Abstract: A gas turbine engine is disclosed having a tip clearance control system. The tip clearance control system has a cabin blower system, a casing arranged in use about a rotor of a gas turbine engine and a fluid delivery passage. The cabin blower system having a cabin blower compressor arranged in use to compress fluid used in a cabin of an aircraft and to compress fluid conducted via the fluid delivery passage into heat exchange with the casing.

Abstract: A ceramic airfoil system includes a ceramic airfoil shell support by a pair of radially extending pins which penetrate through the shell and connect with a carrier. This pins are disposed at the leading and trailing edges of the airfoil and can be preloaded against the corresponding leading and trailing edge walls to manage thermal growth rates.

Abstract: A gas turbine engine (10) comprises a main fluid flow exhaust nozzle (30) bounding a main fluid flow path, and a cooling nozzle (38) provided upstream of the main fluid flow exhaust nozzle (30) in the main fluid flow path. The cooling nozzle (38) is arranged to provide cooling air to a surface (36) of the main fluid flow exhaust nozzle (30), the cooling nozzle (38) comprises first and second outlets (44, 46). The first outlet (44) is located adjacent the main fluid flow exhaust nozzle surface (36) and is spaced from the main fluid flow path by the second outlet (46). The second outlet (46) comprises a convergent divergent nozzle configured to accelerate cooling air exhausted from the second outlet (46) to a velocity greater than air exhausted from the first outlet (44).

Abstract: A method (30) of controlling fuel flow in a gas turbine engine. First, detect a surge condition. Set fuel flow demand (Wf_D) proportional to compressor discharge pressure (P30). Detect actual fuel flow (Wf_A). Then apply an enhanced schedule (50) for fuel flow demand (Wf_D) while fuel flow demand (Wf_D) is less than a predefined proportion (k) of actual fuel flow (Wf_A). Also a gas turbine engine (10), fuel flow system (68) and fuel flow control system (76) each implementing the method (30).

Abstract: A method of manufacturing a winding assembly for an electrical machine, the method comprising: forming, by three-dimensional, 3D, printing, an electrically insulating body comprising a channel defining a winding path, the channel having an inlet and an outlet; heating the electrically insulating body to a temperature above the melting point of an electrically conducting material; flowing the electrically conducting material through the inlet to the outlet to fill the channel; and cooling the electrically insulating body to solidify the electrically conducting material within the channel, thereby forming said winding assembly.

Abstract: A combustion staging system includes a splitting unit receiving a metered fuel flow and controllably splitting the received flow into pilot and mains flows for injecting at pilot and mains fuel stages performing staging combustor control. Pilot and mains fuel manifolds distribute fuel from the unit, which can select pilot-only and pilot and mains operations. A cooling flow recirculation line provides a cooling flow to the mains manifold during pilot-only operation, and a return section to collect mains manifold cooling flow. A fuel recirculating control valve open position allows the cooling flow to enter a delivery section during pilot-only operation; a shut off position prevents the cooling flow from entering the delivery section during pilot and mains operation. The unit can divert a mains flow portion into the delivery section during pilot and mains operation, the diverted portion re-joining the rest of the mains flow in the mains fuel stages.

Abstract: There is disclosed an auxiliary rotation device 28 for a gas turbine engine 10. The auxiliary rotation device 28 comprises: an electric machine 30 configured to be coupled to a rotor of the gas turbine engine 10; and a dedicated electrical storage device 32 coupled to the electric machine 30. During a period of powered operation of the gas turbine engine 10 the electric machine 30 is configured to act as a generator so as to charge the dedicated electrical storage device 32. Following the period of powered operation of the gas turbine engine 10 the electric machine 30 is configured to act as a motor by discharging the dedicated electrical storage device 32 so as to cause the rotor to rotate for a period of time to provide even cooling of the rotor around its circumference. There is also disclosed a method of cooling a rotor of a gas turbine engine 10 using an auxiliary rotation device 28.

Abstract: A method of constructing a nuclear reactor module includes providing formwork defining a chamber in which is mounted a nuclear reactor comprising a nuclear reactor pressure vessel configured to contain nuclear fuel when in use, the formwork being housed within a containment structure configured to contain an internal pressure generated by an escape of coolant from a reactor coolant circuit. The method further includes filling one or more voids within the formwork with concrete through at least one concrete supply pipe that extends from outside of the containment structure, through the containment structure, and to the formwork; and venting the one or more voids within the formwork through one or more vent pipes, thereby forming a concrete support structure for the nuclear reactor.

Abstract: A gas turbine engine (10) for an aircraft comprises an engine core (11) comprising: a compressor system comprising a first, lower pressure, compressor (14), and a second, higher pressure, compressor (15); and an outer core casing (70) surrounding the compressor system. The gas turbine engine further comprises a fan (23) located upstream of the engine core (11), the fan comprising a plurality of fan blades.

Abstract: An example system may include a computing device and an additive manufacturing tool. The computing device may define a digital representation of an inclined channel at least partially within a component, including an angle ? based on a formula ?=2 tan?1 [tan(?/2)/sin(?)]. The inclined channel may define a longitudinal axis inclined at the angle ? relative to a build direction, and may include a gabled roof configured to collapse into an arched roof. The angle ? is a predetermined interior angle of the gabled roof measured in a plane substantially parallel to the build direction. The angle ? is an interior angle of the gabled roof in a plane substantially normal to the inclined longitudinal axis. The computing device may control, based on the digital representation, the additive manufacturing tool to deposit a material along the build direction to fabricate the component including the inclined channel.

