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nadeemnisa
30-01-2009, 10:05 PM
:confused:Please tell me the formula of flow rate of air blower (centrifugal type).

Regards
Nadeem
Brian_UK
30-01-2009, 10:45 PM
Sorry, we are not manufacturers of ventilation fans here.

I suggest you ask somewhere else as this is a refrigeration forum.
Entropie
20-02-2009, 09:40 AM
There are generally two possibilities that i know. One is to measure the air velocitiy in the attached duct work. Using the formula volume flow=hydraulic area (ductwork)* measured velocity, will give you the answer. The other possibilty is to utilize the the absorbed power vs. volume flow / differential pressure chart of the fan manufacturer. Therefore you have to measure the absorbed power of the fan motor. Hope that helps.

regards

Entropie
cool_tech
22-02-2009, 09:02 AM
hi all
the formula is Pt= Ps+Pv
Pressure total = Pressure staitis + pressure velocity
or
quantity= area*volume
if the duct is 2 metres by 2 metres volume is 2 metres/second
= 2x2=4 x 2m/sec= 8 cubic metres/second x that by 1000 = 8 litres a second
frank
22-02-2009, 07:57 PM
hi all
the formula is Pt= Ps+Pv
Pressure total = Pressure staitis + pressure velocity
or
quantity= area*volume
if the duct is 2 metres by 2 metres volume is 2 metres/second
= 2x2=4 x 2m/sec= 8 cubic metres/second x that by 1000 = 8 litres a second

I think you mean velocity not volume.

8m3/s = 8000l/s
wambat
22-02-2009, 08:23 PM
CFM = Q/1.08 x TD

Q = Total BTU or another way is this:
http://www.1728.com/flowrate.htm
Brian_UK
22-02-2009, 10:58 PM
His question is how much air will a centrifugal fan produce, not how to measure it in a duct.
jteixiera
30-03-2009, 07:58 AM
Volume flow rate = Area of the duct X velocity

remember area = pie X diameter squared/ 4
glenn1340
30-03-2009, 06:46 PM
Try this:
www.vent-axia.com/knowledge/handbook/section2/fanlaws.asp (http://www.vent-axia.com/knowledge/handbook/section2/fanlaws.asp)
bharatbaldwa
26-06-2009, 07:53 AM
i too have an blower...its 550 cub.mt per min, and t manufacturer says a value 60mmAq...
I am not sure as to what pressure value to be taken if I use ideal gas law to calculate mass/molar flow rate to calculate air velocity

pls suggest