilation of air conditioning equipment and household electrical appliances; drying and selection of grain; wind tunnel air and hovercraft inflating and propulsion.
The function of centrifugal fan
The working principle of centrifugal fan is basically the same as that of turbo compressor. Only because the gas velocity is low and the pressure changes little, it is not necessary to consider the change of gas specific volume, that is, to treat the gas as an incompressible fluid.
Centrifugal fans can be made into two types, namely right-handed and left-handed. Viewed from the side of the motor, the impeller rotates clockwise. It is called the right rotating fan, and is rotated counterclockwise.
Centrifugal fan is based on the principle of converting kinetic energy into potential energy, and accelerates the gas with high speed rotating impeller, then decelerates and changes the direction of flow, so that kinetic energy can be converted into potential energy (pressure). In a single-stage centrifugal fan, the gas enters the impeller from the axial direction, and the gas passes through the impeller to change into radial and then enters the diffuser. In diffusers, gas changes the direction of flow, causing deceleration, which reduces kinetic energy to pressure energy. The increase of pressure occurs mainly in the impeller, followed by the diffusion process. In a multi-stage centrifugal fan, the air return is used to make the air flow enter the next impeller, resulting in higher pressure.
Centrifugal fan In essence, it is a variable flow constant pressure device. When the speed is constant, the pressure flow theory curve of the centrifugal fan should be a straight line. Because of the internal loss, the actual characteristic curve is curved. The pressure generated by the centrifugal fan is influenced by the inlet air temperature or density variation. The highest inlet temperature (the lowest air density) produces the lowest pressure. For a given pressure and flow characteristic curve, there is a power and flow characteristic curve. When the blower runs at constant speed, the power required for a given flow increases with decreasing intake temperature.
Tags: Centrifugal fan