WO2009154496A1

WO2009154496A1 - Hollow blade of a ship propeller

Info

Publication number: WO2009154496A1
Application number: PCT/RU2008/000363
Authority: WO
Inventors: Валерий Яковлевич ВЕКСЛЯР; Геннадий Дмитриевич МОРОЗКИН; Валентин Павлович ВИНОГРАДОВ; Валентин Иванович ВАНЮХИН
Priority date: 2008-06-09
Filing date: 2008-06-09
Publication date: 2009-12-23
Also published as: EA017191B1; CN102046462B; CN102046462A; EA201001474A1

Abstract

The inventive hollow blade of a ship propeller comprises a top (4), a blade root (1), the walls of leading and exit edges which walls are interconnected by a plating (5) and form respectively the pressure and suction helicoidal surfaces and the blade outline, and an inner framework, wherein the hollow blade is scimitar-shaped and is cast-welded, the inner framework consists of a longitudinal load-bearing bar (6) and transversal load-bearing elements (7), the longitudinal load-bearing bar (6) is radially arranged in the cavities (8, 9) of the hollow blade along the length and the outline thereof, coinciding with the greatest thicknesses of the blade cross-sectional profile, and is welded to the blade top (4) by one end and to the blade root (1) by the other end, the transversal load-bearing elements (7) are disposed along the cylindric generators, the ends thereof are welded to the wall (2) of the leading edge and to the wall (3) of the exit edge, respectively, and the middle part thereof is connected to the longitudinal load-bearing bar (6). Furthermore, the mass of the leading edge is increased as much as possible and the mass of the exit edge is reduced as less as possible, on the blade segment extending from the blade span size which is equal to 0.5 of the propeller radius up to the blade root (1).

Description

Ship Propeller Hollow Vane

The invention relates to the field of shipbuilding, namely to the design of the blades of ship propellers and can be applied in the design of propellers, impellers of water-jet propulsion devices, etc.

High requirements for vibration and noise levels on ships in order to improve habitability, for example, on cruise ships and increase the reliability of the operation of various equipment, including hydroacoustic, for example, on fishing and research vessels, as well as on ships and submarines of the Navy, have led to the development of various techniques reduction of noise of propellers. One of the methods for reducing the noise emission of propellers is to reduce their rotation frequency, which entails an increase in the diameter of the propellers (for example, on cruise ships up to 8 m or more). The latter circumstance requires a reduction in the weight of the screw in order to reduce the increasing loads on the shaft line, which are aggravated by their non-stationary nature. One of the ways to reduce the weight of the propellers is to use the design of hollow blades, which along with reducing the weight of the propellers, reduce the vibration of the blades with the transmission of forces through the hub and shaft shaft to the housing structure.

However, the implementation of the hollow design of the propeller blades does not completely exclude the vibrations of the outgoing edge of the blades under the influence of vortices coming off the edge of the blades - edge noise (Yu.L. Levkovsky “The row of propellers”, Central Research Institute named after academician A.N. Krylov, St. Petersburg ,

2005).

Known design of the blade according to patent N ° 2117603, which contains the incoming and outgoing edges, has a profiled cross-sectional shape in which the center of mass and the axis of stiffness of the cross-sectional profiles are shifted to the axis of the hydrodynamic foci of the cross-sectional profiles to exclude self-oscillations, which is achieved by installing weighting inserts or performing the back of the blade with cavities. Such blades do not allow to achieve the necessary noise reduction, as well as the weight of the propellers.

