Pressure Drop Of Four-Way Pipe Fitting/cross

Hello everyone,

I am currently trying to calculate the pressure drop for the modification of an existing piping system in a tank vapour system. The problem I am facing is that instead of regular elbows or bends, every change of direction of the line is done with a four-way pipe fitting (they look similar to this one: http://www.testbourn...-cross-aluminum), so e.g. the flow enters from the left branch and leaves at the the bottom branch, while the top and right branch are closed with a blind flange. We are not entirely sure why these four-way fittings were used in the first place, our best guess is that it has to do with the double-jacket that is used to heat the lines.

Are any K-values documented for this situation anywhere?

So far I haven't found anything, so I resorted to using a K value of 1,7 (Figure 2-16 from Crane TP 410), but I'm unsure if the additional branch causes further turbulence and pressure drop that is not accounted for in the aforementioned K-value.

Unfortunately there are quite many of these fittings in the most critical part of the line system, and they cause about 50% of the total pressure drop (using the K value of 1,7), so it's probably worthwhile to find a proper K-value.

Any help would be appreciated.

Kind regards

Philipp

Hi,

I would consider that as 90 degree short radius elbow and do the calculations

Regards

Could you find a section of piping where you could reasonably compare a calculated dP to measured dP and adjust the calculated value by varying the K that you use as the baseline? This way, you would have a better approximation for the other points in your network as well.

In my opinion you can consider fitting as a standard tee with flow through branch. 

Hi,

Consider the pamphlet attached(KSB)  you will find a combination of elbows .

Another good resource is pipe flow , a practical and comprehensive guide by Donald C.Rennels and Hobart M. Hudson

Good luck 

Breizh

Edited by breizh, 01 March 2020 - 04:41 AM.