RV Inlet dP - small tees

[Bill3752]

How do you folks handle the inlet dP calcs for the following case: Flow from vessel runs through tee (i.e. run-thru tee), where the side tee is a bleed line that is valved off. I have run into several situations where the size tee is say 1", whereas the run thru (main line) is 4" - 20". Doesn't seem like the standard L/D = 20 would apply here. Take the case where a bleed line is 1/8" on a pipe with diameter 10"; I can't imagine I would get the same dP as with a 10 x 10 tee, especially if the tee were valved out.

Thanks, Bill

 

[JohnGP]

A bleed line, especially if closed off, is not going to have much (if any) influence on head loss through the run. My old copy of Miller's Internal Flow Systems indicates that the flow loss co-efficient for the run is close to zero until the flow to the branch exceeds 50% of the flow coming into the tee.
Cheers,
John

 

[Bill3752]

John thanks for the input. Would it be possible to scan that page and post it here? I could not find a copy in the local University Library.

I was told yesterday that another approach is to assume the tee is simply a piece of pipe when the side branch diameter is <=50% of the main run.

 

[JohnGP]

Here you go.
Cheers,
John

 

[Bill3752]

Thanks much John!