Centrifugal fans are used as the main ventilation equipment in most occasions where ventilation is required, but in the production workshop, a device that expands outwards, that is, a diffuser, is often installed at the outlet of the volute. Then why install a diffuser What about the device? What is the function of the centrifugal fan diffuser?
1)Reasons for installing diffusers in centrifugal fans
In many occasions, the centrifugal fan has a large outlet speed, and the corresponding kinetic energy is also large. If the fan is used for extraction ventilation, this part of the kinetic energy will be lost as useless work. In order to effectively use this part of the kinetic energy, the An outlet diffuser is added behind the outlet of the volute of the centrifugal fan. When the airflow passes through the diffuser, due to the continuous expansion of the channel area, part of the kinetic energy will be converted into static pressure energy, thereby improving the static pressure and efficiency of the centrifugal fan and reducing the dynamic pressure loss at the diffuser outlet.
2)The function and principle of centrifugal fan diffuser
1. The role of the diffuser: The centrifugal fan diffuser is also called the outlet diffuser, which can convert the kinetic energy of the air into pressure energy. decrease), so the pressure energy (static energy) increases. The function of the diffuser installed at the fan outlet is to convert part of the kinetic energy of the airflow at the fan outlet into static pressure energy, reduce the flow loss at the outlet, and improve the static pressure efficiency of the centrifugal fan.
2. The principle of the diffuser: In a single-stage centrifugal fan, the gas enters the impeller from the axial direction, and the gas changes into the radial direction when it flows through the impeller, and then enters the diffuser. In a diffuser, the gas changes the direction of flow causing a deceleration, which converts kinetic energy into pressure energy. The pressure increase occurs mainly in the impeller, and secondly in the diffusion process.
3) the installation requirements of the diffuser
1. Since the airflow at the outlet of the fan is usually deflected toward the rotation direction of the impeller, the outlet diffuser should spread in the same direction, not in the opposite direction of the optional impeller.
2. The width of the diffuser is generally equal to the width of the volute of the centrifugal fan.
3. The diffuser generally has a diffusion angle that is deflected by 6 to 8 degrees in the direction of rotation of the impeller, so that the speed carried by the airflow can adapt to the helical motion of the gas and reduce the vortex loss.
4. Sometimes in order to reduce the length of the diffuser, the deflection angle of the diffuser can be appropriately increased to 10 to 12 degrees.
Regarding the role of the industrial centrifugal fan diffuser, the above is the entire content of the centrifugal fan manufacturer’s explanation. I hope it can be helpful to everyone. There are two types of diffusers commonly used in centrifugal fans: equal-width asymmetric diffusers and conical diffusers. You can choose them according to your needs when designing and selecting fans.
