Abstract: A film starter structure for a combustor of a gas turbine engine which includes a plurality of circumferentially spaced, axially extending ribs formed on a radially inner surface of a forward section of an outer combustor liner adjacent a combustor dome. An annular ring overlays the ribs for defining a plurality of air passages. A support extends from the combustor dome and supports the outer liner about the dome. Compressor discharge air is introduced into the air passages and exits the air passages along the inner surface of the outer liner for establishing a cooling film barrier on the outer combustor liner surface. A spring seal between the combustor dome and the inner ring seats the dome within the ring and establishes a seal for preventing leakage air therebetween and allowing independent radial expansion of the liner and dome by compressing the spring seal.

Abstract: A gas turbine engine fan assembly includes an equal number of rotor blades and stator vanes spaced axially therefrom. An annular duct surrounds the blades and vanes and has an inlet for receiving air and an outlet for discharging at least a portion of the air upon compression by the blades. The fan duct further includes a passive acoustic liner tuned for attenuating at least one harmonic noise tone generated by the blades, with a fundamental blade passing frequency noise tone being actively attenuated by a plurality of anti-noise sound transmitters disposed in the fan duct.

Abstract: An improved, highly stable blade-to-blade vibration damper configuration which provides substantially continuous blade vibration damping and sealing of an interplatform gap due to positional stability thereof. Disposed in a subplatform cavity, the damper is comprised of a generally triangular shaped body having a vertex thereof aligned with the interplatform gap. A primary damper load face abuts a first inclined platform load face and a secondary damper load face abuts a second inclined platform load face. Maintenance of sliding planar contact between primary and first load faces and sliding linear contact between secondary and second load faces is afforded by orienting inclined platform faces to have an included angle greater than that of the damper vertex and offsetting a damper center of gravity toward the primary load face. The damper may include one or more legs to orient the damper in the cavity and one or more extending tabs to discourage hot gas flow thereby.

Abstract: A modified inverter/converter unit electronically commutates a switched reluctance machine to provide multiple voltage levels for engine and aircraft applications. A set of power switching transistors apply an exciting current to windings in the switched reluctance machine to produce power at a first voltage level. Additional voltage levels may be provided by using the turns ratio from a plurality of transformers and the switching frequency from the power switching transistors. Alternatively, additional voltage levels may be provided by using windings of a plurality of transformers internal to the switched reluctance machine.

Abstract: A turbine disk cooling system for a gas turbine engine of a type having a compressor section including first and second disks connected by a seal and defining a compressor interstage volume, a turbine section including first and second stage disks connected by a seal and defining a turbine inner stage volume, and a compressor shaft interconnecting the compressor disks with the turbine disks including orifices located in the compressor seal for allowing air in the compressor section to enter the compressor interstage volume, and a radial inflow impeller for guiding the compressor air towards the compressor shaft. The impeller including a plurality of radially-extending conduits suspended in the compressor interstage volume, the conduits having a plurality of interior, radially-extending passages for conveying the compressor air from the orifice to the compressor shaft.

Abstract: A coupling assembly for fluid carrying tubes in a gas turbine engine include first and second fittings fixedly joined to respective ones of the tubes. The first and second fittings include respective first and second mating flanges which are joined together by a clamping band which is adjustable therearound. The first and second flanges include oppositely facing first and second flat faces, with the first flange having a counterbore extending inwardly from the first face, and the second flange having a pilot tube extending outwardly therefrom for being inserted into the counterbore. An annular seal is disposed between the first and second fittings for providing a leak-proof coupling upon clamping together of the two fittings by the clamping band.

Abstract: A method is provided for making a two-piece hollow airfoil having a complex geometry. Two metal sheets are formed into initial shapes so as to have a mean camber and twist. A series of raised ribs is machined onto the external side of each of the two sheets. The two sheets are joined together and sealed to form an in-process assembly. The assembly is subjected to high temperature and pressure to diffusion bond the sheets together at selected points. The assembly then subjected to internal pressure at high temperature in order to inflate and superplastically deform the assembly to the desired shape. Excess material is machined off after the inflation step.

