Headloss through a diverting Wye fitting

[Kevlo79]

I'm working on the design of pumped biosolids system in which I have a diverting Wye fitting (lateral) prior to the pump suction. I need to determine the dynamic losses through this fitting. The pump is fed by gravity from a holding tank that is significantly higher in elevation. The system has a second pump that acts as a backup and has a true wye fitting that I also need to determine losses through (only one pump will drive at a time). I'm sure the difference in loss comparing these fittings to a 45deg bend is minor but my engineering ocd has decided that it's time to find the correct formulas! I appreciate any help!

 

[katmar]

This situation (all flow in branch, no flow in run) is described by Idelchik 3rd Ed Fig 7-8. This shows a K value of 0.6 at Re = 4,000, decreasing to a K of 0.5 at Re = 40,000 for a 45 degree wye. These values are slightly more than double what I would expect for a long radius 45 degree bend. But at the velocities normally used in pump suctions this would result in such a small pressure drop it could really be ignored. The uncertainty in the pressure drop due to your solids will be far more significant.

Katmar Software - Uconeer 3.0

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[bimr]

The only resource that discusses headlosses in depth is the Cranses Technical Paper 401. The other sources are rougher estimates. For that reason, the other sources do not go into much depth because it is pointless to make a precise rough estimate.