Abstract: A rotor blade system with reduced blade-vortex interaction noise includes a plurality of tube members embedded in proximity to a tip of each rotor blade. The inlets of the tube members are arrayed at the leading edge of the blade slightly above the chord plane, while the outlets are arrayed at the blade tip face. Such a design rapidly diffuses the vorticity contained within the concentrated tip vortex because of enhanced flow mixing in the inner core, which prevents the development of a laminar core region.

Abstract: A device for mixing a flowable or pourable medium has a container for receiving the medium and a rotatable shaft having radially projecting support arms and rotatable in a direction of rotation. Mixing elements are connected to the radially projecting support arms. The mixing elements are tubular and formed as coil-shaped spirals conically shaped at least across a partial length of the coil-shaped spirals. The coil-shaped spirals have a first end face and a second end face. The first end face points in the direction of rotation and has a cross-section greater than the cross-section of the second end face. The coil-shaped spirals have a central axis having a slant angle relative to a plane of rotation of the two mixing elements. The support arms and the coil-shaped spirals connected to the support arms, respectively, are formed of a single wire as a monolithic part, respectively.

Abstract: A rotor which has a cone shaped tube with a large air input end and a smaller air output end. The cone shaped tube increases air pressure as the air passes through the tube and provides more lift.

Abstract: An active control device is disclosed comprising an array of actively controlled oscillating air jets disposed on an aircraft structure. In a preferred embodiment, the device senses parameters associated with incipient unsteady aerodynamic excitation, such as free stream gusts, shed wakes in rotor and turbomachinery flows, or oscillatory motion of trailing edge control surfaces such as ailerons. These parameters are provided as input signals to a processor. Based on the input signals, the processor generates output signals that are used to operate the air jet array in a manner counteractive to the unsteady forcing. The air jet array can be used on numerous aircraft structures, including rotor blades, wings, engine inlets, engine exhausts, blunt surfaces and nozzles.

Abstract: A fan blade provided with an active carbon filter bed, wherein, an opening is provided in the center of the fan blade, and said opening is covered with an active carbon filter bed. And said active carbon filter bed can be in the form of powder, grain or fiber attached by any means to non-woven fabric, fiber layer, staple on the base filter element of porous PE or PU foam. Furthermore, both of the active carbon filter bed and the fan blade can be adhered to each other by glue, adhesive band, equi-directional magnet or other adhesion or structure.

Abstract: A method for the enhanced performance of a propeller/rotor. In which the conventional blades have been modified by the addition of a surface parallel or a cavity created within the existing blade plane from the leading edge to the trailing edge, encompassing the complete blade. An opening is created in the leading edge of blades with the rear trailing edge being sealed. The trailing face of the blades have a opening machined into the surface opposite and as close to the trailing edge, and as far behind the leading edge opening. The opening (exhaust) location maybe relocated to achieve different desired effect. The created chamber causes the water/air entering to be pressurized after being scooped into the chamber. Forcing the water/air to exit the machined exhaust opening under far greater pressure. Therefore increasing the thrust and efficiency of the propeller.

Abstract: An aerofoil (22,24), preferably of a high lift, highly loaded design, for an axial flow turbo machine (10). The aerofoil having a span, a leading edge (LE), a trailing edge (TE) and a cambered sectional profile comprising a pressure surface (30,72) and a suction surface (28,70) extending between the leading edge (LE) and trailing edge (TE). The aerofoil (22,24) having at least one aerofoil cross bleed passage (36,37,78,80) defined in the aerofoil (22,24) which extends from the pressure surface (30,72) through the aerofoil (22,24) to the suction surface (28,70). The at least one passage (36,37,78,80) preferably disposed generally at a location on the suction surface (28,70) at which boundary layer separation from the suction surface (28,70) would normally occur.

Abstract: A controlled passive porosity system includes a lifting device for operation in a multi-phase liquid, the lifting device having a low pressure surface with a plurality of holes and a high pressure surface with a plurality of holes. A common plenum is disposed within the lifting device and allows fluid communication between liquid adjacent the high pressure surface and liquid adjacent the low pressure surface. When cavitation occurs adjacent to the low pressure surface, a series of valves associated with the holes allows selective and localized fluid communication between the surfaces. The fluid communication has the effect of raising the pressure of the liquid in the area of cavitation, thereby eliminating the cavitation. In an alternate embodiment, the lifting device includes a first plenum, a second plenum, and an intermediate fluid passage, the fluid passage fluidly connecting the first plenum and the second plenum.

