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!

Conditions are adiabatic and reversible about a turbine

  1. Nov 14, 2006 #1
    Why is it when the conditions are adiabatic and reversible about a turbine, the assumption is its isentropic?
     
  2. jcsd
  3. Nov 14, 2006 #2

    Astronuc

    User Avatar

    Staff: Mentor

  4. Nov 16, 2006 #3

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    If dQ = 0, then dS = dQ/T = 0.

    This would seem to imply that all adiabatic processes are isentropic (constant entropy - ie dS = 0) which is not true. The relation: dS = dQ/T assumes a quasi static process in which the system is always at equilibrium. If the process is quasi-static and adiabatic, the process is isentropic.

    I don't see how this would apply to a turbine, however. The expanding gas is necessarily dynamic (in order to drive the turbine), not quasi-static/reversible.

    AM
     
  5. Nov 17, 2006 #4
    you are missing a few terms in your entropy equation. You can't simply assume that dS=dQ/T.
     
  6. Nov 18, 2006 #5

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    I am not assuming that dS = dQ/T. That is the thermodynamic definition of dS.

    AM
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Conditions are adiabatic and reversible about a turbine
  1. Rotor steam turbine (Replies: 6)

Loading...