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WO2010023522A2 - Device for channelling a flow of water around the hub of a boat propeller - Google Patents

Device for channelling a flow of water around the hub of a boat propeller Download PDF

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Publication number
WO2010023522A2
WO2010023522A2 PCT/IB2009/006556 IB2009006556W WO2010023522A2 WO 2010023522 A2 WO2010023522 A2 WO 2010023522A2 IB 2009006556 W IB2009006556 W IB 2009006556W WO 2010023522 A2 WO2010023522 A2 WO 2010023522A2
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WO
WIPO (PCT)
Prior art keywords
propeller
ring
hub
around
housing
Prior art date
Application number
PCT/IB2009/006556
Other languages
French (fr)
Other versions
WO2010023522A3 (en
Inventor
Yvan Brulhart
Giuseppe Parenti
Original Assignee
Drs Drag Reduction Systems Sa
Magising Pte. Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Drs Drag Reduction Systems Sa, Magising Pte. Ltd filed Critical Drs Drag Reduction Systems Sa
Publication of WO2010023522A2 publication Critical patent/WO2010023522A2/en
Publication of WO2010023522A3 publication Critical patent/WO2010023522A3/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
    • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
    • B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/28—Other means for improving propeller efficiency
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
    • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
    • B63H5/14—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in non-rotating ducts or rings, e.g. adjustable for steering purpose

Definitions

  • propeller blades In motorboats, ships, steamers, ferries, or inboard pleasure craft, "in-board” or “outboard”, the propeller blades are attached to a propeller hub and immersed in propulsion service position of the boat.
  • Document FR 2233225 discloses a device for protecting against the cavitation of a marine propeller whose axis is oblique with respect to the general direction of flow of water, comprising a tube coaxial with the propeller shaft located just in upstream of this helix.
  • the tube is either cylindrical with a decreasing wall thickness in the direction of the helix or conical by flaring towards the helix.
  • the disadvantage of this device lies in the fact that it only applies to boats with an oblique propeller shaft and that if the flow of water passing through the tube is well channeled, that circulating around the tube is put in turbulence.
  • the present invention aims to provide a simple device, robust and inexpensive to increase the efficiency of the propeller and reduce the wear of the hub and the central part, near the propeller hub, the blades of the 'propeller.
  • This device for channeling the flow of water around the hub of a boat propeller whose propeller shaft can be oblique or parallel to the flow of the water is intended to prevent the water from forming. flow around the propeller shaft and the propeller hub does not come off the surface of this hub of the propeller, thereby reducing or avoiding cavitation phenomena on the central part, close the propeller hub, and direct a non-swirling water flow against the blades of the propeller to increase its performance and extend the duration of use of a propeller.
  • the present invention relates to a device for channeling the flow of water around the hub of a ship propeller which is distinguished by the fact that it comprises at least one ring fixed around the propeller shaft housing or the base of the propeller upstream of this propeller, in that the ring has in longitudinal section the general shape of the section of an aircraft wing; and in that the axial length of this ring is smaller than its diameter.
  • the invention also relates to particular forms of said device comprising the features listed in the dependent claims.
  • the accompanying drawing illustrates schematically and by way of example an embodiment of a device for channeling the flow of water around the hub of a boat propeller.
  • FIG. 1 schematically illustrates, in section, a part of the stern, or rear part of a ship, through which the propeller shaft casing in which the propeller shaft is pivoted by bearings, this shaft connecting a motor not illustrated to the hub of a propulsion propeller of the ship.
  • This figure illustrates the state of the art.
  • Figure 1a is a view similar to Figure 1 but having the device for channeling the flow of water around the hub of the propeller.
  • Figure 2 is a partially sectional view and on a larger scale of the rear portion of the housing surrounding the propeller shaft provided with the device according to the invention.
  • Figure 3 is a view similar to Figure 2 but viewed from above and not from the side.
  • FIG. 4 is a section along the line A-A of FIG.
  • Figure 5 is an elevational view similar to Figure 2.
  • Figure 6 illustrates in perspective a variant of the two-ring device.
  • FIG. 1 illustrates partially and in section the rear or stern portion of a motor vessel.
  • This figure shows a propeller shaft casing 1 passing through the hull 2 of the ship, this propeller shaft casing 1 being fixed to the hull 2 by supports 3,4,5.
  • a propeller or transmission shaft 6 is pivoted in this propeller shaft housing 1 by bearings 7,8,9 and connects the output shaft of an engine located in the vessel (not shown) to the hub.
  • 10 of a propeller here comprising four blades 11.
  • This propeller 10,11 is integral with the rear end of the propeller shaft to be rotated by it.
  • the rear portion of the propeller shaft housing 1 has several frustoconical zones a, b, flaring backward.
  • These frustoconical zones as well as some curved shapes of the hub of the propeller can cause a detachment of the flow of water around the propeller shaft housing 1 and the hub of the propeller generating a turbulent flow s' extending around the hub 10 of the propeller and causing fluid swirls and which can cause cavitation in the central zone c, close to the hub, blades 11 of the propeller 10,11 causing premature wear of these blades 11 and preventing these areas of the blades of the propeller from contributing to the propulsion of the boat.
