Calculate the flow coefficient and pressure drop through valve
Calculate the flow coefficient and pressure drop through valve
(OP)
Hi
I am wondering would ye be able to help me out? I am instructed with the task of calculating the pressure drop and flow coefficient for a valve. Please see basic diagram attached for layout of valve. I need to find the pressure drop and flow coefficient when the ram is closed at different percentages. would ye be able to tell me the necessary equations that i need to do this. note internal diameter is 100mm at inlet and 50mm at outlet.The valve shown would be connected to the bottom a reactor etc. the pressure entering is set at 100 bar. Thanks for yer help in advance
Regards Dave
I am wondering would ye be able to help me out? I am instructed with the task of calculating the pressure drop and flow coefficient for a valve. Please see basic diagram attached for layout of valve. I need to find the pressure drop and flow coefficient when the ram is closed at different percentages. would ye be able to tell me the necessary equations that i need to do this. note internal diameter is 100mm at inlet and 50mm at outlet.The valve shown would be connected to the bottom a reactor etc. the pressure entering is set at 100 bar. Thanks for yer help in advance
Regards Dave





RE: Calculate the flow coefficient and pressure drop through valve
if this is a custom made valve, then you will need additional means of measuring pressure and flow. no doubt, a time-consuming task.
good luck!
-pmover
RE: Calculate the flow coefficient and pressure drop through valve
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Calculate the flow coefficient and pressure drop through valve
The Cv is measured using simple tests with air or water. The Xt is important only if the application will involve a flow of gas that involves a pressure drop greater than about 50% of the inlet absolute pressure. So, if the Reactor is below 50 bar when the supply pressue is 100 bar, then you will need to also calcualte the Xt value.
RE: Calculate the flow coefficient and pressure drop through valve
RE: Calculate the flow coefficient and pressure drop through valve
If you cannot find manufacturers with similarly constructed valves, then ask your professor that gave you the problem for some help.
RE: Calculate the flow coefficient and pressure drop through valve
It will at least provide a near equivalent which can help you see if your calculations are on the right lines.
The link is here FISHER:
JMW
www.ViscoAnalyser.com
RE: Calculate the flow coefficient and pressure drop through valve
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Calculate the flow coefficient and pressure drop through valve
dP = 0.5*rho*Q^2*(1/Ac^2 - 1/A1^2)
(Ac=throat area, assume physical area-circular segment). Using following conversion-factors an expression for the flow coefficient Cv (US gpm @ 1 psi pressure drop)
1 psi = 6894.7 Pa
1 US gpm = 6.309E-5 m^3/s
Cv = sqrt(6894.7*(1/Ac^2-1/A1^2)^(-1) /(rho * 0.5) )/6.309E-5
At large/fully open the geometry kind of resembles a junction. Perhaps the loss coeff for this geometry can be used as a rough estimate
Good luck
RE: Calculate the flow coefficient and pressure drop through valve