Abstract: There is disclosed an axial flow machine (10) comprising an annular flow path (23); a stator ring (38) comprising a plurality of stators mounted at their radially outer ends and extending into the annular flow path (23); a non-rotating body (24) axially adjacent the stator ring (38); and an annular shroud (42) disposed between the radially inner end of the stator ring (38) and the body (24). The shroud (42) is supported on the stator ring (38) and moveable relative the body (24); and the shroud (42) cooperates with the body (24) to inhibit a flow through a clearance pathway (78) therebetween.

Abstract: There is disclosed an axial flow machine (10) comprising an annular flow path (23); a stator ring (38) comprising a plurality of stators mounted at their radially outer ends and extending into the annular flow path (23); a non-rotating body (24) axially adjacent the stator ring (38); and an annular shroud (42) disposed between the radially inner end of the stator ring (38) and the body (24). The shroud (42) is supported on the stator ring (38) and moveable relative the body (24); and the shroud (42) cooperates with the body (24) to inhibit a flow through a clearance pathway (78) therebetween.

Abstract: A method of inhibiting ice accretion within a turbine engine, including the steps: (a) operating the turbine engine at a predetermined engine speed; and (b) driving the compressor of the turbine engine at an elevated speed which is greater than the nominal speed of the compressor at the predetermined engine speed so as to inhibit ice accretion within the compressor.

Abstract: A method of inhibiting ice accretion within a turbine engine 4, 6, comprising the steps: (a) operating the turbine engine 4, 6 at a predetermined engine speed; and (b) driving the compressor 8, 10 of the turbine engine 4, 6 at an elevated speed which is greater than the nominal speed of the compressor 8, 10 at the predetermined engine speed so as to inhibit ice accretion within the compressor 8, 10.

Abstract: A rotor (38) for a gas turbine engine (10) has a low emissivity surface finish, or high emissivity surface finish (44), on at least a portion of its surface (42) to reduce temperature differentials between an upper portion and a lower portion of the rotor (38). This reduces bowing of the rotor (38) to allow the gas turbine engine (10) to be started without harmful vibrations of the rotor (38).

Abstract: A control arrangement (10) comprises a first selectable controller (12) for controlling an action, and a second selectable controller (14) for controlling the action. The arrangement also includes a selector (22) for selecting one of the controllers (12, 14) to control the action. The arrangement (10) further includes a first heat exchanger (16) associated with the first controller (12) to effect a transfer of heat between the first controller (12) and the first heat exchanger (16). The arrangement also includes a second heat exchanger (18) associated with the second controller (14) to effect a transfer of heat between the second controller (14) and the second heat exchanger (18).

Abstract: Apparatus for maintaining the temperature of a component of a gas turbine engine below a predetermined maximum working temperature comprises a reservoir for a cooling fluid having a boiling point below the working temperature and in which the component is immersed or with which it is in contact. At least two heat exchangers are associated with the reservoir and operable to effect condensation of vaporised cooling fluid and return of same to the reservoir. Preferably the apparatus is a closed system incorporating three heat exchangers respectively adapted to effect heat exchange with engine fuel, compressed air derived from a fan or low pressure compressor of the engine and ambient air. Means may advantageously be provided to ensure return of condensed cooling fluid to the reservoir when the attitude of the reservoir is altered as a result of aircraft maneuvers.

Abstract: Apparatus for maintaining the temperature of a component of a gas turbine engine below a predetermined maximum working temperature comprises a reservoir for a cooling fluid having a boiling point below the working temperature and in which the component is immersed or with which it is in contact. At least two heat exchangers are associated with the reservoir and operable to effect condensation of vaporized cooling fluid and return of same to the reservoir. Preferably the apparatus is a closed system incorporating three heat exchangers respectively adapted to effect heat exchange with engine fuel, compressed air derived from a fan or low pressure compressor of the engine and ambient air. Means may advantageously be provided to ensure return of condensed cooling fluid to the reservoir when the attitude of the reservoir is altered as a result of aircraft maneuvers.

Abstract: An engine nozzle is described in which the nozzle is deformable from a first state, typically a round shape, to a second state which may approach a polygon or have a fluted edge. The first and the second state defining different nozzle cross-sections whereby the nozzle can be adjusted between the first and second state for a nozzle cross-section optimised for engine efficiency. Deformation in the nozzle may be achieved through use of shape memory materials, pressure chambers, piezo-electric element deformation or other technique.

Abstract: Apparatus for maintaining the temperature of a component of a gas turbine engine below a predetermined maximum working temperature comprises a reservoir for a cooling fluid having a boiling point below the working temperature and in which the component is immersed or with which it is in contact. At least two heat exchangers are associated with the reservoir and operable to effect condensation of vaporised cooling fluid and return of same to the reservoir. Preferably the apparatus is a closed system incorporating three heat exchangers respectively adapted to effect heat exchange with engine fuel, compressed air derived from a fan or low pressure compressor of the engine and ambient air. Means may advantageously be provided to ensure return of condensed cooling fluid to the reservoir when the attitude of the reservoir is altered as a result of aircraft manoeuvres.

