1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Work to close valve

  1. Jan 26, 2013 #1
    Yesterday I was on the Czech Physics Olympiad. There were many examples. To one, however, I did not invent anything, because I don't learn Hydrodynamics to much.
    I want to understand it better, so I want to ask you how you calculate it, please. I'm sorry, I did not give my progress here, but I have not it, because I do not know much about Hydrodynamics. I spent two hours thinking but I did not invent it.

    So... example:

    Liquefied gas flowing in a pipeline. You want to close the pipeline. To close the pipeline you must close a valve (move plate across pipeline).
    - in a large reservoir, where pipeline is connected, the pressure is 2 MPa
    - valve (plate) has a thickness 10 cm
    - pipe has a square cross section with a side length 1 m
    - liquefied gas has a density 480 kg/m3 and and flow 20 m3/s

    What is the value of work to close the valve?

    Thanks... And if you don't understand me, write, i will try to write it better.
  2. jcsd
  3. Jan 26, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    Imagine the valve is half closed - what does the system look like?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook