×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Polytropic Efficiency

Polytropic Efficiency

Polytropic Efficiency

(OP)
Can someone please correct me on my interpretation and explanation of polytropic efficiency, because Saravanamuttoo et al explanations are pretty atrocious. I see it as (applied to compressors, axial, that is):

NB Assumption: Every individual stage of an axial flow compressor has the same isentropic efficiency to each other
If we cascade more than one stage, the efficiency of the next stage will "act upon" the efficiency of the previous stage thus constantly decreasing overall efficiency as we cascade more.
Thus if we could take one stage to achieve the same pressure rise, the isentropic efficiency will only be multiplied once across the single stage.

In lames terms, if one stage gives 0.9 efficiency and we couple 5 stages, then the overall comp efficiency will be 0.9^ 5 = 0.59049

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources