Pipe Flow Calculations Forum

OK... Using a U-tube to measure suction pressure. It reads 8.1 inchesWC on the large diameter (4" pipe) and 21.2 inchesWC on the venturi throat (3.025"). Should I be using 398.9 inchesWC for p1 value and 385.8 inchesWC for p2? Tried this, and the flow still calcs to 21% over manufacturers ...

I hope this hasn't been covered yet. I tried the search feature with no luck... I'm trying to measure flowrate (either mass or volumetric, I don't care) for a ring blower. The blower is controlled with a VFD, and will have varying backpressure. I'd like to use a venturi/nozzle/orifce (still working ...