Pressure Drop Calculations for Double-walled Pipe

[swilson3]

Hi all,

I am looking to (roughly) calculate pressure drops for ventilation air across the outer area of double walled fittings (elbows, straights). I can't seem to find any literature on how to best approximate this type of losses. ie a DN125 pipe inside the DN300 pipe where the ventilation air flows through the outer section of the pipe.

Thanks!

sw

 

[Artisi]

how about only posting in one forum.


It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[bimr]

You probably will have to obtain this information from a manufacturer of double wall piping.

 

[LittleInch]

You need to do a search on this site and others for "flow in annular"

Then you find things like this....

https://www.eng-tips.com/faqs.cfm?fid=1142

It isn't a very common issue so there isn't much about, but the methods in the FAQ look pretty good to me.

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

 

[MortenA]

use equivalent diameter (more here):

http://web2.clarkson.edu/projects/subramanian/ch330/notes/Pipe Flow Calculations.pdf