1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Thermodynamic cycle

  1. Oct 10, 2005 #1
    Sorry about the double post, I had technical difficulties that I was working on and the title of my orginal post got screwed up.

    I'm having problems getting started on this one.

    A gas undergoes a thermodynamic cycle consisting of 3 processes

    process 1-2 compression with pressure(p)*volume(V) = constant, from
    [tex]p_{1} = 1 bar[/tex]
    [tex]V_{1} = 1.6m^3[/tex]
    to
    [tex]p_{2} = ?[/tex]
    [tex]V_{1} = .2m^3[/tex]

    [tex]U_{2}-U_{1}=0[/tex]

    process 2-3
    Constant pressure to [tex]V_{3}=V_{1}[/tex]

    process 3-1
    Constant Volume, [tex]U_{1}-U_{3} = -3549kJ[/tex]

    There are no significant changes in kinetic or potential energy.
    Determine the heat transfer and work for process 2-3 in kJ.

    I don't have any problems finding[tex]p_{2}[/tex] or the work needed to compress the gas, but I'm not really sure where to go from there.

    [tex]p_2=\frac{p_1V_1}{V_2}[/tex]

    [tex]W=\int p dV[/tex]

    When I work these out, I end up with 333kJ for W and 8 bar for p2.

    If someone could give me a quick push in the right direction, that would be great.
     
  2. jcsd
  3. Oct 10, 2005 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    The work done between 2-3 is just [itex]P_2\Delta V = P_2(V_3-V_2) = P_2(7*V_2)[/itex]

    The change in internal energy is [itex]U_3-U_2 = U_3-U_1[/itex], since [itex]U_2=U_1[/itex]

    Use [itex]\Delta Q = \Delta U + W[/itex] to find the energy (heat) flow into the system.

    AM
     
    Last edited: Oct 11, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Thermodynamic cycle
  1. Thermodynamic Cycle (Replies: 3)

  2. Cycle (thermodynamics) (Replies: 8)

Loading...