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Steady Flow Energy Equation basics

  1. Oct 14, 2014 #1
    Right, I'm sure this is bread and butter to a lot of you but I have just been introduced to the SFEE.
    mgz+0.5mC^2+H +Q = mgz + 0.5mC^2 +H+W

    Where Q is the heat transfer, W is work done and H is enthalpy. Where is it assumed that the heat energy is in the energy balance? If heat is added where is this balanced out on the other side of the equation?
    Does the heat become internal energy?

    Basically I'm asking why we don't have Q on both sides?

  2. jcsd
  3. Oct 14, 2014 #2
    Here is a nicely worded explanation:

    http://personalpages.manchester.ac.uk/staff/john.chinn/Thermo1/SFEE1.pdf [Broken]
    Last edited by a moderator: May 7, 2017
  4. Oct 15, 2014 #3


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    The Q in the equation is the NET heat transfer into the system (control volume). If you wish, you can represent it differently as Q = Qnet = Qin-Qout, and then rearrange so that Qin is on one side of the equation, and Qout is on the other.

    Similarly, the W is the NET work output from the system (control volume) and can be represented as W = Wnet = Wout-Win.
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