Headloss across the Flow Control Valve

[Prasanna M]

Hi All,

          I just want to know how does EPAnet calculates Head loss across the Flow Control Valve. Its clear that unlike in pipes, head loss for FCV is not mentioned in unit head loss and rather simply as "Head loss". It makes a huge difference. I tried to hand calculate the loss across valve. But it requires valve coefficient Kv. So how  to determine Kv and How does EPAnet assumes Kv values??


Regards,
Prasanna M

[Lucas Vasconcelos]

mmm. A FCV eliminates all head that would allow higher flow than its setting, and causes no headloss if its setting point is higher than the maximum possible flow. Its diameter is not used. :-)
Building a little and simple system and playing around with the available predefined valves helps understanding how they behave. They're all ideal valves and are simulated with a couple ifs in the code rather than a mathematical model. :-)

Real valves can be modeled with a valve curve. Just set the valve to GPV (General Purpose Valve), create a curve with the valve's flow-headloss function, (QxHeadloss points) and inform the curve's name in the GPV's setting.