Regarding the rotational speed of multi-stage pump impellers
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I would like to ask: what are the consequences if the impellers of a multi-stage pump have different rotation speeds – one at the front and another at the back – or is it necessary for their rotation speeds to be identical?
The impellers of multi-stage pumps are mounted on the same shaft; how can they have different rotational speeds?
What you are considering can be understood as a multi-stage pump, which is essentially a series of centrifugal pumps. For series centrifugal pumps, the speed and impeller diameter can be adjusted to meet the process requirements, but their structure is complex and they present many issues.
Okay, thank you. I know very little about centrifugal pumps; I’m still learning about them.
It’s good to dare to think, but innovation can only come from a thorough understanding. There is one thing to consider: something that has been so mature for such a long time – how is it possible that engineering designers could still leave defects behind for future generations to fix??? Isn’t the probability of that too low?:)
It’s a good idea; in a normal coaxial configuration, the flow direction of the fluid at the outlet of each impeller stage must be altered using guide vanes, which results in energy loss. If they are not coaxial as you said, then it is possible to have single-stage forward rotation and double-stage reverse rotation, without the need to change the direction of the medium flow. However, there are too many technical breakthroughs required for this. For example, what material can ensure that the deflection of a hollow shaft and a solid shaft both exceeds 2 meters, and how are the hollow shaft and the shaft inside it supported and lubricated? After all these are achieved, is the energy loss in the transmission system greater than the energy loss resulting from a change in the flow direction of the medium, and so on?