Abstract: An arrangement for attenuating vibrations of blades attached to a peripheral surface of a rotor of an axial turbine. A through hole is formed in each rotor blade in a generally thickness direction of the blade so that the through holes in combination define a single annular passage near a rotor surface when all of the rotor blades are attached to the rotor. A wire is provided to extend through the aligned through holes. Thus, the wire frictionally contacts the through holes when the blades are caused to vibrate due to a gas pressure and a centrifugal force generated upon operation of the axial turbine. Friction contact between the wire and the through holes attenuates vibrations of the blades.

Abstract: In an underwater device adapted to sink in water, the device having a proler disposed in a tail cone portion thereof and operable to rotate in a first direction to move the device toward a surface of the water, an assembly for preventing the propeller from rotating in a second direction during the sinking of the device in the water. The assembly includes a circular shroud fixed to outboard tips of blades of the propeller and encircling the propeller. A ramp is disposed on an outside surface of the shroud. A tail cone ring is fixed to the tail cone portion and surrounds the shroud. A pivotally movable flap is mounted on an inside surface of the tail cone ring. The ramp and the flap are engageable and configured to prevent rotation of the shroud, and thereby the propeller, in the second direction, and to permit rotation of the shroud, and thereby the propeller, in the first direction.

Abstract: A turbine blade which is provided for use in a wet steam region of penultimate and ultimate stages of turbines and is subject to erosive wear caused by impinging water droplets, is treated in a region of leading edges and parts of a blade leaf in such a way as to reduce the erosive wear. In order to reduce the erosive effect of the water droplets, the blade leaf has a surface roughness in the region of its leading edge and its blade back or in at least a partial region thereof. The surface roughness is markedly increased in comparison with the surface roughness of a front side of the blade leaf.

Abstract: A compressor blade vibration reduction mechanism for a high-speed radial impeller for minimizing fatigue failures from various excitation sources. The vibration reduction mechanism includes a plurality of loose-fitting lashing pins coupling each impeller blade to an adjacent impeller blade. Each lashing pin extends through a first aperture in a blade located adjacent to the blade tip and through a second aperture of an adjacent blade. The second aperture of each blade is located a greater distance from the leading edge of the blade than the first aperture. The second aperture is located in an area of the blade having lower vibration during operation than the blade location where the first aperture is located.

Abstract: An aerodynamically optimized mid-span snubber for combustion turbine blades provides sufficient stiffness to ameliorate vibratory stress but does so with minimal degradation of aerodynamic performance. The snubber has an optimized aerodynamic cross-sectional shape that forms when two snubber portions attached to adjacent rotor blades come into contact upon rotation of the rotor at an operational velocity.

Abstract: A friction damper (50) provides friction damping for gas turbine engine airfoils to reduce vibrations thereto. The friction damper (50) includes a plate (52) underlying radially outer shrouds (30) of two adjacent airfoils (20). Friction generated between an outer surface (53) of the plate (52) and undersides (42) of the adjacent shrouds (30) reduces undesirable vibrations in the airfoils (20).

Abstract: Vibration in the blade of a turbo-machine is suppressed by the incorporation of both inner and outer restraints that inhibit deflections of the blade foils. The outer restraint comprises shroud, welded lugs or tie wires that divide the row of blades into a plurality of blade groups by connecting the blades in each group together. The number of blades in each group can be equal to the number of blades in the row divided by the harmonic of the rotor rotational frequency that is closest to the blade resonant frequency of concern. The inner restraint comprises welded lugs or tie wires disposed radially inward from the outer restraint that divide each blade group into a plurality of sub-groups, thereby further suppressing blade vibration. Since the length of the inner restraints is less than that associated with harmonic shrouds, the stresses in the inner restraint, as well as in the blades, due to radial growth of the rotor are maintained within acceptable levels.

Abstract: The total number (M) of plural blades of a blade apparatus is selected so as not to be a prime number and not to be a power multiplier of a prime number. Plural blades are divided into at least a first blade group in which one blade group has the blades of a first integer number (N.sub.1) and a second blade group in which one blade group has blades of a second integer number (N.sub.2). Each of the first integer number (N.sub.1) and the second integer number (N.sub.2) have no common divisor except 1. The total number (M) of plural blades is the product of the first integer number (N.sub.1) and the second integer number (N.sub.2). The blades of the first integer number (N.sub.1) blade group are connected by a first stage connecting member and the blades of the second integer number (N.sub.2) blade group are connected by a second stage connecting member.

