Pressure drop & Noise in T-Globe Valve 1

[Isha90]

How to calculate please,
1. Pressure drop if operating pressure 55.2 bara & temperature 600°C, flow rate 1.166 Kg/S, Cv 9.5 USGPM & bore 19mm
2. Pressure drop if operating pressure 259.6 bara & temperature 599°C, flow rate 1.131 Kg/S, Cv 10.5 USGPM & bore 25mm
3. Noise

 

[CGonsalves]

1. I suggest looking up the equation to determine flow coefficient [Cv = q*(SG/dP)^(0.5)] and work from there.
2. Same as 1 but there's not enough info.
3. I am not sure.

 

[Isha90]

1.In Pressure drop calculation(Steam), Pressure loss grater than fluid pressure.
2.Flow rate, Cv & bore added.

 

[LittleInch]

contact the valve vendor.

Or look up calculations online, especially from valve vendors.

assuming this is liquid, you also need density to get the volume.

noise and checks for choked flow and risk of cavitation also needs additional data on your fluid and its vapour pressures, temperature etc

These are quite high pressures and temperatures - what is it?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Isha90]

Valves are used for drain lines please

 

[CGonsalves]

I'm a little confused about your units here. GPM indicates liquid, but you stated steam. Steam has a different calculation method for Cv.

 

[chemejon]

1. Identify if the condition is critical or not critical by calculating the Cv required for critical pressure drop

F superheat=627.8F (difference in temperature from saturated steam)
k=1+(0.0007*F superheat)
m=9254 lb/hr
Pi=800.6 psia
Cv=9.5

Cv=mk/(1.82*Pi)
Cv=9.142
Valve Cv > Critical Cv,

Thus
Case 1 would be non-critical pressure drop.
Now to calculate pressure drop use the equation for non critical pressure drops

Cv = mk / (2.1 ( (pi + po)*(p1-p2))^1/2)
((Pi+Po)(Pi-Po))^1/2)=mk/2.1Cv
(Pi^2-Po^2)=(mk/2.1Cv)^2
Po^2=Pi^2-(mk/2.1Cv)^2

Po^2= 195127
Po=441.7 psi
dP=800.6-441.7= 358.9=>359 psi

assume ideal gas
density @ inlet conditions = 14.06 kg/m^3
volumetric flowrate=0.08293m^3/s=2.93ft^3/s

P1V1=P2V2
V2=P1V1/P2
V2=5.31 cubic fps

bore=19mm=0.75 in
cross sectional area=0.44 in^2=0.003056 ft^2

velocity = 5.31 ft^3/s /0.003056f ft^2
final velocity = 1737.6 fps

calculate temperature of final steam stream, too lazy to look up steam tables Link

Ti=1112F
Tf=546F

sonic velocity @ outlet conditions aka critical velocity = 1804 fps

mach ratio = 1738/1804=0.963

You can use this link to calculate dBA, but considering its pretty close to Mach 1, its going to be loud af.
Link

Do the same as above for problem 2.

 

[chemejon]

I'm a little confused about your units here. GPM indicates liquid, but you stated steam. Steam has a different calculation method for Cv.

I was thought the GPM was weird too until I found what I forgot after college below.

"The coefficient of flow (Cv) is a formula which is used to determine a valve’s flows under various conditions and to
select the correct valve for a flow application. The Cv was designed for use with liquid flows, it expresses the flow in
gallons per minute of 60º F water with a pressure drop across the valve of 1 psi. However, this same Cv value can be
used to determine gas flows through a valve. The formula becomes more intricate for gases, as gases are a compressible
fluids and are thus affected by temperature."

Link