Software for centrifugal compressor sizing

[CompressorExpert]

I faced with 4 so matured centrifugal compressors (20 years ago) in my project. As we must verify these compressors for new conditions due to process optimisation, I need performance curves for new conditions but I couldn’t get any data from vendor.
Can I use any software to give me guidelines to new operating conditions?

 

[MortenA]

Do you mean if some software can predict your operating curve? My guess is no!

Best regards

Morten

 

[pmover]

I highly recommend you contacting the OEM - original equipment manufacturer - to conduct any investigation or analysis for new process conditions.

good luck!
-pmover

 

[dcasto]

The only company that made software for centifugal was Solar. I don't see that software available any more (it was DOS based). The reason they could do this and nobody else can is that Solar uses off the shelf impellars. They do not get the efficencies that a 100% custom set of impellars will give, but the trade off for off the shelf versus custom.....

In the GPSA data book, they go through some calculation (as provided by Solar) for estimating performance and ranges of expected efficencies, head per stage (wheel), temperatures ect. Once you understand the way it all works, you can then use you packaged simulator or excel spread sheet to get you close enough before going to an OEM for detailed calculations.

 

[mucour]

I have read somewhere that the affinity law can be used for rough estimation if you want to determine new conditions of Head, Flow and Power, speed, Imp. diameter. But using the affinity law for a centr. compr. can only be applicable to a certain pressure limit that I cannot say offhand unless I dig up the material.

May other guys can confirm this.

 

[tgmcg]

Depending on the circumstances, the Fan Law approximation can be VERY accurate method for estimating performance at different conditions. I routinely obtain accuracies to within 1-2% when evaluating compressors for re-rated conditions. To start, you must have a set of performance curves for the current configuration, preferrably from the PTC-10 performance test.

Our compressor performance model incorporates an accurate real gas equation of state for calculating fluid properties.

Generally speaking, the lighter the gas and lower the pressure ratio, the better the accuracy of the Fan Laws. Very often a rough estimate will tell you if your existing machine will be anywhere in the right ballpark.

I always recommend doing these calcs BEFORE talking with the OEM, otherwise they will try to sell you a new machine and you'll have no way of countering. 9 out of 10 times if you ask an OEM about a potential re-rate application, they will try to sell you a new machine. The OEM salesman makes more commission selling the new machine.

Regards,

Tom McGuinness, PE
info@turbosynthesis.com

 

[dcasto]

The GPSA Handbook has some generalized curves and data to get a beginning points on designing centrifugal compressors