Device for reducing the driving power requirement of a watercraft

Abstract

The invention relates to a device for reducing the driving power requirement of a watercraft, in particular a ship, and for arranging in front of a ship propeller in the direction of flow, comprising a flow guidance surface, in particular a nozzle ring or a partial nozzle ring, at least one inner fin projecting from the flow guidance surface, wherein an end of the inner fin is attached to the flow guidance surface and wherein, when the device is installed in a watercraft, another end of the inner fin is attached to a watercraft, and at least one outer fin projecting from the flow guidance surface, wherein one end of the outer fin is attached to the flow guidance surface and wherein another end of the outer fin is designed as a free end, wherein the at least one inner fin and / or the at least one outer fin are produced from a composite material.

Description

[0001] Device for reducing the propulsion power requirement of a watercraft

[0002] The invention relates to a device for reducing the propulsion power requirement of a watercraft, in particular a ship, and for arrangement in the direction of flow in front of a propeller, comprising a flow guide surface, in particular a nozzle ring or a partial nozzle ring, at least one inner fin protruding from the flow guide surface, wherein the inner fin is attached at one end to the flow guide surface and wherein another end of the inner fin is attached to the watercraft when the device is installed on the watercraft, and at least one outer fin protruding from the flow guide surface, wherein the outer fin is attached at one end to the flow guide surface, wherein another end of the outer fin is designed as a free end. The invention further relates to an arrangement comprising such a device, a propeller and a rudder, as well as a ship with such an arrangement.

[0003] State of the art

[0004] A device described above is known from EP 2 591 994 A1. This device shows a device for reducing the propulsion power requirement of a watercraft, comprising a fore-nozzle, wherein at least one outer fin is provided projecting outwardly from the fore-nozzle. Furthermore, the device shown therein can also have an inner fin, which is attached at a first end to an inner wall surface of the fore-nozzle and at a second end to a shaft bearing, in particular a stern tube.

[0005] Such devices known from the prior art for reducing the propulsion power requirement of a watercraft are usually mounted on a vessel, particularly at a short distance or directly in front of the propeller as viewed in the direction of travel. Furthermore, fins attached to the fore-nozzle are designed as (guiding) fins or hydrofoils. The fore-nozzle essentially has the shape of a flat conical section, with both openings, the water inlet and the water outlet, being designed as essentially circular openings, and the water inlet opening having a larger diameter than the water outlet opening. This makes it possible to improve the propeller and, with the fins installed on the fore-nozzle, to reduce losses in the propeller jet through targeted pre-swirl generation.Such a system can significantly reduce power requirements and thus save fuel. Such known devices are typically constructed entirely of steel.

[0006] Description of the invention: task, solution, advantages

[0007] The invention is based on the object of further improving a device for reducing the propulsion power requirement of a watercraft, comprising a flow guide surface, at least one inner fin, and at least one outer fin. In particular, the energy efficiency of the device is to be further improved.

[0008] For this purpose, a device is provided for reducing the propulsion power requirement of a watercraft, in particular a ship, and for arrangement in the direction of flow in front of a ship's propeller. The device comprises a flow guide surface, in particular a nozzle ring or a partial nozzle ring, at least one inner fin protruding from the flow guide surface, wherein the inner fin is attached at one end to the flow guide surface and wherein another end of the inner fin is attached to the watercraft when the device is installed on the watercraft, and at least one outer fin protruding from the flow guide surface, wherein the outer fin is attached at one end to the flow guide surface and wherein another end of the outer fin is designed as a free end.

[0009] According to the invention, it is further provided that the at least one inner fin and / or the at least one outer fin are made of a composite material. By forming the at least one inner fin and / or the at least one outer fin from a composite material, the weight of the device can be reduced, which leads to greater energy efficiency of the device. Due to the good strength properties of composite materials, sufficient strength can be achieved for the loads and stresses to which the device is exposed during operation. This is particularly the case for the at least one fin made of composite material, which, due to its design with a free end, is exposed to the highest bending stresses of all components of the device.Furthermore, the production from composite material allows easier production of the fluid-mechanically advantageous curved profile of the at least one outer fin and / or the at least one inner fin.