  • This turbulent flow also propagates around the end portions of the blades of the propeller which reduces the efficiency.
  • the rear end of the propeller shaft casing 1 is provided with a device for channeling the water flow according to the present invention as illustrated in FIGS. 1a and following.
  • This device for channeling the water flow around the hub 10 of the propeller 10, 11 reduces or eliminates this turbulence zone c as illustrated in FIGS. 1a and following, which reduces or eliminates the wear of the blades of the propeller in their central part, close to the hub 10 of this propeller and allows this area of the blades of the propeller to participate in the propulsion of the boat, increasing the efficiency of the propeller.
  • this device increases the efficiency thereof.
  • This device for channeling the flow of water around the hub 10 of the propeller of a ship consists mainly of a ring 20 surrounding the rear end of the propeller shaft housing 1 just upstream of the hub 10 of the 10,11 helix.
  • This ring 20 has in longitudinal section an airfoil shape having a cylindrical inner face and parallel to its longitudinal axis and a convex outer face.
  • the shape of this curved outer surface is such that the longitudinal section of the wall of the ring 20 has a rounded front edge, an increasing thickness in about one third before the ring and thinner in the two-thirds downstream of the ring. ring to end bevel.
  • the cylindrical inner wall of the ring is parallel to the longitudinal axis of the ring and is disposed at a substantially constant distance for a given point of the outer surface of the propeller shaft housing 1.
  • this ring 20 is located around a conical portion of the propeller shaft casing 1 flaring rearwardly so that the free passage located between the inner surface of the ring 20 and the outer surface of the casing 1 of the propeller shaft has in longitudinal section a frustoconical shape flowing from the downstream upstream of the ring 20.
  • This ring 20 is connected to the casing 1 of the shaft of propeller by supports 21, two, in the example illustrated, in the form of walls extending radially from a generatrix of the propeller shaft housing 1 to a generatrix of the inner wall of the ring. These supports 21 are generally welded on the outer surface of the propeller shaft casing 1 and on the inner surface of the ring 20.
  • the ring 20 by its shape and its position has the effect of redirecting and channeling the flow of water and make this substantially laminar flow not only around the hub 10 of the propeller but also on all the blades of this helix.
  • the ring 20 is generally circular in that the cross section of the casing 1 of the propeller shaft is also circular.
  • the general shape of the ring 20 would be substantially the same as that of the casing 1 of the propeller shaft.
  • These ribs 22 are constituted by sheets or plates welded along a generatrix of the casing 1 of the propeller shaft.
  • These ribs 22 may be welded to the casing 1 along a helical line around the casing 1. This makes it possible to compensate for the rotation of the water flowing around the casing 1 caused by the rotation of the propeller . These ribs 22 also contribute to channeling the flow of water and to reduce or eliminate the turbulence zones around the hub 10 and the propeller 11.
  • the device for channeling the water flow around the hub 10 of a propeller can be adapted to the outboard boats.
  • the ring 20 is disposed just upstream of the propeller around the base of the outboard motor.
  • the shape of the ring 20 is substantially the same as that of the base around which it is fixed and also has in longitudinal section an airfoil profile.
  • the device for channeling the flow of water around the propeller can also be adapted to flat-bottomed boats.
  • the axial length of the ring is very much smaller than its diameter, of the order of two to five times smaller at least, this considerably reduces the weight of the device relative to the tubes of the prior art.
  • the device may comprise several rings one behind the other around the propeller shaft, of equal or different diameters from each other, the ring close to the helix having the largest diameter in case of failure. rings of different diameters. The successive rings are separated by a distance greater than their axial length.
  • the device for channeling the flow of water around the hub of a propeller in order to reduce the corrosion of the central portion of the blades of this propeller and to increase the efficiency of this propeller comprises one or more rings. preferably fixed concentrically to the axis of the propeller, upstream thereof on a propeller shaft housing or the propeller base, this ring having in longitudinal section the general shape of a section of an aircraft wing, the tapered edge being located near the propeller.
  • the ring or rings 20 may be in one or more parts connected to each other. When there are several rings, they can be interconnected by said ribs 22.
  • FIG. 6 illustrates a device for channeling the flow of water around a boat propeller comprising two rings 20, 20a of different diameters formed each of the two parts connected to the ribs 22 by means of hinges in the illustrated example.
  • the two rings are coaxial and spaced from each other by a distance, greater than their axial length, substantially equal to the diameter of the largest ring 20.
  • the rings 20, 20a are connected by radial fins 23, 23a to bearing pieces 24, 24a respectively bearing against the casing of the propeller shaft 1.
  • This embodiment allows easy mounting of the device around propeller shaft housing with hinges. These hinges can be removed as well as the support parts 24, 24a, in this case the radial fins are welded to the propeller shaft housing.
