1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Gas turbine TS cycle question

  1. Mar 24, 2016 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
    I am confused what 5-5b and 5b-6 represent in the above TS diagram. I know that 1-2 is compression, 2-3 is cooling, 3-4 is compression and 4-5 is regeneration (since these are indicated in the block diagram) but as for 5-5b and 5b-6 it is less clear. I mean 5-6 is the combustion chamber but what is the significance of the 5-5b and 5b-6 segments? Why have they split it up like this?
  2. jcsd
  3. Mar 24, 2016 #2


    User Avatar

    Staff: Mentor

    Looking over the diagram perhaps if you can explain what's different between 7 and 7b, you might have your answer for 5b?

    Beyond this I can't assist; I haven't looked at thermo since my student days.
  4. Mar 28, 2016 #3
    Thanks for your reply. Unfortunately, I don't get that part either lol. Haven't encountered it in examples provided by my lecturer so far.
  5. Mar 28, 2016 #4


    User Avatar

    Staff: Mentor

    My guess is that if 6-7 represents the ideal heat exchange, then perhaps 6-7b represents a practical best attainable for that stage. You can't extract all of the heat in a heat exchanger.

    I think the image you attached might be too large, it spills out and forces the rest of the page into small size.
  6. Mar 28, 2016 #5


    User Avatar
    Science Advisor
    Homework Helper
    2017 Award

    My view was that 6-7 represents isentropic expansion in the turbine and 6 - 7b the actual expansion. So 5b might ne needed for the efficiency.
  7. Mar 29, 2016 #6
    Is it possible that the points 5b and 7b refer to another problem?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted