air flow calculation

[cjccmc]

I was hoping to have someone sanity check my calculation. I just need a decent ballpark estimate of how much air will flow thru a 2 inch dia opening in a large irregular shaped volume. Air at 7 psig inside and 0 psig outside. I got 60 scfm? Is that close?

 

[Latexman]

I don't think so. I got over 10X that. Post your calcs for more help.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[cjccmc]

I'm too rusty at this to do it from scratch so I used an efunda calculator that gave me 14 lbm/sec. Now I realize I converted wrong. At 13 ft3/lbm for air that comes out to about 11,000 cfm. My other check was a compressed air design guide that showed 90 scfm as max flow for 2" pipe with 5 psi.

 

[cjccmc]

I just can't do math anymore

I had the wrong fluid density. I ran that online calc again and got 14 ft3/sec = 840 cfm.

 

[Latexman]

That looks good. I recall the number I got was in the 800-900 scfm range.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.