A known design of the hollow blade of a ship propeller (US, 302884, 11.07.68, Ns 9539/68, Sweden, B 63H 1/14), including front and rear walls, interconnected along the edges and forming, respectively, a discharge and a suction screw surfaces made of separate sections with joints on horizontal planes, having an internal power set (horizontal and vertical stiffeners) However, in the specified design of the propeller blade there is a symmetrical contour of the blade, designed only for I reduce the weight of the blade structure, which does not provide for the task of reducing the level of vibration and noise, where the source is a working propeller in conditions of work with a given inhomogeneity of the velocity field from the incoming flow, and the edge noise of the blades due to edge vibration is not reduced blades during the operation of the propeller. The hollow propeller blade according to the Swedish patent Ns 302884, (bull. Ne 15, publ. 04/28/1971) is adopted as the closest analogue. The objective of the invention is to reduce vibration and edge noise of the blade during operation of the propeller, minimize radiation with a discrete spectrum with reduced weight of the blade and high strength characteristics.

The problem is solved in that in a hollow blade comprising a vertex, a root part, walls of the inlet and outlet edges interconnected by a skin and forming, respectively, a screw and suction screw surfaces and a blade contour, as well as an internal power set, according to the invention, a hollow blade it is cast-welded, its contour has a saber shape, and the internal power set is made in the form of a longitudinal force beam and transverse power elements. In this case, the longitudinal force beam is installed in the cavity of the hollow blade radially along its length, along a contour line coinciding with the largest thicknesses of the profiles of the sections of the blade, and welded at one end to the top of the blade, and the other end in its root part. And the transverse force elements are arranged along cylindrical generators, their ends are welded to the walls of the inlet and outlet edges, respectively, and in the middle part to the longitudinal force beam. In the area of the blade, starting from the magnitude of the span of the blade corresponding to 0.50 of the radius of the propeller to the root of the blade, the mass of the incoming edge is maximally increased, and the mass of the outgoing edge is minimized. In addition, the internal voids of the blade are filled with a composite vibration-damping granular material with a low specific gravity.

In addition, the root part of the blade is made with the possibility of fastening to the hub of the propeller by mechanical fastening through vibration damping pads.

In addition, the massif of the blade along the entire contour is made of separate radial sections joined along the dividing lines.

In addition, the cladding of the sections sequentially from the root of the blade to the top has a different thickness, decreasing in the direction of the top of the blade and to the incoming and outgoing edges.

The implementation of a hollow blade, the contour of which has a saber shape (saber degree - θ), the essence and effectiveness of which is to distinguish the blade shape from the symmetrical one, as well as the distribution of the saber shape along the radius of the screw along the blade span, which turns out to be different for each given pattern of velocity field inhomogeneity, provides enhanced propulsive qualities of the propeller while minimizing the levels of pre-cavitation low-frequency acoustic radiation of the propeller caused by the flow of blades in an inhomogeneous velocity field with a discrete spectrum. The material of the blade can be bronze alloy, steel, titanium alloy, any kind of material used for the manufacture of propellers. W

four

To maintain strength characteristics, the geometric shape of the hollow blade of a ship propeller with a saber-shaped contour is provided by a structure consisting of a sheathing and a kit having a cast-welded design, where the main power element of the kit is represented by a 5 powerful longitudinal beam extending radially across the entire span of the blade, coinciding with the trace of the contour the greatest thicknesses of the profiles of the sections of the blade, connecting its top with the root part, and the transverse force elements of the design of the sections of the blade, located in cylindrical surfaces and mating with the main power

10 element, going from the walls of the incoming, leading to the outgoing, trailing edges of the blade, transferring local loads to the longitudinal main power element of the blade set construction. As a result, the design provides support for the casing and the geometric shape of the blade, and in the interaction of the casing and the set all types of loads are perceived:

15 longitudinal, bending and twisting, acting on the blade during rotation of the propeller.

The shape of a hollow blade of a ship propeller fixed in its design with a saber-shaped blade contour provides all strength parameters withstanding all hydrodynamic

20 loads (including reverse), in which the blade geometry is selected, selected from the operating condition of the propeller in the incoming flow for a given velocity field heterogeneity, and, at the same time, while maintaining increased propulsive qualities of the propeller, this also reduces the levels of pre-cavitation acoustic

25 propeller radiation caused by the flow around the blades in an inhomogeneous velocity field with a discrete spectrum.

