Abstract: The invention relates to a combined heat exchanger and fluid filter that can be used in a gas turbine engine for example to simultaneously filter lubricating oil and fuel while transferring thermal energy between the oil and fuel. Conventionally, fuel and oil filters as well as a heat exchanger are separately mounted in an engine with a multitude of pipes conducting fluids between them. The invention packages these components together and achieves several benefits as a results, including: reduction in number of parts, cost of manufacture and installation; containment of the risk of damage or leakage; ease of access for assembly, inspection and maintenance; and simple application to a number of different engines by merely extending the length of the filters/exchanger on a standard manifold design.

Abstract: The invention relates to a method of inhibiting instability during operation of a gas turbine engine, where the instability is due to the uncontrolled interaction between the air filled gap defined by a heat shield and a fuel passage in a conventional fuel injector. The invention is a method of pre-treating the fuel injectors to form a precipitant, such as coke, within the insulating air gap in a controlled and predictable manner prior to installation of the injector into the engine. In this way, the precipitant is present on initial engine operation and impedes the flow of air and fuel within the gap, thus substantially reducing or eliminating engine instability.

Abstract: A structure and a method to form the structure are provided for an impeller bleed passage of a compressor for a gas turbine engine. The compressor has an impeller assembly which includes an impeller rotor rotatably supported within an annular shroud having an inlet and an outlet. The shroud is made of two separate annular segments which are axially spaced apart. Each of the segments is supported separately and independently in a cantilevered manner. Such that a circumferentially continuous, uninterrupted annular slot is formed between the two segments and air passes through the slot without causing a dynamic component to affect the impeller rotor. The width of the slot is adjustable for different engines depending on the requirements of use of a particular engine. The width of the slot is also self-regulating in response to changes in the air pressure within the shroud because of the deformation of the segments. The structure is relatively simple and inexpensive to manufacture.

Abstract: The igniter for the combustor in a gas turbine engine includes a tubular member extending beyond the igniter tip, wherein the tubular member is a porous ceramic or high temperature nickel alloy. Fuel is fed to the bore of the tubular member by capillary action through the porous material of the tubular member and air passes through the porous tubular member to the bore.

Abstract: A Tangential On-Board Injection (TOBI) nozzle or a Radial On-Board Injection (ROBI) nozzle with adjustable flow area in a gas turbine engine for directing a cooling air flow into a rotor assembly of the turbine is disclosed. The TOBI or ROBI nozzle is a unitary cast structure including a plurality of tangentially angled cooling air passages, a number of the passages being cast-closed. After a flow test is conducted using the TOBI or ROBI nozzle, one or more of the cast-closed passages may be selectively machined open if the mass flow of the TOBI or ROBI nozzle does not satisfy the design point. Therefore, the structure of the TOBI or ROBI nozzle is easily fabricated using a casting process with low manufacturing costs while the optimum cooling air flow is achieved by adjusting the total flow area of the TOBI or ROBI nozzle before it is installed to the gas turbine engine.

Abstract: The invention provides a novel sealing device and plenum assembly particularly adapted for forming a plenum inwardly of a circumferential stator blade array in a gas turbine engine. A Tangential On Board Injection plenum (T.O.B.I.) is defined by assembly of: a forward plate; a rearward plate; and a segmented inner shroud disposed between the forward and rearward plates. Releasable elongate fasteners are disposed in joints between a series of inner shroud segments with sealing sheaths laterally surrounding the fasteners. While clamping the shroud segments between the forward and rearward plates, the fasteners and sheaths simultaneously seal the joints and secure the inner shroud segments with forward and rearward plates in a rigid structural assembly.

Abstract: The present invention relates to gas turbines and more particularly to a device for controlling the flow of cooling air through a flowpath in a turbine blade. The device can be inserted in the inlet opening of the blade flowpath and be retained therein. The device comprises a plug member for adjusting the flow of cooling air through the flowpath. The plug member comprises a retaining portion for retaining the plug member at the inlet opening of the flowpath and a blocking portion inserted within the flowpath for reducing the cross-sectional area of the inlet opening. Such a device is inexpensive and can be easily inserted in the inlet opening of a blade flowpath and retained therein.

