NSEARCH
Well-known member
I need the value of the fricition loss through a 2" dia. sch. 40 PVC plug valve. Hook me up!
Friction Loss - plug valve
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J
JasonT33
hL = K * v^2/2g
K = 0.34
K = 0.34
NSEARCH
Well-known member
Equivalent length method.......should be around 1.5 or higher.
J
JasonT33
Sorry didnt know thats what you were looking for
just back calculate using K value...
K = f * (Leq/D)
just back calculate using K value...
K = f * (Leq/D)
J
JasonT33
sorry forgot to give you f
f = 0.019 2" sched. 40
f = 0.019 2" sched. 40
3
3gorgesdam
Jason, I need a bit more detailed procedure here. How did you get friction factor f? I try to use moody diagram, but I don't have enough info to get f. Not knowing Re, only knows relative roughness (e/D). What is the equivalent length for 2" plug valve. Does it have another term for plug valve?
J
JasonT33
If flow is in the zone of complete turbulence, friction factor varies only with valve and fitting size and is independent of the Reynold's number.
This f value is NOT the friction factor of the fluid flowing in the pipe (Darcy equation)
Be careful not to mismatch friction factors, you can get about a 50-60% difference in pressure drop if you do
This f value is NOT the friction factor of the fluid flowing in the pipe (Darcy equation)
Be careful not to mismatch friction factors, you can get about a 50-60% difference in pressure drop if you do
3
3gorgesdam
stil have no clue where you pull out these numbers. one f is Darcy friction factor, one is split factor. in CERM 17-12 I can't tell from the description on loss coefficient K = f*Le/D that f is not Darcy coefficient.
Again, if you could go over my questions one by one, it would be much more helpful. :girl:
Again, if you could go over my questions one by one, it would be much more helpful. :girl:
J
JasonT33
Pull out what numbers?
K value is manufacturer specific.
Ok list the questions one by one and I will answer them. I guess I am confused as to what you are asking.
K value is manufacturer specific.
Ok list the questions one by one and I will answer them. I guess I am confused as to what you are asking.
3
3gorgesdam
What is the equivalent length for 2" plug valve?
How did you come up with f=0.019?
How did you come up with K=0.34.
Thanks for being informative. :study
J
JasonT33
K values and f values in some circumstances are given because they are manufacturer specific. If you find a manufacturer for 2" PVC plug valves, they will give you a typical K value and f values to use.
The way the problem was written initially doesnt give you enough information to get an answer unless you have manufacturer specific values for loss coefficients and friction factors. I just looked up info from a vendor I use for PVC pipe here in Florida. In most circumstances the vendor will have a table of equivalent lengths for the engineer to use.
The way the problem was written initially doesnt give you enough information to get an answer unless you have manufacturer specific values for loss coefficients and friction factors. I just looked up info from a vendor I use for PVC pipe here in Florida. In most circumstances the vendor will have a table of equivalent lengths for the engineer to use.
3
3gorgesdam
Thanks Jason. That explains why I couldn't come up with what you did after reading CERM on Minor Losses over and over yesterday and still missed something. :tone:
J
JasonT33
Thats my fault I wasnt clear in my responses..
For minor losses, you have two options for calculation
equivalent lengths and loss coefficients
Usually with equivalent lengths, you will have a table which give you values for different fitting types, etc.
Loss coeffecients are minor losses expressed as multiples of the velocity.
For the afternoon WR module you will most likely be given data to use in one of the two options outlined above.
Hope this helps.. if you have a specific problem you want me to help you with, post the problem and I can guide you through
Good luck
For minor losses, you have two options for calculation
equivalent lengths and loss coefficients
Usually with equivalent lengths, you will have a table which give you values for different fitting types, etc.
Loss coeffecients are minor losses expressed as multiples of the velocity.
For the afternoon WR module you will most likely be given data to use in one of the two options outlined above.
Hope this helps.. if you have a specific problem you want me to help you with, post the problem and I can guide you through
Good luck
3
3gorgesdam
It does help. I am glad I got a chance to review minor losses due to friction using two different methods. I am only going to deal with WR in the morning. Thanks. :wav
