Diagnosing of rotor systems of marine gas turbine engines in nonstationary states

Vibration tests of marine gas turbine engines are performed as researches on-line and off-line types. Systems on-line type generally monitored one or two vibration symptoms, which asses the limited and/or the critical values of parameters and they potentially can warn and/or shutdown engines. Systems off-line types are usually used for vibration analyzing during non-steady state of work. The paper presents comparison of different methods of analyzing vibration symptoms measured under run-up and shut-down processes of marine gas turbine engines. Results of tests were received on gas turbine engine DR76 type of the COGAG type propulsion system. The engine was not fitted with vibration monitoring system. Main goal of researches was qualified of help fulness and unequivocally results received by methods of synchronous measurement, order tracking and auto tracking. All vibration symptoms were chosen from the methodology of the diagnosing gas turbine engines operated in the Polish Navy, called BDS (Base Diagnosing System). Second purpose was estimation of the possibility of implementation presented methods of vibration analyses of gas turbine engines for on-line monitoring system. Application of periodical or on-line diagnostic procedures makes it possible to operate ship propulsion systems in accordance with their current technical state. The realization of the investigations made reliable verification of the investigation results possible.