DE102011056001A1 - Storage element for semi-balanced rudder provided in rear region of sub ship, has wedge-like profile section including outer profile surface, where plate-like projection expands outer profile surface in transverse direction - Google Patents

Abstract

The element (27) has a wedge-like profile section including a monotonous inclination in a longitudinal direction, and an outer profile surface. A plate-like projection (30) expands the outer profile surface in a transverse direction. Another wedge-like profile section includes another monotonous inclination in the longitudinal direction, and is provided adjacent to the former profile section. The latter inclination is designed opposite to the former inclination. The plate-like projection covers transverse gaps (8, 11) and/or longitudinal gaps (7, 13) of a semi-balanced rudder. An independent claim is also included for a rudder.

Description

The present invention relates to a baffle element for reducing the risk of the occurrence of cavitations on a half-tailing wind, with a first monotonous inclination in the longitudinal direction having wedge-like first profile section in an outer profile surface.

The present invention equally relates to a ship's rudder having a rudder horn member substantially immovable relative to the hull and a rudder blade member rotatably mounted thereto about an axis of rotation, wherein at least one of the rudder horn member and the rudder blade member is substantially perpendicular to the axis of rotation parallel aligned longitudinal gap and / or at least one axis of rotation substantially vertically aligned transverse gap is formed.

For the purposes of this document, "cavitation" is the phase transition of a fluid from the liquid to the gaseous state by lowering the pressure to the level of the vapor pressure of the fluid. According to the law of Bernoulli, the pressure of a fluid is coupled directly with the speed. If the local speed increases, the local pressure lowers. Due to the high speeds in the propeller jet of ships, the local pressure of seawater can be lowered so far that the vapor pressure is reached and the fluid abruptly undergoes a leap in density especially at additional speed increases by Kantenumströmungen or Spaltdurchströmungen. It produces vapor clouds with a multiple of the volume, which previously occupied the same mass in the liquid state. If these clouds of steam hit areas on the rudder where the vapor pressure is exceeded again, this volume collapses abruptly. This collapse can lead to significant erosion of the rudder material.

This problem of erosion due to cavitation has been known for a long time and occurs particularly in large, fast ships which produce high speeds in the propeller jet.

Due to the increase in the speed of the flow through the gap, especially large half-tailed booms in the area between the rudder horn and the blade are affected by cavitation damage.

It was therefore already proposed in the prior art, upstream of cavitation endangered areas of the ship's rudder to attach the flow elements in order to influence the flow conditions such that the pressure conditions made responsible for the formation of cavitations are avoided in the flow conditions occurring during operation. However, these known stowage elements have not proved to be suitable for preventing cavitation in many applications and in many inflow conditions.

Ship rudders of the type mentioned are as so-called Halbschweberuder in large and fast ships in use. Due to the combination of a fixed rudder horn and a rudder blade rotatably mounted thereon, they have both longitudinal and transverse gaps, which may tend to form Spaltkavitationen at certain geometries and in certain incidental flow conditions. The Spaltkavitationen lead to greatly excessive wear in the cavitation and are therefore highly undesirable.

To avoid Spaltkavitationen wedge-shaped attachments have been proposed. It was experimented with wedge-shaped attachments both on the rudder horn and on the moving part, ie on the rudder blade (see. TUHH "Kavitationen Halbschweberudern" of 10 September 2002, retrieved on 14 November 2011 ).

None of the known arrangements, however, have proven to be optimal for the prevention of Spaltkavitationen.

The present invention is therefore an object of the invention to provide a baffle element for reducing the risk of the occurrence of cavitations on a Halbschweberuder of the type mentioned, with which an improved reduction in the risk of the occurrence of cavitation is possible.

With regard to the ship's rudder, the object of the present invention is to improve a ship's rudder of the type mentioned at the outset such that it is less susceptible to split cavitations.

