The fan generates negative pressure by the rotation of the impeller to extract flue gas, maintaining the operation of the boiler system.
The working principle and function of the fan core lie in generating negative pressure through the rotation of the impeller, extracting hot flue gas from the boiler and maintaining stable operation of the system. Below is a specific analysis:
Working Principle
1. Power drive and impeller rotation: When the motor drives the impeller to rotate at high speed, the blades accelerate the airflow. This process is based on the working principle of axial flow fans, and the impeller design follows the principles of fluid mechanics (such as airfoil theory), creating a pressure difference on the blade surface.
2. Energy Conversion: When the flue gas passes through the impeller, kinetic energy is converted into static pressure energy, and further converts kinetic energy into the required pressure through the guide vanes and diffuser. The key components involved here include: inlet guide vanes, outlet guide vanes, diffuser, etc.
3. Negative pressure formation and airflow control: The rotation of the impeller leads to a decrease in exhaust port pressure (Bernoulli's principle), forming a negative pressure zone that promotes the suction and discharge of flue gas. The operating range of the induced draft fan is limited by the stall line; exceeding this may trigger surge (periodic airflow backflow), requiring monitoring and alarm through stall measurement points.