View Full Version : fan flow calculation
nasir
19-03-2007, 08:11 AM
please may anybody can help me , how can i calculate the flow of air in CFM if i have the following information
fan dia = 1000 mm
fan speed= 1500 RPM
pich angle= 17(Deg)
No of Blades= 10
Motor= 18.5 KW
TRASH101
19-03-2007, 01:05 PM
Hello
The info you gave is a bit sparse
is it a plate fan , direct drive, what resistance you working against ???
if it is a centrifugal try contacting NICOTRA fans, as they supply a lot of vent. manufacturers
If it is a plate/ axial /bifurcated you could try ELTA fans
Rayin
19-03-2007, 01:12 PM
Hi Nasir,
As you may know, flow rate (in cfm) = Cross sectional area (in sq. ft) * Velocity (ft/minute). You have to find out the velocity. Then only, I think, you can calculate flow rate.
US Iceman
19-03-2007, 06:29 PM
Or you can contact the fan manufacturer and ask for a fan curve. This curve represents the fan performance at various speeds and static pressure.
nh3simman
21-03-2007, 07:28 PM
fan dia = 1000 mm
fan speed= 1500 RPM
pich angle= 17(Deg)
No of Blades= 10
Motor= 18.5 KW
If I understand your question, you have certain limited information and need to make an estimate of the airflow.
There is always a way to make a good guess.
Motor Power = 1.15 x dp x Q / e
dp is the total pressure drop, say 500Pa
e is efficiency, say 65%
the 1.15 is a number used by some manufacturers to prevent overload.
18.5 = 1.15 x 0.5 x Q / 0.65
Q = airflow in cms
Lc_shi
22-03-2007, 01:10 AM
Very good!
It bases on the basic physical principle of
Power = Pressure diff x flow volume
Make sense:)
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