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Homework Help: Property Tables Question [Thermodynamics]

  1. Jul 12, 2012 #1
    1. The problem statement, all variables and given/known data
    Pressure=P=700 KPa
    Specific Entropy = s = 7.6953 KJ / ( K Kg )

    Find the Specific Enthalpy (h)

    2. Relevant equations
    No equation
    Am using the property tables at the end of the following book :
    Thermodynamics, an engineering approach, by Yunus A. Cengel and Michaek A.Boles 7th edition.

    3. The attempt at a solution
    By obtaining the values of s_f and s_g from Table A.5 and compare it to s, the state is Superheated Vapor.
    This means I will use Table A.6
    The pressure = 700 KPa = 0.7 MPa
    But the most closest pressure to this pressure is 0.6 MPa and 0.8 MPa
    So I will use interpolation like that
    P (MPa) h
    0.6 h1
    0.7 h
    0.8 h2

    h1 and h2 must be calculated in order to apply interpolation to find h
    To find h1,h2 Need to know T of the state
    But I do not how to find it

    Help please.
  2. jcsd
  3. Jul 13, 2012 #2
    Look up double interpolation.
  4. Jul 13, 2012 #3
    I did not get it :\
  5. Jul 13, 2012 #4
    Did not get what? Look it up on Google.
  6. Jul 15, 2012 #5

    rude man

    User Avatar
    Homework Helper
    Gold Member

    If p and s are known, the state is known totally, including sp. enthalpy h and temperature T. Just need to know how to use your (superheated) steam tables.
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