5 replies to this topic

[tingyik90]

Greetings,

 

I'm a graduate process engineer working in an O&G consultation firm currently. Doing pressure drop calculations of pipeline based on isometrics is almost a daily routine.

 

I have a question regarding pressure drop across a splitting Tee. While there are commonly published values of equivalent length pressure drop for flow across a Tee, is there any published materials regarding a splitting Tee with closed end?

 

Diagram:

 

A ------------> B

           |

          C

 

DEP standard includes the equivalent length to be considered for branch elbows and straight run, but my company spreadsheet also takes into account of the vol. flow ratio of each branch and also the diameter ratio of branch. (Sorry that I do not know the source of its formula.)

 

I do know that for flow from A-->B (a straight run), the pressure drop will be negligible if side C is closed (no flow), since you can intuitively think of it as a straight pipe. This is at least true from my company spreadsheet, K-value = 0. However, if the flow is from A-->C with side B closed, will there be significant pressure drop?

 

I do know that the pressure drop calculated using the spreadsheet is more than the equivalent length provided in DEP for a simple 90deg elbow or a flow from Tee side outlet. The problem is, I think the formula in the spreadsheet should be applied to splitting stream with actual flow on all outlets, instead of no flow. The use of flow ratio of C/A = 1.0 in the spreadsheet might not be the correct way of doing it (again, sorry that I do not know about the formula source and it's application limit).

 

I did tried searching online though. I think research by Gardel might be the one my company used, as shown in http://www.thermoped...om/content/268/, but I have no access to the article nor do I understand French.

 

It will be great if someone can tell by experience that indeed, the pressure drop for a closed Tee is larger than a 90deg elbow, perhaps due to turbulence of vena contracta, etc. Even better if there is a source of literature that I can refer to.

 

Thank you very much.

[breizh]

tingyik90 ,

 

Let you get a copy of : Pipe flow  a practical and comprehensive guide by Donald .C .Rennels and Hobart.M.Hudson . There is a chapter dedicated to tees with references to Gardel's works and others.

 

Hope this helps.

 

Breizh

Edited by breizh, 24 February 2015 - 07:17 PM.

[katmar]

The book mentioned by breizh is the most comprehensive discussion on flow through tees that I am aware of.  Another English language reference is the book "Handbook of Hydraulic Resistance" by IE Idelchick - originally in Russian but the 3rd Ed is available in an English translation published by Jaico in Mumbai.

[Zauberberg]

See attached the chapter related to tees from the Rennels and Hudson's book quoted by Pierre and Harvey - it happens to be available in my digital library. Lucky shot.

 

Attached Files

•  Pipe Flow - Tees.pdf   272.26KB   126 downloads

[tingyik90]

Dear all, thank you very much for pointing me to the literature source! especially to Zauberberg for the pdf, that was really helpful!! 

[Zauberberg]

It was a lucky day. All credits go to Pierre and Harvey who have recommended this excellent resource.