Abstract: A last-stage steam turbine bucket having a profile according to Charts I-XXXXI of Table I.The bucket is divided into a number of profile sections each of which is a predetermined radial distance from the root section. Each point on a profile section at the predetermined radial distance from the root is defined by an X-Y coordinate and a radius R along the arc of a circle connecting adjacent points.

Abstract: An improved method of adaptive machining is disclosed which affords automatic blending between a machined surface and a complex variable contour forged surface. An adaptive postprocessor generates an adaptive NC part program from a conventional APT file which has the capability to modify the cutter tool path in real time during the machining cycle based on limited surface measurement data. Variable measurement data taken from each workpiece generates a unique toolpath adapted specifically to the contour of that workpiece being processed, obviating the subsequent need for time consuming manual grinding and smoothing operations between machined and forged surfaces.

Abstract: An axial flow transonic turbofan jet engine includes a hub (26) from which radiate a plurality of rotor blades (50). A casing (12) surrounds and shrouds the rotor blades (50). Part-span dampers (56) are located between adjacent rotor blades (50) in an annular pattern to stiffen the elongated rotor blades (50) during operation. The distal tips (54) of the rotor blades (50) are convexed and spin within a rub strip (62) embedded within the casing (12). The rub strip (62) includes an annularly troughed contour (60) to closely conform with the convex tips (54) of the rotor blades (50). The hub (26) may also include an annularly troughed contour (60) formed along the roots (52) of the rotor blades (50). The annularly troughed contours (60) in the hub (26) and in the casing (12) are radially aligned with the part-span dampers (56) to reduce drag between the casing (12) and the hub (26) caused by the part-span dampers (56) at transonic speeds.

Abstract: Turbine blades are held in groups formed by a series of spaced lugs constituting a lashing structure. Selected lugs have gaps which are "Z"-shaped, the gaps tending to close during untwisting of the blades when the blades are subjected to high centrifugal forces.

Abstract: A method of repairing a turbine blade comprising the steps of ascertaining a normal vibration characteristic of the blade, separating an outer end part of the blade from a residual inner part of the blade and subsequently securing a new end part to the residual part so that a joint between the new end part and the residual part is positioned in a predetermined relationship to said vibration characteristic.

Abstract: A component is provided with a relative undersize in an area to be subjected to increased stress, for instance, through temperature. The component is made of a hardenable steel. The undersize is overlaid with a non-hardenable steel thereby to provide the full size. A second layer on top of the first layer can be provided. When the second layer is metallurgically bonded in a manner that generates heat, it does not cause a heat affected zone in the base hardenable steel. Blades for steam turbines benefit from this procedure.

Abstract: A bladed rotor having blades with blade shrouds includes a deformable protective coating applied to the blades to increase the damage tolerance of the blades during foreign object ingestion. The protective coating deforms upon impact between the shroud and airfoil of adjacent blades. The deformation absorbs impact energy and improves distribution of the impact load transferred between the blades.

Abstract: In a mobile blade of a gas turbine engine comprising a root, a platform, and a vane forming the aerodynamic portion of the blade, the vane is arranged so that the geometric locus of the centers of gravity of successive cross-sections of the vane between the platform and the tip of the blade vane is a curve including at least one straight line portion which is offset relative to a radial straight line contained in the axial plane of symmetry of the blade root and which is joined progressively to the origin where the radial straight line intersects the junction of the vane with the platform and root of the blade. In the case of a blade with an intermediate shoulder or fin on the vane, the locus of the centers of gravity of the vane cross-sections includes a second straight line portion offset relative to the first straight line portion and connecting assembly therewith in the region of the fin.

Abstract: A retrofitted rotor blade having a longer length than an original rotor blade provided for a steam turbine rotor assembly has a tuned airfoil portion with natural resonant frequencies in a plurality of vibrational directions similar to the original rotor blade. Since lengthening the blade causes a decreased and resonant frequency, a unique combination of tuning techniques raises the resonant frequencies to the required levels. The tip of the retrofitted rotor blade is profiled to increase the natural resonant frequency in the second mode of vibration, which is in the axial direction of the rotor.

