The performance of the centrifugal fan is related to many factors, among which the state of the inlet air flow also has a great influence. Generally, in order to adjust the inlet air flow, it mainly relies on the inlet guide vane, that is, the deflector, but it cannot adjust the suction resistance of the air flow, so A collector needs to be installed.
1. The role of centrifugal fan collector
The function of the centrifugal fan concentrator is to suck in and collect the airflow with less resistance, and guide the airflow to evenly fill the inlet of the impeller channel. As an important auxiliary part of the centrifugal fan, the collector and the streamline cover together form a tapered flow channel, which accelerates the airflow and establishes a uniform velocity field and pressure field before the inlet of the centrifugal fan, so as to reduce the flow loss and improve the Centrifugal fan efficiency. The collector is installed in front of the impeller, and the airflow is introduced into the inlet of the fan impeller with a smaller loss. Its geometric shape is different, and the suction resistance is also different. , so that the resistance loss of the airflow entering the impeller is smaller, so as to improve the efficiency of the fan.
2. the form of centrifugal fan collector
The gas flow rate in the collector is not large, the tube length is relatively short, and the flow loss itself is not large. Generally, it can meet the uniform flow field of the inlet conditions and ensure the efficiency. However, the form of the collector will affect the performance of the centrifugal fan. A well-designed collector will have less flow loss, and an unreasonable design will deteriorate the inlet conditions and lead to performance degradation. There are currently three commonly used forms: cylindrical, conical and circle. The three types of collectors have little difference in the influence of the fan pressure rise, and the total pressure efficiency is generally higher in the arc shape, followed by the conical shape, and the cylinder shape is poor.
3. The influence of the collector on the fan
For a centrifugal fan, the collector plays a role in guiding the flow, which plays a decisive role in the inlet airflow condition of the impeller, which in turn affects the aerodynamic performance of the internal flow field of the impeller and the actual operating performance of the fan. If the current collector and the impeller do not cooperate well, the actual operating performance of the fan will not reach the designed performance of the fan:
1. The axial and radial gaps between the collector and the impeller inlet need special control due to the internal leakage of the gas to prevent the pressure and efficiency of the centrifugal fan from being reduced due to improper gaps.
2. The length of the collector inserted into the impeller and the clearance of the impeller inlet ring are directly related to the performance of the fan. Due to the pressure difference between the casing and the collector, the airflow in the casing returns to the impeller inlet through the gap, resulting in leakage loss. The larger the gap, the greater the loss.
The above is the role and influence of the centrifugal fan collector explained by the centrifugal fan manufacturer. I hope it can be helpful to everyone. It is not difficult to see that the current collector and the centrifugal fan deflector have different functions. It cannot change the performance of the fan through active adjustment, so it is necessary to determine a reasonable current collector form when selecting the fan.