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Homework Help: I need help calculating the maximum pressure

  1. Aug 11, 2006 #1

    xto

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    I've serach for almost a day now ,
    just to search the formula to calculate the maximum pressure in the cycle
    A very big thank you and appreciate for the help
     
  2. jcsd
  3. Aug 11, 2006 #2

    berkeman

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    Staff: Mentor

    What cycle specifically are you referring to, xto? Could you please provide a more complete problem description, and show us what you have tried so far?
     
  4. Aug 12, 2006 #3

    xto

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    i)isothermal compresssion from state 1 through a volumetric compression ration of 6 to state 2
    ii) isobaric expansion from state 2 back to the initial volume thus reaching state 3
    iii) isochoric cooling from state 3 back to the original pressure to reach state

    it ask for the mass of air present and the maximum pressure in the cycle

    Given
    R=0.287 kj/kg K
    Cp=1.005 Kj/KG K

    i have done
    pv=nrt
    t=303K
    p=1.2x0.9869
    =1.1832
    V=2.2x1000
    =2.2x10^3

    so (1.1832atm)(2.2x10^3L)
    -----------------------
    (1.005) (303K)

    which the ans is 247.90g Air

    then i use this formula
    vm=(Qp/4 x Z)
    so (2.2x10^3)(1.005)/4x(0.287)
    which get
    1925.958

    i'm not sure if it's rite or not
    please help , thx
     
    Last edited: Aug 12, 2006
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