Warning before pump limit or in case of blade failure on a turbomachine

A method for determining a warning regarding a surge limit for a turbocompressor or of blade damage to a rotor in a turbomachine, the method comprising:

• determining at least two measurement signals each of which corresponds respectively to an output signal of one of at least two sensors which are arranged offset with respect to one another in a circumferential direction of the turbocompressor or of the rotor, said sensors being temperature, pressure or flow velocity sensors;
• calculating a periodicity value from at least one of the measurement signals, which periodicity value indicates a measure for occurrence of periodic signal level changes in the at least one measurement signal for a predetermined first time offset;
• calculating a correlation value from the at least two measurement signals, which correlation value indicates a measure for similarity of the at least two measurement signals to one another for a predetermined second time offset;
• and
• determining the warning based on the periodicity value and the correlation value.

A turbocompressor comprising:

• a control unit;
• and
• at least two pressure, flow velocity or temperature sensors which are offset with respect to one another in a circumferential direction of the turbocompressor,
• wherein the control unit determines at least two measurement signals which correspond respectively to an output signal of one of at least two sensors, calculates a periodicity value from at least one of the measurement signals, which periodicity value indicates a measure for occurrence of periodic signal level changes in the at least one measurement signal for a predetermined first time offset, calculates a correlation value from the at least two measurement signals, which correlation value indicates a measure for similarity of the at least two measurement signals to one another for a predetermined second time offset and determines a surge limit warning based on the periodicity value and the correlation value.

A gas turbine comprising:

• a turbocompressor comprising
• a control unit;
• and
• at least two pressure, flow velocity or temperature sensors which are offset with respect to one another in a circumferential direction of the turbocompressor,
• wherein the control unit determines at least two measurement signals which correspond respectively to an output signal of one of at least two sensors, calculates a periodicity value from at least one of the measurement signals, which periodicity value indicates a measure for occurrence of periodic signal level changes in the at least one measurement signal for a predetermined first time offset, calculates a correlation value from the at least two measurement signals, which correlation value indicates a measure for similarity of the at least two measurement signals to one another for a predetermined second time offset and determines a surge limit warning based on the periodicity value and the correlation value.

A method for determining a surge limit warning for a turbocompressor or a warning of blade damage to a rotor in a turbomachine, said method comprising:

• receiving at least two measurement signals corresponding to output signals of at least two pressure, flow velocity or temperature sensors;
• calculating a periodicity value from at least one of the measurement signals, the periodicity value indicating a measure for the occurrence of periodic signal level changes in the at least one measurement signal for a predetermined first time offset;
• calculating a correlation value from the at least two measurement signals, the correlation value indicating a measure for the similarity of the at least two measurement signals to one another for a predetermined second time offset;
• and
• determining the warning from the periodicity and correlation values.