Abstract: An aerofoil (22,24), preferably of a high lift, highly loaded design, for an axial flow turbo machine (10). The aerofoil having a span, a leading edge (LE), a trailing edge (TE) and a cambered sectional profile comprising a pressure surface (30,72) and a suction surface (28,70) extending between the leading edge (LE) and trailing edge (TE). The aerofoil (22,24) having at least one aerofoil cross bleed passage (36,37,78,80) defined in the aerofoil (22,24) which extends from the pressure surface (30,72) through the aerofoil (22,24) to the suction surface (28,70). The at least one passage (36,37,78,80) preferably disposed generally at a location on the suction surface (28,70) at which boundary layer separation from the suction surface (28,70) would normally occur.

Abstract: Porous surfaces on an aerodynamic structure driven with positive and negative pressures are used in an active control system for attenuating shock waves responsible for high-speed impulsive (HSI) noise. The control system includes an array of apertures in the outer skin of the structure providing fluid communication between the exterior flow stream and an interior volume of the structure. A movable diaphragm within the structure pushes air out of and pulls air in through the apertures under the action of a drive mechanism within the structure, thus creating oscillating air jets. The drive mechanism may be actuated by a controller based on information supplied by a sensor in the leading edge of the aerodynamic structure. The array of apertures may be spaced apart along the outer skin of the aerodynamic structure so as to span a distance of about 15% of the chord length. The oscillating airjets may be provided on multiple surfaces of the aerodynamic structure, including the upper and lower surfaces.

Abstract: Blades, including helicopter rotor blades, gas turbine engine fan blades, air moving machinery fan blades, and the like, have an air inlet near the hub of the blade, which may be on the pressure side of the blade and/or near the leading edge or trailing edge nearer the tip of the blades, with an air plenum between the air inlet and the slots, whereby air is forced into the inlet, through the plenum and out of the slots into the flow adjacent the blades. The slots may be through the suction surface of the blade, typically near the boundary layer separation point, so that air flowing out of the slots into the boundary layer of the suction surface of the blade, thereby delay or prevent the onset of boundary layer separation, or to reduce supersonic shock. The inlet may be near the trailing edge of the blade, near the root, adjacent to the air inlet of the core of a jet engine, to suction off air and reduce fan wake blockage at the core inlet.

Abstract: An active control system for reducing blade-vortex-interaction (BVI) noise generated by a rotor blade. The active control system includes a pressure sensor assembly, a device for changing a lift generated by the rotor blade, and a controller for activating the device upon a detected change in air pressure by the sensor assembly. The sensor assembly is disposed in close proximity to the rotor blade, and is adapted to detect a change in air pressure on a surface of the rotor blade near a leading edge of the rotor blade. The device is adapted to be activated by the controller, to thereby change a lift of the rotor blade. The controller activates the device to change a lift of the rotor blade in order to introduce a compensating pressure onto the surface of the rotor blade. This compensating pressure attenuates the magnitude of the change of air pressure.

Abstract: An active control device for use on an aerodynamic structure is provided. The aerodynamic structure includes an outer aerodynamic skin and an interior volume, wherein the outer aerodynamic skin surrounds the interior volume. The active control device includes at least one aperture disposed on the outer aerodynamic skin and a diaphragm disposed in the interior volume of the aerodynamic structure. The at least one aperture connects the outer aerodynamic skin to the interior volume, and the diaphragm in the interior volume is movable between a first position and a second position. Movement of the diaphragm from the first position to the second position pushes air through the at least one aperture and out of the interior volume. Movement of the diaphragm from the second position to the first position draws air through the at least one aperture and into the interior volume. The diaphragm may be circular, or may be oval-shaped.

Abstract: A ceiling fan for cleaning air in a room wherein each blade of the ceiling fan has a cavity open to the top and bottom surfaces of each fan blade and a filter unit in each of the cavities but within the confines of the fan blade such that, when the ceiling fan is operated, the airflow created by the ceiling fan will be forced through the filter unit from the bottom surface through to the top surface, wherein the filter units can collect airborne particles.