The object directed to a baffle element is achieved according to the invention with a baffle element of the type mentioned at the beginning, which has a plate-like overhang that widens the outer profile surface in a transverse direction. In the present case, transverse direction is understood to be essentially the direction of the axis of rotation, that is to say a direction transverse to the flow of the blocking element in normal driving operation. When a baffle element according to the invention is placed on the rudder profile, a gap arises between the plate-like overhang and the rudder. If the baffle element according to the invention is fastened in the hinge region of a half-beaver swirler, it is able to flow due to the wedge-like profile section To prevent Spaltkavitationen on a parallel to the rotation axis formed gap between the rudder horn and rudder blade on one side. On the other hand, it is possible according to the present invention, due to the plate-like overhang widening in the transverse direction in the transverse direction, to cover the gap of the half-spear thruster orientated at right angles to the rotation axis in such a way that a stream causing slit cavitations is also avoided.

In order to reduce a volume flow through the transverse and / or the longitudinal gap of a half-spear thruster, the overhang is formed in a preferred embodiment of the invention for covering a transverse and / or a longitudinal gap of a half-spear thruster.

In an embodiment of the invention, a width of the overhang in the direction of increasing profile cross-section of the storage element becomes smaller and / or constant. An outer edge of the overhang in the first case approaches in the longitudinal direction of the wedge-like first profile section. This course of the overhang makes the stagnation element according to the invention particularly suitable for attachment in the crossing region of a longitudinal gap with a transverse gap of the ship's rudder, wherein the flow can be deflected according to the invention with advantage of the particularly vulnerable crossing region.

It has proved to be particularly favorable if, in the context of the invention, a longitudinal edge of the overhang intersects the outer profile surface of the damming element at a point of maximum profile depth of the damming element. The overhang thus opens into the wedge-like profile section. If the damming element according to the invention is mounted on a half-spinner so that the point of maximum tread depth is aligned aft, the overhang opens into the wedge-like profile section of the damming element in the aft direction. When fastening the stowage element according to the invention in the crossing region between a longitudinal gap and a transverse gap of the half-swine extruder influencing the flow downstream of the wedge-like profile section can be minimized in this way, so that the effect of the overhang occurs primarily in the area above or below the wedge-like first profile section ,

The object directed to the baffle element is likewise achieved by a baffle element for reducing the risk of the occurrence of cavitations on a half-bobbin winder having a wedge-like first profile section with an outer profile surface having a first monotonous inclination in the longitudinal direction, in which a second monotonous longitudinal inclination having wedge-like profile section, preferably adjacent to the first profile section, is provided, wherein the second inclination is formed opposite to the first inclination. The tread depth of the storage element thus increases initially in the longitudinal direction and then directly or after, for example, a plateau section again. This profile form according to the invention has the advantage that a sharp trailing edge of the damming element is avoided when attaching the damming element to a ship's rudder, for example, to counteract a vortex formation at the trailing edge, which could lead to a reduction of the rudder effect.

In particular, the invention provides that the second inclination is designed to be larger in terms of yield than the first inclination. Illustratively, this means that the first wedge-like profile section is flatter than the adjoining second profile section.

In a further development of the storage element according to the invention with a second wedge-like profile section, this is additionally provided with a plate-like overhang which widens the outer profile surface in a transverse direction, in accordance with the above features.

The task directed to a ship's rudder is achieved according to the invention in a ship's rudder of the type mentioned above, in which at least one tread depth of the rudder horn element increases the damming element to reduce the risk of the occurrence of cavitations in a region upstream of the longitudinal gap and in an area upstream of the transverse gap is arranged on the rudder horn element. It is therefore intended to attach several, in particular two, stowage elements to the rudder horn in order to effectively avoid crevice cavitations. The at least two storage elements can be offset from each other in the flow direction or arranged in parallel. Likewise, they may partially overlap in the transverse direction. It has been shown experimentally that an effective prevention of Spaltkavitationen can be achieved by the use of multiple stowage elements on the rudder horn with the inventive placement.