Abstract: The present invention is addressed to a control logic for determining the occurrence of shaft decoupling in a gas turbine engine. The control logic in the preferred embodiment receives inputs for shaft rotational speed and/or compressor pressure and uses these parameters for making a determination of shaft decoupling in fractions of a second, before serious damage to the gas turbine engine can occur. The control logic also utilizes multiple interval sampling, and sampling over multiple channels to verify any determination of shaft decoupling. Once a shaft decouple has been verified, fuel flow to the engine is cut off, thus shutting down the engine.

Abstract: A compressor for a gas turbine engine, comprising a casing having an inner surface defining a plurality of circumferentially spaced-apart grooves adjacent the tips of a row of rotor blades. Each groove as a depth which is less than half the width thereof in order to increase surge margin at off design points without affecting the performance of the compressor under normal operating conditions.

Abstract: The invention provides in a gas turbine engine combustion chamber, an array of elongate louver strips between fuel nozzles of a combustion chamber dome wall, to cool the dome wall and contain combustion gases in the area between nozzles. The elongate louver strips are each disposed symmetrically along the median line on the inner surface dome wall and extend between each nozzle cup of the annular array. Each strip includes an elongate flange extending into the combustion chamber from the inner dome wall. The flange has an inner surface, and lateral side walls, with the inner surface generally parallel to the inner surface of the dome wall. Compressed air outlets are disposed along each flange lateral side wall, for directing a compressed air film along the inner surface of the dome wall in a direction away from the median line. A compressed air inlet extends from the outer surface of the dome wall to the outlets.

Abstract: The invention provides a novel hardwall fan case for encasing the radial periphery of a forward fan in a gas turbine engine. The fan case includes a rigid annular fan case shell spaced a selected radial distance from the tips of the fan blades, thus defining an annular internal air path surface of the fan case. The shell has a rigid hardwall fore section generally parallel to the blade tips and coated with a fore layer of abradable material. The fore section serves as a hardwall to limit the radial movement of fan blades deflecting under bird strike conditions and thereby to control the erosion of fan case linings. Limiting the radial blade deflection thus maintains the resulting fan tip clearance within acceptable limits. Uncontrolled or excessive erosion of fan case linings during bird strike conditions has in the past led to potentially catastrophic engine surge conditions where highly aerodynamically loaded fans are used that are very sensitive to enlarged tip clearances.

Abstract: An integrated fan and low pressure compressor rotor having a hub with a circumferential array of primary blades. Each primary blade has a forward fan blade portion housed in the engine inlet radially extending from the hub to the fan case and a rearward compressor blade portion housed in the core duct radially extending from the hub to the intermediate case. The fan blade portion and compressor blade portion have aerodynamically aligned lateral airfoil surfaces and platforms such that the fan blade portion and compressor blade portion have continuously merged lateral airfoil surfaces and platforms. The integrated rotor replaces two conventional rotors resulting in cost savings.

Abstract: A stem member for a gas turbine fuel nozzle includes inlet and outlet ends which are respectively adapted to be connected to a fuel adapter which is coupled to a fuel injector and a tip assembly having at least one spray orifice for atomizing fuel into a combustion chamber. The stem member further includes at least one slot which is sealed throughout the length thereof by a slot cover so as to define at least one fuel conduit for directing fuel flow from the inlet end to the outlet end of the stem member. An outer shield can be disposed outwardly of the stem member to protect and limit the transfer of heat from the surroundings to the stem member.

Abstract: An integral inertial particle separator with a de-icing feature in the form of a bifurcated radial intake for a gas turbine engine with an outside wall of the radial intake disposed in contact with heated oil from the engine lubrication system. To discharge particle contaminated bypass air flow from the engine, the separator includes an annular bypass manifold in communication with the bypass duct with vacuum created by an exhaust driven jet air pump.