Abstract: The present invention provides a method and an apparatus for selecting a valid signal from a plurality of redundant sensor signals wherein the sensor signals may include a plurality of measured and modelled signals. The invention comprises a circuit for generating a plurality of first pass/fail signals by performing a series of tests on the sensor signals. The invention further comprises circuitry for assigning a plurality of weighted values to each of the measured sensor signals according to the first and second pass/fail signals wherein the second pass/fail signals are initialized as pass signals. The invention further comprises of circuitry for summing the weighted values for each measured sensor signal and generating second pass/fail signals for each measured sensor signal. The invention also includes circuitry for assigning selection flags to each sensor signal according to the first and second pass/fail signals and circuitry for selecting the valid signal from the selection flags.

Abstract: The present invention provides a cooling apparatus with two spaced apart walls, one of which is a coolable wall, having a cooling flowpath between them wherein the cooling flowpath is converging in the direction of the cooling flow. In one embodiment the coolable wall is an afterburner cooling liner that includes a film cooling means on the hot side of the liner. Another embodiment provides a corrugated or wavy wall afterburner cooling liner wherein each wave includes a forward facing surface, from crest to trough of the wave in the direction of the hot gas flow, and an aft facing surface, from trough to crest. A high density pattern of multi-hole film cooling holes is disposed on the hotter of the two surfaces and a lower density pattern on the cooler one.

Abstract: A pressure transducer adapted to measure the position of a pneumatic valve by measuring pressure immediately downstream of a valve restrictor (e.g. a valve plate or butterfly plate) and comparing that pressure with a pressure measured at a second measurement port.

Abstract: Carbon monoxide and unburned hydrocarbon burnout in gas turbine combustors is promoted by a combustor liner having a plurality of vortex generating members or ridges formed therein. The liner includes a substrate having an inner surface and a thermal barrier coating disposed on the inner surface. The vortex generating ridges are formed in the thermal barrier coating and extend transverse to the mean direction of flow through the liner. The thermal barrier coating is capped with a catalytic material which enhances carbon monoxide and unburned hydrocarbon oxidation. The ridges are defined by raised portions of the catalytic material and are of sufficient height to cause mixing between the hot flame products and the cool incompletely-burned flow along the liner wall. Alternatively, the ridges can be defined by forming corrugations in the substrate and disposing a uniform catalytically-active thermal barrier coating over the corrugated substrate.

Abstract: An aircraft engine firewall seal includes a plurality of discrete, stacked-together sealing disks each have a central hole sized for receiving a feed-through member therethrough, with the disks being larger in outer diameter than the firewall aperture through which the feed-through member extends, and with the central holes being smaller in inner diameter than the firewall aperture. The disks are retained against the firewall by a retainer which fixedly clamps together the disks around the feed-through member for sealing gas flow through the firewall aperture.

Abstract: A wall adapted for use in a gas turbine engine between a first fluid and a second hotter fluid includes a first side over which is flowable the first fluid, and an opposite second side over which is flowable the second fluid. An elongate slot extends partly inwardly and perpendicularly from the second side toward the first side and is provided with the first fluid through a plurality of longitudinally spaced apart holes. The holes are aligned coplanar with the slot and longitudinally inclined to effect longitudinal overlapping of the first fluid inside the slot prior to discharge therefrom as a substantially continuous film.

Abstract: A method and passage system is applicable to hollow structures, such as hollow rib core fan blades, for removing alpha case and contamination, for improving surface texture, and for smoothing diffusion bonded joints to reduce notches and flaws, after fabrication. The passage system allows for venting and full cavity access to permit cleaning of the interior of the hollow structure. The method of cleaning the interior of a hollow structure may comprise applying an etchant to strip the topical layer from the inside of a hollow mechanical structure, such as a hollow core airfoil; or may comprise pumping an abrasive flow through the hollow cavities of the structure.

