Tee junctions are found in most piping systems in many engineering applications. As such, engineers need to determine the pressure losses across these junctions. Steady-state pressure loss coefficients can be calculated using experimental and analytical expressions. However, the calculation of pressure losses across tee junctions can be a tricky task owing to the fact that flow can be merging, dividing, diverging or converging. In some cases, when we have large complex piping systems, we may not even know what flow condition to expect. The calculation or solution of tee junctions can become further complicated when we have reducing tees not to mention changes in fluid phase state. Figure 1 gives an overview of both converging and diverging flow at tee junctions.

Converging & Diverging Flow at Tee Junctions.
Converging & Diverging Flow at Tee Junctions.

This brief blog considers the solution to tee junctions only. FluidFlow also allows engineers to choose the Crane, Idelchik, Miller or SAE pressure loss relationships for bends/elbows. Wye junctions are also accounted for in the software. 

Watch our video on Modeling Tee Junctions