Pressure Loss Calculations in 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

 

[chicopee]

Another word, do you want to figure out the pressure drop within the annular space? if so I would figure out the hydraulic radius of the annular space in order to determine the cross sectional area based on the hydraulic radius from which pressure drop calculations can be performed.

 

[swilson3]

Chicopee,

Thanks for the reply.

Working with the hydraulic radius is essentially what I have been looking at doing, but I am not sure how accurate that simplification is - especially for elbows.

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.)