Centrifugal fans: characteristic curves
In the industrial field, the flow rate and the prevalence of the system must be taken into consideration when selecting the centrifugal blower. Starting from them, through the characteristic curves, it is possible to calculate the efficiency and the fans turns, to find the most suited according to the different situations.
The characteristic curves depend on the design of the fan and the cochlea and are mainly influenced by the curvature and the angle of application of the blades.
For example, we report the characteristic curves of a backward-bladed centrifugal fan:
The air flow rate in m3/h (Q) is indicated on the abscissa axis, while the prevalence (pressure) in m/m of water (Ht) is indicated on the ordinate axis.
From the diagram we can understand that, at a flow rate of 25,000 mc/h and at a prevalence of 400 mmdca the fan is characterized by a yield of 82% and 1930 rpm.