If in an embodiment of the ship's rudder according to the invention arranged in a region upstream of the longitudinal gap damper element and / or arranged in a region upstream of the transverse gap baffle element is designed according to one of claims 1 to 6, it is possible for the ship's rudder according to the invention, the above-described advantageous properties of Stowage element according to the invention to reduce the risk of occurrence of Spaltkavitationen. In particular, the inventive design of the storage element with two wedge-like Profile sections of opposite inclination are used when two stowage elements are arranged on the control horn in the region of the longitudinal gap or the transverse gap.

In a further advantageous embodiment of the ship rudder according to the invention, at least one section of the longitudinal gap adjoining the rudder horn element in the longitudinal direction and / or a cover element overlapping the section of the transverse gap adjacent to the rudder horn element are provided. According to this embodiment of the invention, the covering element can project beyond an intersection region between the transverse gap and the longitudinal gap in order to prevent flow of this region.

The invention will now be described by way of example in a preferred embodiment with reference to a drawing, wherein further advantageous details are shown in the figures of the drawing.

Functionally identical parts are provided with the same reference numerals.

The figures of the drawing show in detail:

1 : Lateral view of a conventional half-swine boar 1 in the stern area of a lower hull 2 consisting of a rudder horn 3 and one about a substantially vertically configured axis of rotation 4 rotatably mounted rudder blade 5 .

2 : horizontal sectional view along the line II-II,

3 : Perspective view of a ship rudder, as well

4 : preferred embodiment of a rudder according to the invention in another embodiment of a storage element according to the invention.

The half-tailed wind 1 is at the bottom of the ship 2 aft, ie downstream from a propeller 6 arranged and used by the propeller 6 incident flow. The 1 clearly shows that the Halbschweberuder 1 in the border area between the rudder horn 3 and the rudder blade 5 one parallel to the axis of rotation 4 aligned longitudinal gap 7 having. Furthermore, the Halbschweberuder 1 in the border area between the rudder blade 5 and the rudderhorn 3 one at right angles to the axis of rotation 4 aligned first transverse slit 8th between a lower section 9 the rudder blade 5 and the rudderhorn 3 on. It is also between an upper section 10 the rudder blade 5 and the rudderhorn 3 a second cross gap 11 available. The 1 shows a ship's rudder according to the prior art without the measures according to the invention for reducing the risk of the occurrence of cavitation and serves so far only to illustrate the geometric relationships.

2 shows in a horizontal sectional view along the line II-II in FIG 1 an inventive embodiment of a storage element 12 to reduce the risk of the occurrence of cavitations at the second longitudinal gap 13 between the rudder horn 3 and the rudder blade 5 , The stowage element according to the invention 12 has a first wedge-like profile section 14 which in turn has a first monotonous longitudinal inclination. The monotonous inclination in the longitudinal direction of the profile section 14 shows up in 2 in that a tread depth 15 between an outer profile surface 16 and a rudder horn profile surface 17 is less than a distance 18 between the outer profile surface 16 of the damming element 12 and the rudder profile area 17 which is measured farther downstream. Notwithstanding that with reference to 2 explained embodiment, the tread depth 15 in the context of the invention also be zero, so that the storage element runs flush into the surrounding rudder profile.

Next is in 2 recognizable that from one point 19 maximum tread depth, ie maximum tread depth 18 between the outer profile surface 16 of the damming element 12 and the rudder horn profile surface 17 , a second profile section 20 to the first profile section 14 borders.

The second profile section 20 is in the opposite direction to the first profile section 14 inclined so that the tread depth of the maximum tread depth 18 in the direction downstream to the tread depth 21 in the area of the second longitudinal gap 13 decreases. Notwithstanding that with reference to 2 explained embodiment, the tread depth 21 be zero in the context of the invention, so that the storage element runs flush into the surrounding rudder profile.

In 3 is shown in perspective view of a ship's rudder according to the invention in a first embodiment. How to recognize, on the one hand, is in one area 22 upstream of the longitudinal gap 13 the baffle element 12 arranged such that the in 2 shown first profile section 14 with increasing tread depth upstream of the adjoining second profile section 20 is arranged with decreasing tread depth.

