Posted:
Mon Mar 15, 2004 10:18 amby chicosaurus
Hi
I am in the process of building a flowbench. I would like to find out if any of you have the formulas (in Excel ?) for calculating the flow across an orifice.
Posted:
Tue Mar 16, 2004 8:29 pmby 84-1074663779
This is the problem, the devil is in the fine details. A lot depends on the diameter/thickness of the orifice and upstream airflow conditions (turbulent/still/laminar).
If the air already has some flow velocity towards the orifice the flow coefficient is going to be very slightly higher. Still air is going to be lower, and highly turbulent air lower still.
I agree with Mouse 0.7 is too high. 0.62 is probably a wee bit low, but it is going to be pretty close and an excellent starting point.
What you end up with will depend on the internal flow dynamics of your particular bench, and it will be different from another bench.