Dyson have invented a different type of vacuum cleaner, using rotating air to create a low pressure zone, so they have some carefully designed components.
I doubt there is anything there that doesn't need to be there.
another day in paradise, or is paradise one day closer ?
From your post history I can see you seem to have a practical interest in compressors. It's not clear what is the overall purpose of this particular thread, but I'll respond taking things at face value.
> What is rotordynamics ?
Something like: the study of dynamics of rotating parts and machinery. No disrespect, but with such a broad question you should start with google. And if you have more specific questions about rotordynamics, you might want to post on forum384
> Why companies spent so much resources on it ?
I would imagine that companies spend the amount of resources that they think will provide an appropriate balance between reasonable initial design/production coasts and reliable long-term operation. If rotordynamics is not adequately considered in rotating machinery design, then vibration often leads to early equipment failure and in some cases unsafe conditions.
I've had my time and customers money wasted by situations where comprehensive rotordynamics calculations were mandatory but not normal for the particular class of machinery. It is very costly to overspecify or underspecify rotordynamics analysis.
geesaman.d - Picking up that thought process, the cynical view would be that those who earn their living in rotordynamic analysis tend to inhabit the standards committees where recommendations / requirements for rotordyanmic analysis are codified (there's no conflict of interest there!?!). A conservative customer picks up the recommendation / requirement from the standards and puts it into their specs… irrespective of what types of alternate analysis / experience the OEM might be bringing to the table.
It's possible, but in my one anecdotal experience, the rotordynamics expert I subcontracted the analysis to was trying to discourage the analysis because it was gross overkill. This same expert was involved in writing the rotordynamics TR for API. So he was definitely not in it to milk hours. He preferred to solve problems that mattered.
It was fun watching the customer provide comments on his reports ("revise and resubmit"), and watch our expert professionally put those comments to bed. I think the reviewer in this transaction was living off of the excess rotordynamic analysis taking place.
A rotodynamic pump is a kinetic machine in which energy is continuously imparted to the pumped fluid by means of a rotating impeller, propeller, or rotor, in contrast to a positive displacement pump in which a fluid is moved by trapping a fixed amount of fluid and forcing the trapped volume into the pump's discharge.
Rotordynamics, also known as rotor dynamics, is a specialized branch of applied mechanics concerned with the behavior and diagnosis of rotating structures. It is commonly used to analyze the behavior of structures ranging from jet engines and steam turbines to auto engines and computer disk storage.
Rotordynamics is a study of rotation and its effects.
The basic concept is when a shaft rotates, vibrations are generated
The study would allow us to predict the rotor condition through various operating conditions.
Essentially, we want to avoid resonance or critical speeds.
If required, deploy damping , stiffness , unbalance response to lower the effects into acceptable conditions.
Once the study meets the API specs , test it to match the study predictions.
Lastly , send out for fabrication or mass production.
