air flow calculations
air flow calculations
(OP)
I am trying to figure out how much air flow is going through a square duct. I have airfoils in line and measuring differential pressure across them. I have the range of the transmitter but don't know how many inches of differential is equivilant to lbs/hr. I have tried to find venturi calculations but have only come up with calculations using pipe diameter. I do have the dimensions of the duct. But other than the specified information, I don't have a whole lot. I would appreciate if anybody could point me in the right direction.





RE: air flow calculations
I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int.
RE: air flow calculations
I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int.
RE: air flow calculations
Your description is a bit sketchy. Differential pressure across some airfoils is not enough to calculate flowrate. If you have a venturi tube, then it's easy and accurate and I can point you to the formulas.
If not, there are a lot of ways to measure airflow. The Dwyer site is a good start. The best method depends on the accuracy you need and the velocity range you expect.
ko (www.ecooling.biz)
RE: air flow calculations
RE: air flow calculations
1. Get average velocity by profiling at regular points over a cross-section of your tube (Dwyer and others have guidelines)
2. Volume flow = average velocity x section area (example: ft3/min = ft/min x ft2)
3. Mass flow = volume flow x air density (example: lb/min = ft3/min x lb/ft3).
You can use this tool to find density: http://www.denysschen.com/catalogue/density.asp
ko (www.ecooling.biz)
RE: air flow calculations
Thanks again.
RE: air flow calculations