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: 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: 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 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: 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: 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 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.

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 located near the evaporator inlet, 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 and controls the valve duty cycle based on the difference of the two temperatures. The second temperature sensor is preferably located on the back wall of the compartment and can be adjacent to the compartment air inlet, adjacent to the compartment air outlet, or between the air inlet and air outlet.

Abstract: A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of noise radiating structure is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating structure is tuned by a plurality of drivers arranged to contact the noise radiating structure. Excitation of the drivers causes expansion or contraction of the drivers, thereby varying the edge loading applied to the noise radiating structure. The drivers are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the drivers, causing them to expand or contract. The noise radiating structure may be either the outer shroud of the engine or a ring mounted flush with an inner wall of the shroud or disposed in the interior of the shroud.

Abstract: A signal enhancement system for separating a composite diagnostic signal detected in a rotating machine into component signals representative of the contributions to the composite signal of a number of independent sources. The signal enhancement system includes at least one signal subtraction loop having a transducer which produces a reference signal based on the rotational speed of a rotating shaft in the machine and an adaptive filter connected to the transducer. The adaptive filter processes the reference signal to produce a component signal which closely approximates the contribution of the rotating shaft to the composite signal. A summer is also included which subtracts the component signal from the composite diagnostic signal to produce a second component signal. Both the first and second component signals are provided as outputs of the system.

Abstract: A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by an expandable ring embedded in the noise radiating element. Excitation of the ring causes expansion or contraction of the ring, thereby varying the stress in the noise radiating element. The ring is actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the ring, causing the ring to expand or contract. Instead of a single ring embedded in the noise radiating panel, a first expandable ring can be bonded to one side of the noise radiating element, and a second expandable ring can be bonded to the other side.

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system. A device for sensing suction line temperature is provided, and a controller is included for controlling the duty cycle of the pulse width modulated solenoid valve. The controller receives input from the suction line temperature sensing device as a basis for controlling the duty cycle. The suction line temperature sensing device may be a temperature sensor disposed on the suction line at the midpoint of the heat exchanger between the suction line and the liquid line. Alternatively, the suction line temperature sensing device may include a first temperature sensor disposed on the liquid line at one end of the heat exchanger and a second temperature sensor disposed on the liquid line at another end of the heat exchanger.

Abstract: Microwave heating is used to desorb successive batches of contaminated adsorbent. The apparatus includes first and second stations and an adsorbent carrier tray displaceable between the two stations. Adsorbent is loaded and unloaded from the tray in the first station and heated with microwave energy in the second station. The tray is loaded by passage under a feed hopper, thereby providing an even bed of adsorbent in the tray. Unloading is performed by rotating the tray to an inverted position so that the adsorbent falls into a bin below. The second station includes an oven chamber which is swept with a purge gas to remove gaseous sorbates desorbed from the adsorbent. The tray can include a gas-permeable adsorbent support structure to facilitate passing purge gas and gasification reactants through the adsorbent bed.

Abstract: Induction heating is utilized to heat polymer matrix composites containing electrically conductive fibers. This is accomplished with an apparatus having a mandrel for supporting a composite workpiece and a helical induction coil disposed around the mandrel. The mandrel, workpiece and induction coil are disposed in an autoclave. The mandrel is a hollow, porous member having a port formed therein which is connected to a vacuum. A vacuum bag is hermetically sealed on the mandrel so as to define an enclosure over the workpiece. A power source is connected to the induction coil and, when activated, causes the coil to generate an oscillating magnetic field lying along the longitudinal axis of the mandrel. The magnetic field induces heat-generating eddy currents in the fibers of the workpiece which are oriented orthogonally to the magnetic field.

Abstract: This invention relates to a gas burner which employs a two stage flame stabilizer. At low input rates, a fully aerated flame is stabilized at the surface of a porous material. At higher input rates, the flame blows off and is held by flame stabilization tabs. Such structures of this type, generally, operate over a very wide range of input rates and employ a highly aerated flame which reduces the flame temperature, slows NOx production, and increases the overall reaction rate by shortening the flame while reducing carbon monoxide (CO) caused by flame impingement.