  • Total power absorbed with the device 17500 Kw
  • the measured exhaust gas temperature without the device was 410 ° and dropped with the device at 360 ° for a nominal power of 90% of the engines.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Hydraulic Turbines (AREA)

Abstract

The device for channelling a flow of water around the hub of a boat propeller comprises at least one ring (20) fastened around the propeller shaft housing (1) or around the base of the propeller upstream of this propeller, and this ring (20) has in longitudinal section the general shape of the section of an aircraft wing. This device can also be formed by at least two longitudinal ribs (22) fastened to the propeller housing upstream of the hub of this propeller, in combination or not with said ring (20). The axial length of the ring or rings is smaller than its diameter.

Description

Dispositif de canalisation du flux d'eau autour du moyeu d'une hélice de bateau Device for channeling the flow of water around the hub of a boat propeller
Dans les bateaux à moteurs, navires, paquebots, ferries ou bateau de plaisance à moteur intérieur, "in-bord", ou extérieur "hors-bord" les pales de l'hélice sont fixées à un moyeu d'hélice et sont immergées en position de service de propulsion du bateau.In motorboats, ships, steamers, ferries, or inboard pleasure craft, "in-board" or "outboard", the propeller blades are attached to a propeller hub and immersed in propulsion service position of the boat.
En marche, le courant d'eau s'écoulant autour du moyeu de l'hélice peut provoquer un phénomène dit de cavitation qui use et endommage la partie des pales de l'hélice se trouvant à proximité du moyeu de l'hélice et le moyeu. Dans certains cas cette usure des parties des pales d'hélice proche du moyeu de l'hélice et de ce moyeu peut s'avérer plus intense et plus rapide que l'usure des parties périphériques des pales de l'hélice et nécessite un remplacement prématuré de l'hélice. Par ailleurs, les phénomènes tourbillonnaires de l'écoulement de l'eau autour du moyeu de l'hélice font que la partie des pales de cette hélice située proche du moyeu, sur environ un tiers de l'étendue radiale des pales, ne participe que peu ou pas du tout à la propulsion du bateau d'où une perte de rendement.When running, the flow of water flowing around the hub of the propeller can cause a so-called cavitation phenomenon that wears and damages the portion of the blades of the propeller located near the hub of the propeller and the hub. . In some cases this wear of the parts of the propeller blades close to the hub of the propeller and this hub can be more intense and faster than the wear of the peripheral parts of the propeller blades and requires premature replacement. of the propeller. Moreover, the swirling phenomena of the flow of water around the hub of the propeller cause the part of the blades of this propeller located close to the hub, about a third of the radial extent of the blades, to participate only little or nothing to the propulsion of the boat resulting in a loss of efficiency.
On connaît du document FR 2233225 un dispositif de protection contre la cavitation d'une hélice marine dont l'axe est oblique par rapport au sens général d'écoulement de l'eau comportant un tube coaxial à l'arbre d'hélice situé juste en amont de cette hélice. Le tube est soit cylindrique avec une épaisseur de paroi décroissant en direction de l'hélice soit conique en s'évasant vers l'hélice.Document FR 2233225 discloses a device for protecting against the cavitation of a marine propeller whose axis is oblique with respect to the general direction of flow of water, comprising a tube coaxial with the propeller shaft located just in upstream of this helix. The tube is either cylindrical with a decreasing wall thickness in the direction of the helix or conical by flaring towards the helix.
L'inconvénient de ce dispositif réside dans le fait qu'il ne s'applique qu'aux bateaux comportant un arbre d'hélice oblique et que si le flux d'eau passant dans le tube est bien canalisé, celui circulant autour du tube est mis en turbulence.The disadvantage of this device lies in the fact that it only applies to boats with an oblique propeller shaft and that if the flow of water passing through the tube is well channeled, that circulating around the tube is put in turbulence.
La présente invention a pour but la réalisation d'un dispositif simple, robuste et peu onéreux pour augmenter le rendement de l'hélice et réduire cette usure du moyeu et de la partie centrale, proche du moyeu de l'hélice, des pales de l'hélice. Ce dispositif de canalisation du flux d'eau autour du moyeu d'une hélice de bateau dont l'arbre d'hélice peut être oblique ou parallèle à l'écoulement de l'eau a pour but d'éviter que l'eau s'écoulant autour de l'arbre d'hélice et du moyeu de l'hélice ne se décolle de la surface de ce moyeu de l'hélice, ce qui permet ainsi de réduire ou d'éviter les phénomènes de cavitation sur la partie centrale, proche du moyeu de l'hélice, et de diriger un flux d'eau non tourbillonnant contre les pales de l'hélice permettant d'augmenter son rendement et d'allonger la durée d'utilisation d'une hélice.The present invention aims to provide a simple device, robust and inexpensive to increase the efficiency of the propeller and reduce the wear of the hub and the central part, near the propeller hub, the blades of the 'propeller. This device for channeling the flow of water around the hub of a boat propeller whose propeller shaft can be oblique or parallel to the flow of the water is intended to prevent the water from forming. flow around the propeller shaft and the propeller hub does not come off the surface of this hub of the propeller, thereby reducing or avoiding cavitation phenomena on the central part, close the propeller hub, and direct a non-swirling water flow against the blades of the propeller to increase its performance and extend the duration of use of a propeller.
