Abstract: A flow control device generates counter-rotating vortices in the boundary layer of the flow in a supersonic inlet diffuser for an aircraft turbine engine. The flow control device comprises a flap attached to the duct wall for selective deployment, wherein it extends into the boundary layer, and retraction, wherein it lies substantially flush with the duct wall. In one embodiment an actuating mechanism comprising one or more shape-memory alloy wires moves the flap between two stable positions. In another embodiment the deployment height of the flap can be controlled as desired, preferably using a shape-memory alloy actuating mechanism. Typically, an array of plural flow control devices is disposed in the inlet duct for selective actuation according to a predetermined schedule.

Abstract: A strainer for an emergency core cooling system (ECCS) in a nuclear power plant comprises a perforated strainer element that is immersed in a reservoir of cooling water, which is drawn through the strainer element into the emergency core cooling system. The side of the strainer element in contact with the cooling water has a contoured configuration for disrupting the formation of a flat bed of fibrous material that can trap small particulate material intended to pass through the strainer element. Incorporating this strainer element into an ECCS strainer enables the strainer to be made more compact, because the debris bed need not be spread over an unduly large area to prevent excessive head loss from the debris load in the event of a reactor loss of coolant accident. The strainer also incorporates a modular construction that uses individual strainer disc modules. Each disc module includes a perforated first disc part having a central opening and a perforated second disc part also having a central opening.

Abstract: An apparatus for attenuating acoustic resonance generated by flow over a cavity in a surface comprises a plurality of flat flaps proximate to an upstream edge of the cavity. The flaps are disposed in an array spaced in a width direction of the cavity edge, and are oscillated by the flow in two degrees of freedom solely by the flow, independent of an actuation mechanism. Each flap includes a first hinge generally coextensive with the surface for enabling oscillation in a first degree of freedom and a second hinge orthogonal to the first hinge and forming a tab for enabling oscillation in a second degree of freedom. The hinges are constructed with torsional spring constants that provide predetermined oscillation frequencies and magnitudes. The apparatus can include a deployment mechanism for moving each flap between a stowed position wherein it is generally flush with the surface and a deployed position wherein the flap can be oscillated by the flow.

Abstract: An apparatus for attenuating acoustic resonance generated by flow over a cavity in a surface comprises a plurality of flat flaps proximate to an upstream edge of the cavity. The flaps are disposed in an array spaced in a width direction of the cavity edge, and are oscillated by the flow in two degrees of freedom solely by the flow, independent of an actuation mechanism. Each flap includes a first hinge generally coextensive with the surface for enabling oscillation in a first degree of freedom and a second hinge orthogonal to the first hinge and forming a tab for enabling oscillation in a second degree of freedom. The hinges are constructed with torsional spring constants that provide predetermined oscillation frequencies and magnitudes. The apparatus can include a deployment mechanism for moving each flap between a stowed position wherein it is generally flush with the surface and a deployed position wherein the flap can be oscillated by the flow.

Abstract: A strainer for an emergency core cooling system (ECCS) in a nuclear power plant comprises a perforated strainer element that is immersed in a reservoir of cooling water, which is drawn through the strainer element into the emergency core cooling system. The side of the strainer element in contact with the cooling water has a contoured configuration for disrupting the formation of a flat bed of fibrous material that can trap small particulate material intended to pass through the strainer element. Incorporating this strainer element into an ECCS strainer enables the strainer to be made more compact, because the debris bed need not be spread over an unduly large area to prevent excessive head loss from the debris load in the event of a reactor loss of coolant accident. The strainer also incorporates a modular construction that uses individual strainer disc modules. Each disc module includes a perforated first disc part having a central opening and a perforated second disc part also having a central opening.

Abstract: A trash rack for an emergency core cooling system of a nuclear power plant comprises at least one wire-mesh upright screen for filtering debris from coolant flowing in the cooling system. The upright screen is mounted in the coolant flow path with its bottom edge on the floor of an area forming part of the cooling system and a top edge is disposed above the floor at a height less than the level to which the coolant can be expected to rise during a loss of cooling accident. The trash rack also uniquely includes a wire-mesh roof screen that has a downstream edge mated with the top edge of the upright screen and extending upstream thereof to an upstream end spaced from the floor, thereby presenting an unobstructed opening between the floor and the upstream edge of the roof screen.

