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Homework Help: Nozzle energy balance

  1. Jun 22, 2010 #1
    Im having difficulty with question b in this problem:
    [PLAIN]http://img705.imageshack.us/img705/9484/therm.jpg [Broken]

    Heres my attempt:
    m(v1^2)*1/2)+h1)=m(v2^2)*1/2)+h2) + Qout
    (v1^2)*1/2)+h1)=(v2^2)*1/2)+h2) + Qout
    where v1 = 200ms^1
    and v2 = 40ms^-1
    and h1 = 3104.9kj/kg
    And my answer is 22,000kj/kg for h2.
    Can anyone see where I'm going wrong?

    The blue writing on the question paper are the correct answers.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jul 1, 2010 #2
    does anyone know how h = 3128kj/kg
    the kinetic energy at the inlet is 20,000kj/kg
    while at the outlet it's only 800.
    How then could it be that h at the outlet is so low?
    Isn't h at the exit dependent on the difference of these kinetic energies?
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