La présente invention a pour objet un dispositif de canalisation du flux d'eau autour du moyeu d'une hélice de navire qui se distingue par le fait qu'il comporte au moins un anneau fixé autour du carter d'arbre d'hélice ou de l'embase de l'hélice en amont de cette hélice, par le fait que cet anneau présente en coupe longitudinale la forme générale de la coupe d'une aile d'avion ; et par le fait que la longueur axiale de cet anneau est plus faible que son diamètre. L'invention concerne également des formes particulières dudit dispositif comprenant les caractéristiques énumérées dans les revendications dépendantes. Le dessin annexé illustre schématiquement et à titre d'exemple une forme d'exécution d'un dispositif de canalisation du flux d'eau autour du moyeu d'une hélice de bateau. La figure 1 illustre schématiquement et en coupe une partie de la poupe, ou partie arrière d'un navire, traversée par le carter d'arbre d'hélice dans lequel l'arbre d'hélice est pivoté à l'aide de paliers, cet arbre reliant un moteur non illustré au moyeu d'une hélice de propulsion du navire. Cette figure illustre l'état de l'art.The present invention relates to a device for channeling the flow of water around the hub of a ship propeller which is distinguished by the fact that it comprises at least one ring fixed around the propeller shaft housing or the base of the propeller upstream of this propeller, in that the ring has in longitudinal section the general shape of the section of an aircraft wing; and in that the axial length of this ring is smaller than its diameter. The invention also relates to particular forms of said device comprising the features listed in the dependent claims. The accompanying drawing illustrates schematically and by way of example an embodiment of a device for channeling the flow of water around the hub of a boat propeller. FIG. 1 schematically illustrates, in section, a part of the stern, or rear part of a ship, through which the propeller shaft casing in which the propeller shaft is pivoted by bearings, this shaft connecting a motor not illustrated to the hub of a propulsion propeller of the ship. This figure illustrates the state of the art.
La figure 1a est une vue identique à la figure 1 mais comportant le dispositif de canalisation du flux d'eau autour du moyeu de l'hélice.Figure 1a is a view similar to Figure 1 but having the device for channeling the flow of water around the hub of the propeller.
La figure 2 est une vue partiellement en coupe et à plus grande échelle de la partie arrière du carter entourant l'arbre d'hélice muni du dispositif selon l'invention. La figure 3 est une vue similaire à la figure 2 mais vue de dessus et non pas de côté.Figure 2 is a partially sectional view and on a larger scale of the rear portion of the housing surrounding the propeller shaft provided with the device according to the invention. Figure 3 is a view similar to Figure 2 but viewed from above and not from the side.
La figure 4 est une coupe selon la ligne A-A de la figure 2.FIG. 4 is a section along the line A-A of FIG.
La figure 5 est une vue en élévation similaire à la figure 2. La figure 6 illustre en perspective une variante du dispositif à deux anneaux.Figure 5 is an elevational view similar to Figure 2. Figure 6 illustrates in perspective a variant of the two-ring device.
La figure 1 illustre partiellement et en coupe la partie arrière ou poupe d'un navire à moteur. On voit sur cette figure un carter d'arbre d'hélice 1 traversant la coque 2 du navire, ce carter d'arbre d'hélice 1 étant fixé à la coque 2 par des supports 3,4,5. Un arbre d'hélice ou de transmission 6 est pivoté dans ce carter d'arbre d'hélice 1 par des paliers 7,8,9 et relie l'arbre de sortie d'un moteur situé dans le navire (non illustré) au moyeu 10 d'une hélice comportant ici quatre pales 11. Cette hélice 10,11 est solidaire de l'extrémité postérieure de l'arbre d'hélice pour être entraînée en rotation par celui-ci. Dans les réalisations courantes existantes illustrées à la figure 1 , on voit que la partie arrière du carter d'arbre d'hélice 1 comporte plusieurs zones tronconiques a,b, allant en s'évasant vers l'arrière. Ces zones tronconiques de même que certaines formes bombées du moyeu de l'hélice peuvent provoquer un décollement de l'écoulement de l'eau autour du carter d'arbre d'hélice 1 et du moyeu de l'hélice engendrant un écoulement turbulent s'étendant autour du moyeu 10 de l'hélice et provoquant des tourbillons de fluide et pouvant provoquer de la cavitation dans la zone centrale c, proche du moyeu, des pales 11 de l'hélice 10,11 entraînant une usure prématurée de ces pales 11 et empêchant ces zones des pales de l'hélice de contribuer à la propulsion du bateau. Cet écoulement turbulent se propage aussi autour des parties terminales des pales de l'hélice ce qui en diminue le rendement.Figure 1 illustrates partially and in section the rear or stern portion of a motor vessel. This figure shows a propeller shaft casing 1 passing through the hull 2 of the ship, this propeller shaft casing 1 being fixed to the hull 2 by supports 3,4,5. A propeller or transmission shaft 6 is pivoted in this propeller shaft housing 1 by bearings 7,8,9 and connects the output shaft of an engine located in the vessel (not shown) to the hub. 10 of a propeller here comprising four blades 11. This propeller 10,11 is integral with the rear end of the propeller shaft to be rotated by it. In the existing current embodiments illustrated in Figure 1, we see that the rear portion of the propeller shaft housing 1 has several frustoconical zones a, b, flaring backward. These frustoconical zones as well as some curved shapes of the hub of the propeller can cause a detachment of the flow of water around the propeller shaft housing 1 and the hub of the propeller generating a turbulent flow s' extending around the hub 10 of the propeller and causing fluid swirls and which can cause cavitation in the central zone c, close to the hub, blades 11 of the propeller 10,11 causing premature wear of these blades 11 and preventing these areas of the blades of the propeller from contributing to the propulsion of the boat. This turbulent flow also propagates around the end portions of the blades of the propeller which reduces the efficiency.
