.TRANSFORM.Fluid.ClosureRelations.PressureLoss.Functions.Tees.K_branchDiverging_Crane

Information

Branch loss coefficient for a dividing-flow tee or wye (Crane TP-410), referenced to the velocity head of the combined (run-inlet) flow:

K_branch = G[1 + H(Qr/β²)² - J(Qr/β²)cosθ]

where Qr = Q_branch/Q_comb, β = D_branch/D_run and θ is the branch angle. The explicit cosθ term captures the take-off-angle dependence (a 45° wye is less lossy than a 90° tee). Validated against Crane Example 7-36 (K_branchDiverging_Crane(0.146,0.146,0.02525,0.01583,45°) = 0.464).

References

Crane Co. Flow of Fluids Through Valves, Fittings, and Pipe (Technical Paper No. 410), 2009.

Interface

function K_branchDiverging_Crane
  extends TRANSFORM.Icons.Function;
  input SI.Length D_run "Run (combined) pipe diameter";
  input SI.Length D_branch "Branch pipe diameter";
  input SI.VolumeFlowRate V_run "Volumetric flow in the run/straight leg (magnitude)";
  input SI.VolumeFlowRate V_branch "Volumetric flow in the branch leg (magnitude)";
  input SI.Angle angle "Angle between branch and run (tee=90 deg, wye<90 deg)";
  output Units.NonDim K "Resistance coefficient";
end K_branchDiverging_Crane;