Abstract: A large air moving fan has a number of hollow airfoil blades extending generally radially from a rotatable hub. The tips of the blades are surrounded by a circumferential shroud leaving a narrow gap between the tips of the blades and the shroud. A fin on the tip of each blade extends substantially perpendicular to the transverse cross section of the blade. The outline of the fin corresponds approximately to the shape the airfoil at the tip of the blade and the fin is curved so as to be substantially parallel to the shroud. It is believed that the fin prevents direct radial flow of a boundary layer of air from the outside surface of the blade into the gap between the tip of the blade and the shroud. This reduces the turbulence adjacent to the tip of the blade since the air traveling radially along the blade does not mix as violently with air passing through the gap from the high pressure side of the fan to the low pressure side of the fan. Noise reduction in the order of 3 db is obtained.

Abstract: A gas turbine engine rotor blade includes an airfoil having first and second sidewalls joined together at leading and trailing edges. First and second tip walls extend from adjacent the leading edge along the respective first and second sidewalls to adjacent the trailing edge and are spaced apart to define a tip cavity therebetween. A first notch is disposed in the first tip wall adjacent to the leading edge for channeling into the tip cavity a portion of combustion gases flowable over the airfoil for reducing the heating effect of the gases on the blade tip. In a preferred embodiment, a second notch is disposed adjacent to the trailing edge for promoting flow through the tip cavity from the first notch.

Abstract: A self bleeding rotor blade and method of operation are disclosed for reducing boundary layer thickness for improved performance. The rotor blade includes an outer surface configured for pressurizing air flowable thereover with bleed apertures being disposed therein for bleeding a portion of boundary layer air from the outer surface during operation and thereby decreasing its thickness for improving aerodynamic performance of the blade.

Abstract: A method of securing a filter element to a blade of a fan includes firstly, forming a cavity within a fan blade so that the cavity has a tip end oriented toward a tip of the fan blade and a root end oriented toward a root of the fan blade. Secondly, form at least one flow passage extending from one broad surface of a fan blade through the cavity to an opposed broad surface of the fan blade, such that air circulates through the cavity via the flow passages upon movement of the fan blade. Thirdly, form an access opening through which a filter element is inserted into the cavity.

Abstract: Higher harmonic control (hereinafter HHC) of helicopter rotor blade vibrations is provided by an actively controlled, rotatable, slotted cylinder which is mounted at an outboard section of each blade. Continuous rotation of each cylinder about its longitudinal axis produces a periodic aerodynamic force on the blade at a frequency of twice the rotational frequency of the cylinder. The amplitude of force is controlled by the size of a slot opening in the cylinder while the rotational speed of the cylinder is synchronized to run at a multiple of the speed of a rotor blade drive shaft. The amplitude and phase of the HHC force is regulated, either manually or by active feedback control, to minimize any vibratory load transmitted to the airframe through the rotor blade drive shaft. A significant advantage offered by this concept relative to other HHC methods, such as high-frequency blade pitch motions actuated either by the swash plate or by moveable tabs at the blade trailing edge, is its low power requirement.

Abstract: A variable pitch propeller mechanism includes a plurality of airfoil-shaped blades on three spaced apart blade arms. The airfoil-shaped blades are pivotally connected to the blade arms and are interconnected to each other by rigid connecting rods so these blades move in unison in response to changing wind conditions. Air flow across the airfoil-shaped blades is also controlled to improve the efficiency of the device.

Abstract: Disclosed is a system and method for suppressing rotor noise by distributing mass and momentum sources and sinks on the rotor blade. A source is located on the blade, and therefore has the directivity of moving, as opposed to a stationary source. Moreover, the motion of the blade with respect to the observer amplifies the sound from the source in a manner similar to the manner in which motion of the blade amplifies all other sources of noise associated with the rotating blade. Two sources can be used to cancel noise. The first source, created by ejecting air from or drawing air into the blade, is used to cancel the "load" portion of rotor noise. The second source, created by developing a radial force with a proplet, is used to cancel the "thickness" portion of rotor noise. More control can be achieved by time modulating the rate of suction or the amplitude of radial force developed by said proplet.