Pour éviter ou réduire cette zone de turbulence on munit l'extrémité arrière du carter d'arbre d'hélice 1 d'un dispositif de canalisation du flux d'eau selon la présente invention comme cela est illustré aux figures 1a et suivantes. Ce dispositif de canalisation du flux d'eau autour du moyeu 10 de l'hélice 10,11 réduit ou supprime cette zone de turbulence c comme illustré aux figures 1a et suivantes, ce qui réduit ou supprime l'usure des pales de l'hélice dans leur partie centrale, proche du moyeu 10 de cette hélice et permet à cette zone des pales de l'hélice de participer à la propulsion du bateau, augmentant le rendement de l'hélice. De plus, en réduisant fortement ou en évitant les turbulences autour des pales de l'hélice, ce dispositif augmente le rendement de celle-ci.In order to avoid or reduce this turbulence zone, the rear end of the propeller shaft casing 1 is provided with a device for channeling the water flow according to the present invention as illustrated in FIGS. 1a and following. This device for channeling the water flow around the hub 10 of the propeller 10, 11 reduces or eliminates this turbulence zone c as illustrated in FIGS. 1a and following, which reduces or eliminates the wear of the blades of the propeller in their central part, close to the hub 10 of this propeller and allows this area of the blades of the propeller to participate in the propulsion of the boat, increasing the efficiency of the propeller. In addition, by greatly reducing or avoiding turbulence around the blades of the propeller, this device increases the efficiency thereof.
Ce dispositif de canalisation du flux d'eau autour du moyeu 10 de l'hélice d'un navire est constitué principalement par un anneau 20 entourant l'extrémité arrière du carter d'arbre d'hélice 1 juste en amont du moyeu 10 de l'hélice 10,11. Cet anneau 20 présente en coupe longitudinale une forme en aile d'avion comportant une face interne cylindrique et parallèle à son axe longitudinal et une face externe bombée. La forme de cette surface externe bombée est telle que la section longitudinale de la paroi de l'anneau 20 présente un bord avant arrondi, une épaisseur croissante dans environ un tiers avant de l'anneau et s'amincissant dans les deux tiers aval de l'anneau pour se terminer en biseau. La paroi interne cylindrique de l'anneau est parallèle à l'axe longitudinal de l'anneau et est disposée à une distance sensiblement constante pour un point donné de la surface extérieure du carter 1 d'arbre d'hélice. Généralement cet anneau 20 est situé autour d'une portion conique du carter 1 d'arbre d'hélice allant en s'évasant vers l'arrière de sorte que le passage libre situé entre la surface interne de l'anneau 20 et la surface extérieure du carter 1 de l'arbre d'hélice présente en coupe longitudinale une forme tronconique allant en s'évasant de l'aval vers l'amont de l'anneau 20. Cet anneau 20 est relié au carter 1 de l'arbre d'hélice par des supports 21 , deux, dans l'exemple illustré, se présentant sous la forme de parois s'étendant radialement à partir d'une génératrice du carter 1 d'arbre d'hélice jusqu'à une génératrice de la paroi interne de l'anneau. Ces supports 21 sont généralement soudés sur la surface externe du carter 1 d'arbre d'hélice et sur la surface interne de l'anneau 20.This device for channeling the flow of water around the hub 10 of the propeller of a ship consists mainly of a ring 20 surrounding the rear end of the propeller shaft housing 1 just upstream of the hub 10 of the 10,11 helix. This ring 20 has in longitudinal section an airfoil shape having a cylindrical inner face and parallel to its longitudinal axis and a convex outer face. The shape of this curved outer surface is such that the longitudinal section of the wall of the ring 20 has a rounded front edge, an increasing thickness in about one third before the ring and thinner in the two-thirds downstream of the ring. ring to end bevel. The cylindrical inner wall of the ring is parallel to the longitudinal axis of the ring and is disposed at a substantially constant distance for a given point of the outer surface of the propeller shaft housing 1. Generally this ring 20 is located around a conical portion of the propeller shaft casing 1 flaring rearwardly so that the free passage located between the inner surface of the ring 20 and the outer surface of the casing 1 of the propeller shaft has in longitudinal section a frustoconical shape flowing from the downstream upstream of the ring 20. This ring 20 is connected to the casing 1 of the shaft of propeller by supports 21, two, in the example illustrated, in the form of walls extending radially from a generatrix of the propeller shaft housing 1 to a generatrix of the inner wall of the ring. These supports 21 are generally welded on the outer surface of the propeller shaft casing 1 and on the inner surface of the ring 20.
