Abstract: Gas turbines with multiple gas flow paths are provided. In this regard, a representative gas turbine includes: a spool; a compressor; a turbine mechanically coupled to the spool; the compressor having a first set of blades and a second set of blades, the second set of blades being located downstream of the first set of blades, the first set of blades and the second set of blades being driven by the spool; and means for enabling the first set of blades to rotate at a lower rotational speed than the second set of blades.

Abstract: Methods for repairing gas turbines are provided. A representative method includes: identifying an affected area of a surface of a component of the gas turbine, the surface of the component defining a portion of a gas flow path through the gas turbine; applying an epoxy-based filler to the affected area; curing the epoxy-based filler; and blending the epoxy-based filler with the surface of the component.

Abstract: A representative gas turbine includes: a high pressure spool; a high pressure compressor; a high pressure turbine mechanically coupled to the high pressure spool; a lower pressure spool; a lower pressure turbine mechanically coupled to the lower pressure spool; a fan having a first set of fan blades and a second set of fan blades, the second set of fan blades being located downstream of the first set of fan blades and being operative to rotate at a rotational speed corresponding to a rotational speed of the lower pressure spool; and a gear assembly mechanically coupled to the lower pressure spool and engaging the first set of fan blades such that rotation of the lower pressure spool rotates the first set of fan blades at a lower rotational speed than the rotational speed of the second set of fan blades.

Abstract: An emergency lubrication system for a turbine engine includes a reservoir 50 containing a reserve quantity of lubricant 52 and having a lubricant inlet 54 and a lubricant outlet 56. A lubricant supply line 62 and a lubricant outlet line 66 each have a respective valves 64, 68 for regulating lubricant flow into and out of the reservoir. A fluid supply line 70 includes a valve 72 for selectively establishing communication between the reserve quantity of lubricant and a source of pressurized fluid. During normal operation the lubricant outlet valve continuously releases lubricant at a normal rate to the component requiring lubrication while the lubricant inlet valve concurrently admits fresh lubricant into the reservoir. During abnormal operation, the lubricant inlet valve closes in response to abnormally low lubricant pressure outside the reservoir thereby preventing backflow of reserve lubricant out of the reservoir.

Abstract: An adapter to permit borescope access inside a gas turbine engine including a compressor stator having a plurality of compressor stator segments comprises a body portion defining a bore extending longitudinally therethrough from a first end to be disposed adjacent to outside surfaces of adjacent compressor stator segments to a second end to be disposed adjacent to inside surfaces of adjacent compressor stator segments. The bore permits a borescope to enter therethrough. The adapter further comprises an attachment portion for circumferentially coupling at least one compressor stator segment to an outer casing of the gas turbine engine.

Abstract: A mechanical drive system for an accessory gearbox of a gas turbine engine is provided. The gas turbine engine includes a high-pressure drive shaft and a low-pressure drive shaft. The mechanical drive system includes a tower shaft and a lay shaft. The tower shaft is connected by a first gear arrangement to the low-pressure drive shaft of the gas turbine engine. The lay shaft is connected by a second gear arrangement to the first tower shaft, and connected to the accessory gearbox.

Abstract: A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a barium-strontium alumino silicate.

Abstract: A method for applying a material to the face 16,18 of a rotor blade 10 is disclosed. The method includes blocking the flow of molten material to adjacent structure of a rotor blade by disposing a pad against the structure.

Abstract: A rotatable seal element 38 is formed of at least two circumferentially continuous rings 48,50. The rings have decreased thickness T.sub.2, T.sub.3 in the outward direction. Various construction details are developed which effect the level of cyclic fatigue life. In one particular embodiment, the seal element has a flat surface 74 extending inwardly from the sides at the interface between the rings.

Abstract: A nickel base superalloy, having either columnar or equiaxed grain structure, which has significantly improved resistance to hydrogen embrittlement, and to fatigue in air. The material is processed so as to be essentially free of script type carbides, .gamma./.gamma.' eutectic islands and porosity. The processing includes heat treating above the .gamma.' solvus temperature to solution the script type carbides and eutectic islands, followed by HIP to eliminate the porosity.

Abstract: A catalyst for oxidizing aqueous organic contaminants includes about 5 wt % to about 20 wt % noble metal crystallites selected from the group consisting of platinum, palladium, ruthenium, iridium, and combinations thereof deposited on a high surface area catalyst support. The crystallites are about 100 .ANG. or smaller. A system for catalytically oxidizing aqueous organic contaminants has a catalyst bed containing such a catalyst, means for heating a reactor feed stream to a desired reaction temperature, means oxygenating the feed stream, and a phase separator for separating gaseous reaction products from a reactor effluent stream.

