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Exergy at a state? need some guidance

  1. Feb 18, 2009 #1
    1. The problem statement, all variables and given/known data

    Consider the hot exhaust gases in the cylinder of an engine (diesel engine) just prior to the exhaust valve opening. (a) Determine the work (power) potential (exergy at a state) of these gases in kW. (b) Can any of this energy be recovered or must it be dumped to the atmosphere? You may assume the cylinder is at bottom dead center with a volume of 2 liters, a gas pressure of 700 kPa, a mean gas temperature of 1100 K, and an engine speed of 1800 rpm.

    2. Relevant equations

    Wu=W-Wsurr= W-P0(V2-V1)

    ??? not real sure here

    3. The attempt at a solution

    i thought that all exergy equations depended on two states........? also im not sure whether this is control volume or closed system, and also not sure how the engine speed plays a part. i would start to assume that it gives off some type of power or energy, but how do you change rpm into kj, or kw?

    quite frankly i am completely lost on this problem.....
     
  2. jcsd
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