Next is in 3 to recognize that in the direction of the axis of rotation 4 up and to the upstream offset to the first storage element 12 another baffle element 23 is arranged. The retarding element 23 is thus, as well as in 3 seen, upstream of the second transverse gap 11 arranged. The second storage element 23 indicates coincident with the first baffle element 12 two profile sections with opposite inclination, wherein the portion with a lower inclination coincides with the first storage element 12 is arranged upstream. 3 shows that in the direction parallel to the flow direction no overlap between the first baffle element 12 and the second storage element 23 exist. However, the second baffle element overlaps 23 the first storage element 12 in the direction parallel to the axis of rotation 4 slightly.

In 3 is also a strip tape 24 to recognize which is parallel to the first transverse slit 8th , the lower section 9 the rudder blade 5 upwards delimiting the inflow end 25 the rudder blade 5 nestles. The ribbon strip 24 is so on the rudder blade 5 attached that a surface normal to that of its wide surface 26 essentially parallel to the axis of rotation 4 is aligned.

Finally shows 4 another preferred embodiment of a rudder according to the invention in another embodiment of a storage element according to the invention. 4 is again a perspective side view, the viewing direction in contrast to 3 essentially to the bug. The helm is like in 1 shown essentially designed as a half-spider. According to the invention, however, it has a baffle element 27 on. The baffle element 27 is upstream of the second longitudinal gap 13 between the rudder horn 3 and the rudder blade 5 arranged such that the lower longitudinal edge 28 of the damming element 27 approximately flush and approximately parallel with the lower edge of the rudder horn 3 is. In the context of the invention has been shown that an arrangement approximately flush with the lower edge of the rudder horn 3 to reduce the risk of cavitation is not critical. Rather, the effect of the invention also already occurs when the baffle element further above the lower edge of the rudder horn 3 is arranged. The baffle element 27 differs from the in 2 and 3 shown stowage elements according to the invention 12 . 23 only a first profile section 14 with a wedge-shaped shape and a longitudinal inclination. Notwithstanding the embodiments of the storage elements 12 . 23 is the shape of the storage element according to the invention 27 with an outer profile surface of the damming element 27 in the transverse direction, that is essentially in the direction of the axis of rotation 4 expanding plate-like overhang 30 Mistake. A longitudinal edge 31 the plate-like overhang 30 cuts the outer profile surface 29 of the damming element 27 in a place of tread depth 32 , From a location of tread depth ( 32 ) starting in the direction of upstream increases a width 33 the plate-like overhang 30 monotone until reaching a maximum width at the upstream longitudinal end 34 of the damming element 27 , At the upstream longitudinal end 34 runs the edge of the plate-like overhang 30 as an extension of the upstream transverse edge of the storage element 27 , The thus formed storage element 27 covers with the plate-like overhang 30 a crossing area between the longitudinal gap 7 and the second cross gap 11 such that on the one hand a portion of the longitudinal gap 7 and on the other hand, a portion of the second transverse gap 11 from the plate-like overhang 30 is covered.

In this way, according to the in 4 shown embodiment of the storage element according to the invention 27 and the ship rudder according to the invention provided therewith, an embodiment of a damming element 27 and its arrangement on the rudder horn 3 proposed, with which the formation of Spaltkavitationen according to simulation calculations can be effectively avoided.

Thus, based on the 1 to 4 in two embodiments of the invention discloses that, optionally or in combination, an arrangement of two baffle elements which along the direction of rotation 4 of the ship's helmsman 1 and offset in the flow direction to each other and / or by means of a baffle element 27 with a plate-like overhang 30 an effective suppression of Spaltkavitationen is possible.