Abstract: An externally powered, self cleaning strainer incorporating a projectile shield, which is capable of operating for an extended period of time. A suitably shaped, motor driven, impeller creates a localized, radially outward flow of fluid in the vicinity of the strainer inlet. The projectile shield has a lower surface shaped to deflect fluid to the strainer at a constant velocity, enabling the impeller to eject debris more efficiently. Maintaining a constant flow through the strainer also avoids additional head loss associated with accelerating flow. The self cleaning strainer may also include a brush attached diametrically opposite to the impeller to aid in removing debris from the inlet side of the strainer. The impeller may also be shaped so that when it is swept past the inlet side of the strainer, it causes a localized, reverse flow through the strainer, thereby removing debris particles from within the strainer.

Abstract: A system and method for accurately estimating the fluctuating pressure loads on components, such as steam dryers, within a BWR steam dome using pressure time history measurements made on components of the BWR facility external to the steam dome. The method uses existing sensors to obtain the pressure time histories. An accurate determination of the fluctuating pressure loads within the steam dome may be obtained by modeling and analyzing the steam delivery system external to the steam dome, including all possible acoustic sources, using acoustic circuit methodology and pressure time histories, and then coupling these results, essentially as part of the boundary conditions, to the solutions for Helmholtz equation within the steam dome.

Abstract: A method and apparatus for light curing of composite materials in which the radiation required to initiate the curing is delivered via one or more lossy fiber optics. The fiber optics are made lossy by methods such as bending the fiber, weaving the fiber into a mat to create periodic micro-bends, tailoring the thickness of the fiber cladding to allow evanescent wave transmission, or simply removing the cladding at intervals along the fiber. Distribution of the light through out the composite material results in dramatic power and time reductions over traditional light curing methods. Unlike thermal curing of composite materials, there is no need for an auto-clave and hence no limit on the size of the part that may be created. Additional benefits include the possibility of curing at operational temperature and so avoiding thermal stresses.

Abstract: A rotor blade has a local geometric twist angle &thgr;=ƒ(r/R), with R being the blade span and r being the distance along the blade span from the axis of rotation. The blade has an inner region between an (r/R)inner=0.20±0.04 and a transition point at (r/R)trams=0.75±0.04, wherein &thgr;inner at (r/R)inner has a positive value and is greater than or equal to &thgr;trans at (r/R)trans. A blade tip region includes a first portion between (r/R)trans and (r/R)min>(r/R)trans, wherein &thgr; continuously decreases from &thgr;trans to &thgr;min at (r/R)min, and &Dgr;&thgr;tip1=|&thgr;min−&thgr;trans|>3°, and a second portion between (r/R)min and the blade tip, wherein &thgr; continuously increases from &thgr;min to &thgr;tip at the tip, and &Dgr;&thgr;tip2=|&thgr;tip−&thgr;min| is at least about 3° and no greater than about 20°.

Abstract: A mechanical actuating device for moving an aerodynamic or hydrodynamic surface includes plural flexure members confined in an elastically deformed condition. The flexure members are movable against the force generated by their elastic deformation to move the device into one of at least three stable positions, in which the device, and therefore the aerodynamic or hydrodynamic surface, are held by the force generated by elastic deformation of the flexure members. Since the flexure members are always elastically deformed, the device “snaps” between discrete, stable positions and is held firmly in each. In another embodiment more flexure members can be used to provide additional stable positions. In one application, the actuating device is used as a trailing edge tab for a helicopter or tiltrotor blade to reduce 1/rev vibrations. The device can be actuated manually or electrically using shape-memory alloy wires to snap the flexure members into their various stable positions.

Abstract: The present invention comprises a system and method for detecting icing conditions in a multi-mode aircraft by indirectly detecting ice accretion through the measurement of aircraft performance related characteristics. Indirect characteristics are used, sometimes in additional to traditional icing sensor input, because it is difficult to safely and effectively position icing sensors in aircraft that may fly in the hover mode or the fixed wing mode as well as modes in between. Typical indirect characteristics might include thrust and rotor response for a given torque. This information is compared to a model of the expected aircraft performance to determine if icing is likely to take place. For example, decreased thrust or lift for a given torque may indicate the onset of icing. Inputs from the traditional icing sensors may also be employed as additional useful, predictive data.

