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Homework Help: Water flow rate equation. HELP

  1. Mar 6, 2013 #1

    Me and 4 others are stumped on our HNC Electrical Project. We need an equation that calculates from the flow rate of water and diameter of a pipe, what amount of electrical power outage can be gotten by using a simple turbine connected to the pipe.

    Any sort of help would be greatly appreciated as we are more than struggling with the whole of this project.


  2. jcsd
  3. Mar 6, 2013 #2
    I guess Bernoulli's principle could be a starting point if velocity is required...
    It states that the sum of the potential energy, kinetic energy and the pressure energy is constant...
    [itex]\frac{1}{2}[/itex]mv2 + mgh + PV = constant

    So, if the initial energy be known, we can compute the velocity and hence the rate at which the water is flowing.
  4. Mar 6, 2013 #3

    rude man

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    Mass flow rate = dm/dt = ρ dV/dt = ρ v A, solve for v.

    v = flow velocity along pipe in m/s
    ρ = density, kg/m^3
    A = pipe area in m^2
    dm/dt = mass flow rate in kg/s
    dV/dt = volumetric flow rate in m^3/s = vA

    So in 1s the delivered K.E. would be 1/2 dm/dt v^2

    Make sense? Not my main field but seems straightforward.
  5. Mar 6, 2013 #4
    Hey Cal,

    Per the forum rules, I can not offer any help without proof that you've attempted to figure it out on your own. Perhaps you can share some specific details about your inquiry and particular steps you've taken to solve your question?

    What is the total head?
    Pipe ID?
    Pipe length?
    Simple turbine??? What kind? Turgo, Pelton, Kaplan, Banki... Water wheel?
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