In order to detect the anomaly we first of all required more valuable data from the steam turbine. Our team therefore proceeded by installing vibration sensors on the bearings and a key phaser allowing us to analyze the health of the turbine drive line.
Through our root cause analysis, we identified an instability during the run-in phase of the seals and diagnosed it as a MORTON phenomenon which is a rotational unbalance in rotating machines. This diagnosis allowed us to define ways to mitigate this critical phenomenon and thereby reduce the risk of failure.
As a result we proposed to modify the machine design and replace the existing ‘oscillating-pads’ bearings with ‘spherical pivot-pads’ bearings adding one degree of freedom to compensate the misalignment of the bearings due to imperfect parallelism between the rotor axis and the bearing axis.
This solution significantly improved the damping. Furthermore, we suggested installing a support stand under the protective shutter to absorb the cantilever load.
The root cause analysis based on real-time data allowed us to quickly and economically define the problem and propose feasible machine design modifications.
Thanks to these modifications the steam turbine has a much higher damping resulting in a significant reduction of the MORTON phenomenon.
For the customer this meant higher reliability, less downtime and an increased lifetime of his critical asset.