For enterprise production, centrifugal fans are often used for boiler induced draft fans and blowers. The guide vanes of the air inlet are temporarily closed each time they are started, and the entire guide vane is the deflector of the fan. The role of the deflector what is it then? What effect does the installation angle of the guide vane have on the fan?
1) The role of centrifugal fan deflector
1. Function: The deflector is a component used at the air inlet of the centrifugal fan to adjust the load of the fan. By changing the angle (opening) of the deflector blades, the performance of the fan can be changed, the working range can be expanded and the economy of adjustment can be improved, and the internal flow of the impeller can be improved, thereby greatly improving the overall efficiency of the fan.
2. Classification: Common deflectors include simple deflectors, axial deflectors and inclined vane deflectors.
(1) The simple deflector consists of several flat guide vanes with rotating shafts evenly distributed along the cross section. It is installed in front of the airflow turning area of the intake box, and the flow is controlled by adjusting the angle of the baffle.
(2) The axial deflector and the oblique-blade deflector are often installed before the air inlet, and are composed of several fan-shaped guide vanes with rotating shafts evenly distributed along the circumference of the fan inlet, and the rotating shaft of each guide vane is driven by a linkage mechanism. , make each guide vane synchronously change the angle from 90° (fully closed) to 0° (fully open), and control the angle of the airflow entering the impeller to adjust the flow.
2)The influence of the guide vane of the deflector on the fan
1. The greater the angle between the guide vane and the horizontal direction, the greater the airflow speed along the direction of the guide plate, but the faster the attenuation of the airflow speed in the horizontal direction.
2. The longer the length of the guide vane, the smoother the change of airflow speed. Under the initial conditions of the same speed of the fan, the longer the length of the deflector, the more obvious the linear trend of the airflow velocity at the same position along the direction of the deflector.
3. When the installation angle of the guide vane is equal to 0°, the guide vane basically has no effect on the inlet airflow, and the airflow will flow into the impeller blade in a radial direction.
4. When the installation angle of the guide vane is greater than 0°, the inlet guide vane will deflect the speed of the airflow inlet by a guide vane installation angle along the circumferential speed direction, and at the same time have a certain throttling effect on the speed of the airflow inlet. The throttling effect will cause the performance curve of the centrifugal fan to drop, so that the operating point changes and the fan flow can be adjusted.
The above is the role of the centrifugal fan deflector and the influence of the guide vane on the fan explained by the centrifugal fan manufacturer. I hope it can be helpful to everyone.