A fan can run at 600 - 2000 RPM, at 2000 RPM it has 50 m3/h airflow.
0% = 0 RPM
100% = 2000 RPM
At 50% = 1000 RPM is the airflow halved to 25 m3/h?
$\begingroup$
$\endgroup$
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
3
Yes it does. Check this link.
The First Fan laws: Volume of Air
The first law of fans is a useful tool when working out the volumetric flow rate supplied by a fan under speed control or conversely working out what the RPM would be to deliver a required volume of air and hence what frequency to set a variable speed drive (VSD) to.
Volumetric flow rate (V, m³/hr) varies directly proportional to the ratio of the rotational speed (RPM) of the impeller.
$V_2 = (\frac{U_2}{U_1})V_1$
Where:
: Volume 1, m³/hr – Original volume of air
: Volume 2, m³/hr – New Volume of air
: RPM 1 u/min – Original Speed
: RPM 2, u/min – New Speed
-
$\begingroup$ It might be worth pointing out that the energy requirement will be far from linear. I seem to remember a cube law in action. $\endgroup$ May 9, 2020 at 7:09
-
$\begingroup$ Don’t fans, like propellors eventually stall? $\endgroup$ May 9, 2020 at 10:48
-
$\begingroup$ @Transistor The link I gave tells about that too(The Third Fan Law: Power); and yup its a cube law. $\endgroup$– Manu GMay 9, 2020 at 13:36