To reduce the vibration and edge noise of the blades, as well as their weight, the inner free cavities of the blades formed between the casing and the internal set are filled with a composite vibration damping

30 granular material with a low specific gravity (0.5-0.8 t / m ³ ), which, after filling the internal hollow volume of the blade, self-expands and helps to reduce the weight of the propeller as a whole. In relation to modern low-noise propellers of a prefabricated design with saber-shaped blades, the hollow part of the blade volume can be approximately 30% of the body volume of the blade (if we take the conditionally-average thickness of the skin forming the suction and discharge sides of the blade profile of about 25 mm).

The claimed design of the hollow blade of a ship propeller can significantly reduce the levels of vibration and noise caused by hydroelastic vibrations of the blades rotating in a free stream with their low weight and high strength characteristics. The invention is illustrated by drawings in which: in Fig.1 is a General view of the blades from the side of the discharge part with the removed fragment of the skin.

In FIG. 2 is a section along A — A of FIG. 1 along the span of the blade. In FIG. 3 - section of the blade according to BB from FIG. 1. The blade includes a root part 1 made of cast, intended for fastening to the hub, with cast front wall 2 of the incoming edge welded to it and the rear wall 3 of the outgoing edge, which, in turn, are welded to the solid part of the top - the end part (ending ) 4 blades, forming the contour of the blade. The wall 2 of the input edge and the wall 3 of the output edge are interconnected along the edges of the casing 5, forming a suction and forcing screw surfaces of the blade (fir.l, 2) and a saber-shaped contour (degree of saber-shaped - θ).

The shape of the hollow blade with a selected saber is fixed externally by the sheathing 5 and from the inside by a power set forming a cast-welded structure, where the main power element of the set is a powerful longitudinal beam 6, which, passing radially along the entire span of the blade (in length), lies on the trace line the contour of the largest thicknesses of the profiles of the sections of the blade and connects the top 4 of the blade with its root part 1 (fir.l) by welding. Additional elements of the power set of the blades are transverse power elements 7 of the cross sections of the blade (Fig.1,2) located in cylindrical surfaces between the wall 2 and the wall 3 of the blade. The ends of the transverse power elements 7 are welded to the walls 2 and 3, respectively, of the incoming and outgoing edges, and the middle parts of the power elements 7 are connected by welding with the main power element - with the longitudinal beam 6, transmitting local loads to it, working together with the main power element the design of the kit, a longitudinal beam 6, at the same time with a casing 5, which defines the outer surface of the suction and discharge shells of the blade, operating in a free flow environment. The metal structure of the blade contains internal cavities: a cavity 8, located relative to the longitudinal beam 6 in the direction of the wall 2 of the incoming edge, and a cavity 9, relative to the longitudinal beam 6 in the direction of the wall 3 of the outgoing edge (Fig. L, 3).

The proposed design of the power set provides support to the casing and together determines the geometric shape of the blade, in which in a single interaction of the casing and the set all kinds of loads are perceived: longitudinal, bending and twisting, acting on the blade during rotation of the propeller.

The position of the surfaces of one of the sides of the internal stiffening ribs - the transverse force elements 7 coincides with the surfaces of the concentric cylinders, the axis of which is the axis of the propeller. The radii of the surfaces of the concentric cylinders differ from each other by an amount equal to about 0.10 part of the radius of the propeller R (about 200-300 mm) so that the theoretical lines of the concentric surfaces obtained to determine the position of the blade sections coincide with the circles corresponding to the position of the relative radii of the propeller starting from 0.30R; 0.4OR; 0.50 R; etc. to the maximum permissible rational position of the theoretical lines of the design of the sections of the blade (metal matrix), at which all strength requirements for the blade are fully provided. In order to achieve the closest approximation of the position of the main power element of the longitudinal beam 6 to the torsion center (to the axis of the hydrodynamic focuses of section profiles) to ensure lower values of hydrodynamic torsional and bending moments, the construction matrix is formed so that the mass of the wall 2 of the incoming edge is maximized, accompanied by a corresponding decrease in the volume of the adjacent inner cavity 8, and the mass of the wall 3 of the outgoing edge is reduced as much as possible, accompanied by a corresponding increase in the volume of the adjacent inner cavity 9. A similar redistribution of the material of the incoming and outgoing edges, starting from the area azmaha blade, close to the relative position of the propeller radius 0,50 ... 0,6OR, is provided until the beginning of the area forming the upper end portion 4 molded (tip) of the blade.