LIST OF REFERENCE NUMBERS

1

 Semi-balanced rudder

2

 under ship

3

 Ruderhorn

4

 axis of rotation

5

 rudder blade

6

 propeller

7

 longitudinal gap

8th

 first cross gap

9

 lower section

10

 upper section

11

 second cross gap

12

 retarding element

13

 second longitudinal gap

14

 first profile section

15

 tread depth

16

 outer profile surface

17

 Ruderhorn profile surface

18

 maximum tread depth

19

 Point of maximum tread depth

20

 second profile section

21

 tread depth

22

Area upstream of the longitudinal gap 13

23

 retarding element

24

 strip tape

25

 oncoming

26

 wide area

27

 retarding element

28

 lower longitudinal edge

29

 outer profile surface

30

 plate-like overhang

31

 longitudinal edge

32

 tread depth

33

 width

34

 upstream longitudinal end

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• TUHH "Kavitationen Halbschweberudern" of 10 September 2002, retrieved on 14 November 2011 [0008]

Claims (9)

Jam element ( 27 ) for duck counteraction against cavitations on a half-tailed powder ( 1 ) having a first monotonous inclination in the longitudinal direction having wedge-like first profile section ( 14 ) with an outer profile surface ( 16 ), characterized in that it has an outer profile surface ( 16 ) in a transverse direction expanding plate-like overhang ( 30 ) having. Jam element ( 12 . 23 ) for reducing the risk of occurrence of cavitations on a half-tail ( 1 ) according to the preamble of claim 1, characterized in that a second monotonous inclination in the longitudinal direction having wedge-like second profile section ( 20 ), preferably to the first profile section ( 14 ) adjacent, is provided, wherein the second inclination is formed opposite to the first inclination. Jam element ( 12 . 23 . 27 ) according to claim 1 or 2, characterized in that the overhang ( 30 ) for covering a transverse ( 8th . 11 ) and / or a longitudinal gap ( 7 . 13 ) of a half-swine swamp ( 1 ) is adapted to a volume flow through the transverse ( 8th . 11 ) and / or the longitudinal gap ( 7 . 13 ). Jam element ( 27 ) according to one of claims 1 to 3, characterized in that a width ( 33 ) of the overhang ( 30 ) in the direction of increasing profile cross-section of the storage element ( 27 ) becoming smaller and / or consistently designed. Jam element ( 27 ) according to one of claims 1 to 4, characterized in that a longitudinal edge ( 31 ) of the overhang ( 30 ) the outer profile surface ( 29 ) of the storage element ( 27 ) in a location of tread depth ( 32 ) of the storage element ( 27 ) cuts. Jam element ( 12 . 23 ) according to one of claims 1 to 5, characterized in that the second inclination is designed to be greater in magnitude than the first inclination. Ship rudder ( 1 ) with a relative to the hull ( 2 ) substantially immobile Ruderhorn element ( 3 ) and a relative thereto about a rotation axis ( 4 ) rotatably mounted rudder blade element ( 5 ), wherein between the rudder horn element ( 3 ) and the rudder blade element ( 5 ) at least one to the axis of rotation ( 4 ) substantially parallel longitudinal gap ( 7 . 13 ) and / or at least one to the axis of rotation ( 4 ) in the substantially vertically aligned transverse gap ( 8th . 11 ), characterized in that in order to reduce the risk of the occurrence of cavitations in an area upstream of the longitudinal gap ( 7 . 13 ) and in an area upstream of the transverse gap ( 8th . 11 ) at least one profile depth of the Ruderhorn element ( 3 ) increasing stowage element ( 12 . 23 . 27 ) on the rudder horn element ( 3 ) is arranged. Ship rudder ( 1 ) according to claim 7, characterized in that in an area upstream of the longitudinal gap ( 7 . 13 ) arranged stowage element ( 12 ) and / or in an area upstream of the transverse gap ( 8th . 11 ) arranged stowage element ( 23 ) is designed according to one of claims 1 to 6. Ship rudder ( 1 ) according to claim 7 or 8, characterized in that at least one of the rudder horn element ( 3 ) adjacent section of the longitudinal gap ( 7 . 13 ) and / or one to the rudder horn element ( 3 ) adjacent section of the transverse gap ( 8th . 11 ) covering cover element ( 30 ) is provided.

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