what is the effect in air flow discharge if i introduce a perforated plate in a duct?
i have opening of 1m x 1m and in that opening i want to mount a perforated plate of the same size with 40% porosity what is the effect in air flow discharge before the perforated plate and after the perforated plate mounting. air velocity is constant at 8 m/s.
what kind of simulation i can do for finding this air flow rate?
is there any standards available for this?
if i want to do practical testing then which methods i can follow?
2 Answers
I don't quite get what air flow discharge means, but this appears to be a standard problem: calculating the -> hydraulic resistance of an obstacle in a fluid.
Here: compressible fluid (air), room temperature (only guessing), humidity noncondensing (again).
There will be kinetic energy converted to thermal as always, which one measures as pressure drop over that barrier. Geometry both large and small matters! There are whole books about this ... see some helpful diagrams here: https://www.schweizer-fn.de/zeta/gitter/gitter.php
Totally dependent on the plate in question. Typically, the manufacturer will supply you with the 'clean' pressure drop (mbar-m^2/m^3/min) value across various grades of filters offered. Values for gaseous or liquid service.
You then use those values, the the desired flow rate, ratio of viscosities and the total filter area to arrive at a pressure drop. It's been a while, but I've never relied on CFD for this, simply due to the disparity in pressure drop across the multitudes of filter media out there.
If you contact a manufacturer, they'll walk you through the process. That's what they're there for. If you're doing this for a CFD study then stick to a simple diffusion plate. Anything more complex and the results are spurious at best.