[0010] The term "composite material" refers to a mixture of two or more pure raw materials. The raw materials that make up a composite material are firmly and inseparably bonded together.

[0011] The flow guide surface can be formed in one piece or in one piece, or can be composed of several individual parts to form a flow guide surface, wherein the individual parts are preferably welded to one another or to the ship's hull.

[0012] The flow guide surface can fundamentally have a variety of shapes. The flow guide surface is arranged and designed such that the water flow is at least partially directed onto a propeller. For example, the flow guide surface can have the shape of a square or rectangular plate. However, arched or curved shapes are preferred. In cross-section, an arched flow guide surface can have a circle, a circular segment, an elliptical segment, or another curved shape. The flow guide surface has a length in the direction of flow, or in the direction of travel of the watercraft. Furthermore, the flow guide surface has a width in a plate-shaped design, or an arc length in an arched design. The thickness of the flow guide surface is referred to below as the profile thickness.Both the length and the width or arc length and the profile thickness can be constant over the entire area of ​​the flow guide surface or have different values. For example, the flow guide surface can also be profiled. For example, one edge of the flow guide surface could be rounded and have a thinner profile thickness than the central area of ​​the flow guide surface. Particularly preferably, the flow guide surface is designed as a nozzle ring or 7. In the design as a nozzle ring, the flow guide surface is closed in the circumferential direction, whereas in the design as a partial nozzle ring it is open in the circumferential direction. Preferably, the embodiment as a partial nozzle ring has a cross-section of an eighth of a ring, a quarter of a ring, a half of a ring, a two-thirds of a ring or a three-quarter of a ring.In the embodiment as a partial nozzle ring, the arc length of the flow guide surface, viewed in cross-section, can preferably be less than 80%, particularly preferably less than 60%, very particularly preferably less than 40% or 30% of the circumference of a conceptually closed nozzle ring. Furthermore, the flow guide surface, when installed, preferably encloses the propeller axis of the ship's propeller at least partially in the circumferential direction.

[0013] Preferably, the flow guide surface is arranged in front of a propeller. This means that the flow guide surface is arranged in front of a propeller of the watercraft in the direction of travel of the vessel or ship. The term "in the direction of travel" here refers to the forward direction of travel of a ship or watercraft.

[0014] It is further preferred that the flow guide surface be arranged at a distance from the propeller. Furthermore, it is preferred that the flow guide surface be arranged at a distance from a shaft bearing of the vessel, in particular a stern tube. A stern tube serves to support a propeller shaft of the propeller of the watercraft or ship. For this purpose, the flow guide surface can be arranged at least partially above, below, or even to the side of the propeller axis. Furthermore, the flow guide surface can at least partially enclose the propeller axis or the shaft bearing.

[0015] Preferably, the flow guide surface is arranged above and at a distance from the propeller axis or the propeller shaft.

[0016] The at least one outer fin is connected at a first end in a suitable manner to the flow guide surface or is fastened to the flow guide surface. The second end of the at least one outer fin is designed as a free end. Thus, the at least one outer fin can protrude from the flow guide surface in any direction, wherein the second end of the at least one outer fin is not connected to the flow guide surface or otherwise fastened to the ship's hull. Preferably, the at least one outer fin protrudes radially outward from the flow guide surface, i.e., away from the stern tube.

[0017] The at least one inner fin is connected in a suitable manner to the flow guide surface at a first end, or is fastened to the flow guide surface. Preferably, the at least one inner fin protrudes inward from the flow guide surface, i.e., toward the shaft bearing or stern tube of the ship. The second end of the at least one inner fin is designed to be attached to the watercraft, in particular in the region of the stern tube, when installed on the watercraft. Preferably, the at least one inner fin protrudes radially inward from the flow guide surface.

