Sudden Vibration Jump

Look for missing turbine blades, some circle has been disturbed.

So sudden! Check CCTV for the location of any disgruntled employee around the time of the event.

Could be anything. Maybe a bearing.

All poster's should be aware that this is an addendum and has other importants elements of the issue addressed in imanshines earlier

Prox Probe X,Y Vibration Discrepency

What did the factory tech have to say about the vibration? Have you called the factory about this vibration? How long has it been since it's overhaul? Has a detailed inspection been performed on the turbine blade root/hub attachments? When was the last dynamic balance been done on the rotating assembly?

Starting with just the basic info., whats the make and model of this turbine unit your talking about?

II don't know but I bet the manufacturer does. No joy over the phone, then?

You might want to check your jerks too.

Dear Mr.imanshines,

Apart from various posting by CR4 members I my answer to you will be as follows:

Is it initially increased or after loading the Turbine.?

Water Droplet in minute quantity might have entered the Turbine, which is very dangerous.

Last stage blades, - steam condition may be wet than design value.

Sudden increase in vaccuum, will cause higher steam velocity at the end of rotor blades causing more vibration.

DHAYANANDHAN.S

DHAYANANDHAN: I can concur that any wet steam slug would cause this, as would any sudden release of "stuck" corrosion product or metal deposit (as copper) in the steam header or automatic steam block valve. A transition suddenly to wet exhaust condition is also a possible suspect, as would be the sudden release of an air pocket from trapped air on the condenser tubes. The real question is did the vibration level ever proceed back "normalcy"? IF not then this unit has to come offline for general safety inspection.

Dear Mr.imanshines,

In continuation to my posting, No.10, I add the following since I for got to indicate yesterday itself.

I mentioned that minute water particles entry along with steam as on possible reason. The Kinetic Energy gained by the water particles and its impact on the blades is enormous and many many folds to that of its own weight since the velocity of Steam entering the Turbine will be in the order of 700 to 800 Metres/Sec.

Let the weight of one water particle be 1 gram or (1/1000) Kg. Consider a Steam Velocity of 750 Metres/Sec. Then the Kinetic Energy gained and hence the impact force will be equal to asper Formula (1/2) x m x V^2 i.e (1/2) x (1/1000) x (750 x 750) = 281.5 Kgs.f i.e one gram of water in weight will gain a kinetic energy which will give (while hitting the blade at a velocity of 750 M/Sec) an impact of 281.5 Kgs. Force - which is tremendous force since the impact force to weight ratio will be (281.5)/(1/1000) = 281500 times, this can be termed as 281500 g which is unimaginable.

This impact will shoot up the vibration.in the Turbine If water particles continue to enter the turbine - the damage can be catastrophic disaster.

DHAYANANDHAN.S

Sir,

Mikka Nandri,

its reall very useful info.. i should look at it!