Grâce à ce dispositif de canalisation du flux d'eau autour du moyeu 10 de l'hélice 10,11 les zones de turbulence en aval du dispositif, autour du moyeu 10 de l'hélice sont fortement réduites ou supprimées, la corrosion des pales de l'hélice est très sensiblement réduite et le rendement de l'hélice est augmenté.With this device for channeling the flow of water around the hub 10 of the propeller 10, 11 the turbulence zones downstream of the device, around the hub 10 of the propeller are greatly reduced or eliminated, the corrosion of the blades the propeller is very significantly reduced and the efficiency of the propeller is increased.
L'anneau 20 de par sa forme et sa position a pour effet de réorienter et de canaliser l'écoulement de l'eau et de rendre cet écoulement sensiblement laminaire non seulement autour du moyeu 10 de l'hélice mais également sur la totalité des pales de cette hélice.The ring 20 by its shape and its position has the effect of redirecting and channeling the flow of water and make this substantially laminar flow not only around the hub 10 of the propeller but also on all the blades of this helix.
Dans l'exemple illustré l'anneau 20 est de forme générale circulaire du fait que la section droite du carter 1 de l'arbre d'hélice est également circulaire. Dans des variantes où ce carter 1 de l'arbre d'hélice serait non circulaire, la forme générale de l'anneau 20 serait sensiblement la même que celle du carter 1 d'arbre d'hélice.In the example illustrated, the ring 20 is generally circular in that the cross section of the casing 1 of the propeller shaft is also circular. In variants where this casing 1 of the propeller shaft would be non-circular, the general shape of the ring 20 would be substantially the same as that of the casing 1 of the propeller shaft.
On a par ailleurs constaté que du fait de la rotation de l'hélice 10,11 l'écoulement de l'eau en amont de l'hélice, sur une certaine distance autour du carter 1 de l'arbre d'hélice, s'écoulait non pas linéairement le long du carter 1 mais subissait également une rotation autour de ce carter d'arbre d'hélice. Pour supprimer ou réduire cette rotation de l'écoulement d'eau autour du carter 1 d'arbre d'hélice et du moyeu 10 de l'hélice le présent dispositif présente dans la forme d'exécution illustrée des nervures 22 s'étendant de l'extrémité avant des supports 21 vers l'amont suivant des génératrices du carter 1 de l'arbre d'hélice.It has furthermore been found that, due to the rotation of the helix 10, 11, the flow of water upstream of the helix, over a certain distance around the casing 1 of the propeller shaft, flowed not linearly along the housing 1 but was also rotated around this propeller shaft housing. To eliminate or reduce this rotation of the water flow around the propeller shaft casing 1 and the propeller hub 10 the present device has in the illustrated embodiment ribs 22 extending from the front end of the supports 21 upstream along the generatrices of the casing 1 of the propeller shaft.
Ces nervures 22 sont constituées par des tôles ou plaques soudées le long d'une génératrice du carter 1 d'arbre d'hélice.These ribs 22 are constituted by sheets or plates welded along a generatrix of the casing 1 of the propeller shaft.
Ces nervures 22 peuvent être soudées au carter 1 le long d'une ligne en forme d'hélice autour du carter 1. Ceci permet de compenser la rotation de l'eau s'écoulant autour du carter 1 provoquée par la rotation de l'hélice. Ces nervures 22 contribuent également à canaliser le flux d'eau et à diminuer ou supprimer les zones de turbulence autour du moyeu 10 et de l'hélice 11.These ribs 22 may be welded to the casing 1 along a helical line around the casing 1. This makes it possible to compensate for the rotation of the water flowing around the casing 1 caused by the rotation of the propeller . These ribs 22 also contribute to channeling the flow of water and to reduce or eliminate the turbulence zones around the hub 10 and the propeller 11.
Le dispositif de canalisation du flux d'eau autour du moyeu 10 d'une hélice peut être adapté aux bateaux hors-bord. Dans ce cas l'anneau 20 est disposé juste en amont de l'hélice autour de l'embase du moteur hors-bord. Dans ce cas la forme de l'anneau 20 est sensiblement la même que celle de l'embase autour de laquelle il est fixé et présente en coupe longitudinale également un profil d'aile d'avion. Le dispositif de canalisation du flux d'eau autour de l'hélice peut être adapté également aux bateaux à fond plat.The device for channeling the water flow around the hub 10 of a propeller can be adapted to the outboard boats. In this case the ring 20 is disposed just upstream of the propeller around the base of the outboard motor. In this case the shape of the ring 20 is substantially the same as that of the base around which it is fixed and also has in longitudinal section an airfoil profile. The device for channeling the flow of water around the propeller can also be adapted to flat-bottomed boats.
Il faut encore remarquer que la longueur axiale de l'anneau est très nettement inférieure à son diamètre, de l'ordre de deux à cinq fois plus petite au moins, ceci réduit considérablement le poids du dispositif par rapport aux tubes de l'art antérieur.It should also be noted that the axial length of the ring is very much smaller than its diameter, of the order of two to five times smaller at least, this considerably reduces the weight of the device relative to the tubes of the prior art. .