Abstract: In order to clamp blades (1, 2, n) of turbomachines to influence the blade vibration occuring in such machines, the shroud plates (1a, 2a, na) are dimensioned in such a way that they are in contact with one another in the installed condition without clearance and without contact force or else they are dimensioned so that they exhibit a gap (3) relative to each other. A prestressed or pretorsioned, clearance-free connection occures between the shroud plates (1a, 2a, na) due to plastic deformation of the shroud plates (1a, 2a, na) in the region of their boundries or of the gap (3).

Abstract: A compressor blade assembly for a compressor operating at transonic or supersonic blade speeds has a part span shroud. The shroud is twisted having a first angle in the direction of airflow on one side of the shock wave and a second angle in the direction of airflow on the other side of the shock wave.

Abstract: A steam turbine of the type employing a plurality of axial entry, integral shroud blades comprises spring means resident in a slot machined in at least one face of each shroud. The spring means urge against the adjacent shroud and reduce relative motion between adjacent blades.

Abstract: An improved bladed rotor structure for an axial structure for a turbine which is easy to disassemble and produces high damping. Coupling members are located between adjacent blade ends to couple adjacent blades together. Anchoring elements affix adjacent blades with the coupling members which are non-rightangular parallelogram-shaped blocks.

Abstract: A steam turbine of the type employing axial entry, integral shroud blades has a pin disposed between adjacent shrouds that extends into tangentially oriented holes in the opposing faces of adjacent shrouds. The pins reduce blade flop during turning gear operation and reduce blade vibration during operation under load.

Abstract: The present invention relates to a damping element for independent blades of a turbomachine in which the blades fastened in the rotor are connected together, preferably in the radially outer region, the connection between two blades consists of an elastically deformable platelet curved towards the center of the rotor, which platelet engages in retention features on the suction side of one blade and on the pressure side of a second, neighboring blade. The retention features on the blades can be either recesses or protruding lugs, in or on which the platelets are supported.

Abstract: In order to damp blade vibrations, the shroud plates of the blades are equipped with magnet inserts.

Abstract: Turbine blades are held in long arc groups by a shroud structure, with gaps between segments of the shroud structure. These gaps are Z-shaped, the gaps tending to close due to untwisting of the blades when the blades are subjected to high centrifugal forces.

Abstract: In the rotor blade ring of an axial flow turbomachine, the rotor blades are each provided at their radially outer ends with a shroud plate and are fastened at their radially inner ends, by means of a root, in a corresponding groove of the machine rotor. The shroud plates are connected together in the peripheral direction by means of wires rolled into turned recesses. Grooves (10), with a clear width (w.sub.1) which is dimensioned larger than the width (w.sub.2) of the shroud plate turned recess (8) provided for the wire (7) to be rolled in, are machined in the end surface (6) of the shroud plate (2). A spacer means (11), surrounding the wire at least in the region of the rolling positions and removable after rolling, is laid in the grooves during the rolling procedure. This material is preferably a hard paper which is burnt to ashes during machine operation.

Abstract: The blade rotor structure of an axial flow elastic fluid utilizing machine such as a turbine is divided into groups by a lashing wire structure. The lashing wires of adjacent groups are flexibly connected to each other by sleeves that are held in place without heating so that the sleeves can be used with electroplated blades without the problems associated with brazing.

Abstract: A rotor assembly for a gas turbine engine has platformless blades and the inner wall of the compressed air annulus is made up of separate annulus members bridging the spaces between pairs of adjacent blades. The invention provides salient feet on the annulus members which are fitted through the narrow necks of re-entrant grooves in a direction radially inwardly of the rotor disc. Wedges are slid between feet and the walls of the grooves to prevent removal of the feet and therefore the annulus members in a reciprocal direction.

Abstract: An offset centrifugal compressor having a plurality of curved blades associated with a rotor and defining, respectively, inducer and exducer sections with a plurality of the blades being formed of at least three blade parts extending generally end-to-end. The adjacent ends of adjacent pairs of blade parts are indexed and immersed relative to each other in both the inducer and exducer section to form a pair of gaps through which a jet of gas may travel from the pressure side to the suction side of the blade to control boundary layer build-up and reduce separation of gas from the blade. An aerodynamically contoured bridge member is located in each gap to provide structural integrity and resonance frequency control, with these bridging members being positioned to avoid obstruction of gas flow in the area adjacent the tip of the blade.

Abstract: Blading for a turbo machine which facilitates manufacturing thereof.