Abstract: Intersecting judiciously located installed holes at the tip section of the airfoil of an internally cooled axial flow turbine blade for a gas turbine engine communicating with a passage adjacent the pressure side and another passage adjacent the suction side of the airfoil provide a resultant flow that creates an aerodynamic seal that opposes the flow of engine working medium leaking into the clearance between the tip of the airfoil and the surrounding annular shroud or outer air seal. The installed holes are in proximity to the intersection of the tip surface with the airfoil pressure side surface.

Abstract: A bulkhead in the form of a rib extending spanwise adjacent the leading edge of the airfoil of a turbine blade of a gas turbine engine serves to stiffen the airfoil to attain protection from impact by foreign objects, but doesn't materially affect cooling effectiveness in the event of a puncture of the skin. Holes extending spanwise in the rib reduce the mass, allow radial flow, and restrict flow into the leading edge. This construct allows a reduction in the thickness of the skin of the airfoil, and hence a weight reduction.

Abstract: An aerodynamic buffer zone in the gap between the tip of an air cooled axial flow turbine blade of a gas turbine engine and its surrounding shroud or seal (outer air seal) is created by discretely discharging a high velocity stream of cooling air from the tip of the blade in a judicious direction. The stream is angularly oriented relative to the plane of rotation of the turbine so that it is discharged in the gap in the direction of the pressure side of the turbine and preferably at between a 15.degree.-45.degree. angle relative to the flat surface of the tip of the blade.

Abstract: The blades and the outer case of an encased engine, such as a turbo engine or the like will expand and contract during periods of operation. Blade expansion and contraction can result from operating temperature changes, rotational velocity changes, or the like. The engine casing includes a segmented seal which is properly spaced apart from the engine blade tips so as to provide optimum operation of the engine. Proximity sensors mounted on the engine detect the radial clearance of the engine blades to the seal segments at all times. The seal segments are mounted on a corrugated piezoelectric support which is electrically stimulated so as to properly adjust the seal segments relative to the blade tips to provide the proper spacing as the blades and case expand and contract. Appropriate stimulation of the piezoelectric support will move the seal segments toward or away from the blade tips as needed.

Abstract: An improved vapor phase soldering machine includes a pair of separate vessels having an open fluid communication path in a wall separating the two vessels. The first vessel contains a liquid mixture of a primary vapor and a secondary vapor, while the second vessel contains a liquid mixture of the primary vapor and a tertiary vapor. Heating means continuously boils the two mixtures to create corresponding vapors within the vessels. The secondary vapor is disposed on top of the primary vapor in the first vessel, while the tertiary vapor is disposed on top of the primary vapor in the second vessel. The printed circuit board with surface mounted devices attached thereto by solder paste is introduced into the secondary vapor of the first vessel for preheating the board and the devices. Then, the board is moved into the primary vapor which is at a temperature high enough to melt the solder paste, thereby forming a bond between the devices and the printed circuit board.

Abstract: Prevention of degradation of ion exchange membranes and/or system hardware in electrolytic systems, during system shutdown, is effected by applying a reverse potential to the electrolytic system during shutdown of operation.

Abstract: A dual-pack, aircraft environmental control system has each pack dedicated to providing a temperature-controlled air supply to a corresponding compartment, either the crew or passenger, of the aircraft. Each refrigeration pack is fed hot, compressed bleed air from an associated turbine engine on the aircraft. During normal operation, the pack associated with a particular compartment on the aircraft provides the air supply with independent temperature control to that compartment. However, during failure of one of the refrigeration packs and the resulting operation of the other pack, the environmental control system is able to provide independent temperature control of the air supplied to each compartment.

Abstract: A monitoring system is disclosed to automatically indicate excessive wear of electrical brushes in deicer assemblies for aircraft. In the preferred embodiment, the indicator system includes an electrical brush with an initially insulated wire embedded in it; and an electrical detection circuit, connected to the brush, with a warning device such as a light. When the brush becomes worn, through excessive "end wear" and/or "flank wear", the insulated wire becomes exposed and eventually stripped at the point of wear. This creates a conductive path from the electrical brush, through the bare wire spot, to the detection circuit. This turns on the warning device to indicate that the brush has become worn and needs replacement.

Abstract: Three separate fuzzy rule sets are applied to three corresponding fuzzy sets developed from various input parameters for providing a pitch engagement/mode selection management system and method for requesting disablement of a blade lock, for disabling such lock when the torque available matches the torque required, and for selecting a motor or brake for creating a differential speed between a rotating pitch change mechanism and a fan shaft of a turbine engine. A fuzzeresis rule set is disclosed for stabilizing the motor/brake mode selection fuzzy logic output.