Hi,
I'm working on my first WPS / PQR and it started me down a path of Codes and Standards. And, as with most things, the more I learn the more I don't know.
I work with a company building Oil Free Screw compressors. Below is what I 'think' is the flow direction of construction standards, is...
Maybe I'm not reading closely enough, but is there a intercooler between the 2nd impeller exit and the third impeller inlet? I couldn't figure that out from the post above.
Edit: I guess you're saying: Impellers 1 thru 3 -> Intercooler -> Impellers 4 thru 6 and Impeller 6 is larger discharge...
Is it true that if the rotor is well balanced and stable that the Morton Effect would still have a minimal impact on vibration?
In other words, you may acknowledge the existence of thermal bending in the rotor, but you can solve it like you are solving unbalance?
I'm mainly an Oil Free Screw...
I also wonder what the effect of oil viscosity, oil inlet pressure and oil inlet temperature has on the problem. I haven't read much on the subject at this point, I'm just thinking aloud. Perhaps the bearings need to be re-designed or perhaps you can get away with a change of oil properties or...
I wonder if you couldn't try to reproduce the actual bearing loads seen in the field on the compressor at test to see if the problem goes away.
You may have to increase pressure ratios to do so.
I'm not sure how much material innovation has to do with the centrifugal compressor community. Maybe a small reduction in HP with lighter / just as strong materials.
I think the advances for CC's / OFS's are going to take place in the manufacturing arena and the service arena. Faster...
API isn't designed to help the user decide which equipment to use or not use. API is a set of standards that describe how best to design something once that something has been chosen.
-Fixed Speed
-H2S service / coker
-Came with an even amt of build up
-P2 =~ 210 PSIA
The customer did add a weight to the balance line for some reason. No one (including customer) seems to know why. History of the machine is bit foggy and since this extra vibration never caused an alarm and...
It's been a while since I've looked at the datasheet from a newbie's perspective, but I believe there should be some data sheets filled out (examples) in the appendix of API 619.
Did you already look there? I work for a company that sells OFS units. If you have specific questions on what is...
Ladies and gents,
We have a unit that gets a few mils of vibration at 52 Hz (3150 Hz). Multi-stage centrifugal compressor (between brg design). Line freq is 60 hz. Motor speed is 1800 RPM. Running speed = 11,500 RPM. Rotor dynamic study checks out with flying colors.
I'm really wondering...
I would like to state my results in case this subject gets searched in the future.
The anticipated cross coupling actually went down to about half of the original guarantee conditions. The cross coupling equation includes two main drivers that changed from new machine to now: Power required...
What's interesting is that the API 684 section on Stability never mentions inlet guide vanes as a possible cross coupling force. I can only assume that IGV's have a very minimal direct effect on the magnitude of the cross coupling force.
Your statement on log dec vs density is correct. It's...
Thanks! I'm looking up the rotordynamic study now to confirm the rotor is stable. I'm sure it is, but it gives me a way to quantitatively show the customer.
Thanks again.
Ladies and gents,
I'm trying to find some correlation (if any) between the amount the IGV is closed versus vibration of a centrifugal compressor rotor. So far, I'm coming up blank. I have a feeling that as long as 1) the passing frequency is safe and 2) the compressor is not in surge that...
Sorry, this is sort of a false post. The other process that uses Fluorosint is not allowed to rub, so we watch clearances closely. This process doesn't require that sort of engineering. My mind was in the wrong place.
Cheers,
The advantage of an open impeller is the reduction in stresses which helps increase the max tip speed. In other words, you could have a high head first stage.
To the others:
Are these open first stage impellers used mainly on high MW machines with high 1st stage flow coefficients?