Abstract: A circular array of rotatable blades formed from blades having an integral shroud with a leading planar surface and a trailing planar surface, the leading planar surface being generally parallel to an axial radial plane passing through the center of the root of the blade and the trailing planar surface, if extended, intersecting the axial radial plane passing through the center of the root of the blade to form an angle generally equal in degrees to 360 divided by the number of blades forming the circular array.

Abstract: Rotor blade and disk structures enabling the disassembly and reassembly of a single rotor blade are disclosed. The concepts are particularly suited to configurations employing interlocking mid-span shrouds which inhibit the withdrawal of a single blade from a disk.In one specific geometry the rotor blade root section (20) and the disk attachment slot (24) are contoured to provide increasing clearance between the bottom of the blade root section and the attachment slot as the blade is withdrawn axially from the slot. Rocking of the blade within the provided clearance enables withdrawal of the blade around the shroud segments (30,32) and airfoil sections (16) of the adjacent blades (12).

Abstract: A power turbine employs a plurality of turbine blades each having a normal lip mounted at the free ends thereof. The plurality of turbine blades are mounted in a paddle wheel type configuration about the turbine power shaft. The paddle wheel blade configuration is interposed between the pressurized fluid inlet and outlet ports for efficient response to the pressurized fluid moving therebetween. Directional fans mounted about the rotating shaft maintain the fluid flow through the turbine so as to assure an optimum power as offered by the rotating turbine shaft. A home power generation system utilizing the turbine is also disclosed herein.

Abstract: Flutter of the tip sections of the blades of an axial-flow steam turbine wheel is inhibited by interconnection of the blades by ball-ended elongate members which are pre-stressed in compression. Each member exerts thrusts on two adjacent blades to pre-stress the blades torsionally each in a sense corresponding to untwisting of the blades. The thrusts are each exerted on the respective blade through socket elements received in respective openings in the blades. Either one or each socket element of each member is in screw-threaded engagement in its opening. Where only one is so engaged, the other is a close sliding fit in its opening.

Abstract: A device for connecting the turbine blades of a turbine having a plate-shaped member provided at the radially outer end of each turbine blade and extended substantially at a right angle to the longitudinal plane of the turbine blade. The plate-shaped member is projected from the leading and trailing edges of the turbine blade, and is provided with through bores formed in each projected portion. Connecting members having cylindrical pins or the like projections are disposed between two adjacent turbine blades in such a manner that the projections are rotatably received by respective through bores. Namely, one of the connecting members is connected to the plate-shaped member of the leading edge of the turbine blade while the other connecting member is connected to the plate-shaped member of the trailing edge of the preceding adjacent turbine blade.

Abstract: An improved blade rotor structure for an axial flow turbine substantially reduces vibratory stress at resonant frequencies by rigidly connecting the blades to each other in groups equal in number to an integer multiple of the resonant frequency of the blades (i.e. a harmonic frequency) divided by the rotor running speed. Flexible tie means are used for connecting adjacent groups of blades together for substantially reducing axial-torsional vibration of the blades.

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: A method and apparatus for suppressing vibration in turbine blading and the like is disclosed. A damping tube is inserted through an aperture in each of a plurality of turbine blades. By expanding the damping tube after it is inserted in the blades the tube is firmly secured to each blade. A wire may be inserted through the damping tube and is secured by crimping the expanded tube portions. The tube may be divided into circumferential segments with each tube being widened for example by means of a center punch at an end portion which extends through the final blade of each segment.

Abstract: A coupling device of moving blades of a steam turbine comprises a pair of projections provided on the inner and outer surfaces of the adjacent moving blades. One of the projections is provided with a hemispherical recess which loosely and slidably receives a corresponding hemispherical projection provided for the other projection when the moving blades are assembled.

Abstract: A device for interconnecting turbine blades comprises a pair of projections extending towards each other from the opposing sides of the tips of adjacent blades, having an inclined inward surface, and having a radially extending perforation. A cover piece has a pair of inclined outward surfaces conforming to the inward surfaces of the projections. The cover piece also has lugs extending through the perforations in the projections. One of the lugs has its end peened to form an overhang for abutting the projection. The perforation of the opposite projection is elongated to permit untwist of the turbine blades.

Abstract: A turbomachinery blade, which includes an airfoil and a projection from the airfoil for the purpose of abutting contact with the surface of an adjacent member is provided with a surface means having an improved combination of adhesive wear resistance and impact toughness through the attachment to the contact surface of a discreet wear pad. The pad comprises a substantially fully dense, compacted, sintered member of a material selected from carbides, nitrides and borides, with or without a suitable binder, the pad being of a thickness of at least about 0.01 inches and having thermal expansion characteristics compatible with the projection over the range of intended operating temperature.

