stainless steel pick up 1

[hydroworks]

We have a 3 MW turbine water turbine runner we are mounting on a generator shaft using an intermediate tapered sleeve and oil injection to make or break the taper. The runner is a martensitic stainless steel (CA6NM) and we have tried low and medium carbon steels for the intermediate sleeve. Whilst there are many variables complicating the situation here, even with good oil distribution, we are getting pick up on the nose of the intermediate cylinder. Our next step is to try NiALBronze for the sleeve material. Does anyone have experience of this type of problem?

 

[MikeHalloran]

If the proportions are anywhere near like you've sketched them, the pressure at the distal end of the shaft is probably much greater than the pressure at the proximal end. I.e., the runner hub probably stretches more where the runner web doesn't constrict its radial expansion. For materials with similar mechanical properties, you might be able to compensate for that with mismatched tapers, but it would be tricky.

I think you're on the right track with an intermediate material of lower modulus.




Mike Halloran
Pembroke Pines, FL, USA

 

[EdStainless]

The lower hardness and modulus of the NAB should both help the fit and minimize surface damage. The stress on this part can't be too high. Make sure that your NAB isn't too hard.

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Plymouth Tube

 

[hydroworks]

thanks Mike for a good response. The NiAL bronze worked with a ground surface on the intermediate sleeve.