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Hydraulic head as a function of flow rate

  1. Oct 27, 2018 #1
    Hello!
    1. The problem statement, all variables and given/known data
    Symbols and variables:

    ##\dot{V}## : flow rate
    ##H## : Hydraulic head
    ##g = 9.81 \frac{N}{kg}##
    ##P_{atmosphere} = 101325Pa##
    ##\rho = 1000\frac{kg}{m^3}##
    I am given a piping system, with serie and parallel pipes, they start from one point and go back in to one point.

    I need to plot the hydraulic head (the medium in the piping system is water at 20°C, and the local flow loses are negligible) in function of the flow rate, for ##H(\dot{V}=0 \frac{m^3}{s})## to ##H(QMax)##.
    With ##QMax## the flow rate where the hydraulic head is 3 times the hydraulic head by zero flow.

    The question:
    1. How can I calculate the hydraulic head by zero flow
    2. How can I calculate the maximal flow rate
    My instruction paper is in dutch (reason why i didn't upload it)
    2. Relevant equations
    In my instruction paper:
    $$H = \frac{P_{In} - P_{atmosphere}}{g\rho}$$
    Further the mechanical equation out of my syllabi:
    $$H_1 - H_2 = R\dot{V}$$
    3. The attempt at a solution
    In appendix.
    I also includes a plot from what I think the solution is. (hydraulic head in function of flow rate)

    But what i don't understand, how can (according to my solution) the hydraulic head be negative.
    Does someone know how or knows a resource.

    Thanks in advance,
    Good day!
     

    Attached Files:

  2. jcsd
  3. Oct 31, 2018 #2
    Is there a diagram?
     
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