Dans des variantes, le dispositif peut comporter plusieurs anneaux les uns derrière les autres autour de l'arbre d'hélice, de diamètres égaux ou différents les uns des autres, l'anneau proche de l'hélice présentant le plus grand diamètre en cas d'anneaux de diamètres différents. Les anneaux successifs sont séparés par une distance supérieure à leur longueur axiale.In variants, the device may comprise several rings one behind the other around the propeller shaft, of equal or different diameters from each other, the ring close to the helix having the largest diameter in case of failure. rings of different diameters. The successive rings are separated by a distance greater than their axial length.
D'une manière générale le dispositif de canalisation du flux d'eau autour du moyeu d'une hélice en vue de réduire la corrosion de la partie centrale des pales de cette hélice et d'augmenter le rendement de cette hélice comporte un ou plusieurs anneaux fixés de préférence concentriquement à l'axe de l'hélice, en amont de celle-ci sur un carter d'arbre d'hélice ou l'embase de l'hélice, cet anneau présentant en coupe longitudinale la forme générale d'une coupe d'une aile d'avion, le bord effilé étant situé à proximité de l'hélice.In general, the device for channeling the flow of water around the hub of a propeller in order to reduce the corrosion of the central portion of the blades of this propeller and to increase the efficiency of this propeller comprises one or more rings. preferably fixed concentrically to the axis of the propeller, upstream thereof on a propeller shaft housing or the propeller base, this ring having in longitudinal section the general shape of a section of an aircraft wing, the tapered edge being located near the propeller.
On a remarqué que la présence de nervures 22 le long du carter d'arbre d'hélice 1 , même sans anneau 20, permettait de réduire la rotation de l'écoulement de l'eau autour du moyeu de l'hélice et donc d'en diminuer l'usure et d'en augmenter le rendement.It has been noted that the presence of ribs 22 along the propeller shaft casing 1, even without a ring 20, makes it possible to reduce the rotation of the flow of water around the hub of the propeller and thus reduce wear and increase the efficiency.
Le ou les anneaux 20 peuvent être en une ou plusieurs parties reliées les unes aux autres. Lorsqu'il y a plusieurs anneaux, ils peuvent être reliés entre eux par lesdites nervures 22.The ring or rings 20 may be in one or more parts connected to each other. When there are several rings, they can be interconnected by said ribs 22.
La figure 6 illustre un dispositif de canalisation du flux d'eau autour d'une hélice de bateau comportant deux anneaux 20, 20a de diamètres différents formés chacun des deux parties reliées aux nervures 22 à l'aide de charnières dans l'exemple illustré. Les deux anneaux sont coaxiaux et distants l'un de l'autre d'une distance, supérieure à leur longueur axiale, sensiblement égale au diamètre du plus grand anneau 20.FIG. 6 illustrates a device for channeling the flow of water around a boat propeller comprising two rings 20, 20a of different diameters formed each of the two parts connected to the ribs 22 by means of hinges in the illustrated example. The two rings are coaxial and spaced from each other by a distance, greater than their axial length, substantially equal to the diameter of the largest ring 20.
Les anneaux 20, 20a sont reliés par des ailettes radiales 23, 23a à des pièces d'appui 24, 24a respectivement venant s'appuyer contre l'enveloppe de l'arbre d'hélice 1. Cette réalisation permet un montage aisé du dispositif autour du carter d'arbre d'hélice grâce aux charnières. Ces charnières peuvent être supprimées de même que les pièces d'appui 24, 24a, dans ce cas les ailettes radiales sont soudées sur le carter d'arbre d'hélice.The rings 20, 20a are connected by radial fins 23, 23a to bearing pieces 24, 24a respectively bearing against the casing of the propeller shaft 1. This embodiment allows easy mounting of the device around propeller shaft housing with hinges. These hinges can be removed as well as the support parts 24, 24a, in this case the radial fins are welded to the propeller shaft housing.
Des essais en mer ont été réalisés sur le ferry « Mega Smeralda » de la société Corsica Ferries sur un même parcours avec et sans le dispositif de canalisation d'eau décrit ci-dessus et les résultats montrent que pour un même nombre de tours par minute de l'arbre d'hélice, et donc une même vitesse de croisière, la puissance des moteurs est réduite de plus de 10% si le ferry est équipé du dispositif décrit. En effet, on a lors de ces essais, relevé les données suivantes :Sea trials were carried out on the Corsica Ferries 'Mega Smeralda' ferry on the same route with and without the above mentioned water line device and the results show that for the same number of revolutions per minute of the propeller shaft, and therefore the same cruising speed, the power of the engines is reduced by more than 10% if the ferry is equipped with the device described. Indeed, during these tests, the following data were collected:
Tours par minute avec et sans le dispositif : 500RPMs with and without the device: 500
Puissance totale absorbée sans le dispositif : 19500 KwTotal power absorbed without the device: 19500 Kw
Puissance totale absorbée avec le dispositif : 17500 Kw De plus, la température mesurée des gaz d'échappement sans le dispositif était de 410° et tombe avec le dispositif à 360° pour une puissance nominale de 90% des moteurs. Total power absorbed with the device: 17500 Kw In addition, the measured exhaust gas temperature without the device was 410 ° and dropped with the device at 360 ° for a nominal power of 90% of the engines.