Abstract: A mixer is disclosed for absorbing and mixing gases in liquids, or for mixing a liquid with another liquid and/or atomizing a liquid in a gas. The mixer includes an impeller with blades which are bent backward, the blades being surrounded on both sides by a front wall comprising an exhaust opening and a back wall sealing off at least the entire conveying area. A sectional chamber, which is built together with the coaxial hollow main shaft stub, is constructed in the shaft of the impeller and at least two blades are assembled with a pipe for propellant. The inner end of the pipe adjoins a sectional chamber and a nozzle is provided on the outer end. The impeller is closed off with a casing, injectors coaxial with primary nozzles are led through a casing, a mixing nozzle of the injectors is attached on three sides to the casing of the impeller, the front wall and the back wall while connected with a blade on the fourth side.

Abstract: A stirring mechanism, with a plurality of hollow, at least partially conically shaped stirring elements, which are provided with two openings, are symmetrically offset and are fixed on the stirring shaft (2) at least approximately tangential to an imaginary circular cylinder coaxial to the stirring shaft.In the starting phase, the stirred substance flows laminarly through the stirring elements 8. However, as soon as they have reached a predetermined minimum velocity of about 1.3 m/s, the flow inside the stirring elements 8 is forced to reverse by dynamic pressure. The resultant counterflow (11, 12, 13) brings about an outstanding, extensive and nevertheless extremely gentle stirring effect with low power consumption. Also, an effective and uniform gassing can be obtained with simple means, without the stirring velocity having to be increased.

Abstract: An impeller forming a unit with the spherical rotor of a sphero-pump consists of a disc with vanes and an inlet member, both made by injection molding from resin. A rotor plate made from a thick gauge sheet metal covers the vanes and is held in position by rivet type protrusions on the inlet member and compensates the weight of the rotor.

Abstract: A radiator fan is disclosed which comprises a plurality of blades, each having formed therethrough a number of passages each of which extends in such a direction as not to be influenced by dynamic pressure which the blade is subject to.

Abstract: An arrangement for controlling the air flow past an aerodynamic profile, (such as an aerofoil surface of a wing, tail plane, or fuselage of an aircraft or missile, a propeller, helicopter rotor, or blading of a turbo-engine fan or wind impeller) by providing a number of orifices of small diameter spaced apart in the profile surface in the longitudinal direction of the profile transversely to the direction of air flow over the profile and to the chordwise direction of the profile. Fluid is either discharged or drawn in through the orifices perpendicularly to the air flow in the region of separation of laminar flow. The orifices have a coefficient of flow (i.e., either a discharge or an intake coefficient) C.sub.Q =(V/FV) of up to 10.sup.-4 for a Reynolds Number less than 3.times.10.sup.6, where v=volume flow of the fluid through the discharge orifices, F=profile area and V=velocity of the air stream flowing over the wing or blade.

Abstract: Water inlets (16) are formed on the sides of the gearcase (13) of a marine propulsion unit. Ramps (26) and (27) are formed in the gearcase (13) ahead of the inlets (16) to direct flow to the inlets (16). The ramp (26) ahead of the upper ports (16) has a greater depth to provide a substantial flow of water at positive pressure, while the ramp (27) ahead of the lower ports (16) has a lesser depth to avoid disturbances in flow when the unit is operated at high speeds where the upper inlets (16) are normally above the resting surface of the water.

Abstract: A device for producing a force when in a moving fluid, such as air or water, and a method for using said device. The device may be placed in a fluid moving in a first direction for producing a force in a second direction, which is substantially transverse with respect to the first direction. The device avoids the use of large sail areas needed where the force derived from wind is proportional to said area. The device according to the invention comprises an elongated body having in cross-section a rounded symmetrical profile, which defines an elongated and rounded leading portion whose thickness increases from the front to the rear and a rounded trailing portion whose thickness decreases from the front to the rear, the leading portion being longer than the trailing portion. The device according to the invention is also provided with at least one flap, which projects from the body and which is located on the trailing portion of the profile.

Abstract: An air jet spoiler arrangement is provided for a Darrieus-type vertical axis wind-powered turbine. Air is drawn into hollow turbine blades through air inlets at the ends thereof and is ejected in the form of air jets through small holes or openings provided along the lengths of the blades. The air jets create flow separation at the surfaces of the turbine blades, thereby inducing stall conditions and reducing the output power. A feedback control unit senses the power output of the turbine and controls the amount of air drawn into the air inlets accordingly.

