The principle and structure of centrifugal fan
Feb 07, 2025
The principle and structure of the centrifugal fan are mainly based on the centrifugal force to achieve gas transportation. The core is composed of impeller, casing, air inlet and other components. The following is a specific analysis:
I. Working principle Centrifugal force drives gas movement
When the motor drives the impeller to rotate at high speed, the blades force the gas to move in a circle with the impeller, generating centrifugal force. Under the action of centrifugal force, the gas is thrown from the center of the impeller to the edge, and the kinetic energy increases.
Kinetic energy is converted into pressure energy
The thrown gas enters the volute-shaped casing (diffuser), the flow rate decreases, the kinetic energy is converted into pressure energy, and finally discharged through the outlet. At the same time, a low-pressure area is formed in the center of the impeller due to gas discharge, and the external gas is continuously sucked in from the air inlet to complete the cycle.
II. Core structural components
1. Impeller
Composition: blades, front disc (wheel cover), rear disc (wheel disc), shaft disc (wheel hub).
Design influence: Backward blades (β>90°): small energy loss, high efficiency, but low output static pressure.
Forward blades (β<90°): high output static pressure, but high noise and low efficiency.
2. Casing (volute)
Function: collect and guide gas, convert kinetic energy into pressure energy through spiral structure.
Material: usually welded thin steel plates, strength and gas flow efficiency must be taken into account.
3. Air inlet (collector)
Optimize the gas intake path and reduce flow resistance.
4. Drive device
The motor is connected to the impeller through the main shaft to provide rotational power.
5. Auxiliary structure
Ring wall and seat: used to fix the rotor and form a storage space to enhance stability.
Adjust the damper: control the gas flow to meet the needs of different working conditions.