
Centrifugal Fans have a motor in the center to which the impeller is attached, and don't have a frame like that of axial fans.
While axial fans draw in air axially and discharge it in the same direction from the other side, Centrifugal Fans draw in air axially and discharge it radially, changing the direction by 90°. Centrifugal Fans can be optimized by attaching an inlet nozzle so that air can be efficiently drawn in. The inlet nozzle helps Centrifugal Fans draw in air efficiently by separating the inlet space and outlet space, maximizing the performance.
Fig.1 Centrifugal Fan structure
Fig.2 Wind speed comparison with axial fan
Fig. 3 System impedance and P-Q performance curves
The structure of Centrifugal Fans is completely different from that of axial fans, so there is no stall region in the P-Q performance curve, whereas axial fans have one in the horizontal part of the P-Q performance curve. Therefore, the P-Q performance curve of Centrifugal Fans is almost a straight line. Also, the power consumption curve and the sound pressure level curve vary by model.
Fig. 3 System impedance and P-Q performance curves
Since Centrifugal Fans don't have a stall region in the P-Q performance curve, the operating range against the system impedance curve is wider than that of axial fans. Although the power consumption curve and sound pressure level curve of Centrifugal Fans vary by model, the sound pressure level and power consumption can be lower than axial fans used at the same operating point.
Being capable of drawing in air strongly with high static pressure, Centrifugal Fans are suitable for applications that require large air displacement, such as ventilating the interiors of large equipment and cooling heat exchangers.
Date of publication: December 16, 2020