Abstract: An electric machine including a stator having a fully non-magnetic core and stator windings formed of a non-superconducting transposed conductor to reduce eddy current losses. It further includes a rotor having a fully non-magnetic core and superconducting windings or superconducting magnets which produce a magnetic field for interaction with the stator windings. A cryogenic cooling system is arranged to cool the stator windings to reduce conduction losses in the stator windings.

Abstract: An apparatus measuring thrust of an aircraft gas turbine engine includes a core shaft connecting a turbine and compressor, a fan and gearbox with a sun gear driven by the core shaft, a plurality of planet gears, an annulus gear mounted in a static structure, and a planet carrier driven by the fan via fan shaft. The apparatus includes a sensor to measure force applied by the annulus gear on the static structure and first and second sensors to measure rotational speed of the core and fan shafts. A processor determines restoring torque on the annulus gear from measurement of force applied by the gear on the static structure, torque applied to the fan by the planet carrier using rotational speeds of core and fan shafts and restoring torque on the annulus gear, and thrust of the fan from torque applied to the fan and the fan's rotational speed.

Abstract: A joint for coupling ducts, the joint including: a flexible conduit section extending along an axial direction from a first end to a second end; a first connector at a first end of the flexible conduit, arranged to releasably couple the flexible conduit section to a first duct; a first bearing member extending from the first connector, and forming a first bearing surface defining a first plane, wherein the axial direction passes through the first plane; a second connector at the second end of the flexible conduit, arranged to releasably couple the flexible conduit section to a second duct; a second bearing member extending from the second connector, the second bearing member forming a second bearing surface facing the first bearing surface and defining a second plane, wherein the axial direction passes through the second plane; a rod extending between the bearing surfaces.

Abstract: A fixture for locating a straight edge of a curved surface of a part and holding the part in a fixed position during performance of a machining operation on the straight edge is described. The fixture includes: one or more supports for seating a convex curved surface of the part, one or more detachable end stops arranged to extend in a plane orthogonal to that in which the supports sit and against which, in use, the straight edge can be aligned, and a clamp arranged, in use, to push the convex curved surface against the supports such that the straight edge contacts the supports without obstruction of the straight edge.

Abstract: A turboshaft engine has a principal rotational axis and comprises a power turbine, tail bearing housing, and exhaust collector arranged in axial flow series along the axis. The tail bearing housing has radially central region defining flow chamber for cooling air, and an annular duct defined around the central region and which forms at least part of exhaust flow passage for the flow of exhaust gases from the power turbine to the exhaust collector. The flow chamber is provided in fluid communication with the exhaust collector via at least one exhaust port formed in the tail bearing housing such that the flow of exhaust gases along the exhaust collector during operation of the engine educes flow of cooling air through the central flow chamber by drawing air through the or each exhaust port and into the exhaust collector.

Abstract: An electrical fault detector is shown for installation in electrical network (101) of the type comprising a first voltage source (104) and a second voltage source (107), each of which have a respective positive rail (105,108) connected by a positive concentrator (110) and a respective negative rail (106,109) connected by a negative concentrator (111). The detector comprises an inductor (112) for location in one of: the positive concentrator between the connections of the positive rails thereto, and the negative concentrator between the connections of the negative rails to thereto. The detector also comprises a fault identification device (113) configured to monitor the voltage across the inductor, and generate a fault signal in response to the voltage across the inductor exceeding a threshold.

Abstract: A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine has high efficiency together with low noise, in particular from the turbine that drives the fan. The contribution of the turbine noise emanating from the rear of the engine to the Effective Perceived Noise Level (EPNL) is in the range of from 7 EPNdB and 30 EPNdB lower at a take-off lateral reference point than at an approach reference point.

Abstract: Described is a shaft support system for a gas turbine engine comprising: a rotatable fan shaft; first and second support structures extending in parallel from the shaft to a load bearing structure to provide radial location of the shaft within an engine casing, wherein the first support and second support structures include first and second respective mechanical fusible joints; wherein the first fusible joint is a two-stage fuse which partially fails within a first predetermined load range, the second fusible joint fails within a second predetermined load range which is different to the first load range, and the first fusible joint fully fails only when the second fusible joint has failed.

Abstract: A gas turbine engine including a compressor, a turbine having one or more stages and a combustor, the combustor being located between the compressor and turbine. The gas turbine engine further includes a bleed from a core defined by a core duct, the core duct surrounding and extending between the turbine and combustor at least. The bleed includes at least one inlet located downstream of the combustor and upstream of at least one of the turbine stages. The turbine is arranged in use to drive the compressor. The bleed is arranged to be controllable in use to selectively bleed air from the core through the inlet and to thereby control the power delivered by the turbine to the compressor.

Abstract: A flow feature detection method is described. The method includes storing a plurality of points at locations over a region in which vortex detection is to be performed. A value for each of a plurality of fluid flow parameters, such as velocity, pressure and density, is determined at each point. The points are grouped as being contained in either a flow feature portion or normal flow portion of the region according to one or more statistical distribution for the fluid flow parameters. A point is identified as being indicative of the flow feature by identifying multiple further points at least partially surrounding the point, and determining a plane in which the flow feature is identifiable based upon the relative values of the one or more fluid flow parameter for the further points. The method may be used to detect vortices and to identify a two-dimensional plane representative of a vortex.