The working principle of a centrifugal blower is similar to that of a centrifugal fan, except that the compression process of air is usually carried out through several working impellers (or stages) under the action of centrifugal force. The blower has a high-speed rotating rotor, and the blades on the rotor drive the air to move at high speed. The centrifugal force causes the air to flow along the involute shape of the casing to the fan outlet, and the high-speed airflow has a certain wind pressure. New air enters and replenishes from the center of the casing.

The working principle of a single stage high-speed centrifugal fan is that the prime mover drives the impeller to rotate at high speed through the shaft. The airflow enters the high-speed rotating impeller from the inlet axial direction and becomes radial flow, which is accelerated. Then, it enters the expansion chamber, changes the flow direction and decelerates. This deceleration effect converts the kinetic energy in the high-speed rotating airflow into pressure energy (potential energy), maintaining a stable pressure at the fan outlet.

In theory, the pressure flow characteristic curve of a centrifugal blower is a straight line, but due to friction resistance and other losses inside the blower, the actual pressure flow characteristic curve gradually decreases with the increase of flow rate, and the corresponding power flow curve of the centrifugal blower increases with the increase of flow rate. When the fan operates at a constant speed, the operating point of the fan will move along the pressure flow characteristic curve. The operating point of the fan during operation not only depends on its own performance, but also on the characteristics of the system. When the resistance of the pipeline network increases, the pipeline performance curve will become steeper. The basic principle of fan regulation is to obtain the required operating conditions by changing the performance curve of the fan itself or the characteristic curve of the external pipeline network.