Abstract: A cantilevered structure comprises two cantilevers of unequal length adapted to span a gap (L) and overlap at their free ends so that load transfer may take place from the longer to the shorter cantilever. The cantilevers have the same Youngs Modulus, cross-sectional shape and same load per unit length applied to them, and the line of action of the load transfer between the cantilevers is up to 34% of the distance (L) between their encastres. The sum of the leading moments at the encastres of such cantilevers is lower than is the case with overlapping cantilevers where the line of action of load transfer between them is more than 34% of the distance between their encastres.

Abstract: A turbomachine rotor arrangement is provided having a rotor wheel and blades thereon with a tie pin for interconnecting adjacent blades. A plurality of blades respectively define tie holes wherein the tie holes of adjacent blades are disposed with the radial heights of said holes being different and with the tie pin disposed in the tie holes so as to be acted upon by respective different amplitudes of vibration than said adjacent blades during rotation.

Abstract: A sealing arrangement for preventing compressor fan air loss through the relatively wide gaps between adjacent blade platforms required in order to allow for rotation of the blades around their minor root axes in response to bird impact and the like. A thin flexible ribbon-like seal is bonded to one of the two adjacent blade platforms in the fan structure. At the gap, the seal includes a thickened wedge shaped portion with at least one invagination on the inner side facing the rotor axis. At the operating speed of the compressor fan, centrifugal force causes the thickened portion to be forced into the gap between adjacent platforms producing the required seal.

Abstract: A rotor blade stage for a gas turbine engine comprises an annular array of aerofoil blades. Each blade is provided with circumferentially extending platforms which are arranged so as to circumferentially spaced apart from the platforms of adjacent blades. Elastomeric dampers are interposed between adjacent blades and are so adapted that upon rotation of the array of blades, each of the elastomeric dampers is centrifugally urged into engagement with the radially inner faces of adjacent platforms of adjacent blades.

Abstract: An impeller of an axial-flow fan comprises a hub which carries blades installed thereon with the aid of attachment fittings in the form of a swivelling base with an extension. Each of the swivelling bases supports at least two blades. The distance between the blades installed on a single base varies from 0.15 to 0.3 .alpha. where .alpha. is the angular distance between the pivots of the adjacent swivelling bases. The blades installed on a single base are rigidly secured thereto at one end and joined to each other by a connector at the other end, thus forming a rigid system.

Abstract: A turbine rotor having twisted blades, are, in the vicinity of their radiy outer portions integrally connected with each other to prevent any rotation in either direction of one blade in relation to its neighboring blades. The blades are prestressed during assembly by being un-twisted through an angle which is less than or equal to and in the same direction as the angle through which said blades would be un-twisted during rotation if they were free to rotate in relation to each other.

Abstract: A rotor blade system which is adapted for long term reliable operation in a gas turbine engine is disclosed. Techniques for altering the natural frequency of the blade system to reduce the detrimental combined effects of external excitation and self-excitation are developed. One structure shown utilizes a shroud for the control of self-excitation in combination with a pin root to lower the fundamental first natural bending frequency of the blade system below the level of the 2E frequency at idle.

Abstract: An improved blade rotor structure for an axial flow turbine substantially reduces vibratory stress at resonant frequencies by rigidly connecting the blades to each other in groups equal in number to .[.an integer multiple of.]. the resonant frequency of the blades (i.e. a harmonic frequency) divided by .Iadd.an integer multiple of .Iaddend.the rotor running speed. Flexible tie means are used for connecting adjacent groups of blades together for substantially reducing axial-torsional vibration of the blades.

Abstract: Rotor blade and disk structures enabling the disassembly and reassembly of a single rotor blade are disclosed. The concepts are particularly suited to configurations employing interlocking mid-span shrouds which inhibit the withdrawal of a single blade from a disk.In one specific geometry the rotor blade root section (20) and the disk attachment slot (24) are contoured to provide increasing clearance between the bottom of the blade root section and the attachment slot as the blade is withdrawn axially from the slot. Rocking of the blade within the provided clearance enables withdrawal of the blade around the shroud segments (30,32) and airfoil sections (16) of the adjacent blades (12).