[0018] The term "fin" refers to a guide fin or a hydrofoil, which is preferably arranged in a fixed manner on the flow guidance surface. In principle, the term "fin" can be understood to mean any guide device influencing the propeller inflow, wherein the fin preferably has an airfoil profile, i.e., comprises a suction side and a pressure side. Thus, in the present context, fins are flow guidance surfaces in the sense of stators, which are arranged on the flow guidance surface and influence the propeller inflow. In particular, it is preferred that the fins have an outwardly curved suction side, in particular in the shape of a circular arc, and a substantially flat pressure side.

[0019] The profile of the at least one inner fin and / or the at least one outer fin can be uniform or different across its length. In particular, the profile can be twisted, ie, twisted, when viewed along the longitudinal direction of the at least one inner fin and / or the at least one outer fin.

[0020] The at least one inner fin and the at least one outer fin can be formed independently of one another and each individually attached to the flow guide surface. In an alternative embodiment, however, the at least one inner fin and the at least one outer fin can also be designed as a single piece, where such a single piece fin extends through the flow guide surface. The at least one outer fin and the at least one inner fin can also be arranged one behind the other or offset from one another, viewed in the radial direction.

[0021] Preferably, more than one outer fin and / or more than one inner fin are provided. Particularly preferably, more than two outer fins and / or more than two inner fins are provided, and most preferably, exactly three inner fins and / or exactly three outer fins are provided.

[0022] The composite material is preferably a GFRP (glass fiber reinforced plastic), E-composite, E-glass, foam, plastic, or carbon fiber, or comprises mixtures thereof. Alternatively or additionally, the composite material can preferably contain reinforcing non-metallic fibers, in particular Kevlar fibers, glass fibers, basalt fibers, ceramic fibers, aramid fibers, or carbon fibers. The reinforcing non-metallic fibers are particularly preferably Kevlar fibers. These preferred embodiments advantageously ensure high and sufficient strength of the at least one outer fin and / or the at least one inner fin.

[0023] The flow guide surface is preferably made of metal, in particular steel. It is further preferred that the at least one inner fin, particularly preferably all of the inner fins, are made of metal, in particular steel. In this preferred embodiment with the flow guide surface and inner fin(s) made of metal, only the at least one outer fin, preferably all of the outer fins, are made of composite material. The outer fins are exposed to particularly high bending loads, so the use of composite material, especially if it is fiber-reinforced, is particularly advantageous for the outer fins. For the inner fins, on the other hand, high strength is important, so it can be advantageous to make them from steel.

[0024] The flow guide surface preferably has at least one fin receptacle, in particular made of metal, for mounting the at least one inner fin made of composite material and / or the at least one outer fin made of composite material. The fin receptacle is preferably designed to be form-fitting with regard to receiving the at least one inner fin and / or the at least one outer fin. Furthermore, the fin receptacle is preferably firmly connected to the surface, in particular by welding. The fin receptacle is particularly preferably designed as a nozzle into which an end region of the at least one inner fin and / or the at least one outer fin can be inserted and then connected thereto.The fin holder makes it possible to achieve a permanent and stable attachment of the at least one inner fin made of composite material and / or the at least one outer fin made of composite material to the flow guide surface, which in particular is made of metal, in a simple and safe manner.

[0025] Preferably, the at least one inner fin made of composite material and / or the at least one outer fin made of composite material is connected to the flow guide surface and / or the fin receptacle by bolting, gluing, screwing and / or welding.

[0026] The composite material preferably contains a reinforcing non-metallic fiber, wherein the at least one inner fin made of composite material and / or the at least one outer fin made of composite material has a connecting element at its end facing the flow guide surface, which comprises a hybrid textile structure made of the reinforcing non-metallic fiber and at least one metallic fiber, wherein the metallic fiber is preferably selected from the group consisting of iron, steel, copper, bronze, aluminum, titanium, gold, and silver, particularly preferably steel, aluminum, and titanium. By means of such a connecting element, a stable connection can be reliably established between the flow guide surface and the at least one outer fin or the at least one inner fin.

