Systems and methods for shutting down a gas turbine engine in response to a severe mechanical failure include determining a rate of change of one or more process conditions. If the rate of change of the one or more process conditions exceeds a respective predetermined failure threshold, a potential severe mechanical failure of the gas turbine engine may be determined. Steps may be taken to confirm the potential severe mechanical failure of the gas turbine engine. In response, an engine restart is prevented.

Aircraft turbine engine (10), comprising at least one first compressor, an annular combustion chamber (70) and at least one first turbine (46), which define a first flow duct (22) for a primary flow, characterised in that it comprises, between said combustion chamber (70) and said first turbine (46), a device (55, 55′) for discharging at least part of said primary flow.

A method is provided of controlling a gas turbine having a shaft connecting a compressor to a turbine, as well as having a reheat system, and a gas turbine. The method includes the steps of: operating the engine using the reheat system to provide a mass flow rate of reheat fuel into a gas flow of the gas turbine engine downstream of an exit of the turbine; detecting a shaft break event in the shaft; and in response to this detection, maintaining the mass flow rate of the reheat fuel being provided into the gas flow downstream of the turbine exit, whereby the maintained mass flow rate of reheat fuel raises a back pressure downstream of the turbine and thereby reduces a rotational speed of the turbine.

This power generation system (20A) includes a plurality of power generation units (50A, 50B, 50C, . . . ) which are provided in parallel, wherein each of the power generation units (50A, 50B, 50C, . . . ) includes an expander (26) configured to be rotated by a working medium, a power generator (28) configured to generate power through rotation of the expander (26), a rectifier (29), a medium circulation system (22) configured to pump the working medium into the expander (26), a relay (70) configured to interrupt power between the power generator (28) and an external power system (30), an operating unit (40A, 40B) configured to be operated when maintenance starts, and a relay driving unit (71) configured to interrupt power between the power generator (28) and the external power system (30) by the relay (70) when the operating unit (40A, 40B) has been operated.

A shaft event is detected, such as a shaft shear, a shaft decoupling, and/or a shaft failure in a gas turbine engine comprising a first spool and a second spool different from the first spool. First and second parameters indicative of the power of the first spool and a load transfer through a shaft of the second spool are obtained. A detection threshold is determined as a function of the first parameter. The second parameter is compared to the detection threshold. The shaft event is detected when the second parameter is beyond the detection threshold and then a signal indicative of the shaft event is transmitted.

A monitoring system for monitoring one or more properties associated with a rotating shaft is provided. The system includes a first phonic wheel which is mounted coaxially to the shaft for rotation therewith, the first phonic wheel comprising a circumferential row of teeth. The system further includes a first sensor configured to detect the passage of the row of teeth of the first phonic wheel by generating a first alternating measurement signal. The system further includes a processor unit configured to determine the durations of successive first speed samples. Each first speed sample is a block of n successive cycles of the first alternating measurement signal, where n is an integer, and in which the beginning of each cycle is a zero-crossing point from the previous cycle and the end of each cycle is the corresponding zero-crossing point to the next cycle. At least one axial location of the first phonic wheel every m.sup.th tooth of the row of teeth of the first phonic wheel has a circumferential thickness which is different from that of the other teeth of the first phonic wheel, where m is an integer, m≠n, and m is neither a factor nor a multiple of n. When the first sensor is positioned at said axial location of the first phonic wheel and at any given rotational speed of the first phonic wheel, the durations of the successive first speed samples display a characteristic repeating pattern of longer and shorter sample durations relative to the average duration of the successive first speed samples. The amount by which the longer and shorter sample durations differ from the average duration is in proportion to the amount by which the circumferential thickness of the m.sup.th teeth differs from that of the other teeth at said axial location of the first phonic wheel. The processor unit monitors the properties associated with the rotating shaft from the characteristic repeating pattern.

A monitoring system for monitoring one or more properties associated with a rotating shaft is provided. The system includes a first phonic wheel which is mounted coaxially to the shaft for rotation therewith, the first phonic wheel comprising a circumferential row of teeth. The system further includes a first sensor configured to detect the passage of the row of teeth of the first phonic wheel by generating a first alternating measurement signal. The system further includes a processor unit configured to determine the durations of successive first speed samples. Each first speed sample is a block of n successive cycles of the first alternating measurement signal, where n is an integer, and in which the beginning of each cycle is a zero-crossing point from the previous cycle and the end of each cycle is the corresponding zero-crossing point to the next cycle. At least one axial location of the first phonic wheel every m.sup.th tooth of the row of teeth of the first phonic wheel has a circumferential thickness which is different from that of the other teeth of the first phonic wheel, where m is an integer, m≠n, and m is neither a factor nor a multiple of n. When the first sensor is positioned at said axial location of the first phonic wheel and at any given rotational speed of the first phonic wheel, the durations of the successive first speed samples display a characteristic repeating pattern of longer and shorter sample durations relative to the average duration of the successive first speed samples. The amount by which the longer and shorter sample durations differ from the average duration is in proportion to the amount by which the circumferential thickness of the m.sup.th teeth differs from that of the other teeth at said axial location of the first phonic wheel. The processor unit monitors the properties associated with the rotating shaft from the characteristic repeating pattern.

Aircraft turbine engine, including at least one first compressor, an annular combustion chamber and at least one first turbine, which define a first flow duct for a primary flow. Between the combustion chamber and the first turbine is a device for discharging at least part of the primary flow.

A safety apparatus for containing a release of energy from a tension stud of a rotor assembly, the safety apparatus includes an elongate member defining a longitudinal axis and at least two arms projecting away from the longitudinal axis of the elongate member. In use, in a first orientation, the elongate member is configured to be connected to a tool apparatus for applying a load energy to the tension stud and the at least two arms of the safety apparatus are configured to overlap with at least part of the tool apparatus in the direction of the longitudinal axis of the elongate member to contain the release of energy therebetween.

A method is provided involving a turbine engine. During this method, data is received indicative of twist of a shaft of the turbine engine. The data is monitored over time to identity one or more reversal events while the turbine engine is operating, where each of the reversal events corresponds to a reversal in a value sign of the data. Shaft shear is identified in the shaft based on occurrence of N number of the reversal events.