# What's the flow resistance of a honeycomb sieve?

Honeycomb sieves are starting to see applications in wastewater screening. What is the flow resistance of a honeycomb screen?

I would expect something similar to the Kirschmer formula (used for bar screens):
Headloss = constant, dependent on bar shapes X function of square of velocity

(Actually, the Kirschmer formula would be corrected for angle and for loading of the screen)

where velocity means in the screen, so the free survece is taken into account. While a honeycomb can have a far larger free surface compared to a screen with holes, I would expect the first factor to be different to, as the thinner bars in the honeycomb allow for a different flow regime immediatly downstream.

What is the headloss for flow through a honeycomb screen?

• Might help to provide drawings and 3-D dimensions of the various screens you are discussing. – Carl Witthoft May 23 '18 at 17:51
• approx 6mm diameter of the holes, <1mm width of 'bars', thickness of about 10mm or less in flow direction ... if my hunch is correct, the hole size will determine flow velocity and the shape, width and thickness will determine the constant. So this question should be answerable without the exact dimensions. – mart May 23 '18 at 20:38