Basic structure, working principle, performance curve, and common faults of centrifugal fans

Centrifugal fan is a common and important aerodynamic equipment. Understanding its basic structure, working principle, performance curve, and common faults can help everyone better use and maintain it.

Basic structure:

The basic structure of a fan includes the main components such as the volute, impeller, drive device, and housing. The snail shell is the outer shell of a fan, with a conical or spiral shape, used to guide the flow of gas.

The impeller is the core component of a fan, usually a curved blade, responsible for accelerating gas and generating airflow.

The driving device can be an electric motor or other power source used to drive the impeller to rotate. The shell wraps around the entire structure, providing protection and support.

Working principle:

The working principle of a fan is based on the principles of momentum conservation and energy conservation. When the impeller rotates, the air is accelerated by the blades, forming a high-speed airflow. Due to the conservation of momentum, air generates opposite reaction forces while accelerating, causing the gas to be pushed towards the volute.

In the snail shell, gas expands, generates airflow, and is discharged. Throughout the process, the centrifugal fan converts mechanical energy into kinetic energy of the gas, achieving acceleration and transportation of the gas.

Performance curve:

The performance of a fan is usually represented by a performance curve, which includes parameters such as flow rate, head, and efficiency.

Flow rate represents the volume of gas passing through a fan per unit time, head represents the gas pressure that the fan can provide, and efficiency represents the effectiveness of energy conversion.

The performance curve is an important basis for the design and selection of wind turbines, and different points are selected at different positions on the performance curve under different operating conditions.

Common faults:

Although centrifugal fans are stable and reliable equipment, some common malfunctions may still occur. This includes:

Bearing failure: Long term operation or improper use may cause bearing wear or damage, which in turn can affect the stability and efficiency of the fan.

Unbalance: The imbalance of the impeller or drive device may cause vibration and noise, affecting the normal operation of the fan.

Spiral shell wear: Due to the impact and friction of air particles, the inner wall of the spiral shell may wear, affecting the performance of the fan.

Motor malfunction: Motor malfunctions include overheating, insulation damage, etc., which may cause the fan to fail to start normally or provide sufficient power.

Import blockage: If the inlet is blocked by debris, it will cause a decrease in airflow, affecting the flow rate and performance of the fan.

Regular maintenance and inspection are crucial to prevent and resolve these common faults. Regular replacement of bearings, cleaning of volutes, balancing of impellers, and maintenance of motors are all measures that help extend the service life of fans and ensure their efficient and stable operation.

Overall, as a key gas conveying equipment, centrifugal fans require a deep understanding of their basic structure, working principle, performance curve, and common faults. Through proper selection and maintenance, fans will provide reliable ventilation and air conditioning solutions for various industries.