Vent Hole Size

Juanito70 · Apr 18, 2018

I would like some help on how to calculate (or an equation to use) to figure out if a vent hole the size of 5 inches is large enough to prevent a vessel from pressurizing. The vessel is 2170ft^3 and the airflow being pumped into the vessel is 80lbs/min. The vessel in at 80 degrees F and at sea level. How do I go about calculating to find out if the vent size of 5 in is enough to prevent the vessel to over pressurize? Please also let me know if I need to provide more information.

rb1957 · Apr 19, 2018

on a simplistic level, if the outlet is a larger area than the inlet then you wouldn't expect appreciable pressure change. Of course this assumes a whole bunch of things like ...
there is good communication between inlet and outlet (not like they're on opposite ends of a maze),
that the inlet pressure is close to the vessel pressure.

if you want an accurate answer then you need to do a pressure flow analysis (like decompression). You have a vessel at a stable pressure (maybe with balanced in and out flows), an inlet flow starting at t=0, and this'll determine how the vessel pressure changes as the outlet flow adjusts to the changed inlet flow. Or maybe you've got a closed vessel and at t=0 you add your inflow and open the outlet.

btw, "vent hole size of 5inches" ... vent diameter of 5" or vent area of 5sq.in ?

another day in paradise, or is paradise one day closer ?

Sparweb · Apr 19, 2018

The FAQ's here:

https://www.eng-tips.com/faq.cfm?pid=378

contain several examples.

STF

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Vent Hole Size

Juanito70

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