Abstract:
In a gas turbine engine, compressor delivery air is fed into air inlets in hollow turbine nozzle guide vanes, and then ejected into the gas stream via holes in the vane walls. Valving is provided so as to provide modulation of the cooling airflow over and above the modulation achieved by compressor output when it changes with engine power setting. Excessive cooling of the gas stream is thus prevented.
Abstract:
The invention relates to variable guide vane arrangements for axial flow compressors of aircraft gas turbine engines. The variable guide vane arrangement comprises a plurality of stator vanes rotatably mounted in a stator structure of the compressor. A control ring surrounds and is normally coaxially with the compressor axis, and a plurality of operating levers extend from the control ring to their respective stator vane. The control ring is movable laterally with respect to the axis of the compressor so that the stator vanes in a first half of the compressor are rotated in one direction so that the first half of the compressor operates at a higher pressure ratio and the stator vanes in a second half of the compressor are rotated in the opposite direction so that the second half of the compressor operates at a lower pressure ratio. The half of the compressor operating at a higher pressure ratio is arranged to coincide with a zone of the compressor which has a low intake pressure caused by the inlet flow distortions.
Abstract:
A turbine for a gas turbine engine is provided with a rotary stage comprising an annular array of rotor blades surrounded by an annular shroud member. The shroud member is hollow, the hollow interior being provided with a heat transfer medium which, in operation, functions as a condensable vapor and liquid whereby the shroud member is a heat pipe. The shroud member is further provided with a wall adjacent the aerofoil blade which is adapted to be penetrable by a detached blade or blade portion. The wall of the shroud member is dimensioned so that any such detached blade or blade portion which penetrates the wall enters the hollow shroud ring and is retained within it.
Abstract:
Use of an optical fiber for the direct receipt of heat radiation for transmission to a remote pyrometer is enabled by the provision of an apertured, contaminant free compartment in the component being heated, and aligning the heat receiving end of the optical fiber with the aperture so as to receive radiated heat from within the compartment.
Abstract:
A variable guide vane arrangement includes a control ring located in a fixed axial position and an operating lever having a first end and a second end which is secured to the control ring with the first end positioned between two flanges and secured thereto by a pin; the second end is connected to a portion which fits into a bore and is slidable with respect thereto to vary the length of the operating lever.
Abstract:
In an annular array of stator aerofoil vanes (25 ) each of the vanes (25 ) has a flank portion (35 ) which is pivotally attached to the remainder of its associated vane (25). Actuation means (60) are provided to pivot each flank portion (35) relative to the remainder of its associated vane (25 ). Such movement of the flank portions (35 ) provides variation in the cross-sectional areas of the throat (61) defined between adjacent stator vanes (25).
Abstract:
A cooled aerofoil blade for a gas turbine engine has a hollow trailing edge region in which bridging members interconnect the convex and concave flanks of the blade. The bridging members are each provided with angled cooling passages which are in operation exposed to a cooling air flow and direct that flow onto the internal surfaces of the convex and concave flanks so as to provide impingement cooling thereof.
Abstract:
In a multi stage ducted fan or ducted propeller gas turbine engine, a fan flow exit path is provided in the cowl between axially adjacent stages of blades. The stage of blades downstream of the exit are each pivotable to attitudes which on continued rotation of the stage, induces a reverse flow of ambient air into the duct via the nozzle. The normal and reversed airflows meet under the exit path and pass therethrough to atmosphere. The need for blocker doors in the duct is obviated and energy is imported to the fan air passing through the exit by both stages of blades.
Abstract:
A turbine blade tip clearance control system has a rigid two part outer casing (42) which sandwiches a control ring (48) therebetween, and an air pressurised flexible inner casing (28) which carries shroud segments (22) within it. Struts (40) span the annular space between the casings (42, 28) and prevent flexing of casing (28) until blade tip clearance needs adjusting, whereupon, ring (48) is heated, along with the adjacent portion of outer casing (42) and expands, allowing casing (28) to flex outwards, thus lifting the shroud segments (22) away from the blade tips (24).Closure of the tip clearance is achieved by cooling ring (48), the resulting contraction thereof, via the struts (40), flexing the inner casing (28) and shroud segments (22) inwards, against the air pressure.
Abstract:
A ducted fan gas turbine engine is provided with a fan which is carried by a shaft. Frangible fuse pins maintain the shaft carrying the fan coaxial with the engine longitudinal axis. In the event of severe fan damage, the fuse pins fracture and the fan shaft orbits about the engine longitudinal axis. A spoked resilient member is provided to exert a radially inward restoration force upon the fan shaft following such an event in order to reduce vibration.