Abstract: A mechanical actuating device for moving an aerodynamic or hydrodynamic surface includes at least one flexure member confined in an elastically deformed condition. The flexure member is movable against the force generated by its elastic deformation to move the device into one of a plurality of stable positions, in which the device, and therefore the aerodynamic or hydrodynamic surface, are held by the force generated by elastic deformation of the flexure member. Since the flexure member is always elastically deformed, it “snaps” between discrete, stable positions and is held firmly in each. In another embodiment more flexure members can be used to provide additional stable positions. In one application, the actuating device is used as a trailing edge tab for a helicopter or tiltrotor blade to reduce 1/rev vibrations. The device can be actuated manually or electrically using shape-memory alloy wires to snap the flexure members into their various stable positions.

Abstract: A fire fighting system uses a bucket suspended from a helicopter to deposit fire retardant onto a fire from an opening in the bottom of the bucket. The bucket has a predetermined configuration and a valve for controlling the area of an opening through which the retardant is deposited when the bucket is suspended from the helicopter. A suitable mechanism, such as an electrically driven valve actuator, varies the area of the opening to deposit the retardant at a volume flow rate as a desired function of time while the helicopter flies along a drop line. The mechanism varies the area of the opening in accordance with a schedule determined before discharge is begun according to the configuration of the bucket, the flow characteristics of the opening as the valve changes the area thereof, and the initial amount of the retardant material in the bucket.

Abstract: This invention relates to a system and method for reducing the primary vortex wake structure generated by a lifting body mounted on an object moving through a fluid. This is achieved by first, altering the generated initial vortex wake to make it vulnerable to rapid breakup; and, second, producing disturbances to this wake with secondary vortices from auxiliary lifting surfaces, called vortex leveraging tabs, to instigate this breakup. This invention relates to various fields of uses to include vortices generated by any type of lifting body moving through a fluid to include aircraft and watercraft, such as surface vessels and submarines.

Abstract: A system for alleviating scouring damage at the base of a structure anchored in the bed of a body of liquid flowing at a velocity relative to the structure, such as a bridge pier in a river bed, comprises a plurality of hollow vehicle tires surrounding the structure in a matrix of plural stacks of tires connected together with their toroidal axes substantially aligned. Each stack comprises a predetermined number of tires so that the top surface of the matrix forms a predetermined angle relative to horizontal.

Abstract: A suction strainer for straining water from the emergency suppression pool of a boiling water reactor includes a plurality of stacked, perforated disks having an internal core with a minimum internal radius r(x) that decreases with increased distance from the intake of the strainer, so that the core has a tapered profile. Internal radius r(x) may vary linearly or exponentially or a combination of both. The stacked, perforated disks each include a first surface that faces in the direction of the intake and a second surface, that faces away from the intake. A circumferential band may connect the first and second surfaces together.

Abstract: An actuating device can change a position of an active member that remains in substantially the same position in the absence of a force of a predetermined magnitude on the active member. The actuating device comprises a shape-memory alloy actuating member for exerting a force when actuated by changing the temperature thereof, which shape-memory alloy actuating member has a portion for connection to the active member for exerting thereon a force having a magnitude at least as large as the predetermined magnitude for moving the active member to a desired position. Actuation circuitry is provided for actuating the shape-memory alloy actuating member by changing the temperature thereof only for the time necessary to move the active member to the desired position.

Abstract: The present invention features a technique and system for achieving sufficiently stable, thick liquid films on an aircraft surface during a rain storm in flight, wherein such stable and thick films can be measured to determine liquid water content (LWC) in the air, and (by known correlation) rain fall rate. Rainfall impinging upon an airflow surface of an aircraft, such as a wing portion, is gathered and confined within a weir-like structure. The flow of the rain is constricted within this device to increase the film thickness and reduce shear between air and liquid boundaries, whereby a stable film surface for measurement is provided.