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Homework Help: Thermodynamics of a perfect liquid, help please

  1. Jan 26, 2010 #1
    1. The problem statement, all variables and given/known data

    Water, assumed to be a perfect liquid, has a density of 1000 kg/m3 and a specific heat of 4184 J/kgK. The water undergoes an adiabatic, frictionless process in which its pressure is raised from 200 kPa to 1500 kPa. Find:
    1. change in temperature
    2. change in specific internal energy
    3. change in specific enthalpy
    4. temperature change required for isobaric process to change the enthalpy that same amount as in part 3

    2. Relevant equations

    ds = c ln(P2/P1)
    Tds = de
    Tds = dh

    3. The attempt at a solution

    I have done the following, is this correct logic?

    1. ds = c ln(P2/P1) = 4184 ln(1500/200) = 8430
    Tds=cdT => dT = Tds/c = (298*8430)/4184 = 600K
    so change in temp dT = 600K

    2. Tds = de
    de = 298 * 8430 = 2512 kJ/kg

    3. Tds = dh
    dh = 298 * 8430 = 2512 kJ/kg

    4. Im not quite sure how to do this part.

    Any help or suggestions are appreciated.
  2. jcsd
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