Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Relation between flowrate and butterfly valve opening

  1. Aug 8, 2011 #1
    is it right to say that valve opening for both ball & butterfly valve is directly proportional to flowrate passing through it?

    say 100 m^3/hr at 100% opening
    50 m^3/hr at 50% opening??

    thanks in advance..
  2. jcsd
  3. Aug 8, 2011 #2


    User Avatar

    Staff: Mentor

    Definitely not. Flow starts fast, then levels-out. Think a sideways parabola, with valve position horizontal and flow vertical.
  4. Aug 8, 2011 #3
    so i need to compute the flowrate using bernoulli taking into account % opening of the valve in the friction loss term?

    if so, where can i find values of Kf for both ball and butterfly valves..

    tnx a lot..
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook