Failure of rotor for centifugal blower

[mthakur]

Hi, just wondering if anyone has come across a similar failure of centrifugal blower impeller where its shroud has cracked through and through from two places and all vanes are twisted. Please share your experience on such failure and elaborate bore stress which is the probable cause (excessive bore stress) of this failure. The fan dia is 1.3 M while the speed is 1100 rpm. Regards

 

[metengr]

mthakur;
I hate to burst your bubble (no pun intended) but you need to have the failed impeller subjected to a proper metallurgical failure analysis. Have you done that?

 

[bklauba]

I agree with metengr that such data would be very helpful.

One question: Is there (as I have often seen) a vibration sensor feeding a vibration level (perhaps with spectral preferences) alarm system, as part of the plant automation system?

One of the things that plague blowers is becoming encrusted with debris, or suffering erosion (due to abrasives, exposure to acids, etc.) that throw these things WAY OUT of dynamic balance, given enough time. Hence, the vibration monitor as a "watch-dog" to avoid catastrophic failure.

BK

 

[sms]

What leads you to believe it is bore stress? Were the interference fit done improperly? Was the blower subjected to an operating condition it was not designed for? Over speed?

My experience with this sort of impeller failure is that it is much more often a funtion of impeller resonance. Impeller resonances are very undamped, and when the operating conditions become just right to excite them the impeller practically blows apart.

I have seen impeller resonance in pumps, compressors, fans, etc.

Can you upload pictures so we can see the damage? It sounds like a two diameter mode resonance where the impeller is broken in half.

I agree with the above, a failure analysis is warrented.

"Why don't you knock it off with them negative waves? Why don't you dig how beautiful it is out here? Why don't you say something righteous and hopeful for a change?" Oddball, "Kelly's Heros" 1970

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