Abstract: The invention relates to an air purge system for preventing coke buildup in gas turbine engine fuel injectors, and in particular in the relatively small orifice pressure atomizers of a primary fuel injector. The inventors have recognized that after engine shutdown, residual engine heat is sufficient to cause fuel on wetted surfaces of the injectors to decompose and deposit coke. Especially critical are small orifices in injectors positioned towards the upper side of an engine, since rising hot gases accumulate and heat the upper engine area significantly for a long period after engine shutdown. Coke buildup leads to narrowing of the fuel injector orifices, and without adequate maintenance leads to uneven burning and eventually can incapacitate the engine. Fuel injectors are often located in relatively inaccessible interior portions of the engine. Extending the service life of an injector can result in significant maintenance cost savings and engine downtime.

Abstract: The invention provides a diffuser assembly constructed of internal and external concentrically nested bowl-shaped shells for directing an outward flow of compressed air from a centrifugal compressor impeller to an axially rearward diffused annular flow. The shells can be easily manufactured from nested metal castings thereby eliminating much of the cost and time involved in fabricating prior art diffusers of multiple formed tubes brazed to a separately machined hub. The novel diffuser assembly has two concentrically nested bowl-shaped shells, each shell having an inner peripheral compressor impeller casing about a central opening, and an outer edge. Opposing nested surfaces of the shells have an array of mating grooves separated by abutting seam edges thus defining individual diffuser ducts extending from the compressor impeller casings to the outer shell edges when the shells are secured together.

Abstract: The system provides engine maintenance information automatically from fault code data received from an onboard engine performance monitoring computer. The maintenance information is provided by an HTML repair guide electronically called by the control system using the fault code as part of the page address in the HTML guide. The control system automatically ensures that all fault codes are responded to, i.e. that maintenance personnel carry out the appropriate maintenance actions in response to each and every fault code, with a view to improve quality assurance of maintenance. Maintenance actions of maintenance personnel are automatically for the purposes of validating and/or generating warranty claim applications. The system also has a warranty claim report generator for processing aircraft maintenance action log data.

Abstract: A bleed valve is in fluid communication with the compressor fluid flow path and the bypass fluid flow path whereby a piston extends radially of the valve and includes a piston head radially remote from the compressor fluid flow path. A pneumatic chamber surrounds a portion of the piston head, and air from a source downstream of the impeller is introduced into the chamber. The piston including a valving member and a rigid sleeve connecting the piston head to the valving means opens or closes the communication between the compressor flow path and the bypass flow path. A precompressed spring is associated with the piston to normally urge the piston radially outwardly relative to the compressor fluid flow path to a valve open position, and when the pneumatic pressure in the chamber surrounding the piston head overcomes the precompressed spring, the valve is closed.

Abstract: A gas turbine engine blade tip clearance control system and method is described. An annular housing is formed about an engine casing to which an annular shroud segment assembly is secured and closely spaced about blade tips of a stage of blades. The annular housing forms an air passage means communicating with the casing for directing a cooling air stream to the casing. A thermally operable passive ring valve is formed by two overlapped metal ring segments having a dissimilar coefficient of thermal expansion selected whereby to produce a radial gap between the ring segments when the valve temperature reaches a predetermined value. The radial gap admits a cooling air flow into the housing for cooling the casing and its associated shroud segment assembly to control radial growth and thereby prevent blade tip pinching.

Abstract: The invention provides a turbine blade retention device installed in an axially extending gap between the blade root bottom and the slot floor. The retention device has two parts: a blade root retention clip and a spacer bar. The clip has an elongated web of a selected web thickness and width less than the width of the slot floor. The clip includes a forward and a rearward transverse flange extending radially outwardly and extending laterally from forward and rearward ends of the web. The flanges serve to engage the forward and rearward faces of the rotor hub disk respectively, and to engage forward and rearward faces of an associated blade root. The height of at least one flange is less than the gap depth to permit conventional sliding installation the blade root. The spacer bar is installed in the gap between the clip and slot floor to hold the clip radially outward in engagement with the forward and rearward faces of the blade root.