Abstract: A fluid flow control valve (60) comprises a valve seat (62) and a valve stem (64) which is movable towards or away from the valve seat (62) to control the fluid flow through the valve (60). A magnetostrictive element (66) is arranged to move the valve stem (64) towards the valve seat (62) and a spring (68) is arranged to move the valve stem (64) away from the valve seat (62). A valve wall (70) encloses the valve seat (62), valve stem (64), spring (68) and magnetostrictive element (66). A magnetic coil (72), a keeper (74) and a permanent magnet (76) are arranged around the valve wall (70). The fluid flow control valve (60) is used to modulate the supply of fuel to a gas turbine engine combustion chamber to reduce combustion noise especially in premixed lean burn combustion chamber. The advantage is that there are no seals in the valve wall where leakage may occur and the valve is modular.

Abstract: A rotor (38) for a gas turbine engine (10) has a low emissivity surface finish, or high emissivity surface finish (44), on at least a portion of its surface (42) to reduce temperature differentials between an upper portion and a lower portion of the rotor (38). This reduces bowing of the rotor (38) to allow the gas turbine engine (10) to be started without harmful vibrations of the rotor (38).

Abstract: A rotor (38) for a gas turbine engine (10) has a low emissivity surface finish, or high emissivity surface finish (44), on at least a portion of its surface (42) to reduce temperature differentials between an upper portion and a lower portion of the rotor (38). This reduces bowing of the rotor (38) to allow the gas turbine engine (10) to be started without harmful vibrations of the rotor (38).

Abstract: A fluid flow control valve (60) comprises a valve seat (62) and a valve stem (64) which is movable towards or away from the valve seat (62) to control the fluid flow through the valve (60). A magnetostrictive element (66) is arranged to move the valve stem (64) towards the valve seat (62) and a spring (68) is arranged to move the valve stem (64) away from the valve seat (62). A valve wall (70) encloses the valve seat (62), valve stem (64), spring (68) and magnetostrictive element (66). A magnetic coil (72), a keeper (74) and a permanent magnet (76) are arranged around the valve wall (70). The fluid flow control valve (60) is used to modulate the supply of fuel to a gas turbine engine combustion chamber to reduce combustion noise especially in premixed lean burn combustion chamber. The advantage is that there are no seals in the valve wall where leakage may occur and the valve is modular.

Abstract: An apparatus for detecting pressure in a hollow fan blade of a turbofan gas turbine engine comprises a magnetostriction transducer arranged in a sub chamber of the fan blade which is interconnected to a main chamber. A magnetic coil is arranged in the fan casing of the turbofan remote from the fan blade, and an alternating current is supplied from a supply to the magnetic coil to produce an alternating magnetic field. The alternating magnetic field causes the magnetostriction transducer to generate vibrations in the fan blade and the magnetostriction transducer. A magnetic search coil detects changes in the magnetic field, which corresponds to the vibrations, and a processor analyses the vibrations to determine if there has been a change in the resonant frequency of the vibrations which is indicative of a change in the pressure in the fan blade. The processor supplies a signal to a display or to an alarm. The change in the pressure is indicative that the fan blade is cracked and needs replacing.

Abstract: An apparatus (42) for inspecting an as cast turbine blade (40), with impingement cooling passages (36) (see FIG. 2 ), comprises a vacuum pump (52) arranged to evacuate the interior of the turbine blade (40) through pipe (48) and valve (54) and a supply of steam (46) arranged to supply steam to the interior of the turbine blade (40) through the pipe (48) and a valve (50). An infrared camera (56) is arranged to view the outer surface (32) of the turbine blade (40) to detect hot spots produced on the outer surface (32) of the turbine blade (40) by jets of steam impinging on the inner surface (35) of the turbine blade (40) from the cooling passages (36). A processor (60) records the images produced by the camera (56) and analyses the images to determine if the cooling passages (36) have been formed and if they have been formed in the correct position.

Abstract: A power component such as a power transistor is mounted on an insulating substrate of, e.g., beryllia by using a thick film deposition technique. A first layer (2) is deposited and a second layer (3) is deposited over the first layer to produce a regular series of troughs and lands, in the preferred embodiment troughs and ridges, whereby voiding in the solder bond is minimized if not eliminated to thus maintain a good thermal conductivity between the component and the substrate.

Abstract: Apparatus for treating a flow of material by an electric arc generates free radicals and/or atoms, and charged species, in ground or excited states. A cathode (13) and an anode (14) are arranged for striking an arc across a preferably annular gap and provide a pathway for flow of material through the gap between the cathode and anode. Each electrode has a region providing a continuous closed path for the anode spot or cathode root respectively to travel around, and means, preferably magnetic means (19), for producing movement of the arc cause the anode spot and cathode root to travel around their paths in the same sense and in substantially the same time. Preferably the paths are circular paths in parallel planes on the anode and cathode respectively, and the length of the arc remains substantially constant during travel of the anode spot and cathode root around the paths. Preferably the cathode (13) comprises a rod having a plane end face with a circumferential edge for striking the arc.