Abstract: Lean direct injection is used in a gas turbine combustor to reduce NO.sub.x emissions. The combustor has a multi-hole perforated plate disposed at the head end of the combustion chamber. The plate has a plurality of independent fuel jets and air jets for separately injecting fuel and air, respectively, into the combustion chamber in amounts which produce a lean fuel-air equivalence ratio. The perforated plate permits the fuel and air to be injected separately without any mixing outside of the combustion chamber. Fuel is delivered to the fuel jets by a fuel manifold having a branch connected to each one of the fuel jets. Air can be delivered to the air jets by an air plenum chamber located upstream of the perforated plate and in fluid communication with the air jets.

Abstract: An open magnet having two magnet assemblies arranged in a spaced-apart, parallel relationship to define a working space therebetween is provided for magnetic resonance imaging. Each assembly has an annular superconductive coil and a ferromagnetic field enhancer encircled by the superconductive coil. The field enhancers are substantially cylindrical ferromagnetic pole pieces which are encircled by a respective one of the superconductive coils. The magnet assemblies are attached to a C-shaped support frame which is rotatively mounted to a pedestal member. The frame can thus be rotated between vertical and horizontal imaging positions. The field enhancers are shaped so as to maximize homogeneity in the imaging volume while keeping their weight and volume to a minimum. The specific shape of the field enhancers is determined with a nonlinear optimization design method.

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system using a simple vapor compression cycle. The refrigeration cycle includes a phase separator which receives two phase refrigerant from the condenser and supplies liquid refrigerant to the pulse width modulated solenoid valve. A liquid level sensor is disposed in the phase separator, and a controller for controlling the duty cycle of the pulse width modulated solenoid valve is provided to receive input from the liquid level sensor. The liquid level sensor can be of the type which provides a continuously variable signal as a function of liquid level, or it can be a liquid level switch which controls valve duty cycle on the basis of whether the phase separator liquid level is above or below a set level. Alternatively, two liquid level switches can be provided.

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system using a dual evaporator, two-stage cycle. The refrigeration cycle includes a phase separator which receives two phase refrigerant from the low temperature evaporator and supplies liquid refrigerant to the pulse width modulated solenoid valve. A liquid level sensor is disposed in the phase separator, and a controller for controlling the duty cycle of the pulse width modulated solenoid valve is provided to receive input from the liquid level sensor. The liquid level sensor can be of the type which provides a continuously variable signal as a function of liquid level, or it can be a liquid level switch which controls valve duty cycle on the basis of whether the phase separator liquid level is above or below a set level. Alternatively, two liquid level switches can be provided.

Abstract: A circuit interruption device having a plurality of micromechanical switches mounted on a substrate in a parallel-series array. The array includes a plurality of line branches connected in parallel in a circuit line. Each of the line branches has at least two of the switches serially connected therein. The micromechanical switches each has a pair of contacts formed on the substrate, a bridging contact movably formed on the substrate, and an actuator for causing the bridging contact to move in and out of contact with the contacts. The bridging contact can be either a member slidably disposed in a channel formed on the substrate or member attached to an end of a cantilever having its other end attached to the substrate. The actuator is controlled by a trip device which is also mounted on the substrate. The trip device senses the current in the circuit line and causes the switches to open when a predetermined level of current in the line is exceeded.

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system. A first temperature sensor is disposed on the suction line, and a second temperature sensor is disposed in a compartment to be cooled. A controller is included for controlling the duty cycle of the pulse width modulated solenoid valve. The controller receives inputs from the two temperature sensors as a basis for controlling the duty cycle. The first temperature sensor can be located either inside or outside of the compartment. Preferred exterior locations include: immediately outside of the compartment, at the inlet of the compressor, at the inlet of the heat exchanger between the suction line and the liquid line, and at the outlet of the heat exchanger.