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7.5 Calculating Mass Flow with the SuperFlow Flowbench
SuperFlow flow benches measure flow “as if you had tested at 60 F and at Sea Level, or 29.92 inches
of mercury. We call this “Flow Bench Flow”. In order to estimate mass flow of air that is actually flowing
through your part, we must first convert the Flow Bench Flow to ACFM.
You must collect the ambient barometric pressure and the temperature of the air that is flowing through
your part first. If your flow bench is equipped with FlowCom, then those measurements can be collected
from the FlowCom. Once you have the atmospheric conditions, you can calculate the density of the air as
follows:
1.
Collect Orifice Temperature in Deg F.
2. Collect Barometric Pressure (Baro_P) in InHg.
3.
Convert Orifice Temp to Degrees Rankin:
T = Orifice Temp +459.67
4. Calculate Air Density (lb/cu. Foot):
AIR DENSITY = 0.0763
X
BaroP
29.92
519.67
(T + 459.67)
X
5. Calculate ACFM:
ACFM = FLOW
X
29.92
BaroP
(T + 459.67)
519.67
X
6. Calculate Mass Flow: (Lb/sec this case)
MASS FLOW (Qm) = Air Den
x
ACFM
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7.0 Flowbench Theory
