mixing up two blade manufactures in steam

[mjsamman]

Hi Dears,
We have a low pressure (LP) steam turbine (double flow). The last stage has 54 blades of ALSTOM made. We want to make feathering for 27 blades for the same row. 27 blades must be removed and install the feathered ones,alternatively.
My question is: Can we mix up between two blade manufactures such that 27 feathered blade is EthosEnergy made and 27 (not feathered) by ALSTOM made.

Is there any induced vibration or any significant problem for mixing up two manufactures in turbine blades?

Thanks

 

[stgrme]

I don't know what you mean by a "feathered" blade. Please describe how a "feathered" blade differs from a "normal" blade.

I suggest that you move this post to the Engine & turbine engineering forum. Someone there may be familiar with "feathered" blades. If none there is familiar, I suggest that you ask EthosEnergy about mixing "normal" blades and "feathered" blades in the same row.

Best of luck!

 

[rb1957]

"feathering" implies to me pitch control ... the blades feather (rotate, like propeller blades) into the wind to reduce drag (when not needed for power)

another day in paradise, or is paradise one day closer ?

 

[chicopee]

So 27 blades would have one pitch and alternately the 27 remaining blades would a different pitch. To me that's weird and probably undesirable, so about asking ALSTOM. Have you considered resetting the pitch of the 54 blades to an intermediate pitch? Let us know what ALSTOM said.

 

[dhengr]

Mjsamman:
It better be every other blade and absolutely symmetrical or you could end up with some real nasty wobble and vibration, which would be its death knell. I’d still want to talk to the original stream turbine manufacturer about this change, and get their blessing.

 

[racookpe1978]

No. Your original blade vender has spent their millions of dollars in testing and analyzing (and also guessing and using experience from their earlier turbines) to get the best efficiency out of the set of rotating blades and fixed vanes they can deliver with (1) crashing the turbine rotor, crashing the blade tips and seals with the casing as the unit heats up, vibrating out of spec, and while to give you the smallest possible gap between seals, rotor, blades and blade roots, and the turbine vanes and cylinder.

Mixing two venders makes no sense. Threatens ANY hope you would have when the turbine crashes later.

 

[weldstan]

Misamman:
Your proposal will most probably lead to turbine failure and loss of all warranty from the manufacturer. Consult with Alsttom and by all means obtain their written approval for the changes proposed.

 

[snoopnoon]

By feathering, I am going to assume you mean there are radial grooves cut into the blade for moisture control along the edge of the vane. LP blades are the most critical blades when it comes to vibration and is where 95% of the R&D money is spent trying to optimize and provide a safe working design that will last more than a few months of operation. I highly advise against putting any 3rd party part on half the wheel. If that were the case, i would ask they provide the warranty in the event of failure.