The internal cavities 8 and 9, located relative to the longitudinal beam 6 in the direction of the walls 2 and 3, are filled with a cellular core consisting of a composite vibration damping material with a specific gravity of 0.5-0.8 t / m ³ . (Fig. 3).

By analogy with the prefabricated propellers having solid cast vanes in the root part 1 of the hollow blade, it is possible to fasten it to the propeller hub by mechanical fastening through vibration damping pads 10.

The root part 1 with molded walls 2 and 3 of the inlet and outlet edges welded to the solid part of the vertex 4, and the sheathing 5, as well as the elements 6 and 7 of the power set (Figs. 1,2,3) form the whole complex of a hollow geometric shape of the hollow structure cast-welded blades form a kind of metal matrix. The metal matrix of the blade structure provides all the strength parameters supported by calculations in the field of elastic deformations necessary to withstand all existing operational hydrodynamic loads, including torsional and bending moments that may occur during operation of the propeller (including during reverse) in an aqueous medium. Based on the previously performed studies in relation to the prototypes (analogues) of the present invention, it follows that with rationally selected structural elements of the set and sheathing of a hollow blade having a saber-like contour, with the maximum possible approach of the center of bending and torsion of the blade sections to the center of application of hydrodynamic forces, conditions are created to achieve a reduction in the bending-torsional vibrations of a dynamically deformable blade arising from hydrodynamic loads, even in the presence of the highest degree of blade saber (high skеw), when due to the formation of the geometry of the hollow blade with a metal structure that does not differ externally from the solid cast blade with all the requirements for propellers fulfilled in terms of mechanical strength, including erosion resistance and impact resistance, reliability and operational durability of hollow blades of the claimed design.

To implement a cast-welded blade design, taking into account the real diameters of the propellers, the blade array for the convenience of its manufacture can be divided into a number of separate sections - parts of the metal matrix of the blade, which can be made in the form of separate castings, and then docked in the places of the connecting faces - separation sections , the contour of which lies on the corresponding surfaces of the concentric cylinders of the sections of the blade defining the location of the separation of the blade into sections. In the general case, such parts-sections of the blade, from which a large blade is made with a large diameter, can be from 3 to 5, which depends on the diameter of the propeller and the size of the blade.

For the manufacture of cast parts for the design of the blades, all modern casting technologies are used (precision injection molding, pressing of sheathing of 5 shells, etc.). Blade sections are assembled on beds that are close in design to ship assembly hull production. After rough assembly of the paddle blade internal cavities with a composite material, in accordance with the adopted technology of screw production, the blades go first to the primary machining, and then to the assembly and final finishing of the propellers of the assembled structure. At the same time, the performance of a hollow propeller blade is ensured (for example, by erosion and impact resistance characteristics) at the level of conventional ship propellers.

Sheathing 5 of each section of the blade - sequentially in the direction from the root to the top is made of material of various thicknesses. The front and rear walls of the section are made of several sheets of various thicknesses connected by welding, varying from the root of the blade to its apex, starting from a larger thickness to a smaller one and with different thicknesses of sheets symmetrically decreasing to the edges of the incoming and outgoing (rear) walls - the outgoing edges of the blade along to both sides of the main power element 6 of the set of blades.

