Pressure Surge Equation for Gases
Pressure Surge Equation for Gases
(OP)
Hi,
I was wondering if there was equation to solve for pressure surges for gases (natural gas in my case) on slow closing valves.
As the only ones I have found is for imcompressible fluids: P = 0.07VL / t + P1, where P1 is the inlet pressure, V is the flow velocity in ft/sec, t is the valve closing time in seconds and L is the upstream pipe length in feet.
Thanks.
I was wondering if there was equation to solve for pressure surges for gases (natural gas in my case) on slow closing valves.
As the only ones I have found is for imcompressible fluids: P = 0.07VL / t + P1, where P1 is the inlet pressure, V is the flow velocity in ft/sec, t is the valve closing time in seconds and L is the upstream pipe length in feet.
Thanks.





RE: Pressure Surge Equation for Gases
Best regards
Morten
RE: Pressure Surge Equation for Gases
RE: Pressure Surge Equation for Gases
Two phase flow will give you surges. This is a very complex subject.
RE: Pressure Surge Equation for Gases
"We don't believe things because they are true, things are true because we believe them."
RE: Pressure Surge Equation for Gases
And dry gas in any condition will not "surge".
Then of course we could start to discuss surges in a compressor - thats the word surge - and gas.
I think we should help the guy. Not confuse matters.
From Wikipedia: surge and lurch, is the rate of change of acceleration; that is, the derivative of acceleration with respect to time, the second derivative of velocity, or the third derivative of position.
Thats pretty OK.
From Webster: to rise and move in waves or billows : swell <the sea was surging> Not so bad either.
IMHO surge = "water hammer". But when its a liquid but its not water its easier to use surge
Best regards
Morten
RE: Pressure Surge Equation for Gases
I see where your coming from. The original posting said the gas was "natural gas". Until processed natural gas contains liquids. I was just trying to warn the original poster of issues that may have not been considered.