Air flow measurement

[rth]

I need to measure accurately air flows in the range 0.009 to 0.39 kg/sec. The air is at ambient temperature and near atmospheric pressure. I have used vortex shedding meters in the past for this application but am having great difficulty in locating a supplier of these or any other suitable devices. Any suggestions appreciated.

 

[walz]

You are looking for something to measure mass flow rate...

Try to find volume flow rate metering device.
Multiply the volume flow rate with the density of air (at ambient temperature and atmospheric pressure) to calculate the mass flow rate.

m3/s x kg/m3 = kg/s.

Now since the mass flow rate is known, muliply it with specific volume (m3/kg) to find the range of this meter.

Roughly the specific volume at these conditions of air is 0.858 m3/kg. Hence

0.009 kg/s x 0.858 m3/kg = 0.005265 m3/s = 11 CFM
0.39 kg/s x 0.858 m3/kg = 0.3346 m3/s = 710 CFM

So the range of your flow meter (Volume) becomes 11-710 CFM

I think you can find a good flow meter of this range and then muliply the result with the density to calculate Mass flow rate again

 

[danw2]

Thermal dispersion meters read out directly in mass units.

People like Kurz or Sierra Instrument do insertion flow meters for ducts.