Problem

When using Discharge Coefficient or Valve Characteristics Curve as the Coefficient Type of a TCV (throttle control valve), what should be entered as the "Headloss Setting" for a boundary override in Darwin Calibrator?

Solution

Darwin Calibrator currently only supports the Headloss Coefficient method for TCV boundary overrides and will override what you have selected in the model with the headloss coefficient that you have entered. Related Enhancement # 630550.

This "headloss setting" is the headloss coefficient (standard K in the headloss equation) that the valve will use for that respective field data snapshot.

When using "Discharge Coefficient" or "Valve Characteristics curve" as the TCV's Coefficient type, Darwin will override this with the type "headloss coefficient" and force the headloss coefficient that you enter as the "headloss setting".

To find the appropriate headloss coefficient (headloss setting) to use for the valve, run a steady state simulation with your TCV set the way you want it in that snapshot. For example if you want it to be 50% closed and you're using the Valve Characteristics Curve Coefficient Type, set the "Relative Closure (initial)" to 50%. if you're using Discharge Coefficient as the Coefficient Type, set the appropriate value in the "discharge coefficient (initial)" field. After computing steady state, look in the Results section of the TCV properties and locate the field called "Headloss Coefficient Setting (Calculated)". This is the value you'd use in Darwin Calibrator, to achieve the same headloss characteristics.

See Also