Should compressor Np be adjusted for RPMs to compare to design?
Should compressor Np be adjusted for RPMs to compare to design?
(OP)
I have calculated a polytropic efficiency for a centrifugal compressor at the set of conditions when the survey was conducted. I also have the design curve showing the predicted efficiency vs icfm.
Latest survey:
RPM = 8610
icfm = 14600
Np = 75.6
From Design Curve:
RPM = 8800
icfm = 14600
Np = 79.3
Does this mean that the efficiency is 3.6% below design or do I need to adjust to the design RPM? And if so, how do I do that?
I've used Fan Laws to adjust polytropic head for RPM but I can't find any info on the efficiency.
Thanks!
Latest survey:
RPM = 8610
icfm = 14600
Np = 75.6
From Design Curve:
RPM = 8800
icfm = 14600
Np = 79.3
Does this mean that the efficiency is 3.6% below design or do I need to adjust to the design RPM? And if so, how do I do that?
I've used Fan Laws to adjust polytropic head for RPM but I can't find any info on the efficiency.
Thanks!





RE: Should compressor Np be adjusted for RPMs to compare to design?
I have several surveys of this compressor at different RPMs and I'm just trying to understand if I can compare the efficiencies directly or if I need to compensate for the speed of the compressor.
Thank you!