Abstract: A fan blade, preferably for use with a ceiling fan, is constructed hollow with a top and bottom located so as to provide an air space sufficiently large enough to house one or more germicidal lights, preferably ultraviolet, in such manner that the light will burn while the fan blade rotates. Filtering pads, preferably charcoal impregnated and usually comprised of a plastic foam, are located at the leading and trailing edges of the air space between the top and bottom of the hollow blade for the absorption of smoke and other objectionable odors as the air passes through the lamp area. Preferably the leading edge is provided with pocket means to receive the air. Baffles may be provided to prevent the germicidal light from casting its light outside the confines of the hollow blade. The ends of the blade joining the leading and trailing edges thereof are closed.

Abstract: A rotor blade for a rotor assembly which has a laterally extending shroud is disclosed. Various construction details and design techniques for the shroud which reduce the weight of the blade and increase the cyclic fatigue life of both the rotor blade and an associated component are developed. The shroud of the rotor blade is contoured in the lateral direction for nearly uniform stress distribution.

Abstract: The efficiency of a hydro-electric generator is improved by providing open-ended hollow tubes having influx ends proximate the axis and efflux ends proximate the periphery of a fan-bladed turbine. The jets of water developed by rotation of the fan-bladed turbine are directed against turbine vanes at the periphery of the fan blades. The device is particularly suitable for mounting in a water current such as in an ocean current or river.

Abstract: A hub is provided defining an axis of intended rotation to be disposed generally parallel to the direction of wind movement and the hub is hollow and include opposite ends spaced along the aforementioned axis. One end of the hub is closed and the other end is open to receive therein the wind incident upon the hub. The hub includes a plurality of elongated hollow propeller blades supported therefrom including root and tip ends as well as leading and trailing edges. The blades have their root ends supported from the hub at points spaced thereabout with the root ends opening into the interior of the hub inwardly of the open end thereof and the tip ends of the blades extending outwardly from the hub.

Abstract: A propeller or impeller construction having a plurality of blades mounted on a hub section. The blades are essentially triangular in cross section and are hollow to achieve light-weight and permit center air flow. In addition, the blades may be tapered in such manner that accelerated internal air movement with compression toward the tip ends is enabled. The tip portions of the blades may be vented to provide for air flow through the center and out of the tips, and also the rear structural plate may be vented to the low pressure side of the blades. Blade construction may provide for variations in the pitch angle. The blades are mounted on the hub section by a unique construction which may provide both commonality and interchangeability of parts. This construction also enables the use of shims to facilitate balancing and to change and/or adjust thrust characteristics without changing blades.

Abstract: A helicopter rotor is formed with spars and ribs. The spars form parts of the surfaces, and long slots are constructed in the spars to provide suction and blower slots. Air is withdrawn in slots nearest the leading edge, and engine exhaust is conducted to a suction/blowing device which in turn blows air through slots near the trailing edge. Helicopter engine exhaust is mixed with air and fuel and is recombusted. Air is drawn into a recombustion chamber of a suction/blowing device from suction surfaces on the helicopter rotor blades. This suctioned air is then re-routed to the slots near the trailing edge and blown over the upper and lower surfaces of the blade.

Abstract: A blade ring of high circumferential speed for thermal axially passed through turbines, especially for the last stage of condensing steam turbines, having at least the radially outer portion of its blades lying within the range of transsonic flow or within the range of supersonic flow. Each blade of the blade ring changes from the profile at the foot portion of the blade toward the tip of the blade into a profile defined to a major extent by straight lines or by only slightly curved lines. This profile is about one half of its length at its upper region provided with a slot along the longitudinal axis of the blade. This profile which thus has two sections has one of these sections with its exit edge turned relative to the other section by an angle corresponding to the post-expansion of the supersonic flow into such a direction that the profile part with the exit edge lies in the flow-off direction.

Abstract: Torsional oscillations of helicopter rotor blades are reduced with stall, otherwise leading to such torsional oscillations, precluded consistent with allowable high angle of attack, by sucking air from the boundary layer on the upper surface of the blade near the leading edge thereof at a radial location of 80-90% maximum radius thereof and pumping the sucked boundary layer air, utilizing the inherent centrifugal pumping capability of the blade by establishing an exhaust of the centrifugal pumping passage within the blade which allows adequate pumping for the torsional oscillation reduction purpose consistent with the required rate flow of air.