High Vibration on Axial Compressor


Thread Starter

Jhon wick

Hello experts;

First i give detail of the turbine.

1. Gas turbine model is Centaur 4702 from Solar Inc.

2. Two shaft

3. Gas producer have 15000 rpm 100 %.

4. 11 stage axial flow compressor

5. first, second and third bearing are tilt pad

6. Power turbine have 15500 rpm.

7. Velocity transducer at horizontal and vertical position at 2nd bearing housing, where compressor AFT and diffuser FWD end couple.

I face a very strange behavior of the vibration on gas producer section. At specific Gas producer speed band that is 87 to 91 % we found high vibration at alarm level that is 0.4 IPS rms. Before 87% and beyond 91 % the vibration is well within limit like 0.12 IPS rms.

The spectrum shows 3 times higher amplitude at 2X that is at 1X the amplitude is 0.0769 while at 2X the amplitude is 0.230. Between 1X and 2 X no peak found and before 1X there is no peak. After 2 X to up to 8X no peak found.

This is same on vertical and horizontal position almost identical signature.

Please guide me what are the possible causes?