Constituent concentration sensitivity to pipe roughness

  Product(s): Bentley WaterGEMS, WaterCAD
  Version(s): All
  Environment: N\A
  Area: Modeling
  Subarea: N\A


Will chlorine (constituent) concentration change if I change the pipe roughness?


When the Decay reaction rate is of the first order (or higher), the concentration at time t is represented by:

Ct = C0e-Kt
where K = kbulk + kwall x kf x (Rh(kwall + kf))^(-1)
and kwall = α / Hazen Williams C Factor and α ranges from 0 to 100.

So, the constituent concentration from above equations, we can see, is related to pipe roughness factor. This will not be true when the decay reaction is of the 0th order.

Note: in WaterCAD and WaterGEMS, the Constituents dialog has a check box for "Is Rougness Correlated".

See Also