Claims

REVENDICATIONS
1. Dispositif de canalisation du flux d'eau autour du moyeu d'une hélice de bateau caractérisé par le fait qu'il comporte au moins un anneau (20) fixé autour du carter d'arbre d'hélice (1) ou de l'embase de l'hélice en amont de cette hélice, par le fait que cet anneau (20) présente en coupe longitudinale la forme générale de la coupe d'une aile d'avion ; et par le fait que la longueur axiale de cet anneau est plus faible que son diamètre.1. Device for channeling the flow of water around the hub of a boat propeller characterized in that it comprises at least one ring (20) fixed around the propeller shaft casing (1) or the base of the propeller upstream of this propeller, in that this ring (20) has in longitudinal section the general shape of the section of an aircraft wing; and in that the axial length of this ring is smaller than its diameter.
2. Dispositif selon la revendication 1 , caractérisé par le fait que l'anneau (20) est fixé sur le carter (1) ou l'embase par au moins deux supports radiaux (21) reliant la surface interne de l'anneau (20) à la surface externe du carter (1).2. Device according to claim 1, characterized in that the ring (20) is fixed on the housing (1) or the base by at least two radial supports (21) connecting the inner surface of the ring (20). ) on the outer surface of the housing (1).
3. Dispositif selon la revendication 1 ou la revendication 2, caractérisé par le fait que la coupe longitudinale de l'anneau (20) présente une partie amont arrondie, une partie aval effilée et une partie médiane bombée.3. Device according to claim 1 or claim 2, characterized in that the longitudinal section of the ring (20) has a rounded upstream portion, a tapered downstream portion and a domed central portion.
4. Dispositif selon la revendication 3, caractérisé par le fait que la surface interne de l'anneau est cylindrique et coaxiale à l'arbre d'hélice.4. Device according to claim 3, characterized in that the inner surface of the ring is cylindrical and coaxial with the propeller shaft.
5. Dispositif selon l'une des revendications précédentes, caractérisé par le fait qu'il comporte encore une ou plusieurs nervures radiales fixées en amont de l'anneau (20) le long du carter (1). 5. Device according to one of the preceding claims, characterized in that it further comprises one or more radial ribs attached upstream of the ring (20) along the housing (1).
6. Dispositif selon la revendication 5, caractérisé par le fait que ces nervures sont fixées le long d'une génératrice du carter (1).6. Device according to claim 5, characterized in that these ribs are fixed along a generatrix of the housing (1).
7. Dispositif selon la revendication 5, caractérisé par le fait que ces nervures sont fixées suivant une ligne en forme d'hélice le long du carter (1).7. Device according to claim 5, characterized in that these ribs are fixed along a helical line along the housing (1).
8. Dispositif selon l'une des revendications précédentes, caractérisé par le fait qu'il comporte plusieurs anneaux de diamètres égaux ou différents les uns derrière les autres le long de l'arbre d'hélice et séparés par une distance supérieure à la longueur axiale de chaque anneau.8. Device according to one of the preceding claims, characterized in that it comprises several rings of equal or different diameters behind each other along the propeller shaft and separated by a distance greater than the axial length. of each ring.
9. Dispositif de réorientation du flux d'eau autour du moyeu d'une hélice de bateau caractérisé par le fait qu'il comporte deux nervures longitudinales s'étendant radialement fixées sur le carter d'arbre d'hélice en amont du moyeu de cette hélice.9. Device for redirecting the flow of water around the hub of a boat propeller characterized in that it comprises two longitudinal ribs extending radially fixed on the propeller shaft housing upstream of the hub of this propeller.
10. Dispositif selon la revendication 9, caractérisé par le fait qu'il comporte encore au moins un anneau (20) fixé autour du carter d'arbre d'hélice (1) en amont de cette hélice, par le fait que cet anneau présente en coupe longitudinale la forme générale d'une aile d'avion et par le fait que la longueur axiale de cet anneau est plus faible que son diamètre.10. Device according to claim 9, characterized in that it further comprises at least one ring (20) fixed around the propeller shaft casing (1) upstream of this propeller, in that this ring presents in longitudinal section the general shape of an aircraft wing and the fact that the axial length of this ring is smaller than its diameter.
11. Dispositif selon la revendication 6 ou la revendication 9, caractérisé par le fait qu'il comporte deux nervures longitudinales situées dans un plan vertical. 11. Device according to claim 6 or claim 9, characterized in that it comprises two longitudinal ribs located in a vertical plane.
PCT/IB2009/006556 2008-08-27 2009-08-17 Device for channelling a flow of water around the hub of a boat propeller WO2010023522A2 (en)

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DE1181090B (en) * 1962-01-17 1964-11-05 Shipbuilding Res Trust Reg Device for the protection of propellers
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KR101525791B1 (en) * 2013-05-03 2015-06-04 삼성중공업 주식회사 Flow control apparatus of open shaft type ship

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