When a hollow blade, as an element of a propulsion unit, with saber selectivity optimally selected in a given inhomogeneous velocity field, the blade gradually enters the braking zone or accelerated flow ™ due to which the elementary unsteady forces arising in different parts of the blade reach their maximum at various points in time , and therefore the amplitude of the resulting unsteady force on each blade, and therefore the propeller as a whole, decreases, and the time of the force increases, which leads to reducing spectral levels of forces and minimizing the radiation of a propeller with a discrete spectrum.

The largest vibration amplitudes are observed along the outgoing edges of the blade, i.e. in areas where there is a minimum thickness, and therefore a minimum mechanical resistance with respect to transverse forces. Therefore, filling the internal cavities of the hollow propeller with a composite material leads to the conversion of the energy of the bending vibrations of the sections of the blades into thermal energy associated with a shift within the array of vibration damping material. Placing the composite vibration damping material in the zone of maximum vibrations reduces vibration not only of the end edges of the blade, but of the entire propeller blade as a whole. As a result, the component of sound radiation, usually called edge noise, is reduced, reinforced by hydroelastic vibrations of the outgoing edge of the blade.

Compared with the known designs of the propeller blades, proposed to reduce edge Noise and reduce the vibration of the blades, this design using the filling of the internal hollow volumes of the blades with composite material will lead to a greater increase in the loss of vibrational energy and vibration of the blades, and therefore the resulting sound emission, rather than prefabricated propellers with solid cast vanes by increasing the surface area on which dissipation occurs vibrational energy. Experimental estimates have shown that the levels of vibration and noise of propellers on ships where the main sources of noise of the propeller, impeller of a water cannon, etc. are caused by edge noise and hydroelastic vibrations of their blades can be reduced by more than 8-10 dB. The proposed design of the hollow blade of a ship propeller allows to reduce vibration and noise arising during the operation of the propeller and other blade mechanisms with rotating or fixed blades, streamlined by the flow (impellers, axial pump stators, turbines, etc.) with high strength characteristics and reduced weight.

Claims

Claim

1. The hollow blade of the ship's propeller, including the top (4) and the root part (1), the walls of the inlet and outlet edges interconnected by a skin (5), forming, respectively, the pumping and suction screw surfaces and the contour of the blade, as well as the inner a power set, characterized in that the hollow blade has a saber-shaped contour and is cast-welded, and the internal power set is made in the form of a longitudinal force beam (6) and transverse force elements (7), while the longitudinal force beam (6) is installed in by cavities (8.9) of the hollow blade radially along its length, along a contour line coinciding with the largest thicknesses of the profiles of the sections of the blade, and is welded at one end to the top (4) of the blade, and the other end to its root part (1), and the transverse power elements (7) are arranged along cylindrical generators, their ends are welded to the wall (2) of the incoming edge and to the wall (3) of the outgoing edge, respectively, and their middle parts are connected to the power longitudinal beam (6), and in the area of the blade starting from the magnitude of the span of the blade corresponding to 0.5 radius rebnogo screws up to the root part (1) the mass of the leading edge of the blade is maximized, and the mass leaving the edges - minimally reduced.

2. A hollow blade according to claim 1, characterized in that its internal cavities (8.9) are filled with a composite vibration-damping granular material having a low specific gravity.

3. A hollow blade according to claim 1, characterized in that the root part of the blade is made with the possibility of fastening to the hub of the propeller by mechanical fastening through vibration damping pads (10).

4. The hollow blade according to claim 1, characterized in that the blade array along its entire contour is made of separate radial sections joined along the dividing lines.

5. A hollow blade according to claim 4, characterized in that the sheathing (5) of the sections, fixing the profile of the blade along sections in series from the root part (1) of the blade to its top (4) is made of material of different thickness, decreasing in the direction of the tip - top (4) the blades to both the incoming and outgoing edges.