[0027] The hybrid textile structure preferably has a longitudinal extension along the longitudinal direction of the at least one inner fin and / or the at least one outer fin, wherein a gradient in terms of material composition preferably runs along the longitudinal extension of the hybrid textile structure, such that the hybrid textile structure is formed from 50% to 100% of the metallic fiber at its end facing the flow guide surface and from 50% to 100% of the non-metallic fiber at its other end. Furthermore, the connecting element preferably has a metallic connection element which is connected in a materially bonded manner, preferably welded or soldered, to the end of the end side of the hybrid textile structure facing the flow guide surface. By means of the connection element, the connecting element can be easily connected to the flow guide surface, which in particular is made of metal, in particular by welding.

[0028] Furthermore, the object underlying the invention is achieved by an arrangement for a ship comprising the device described above, as well as a propeller with a propeller shaft and a rudder arranged downstream of the propeller in the direction of flow. The device is arranged upstream of the propeller in the direction of flow and at least partially encloses the propeller shaft. To partially enclose the propeller shaft, the flow guide surface of the device is expediently designed as a nozzle ring or partial nozzle ring.

[0029] Finally, the object underlying the invention is also achieved by a ship comprising the arrangement described above.

[0030] Short description of the characters

[0031] Embodiments of the invention are explained in more detail below with reference to the drawings. They show schematically:

[0032] Fig. 1: a perspective view of a device according to an embodiment of the invention;

[0033] Fig. 2a, 2b: a plan view and a side view of a device according to an embodiment of the invention;

[0034] Fig. 3: a front view in the direction of flow of a device according to an embodiment of the invention;

[0035] Fig. 4: a section through a device according to an embodiment of the

[0036] Invention showing inner and outer fins; and

[0037] Fig. 5: a fin receptacle according to an embodiment of the invention. Detailed description of the figures

[0038] Fig. 1 shows a perspective view of a device according to one embodiment of the invention, thus facilitating the manufacture of the fluidically advantageous curved profile of the outer fins 120. This device 100 comprises a flow guide surface 110 and a plurality of outer fins 120a, 120b, 120c (exactly three) and inner fins 130a, 130b, 130c (exactly three). The outer fins 120a, 120b, 120c are attached to the flow guide surface 110 by means of fin receptacles 140, with one fin receptacle 140 being provided for each outer fin 120a, 120b, 120c. This device 100 is designed to be mounted on a ship (not shown here) in front of a ship's propeller, in the direction of flow. In particular, the ends of the inner fins 130a, 130b, 130c facing away from the flow guide surface 110 are designed to be attached and fastened to a ship, in particular to a stern tube of a ship, in particular by welding.For this purpose, the inner fins 130a, 130b, 130c as well as the flow guide surface 110 are made entirely of metal, in particular steel. The flow guide surface is designed as a partial nozzle ring, which, when installed, preferably partially encloses the propeller shaft. The arc angle of the partial nozzle ring is between 90° and 120°. This partial nozzle ring with the attached fins is advantageously located between an 8 o'clock and 1 o'clock position with respect to the direction of rotation of the propeller (as viewed from the stern of a ship) in order to accelerate the inflow of the propeller and generate counter-vortices to compensate for the vortices generated by the propeller. For this purpose, the outer and / or inner fins preferably have a curved profile. The inner fins 130a, 130b, 130c protrude substantially radially inward from the flow surface 110.The outer fins 120a, 120b, 120c protrude substantially radially outward from the flow guide surface 110 and are arranged radially behind the corresponding inner fins 130a, 130b, 130c. The outer fins 120a, 120b, 120c are made of a composite material, in particular a fiber composite material. The use of a composite material for the outer fins 120a, 120b, 120c enables a weight reduction and easier production of the fluidically advantageous curved profile of the outer fins 120. Figures 2a and 2b show side views, and Figure 3 shows one of the devices 100 shown in Figure 1. Figure 2a shows the device 100 from above, Figure 2b from the starboard side, and Figure 3 shows the device 100 in the direction of flow. In particular, it is shown that the profile of the outer fins 120a, 120b, 120c can be different to enable optimal vortex reduction.Figure 3 also shows that an inwardly projecting support strut 131 is provided at one end of the flow guide surface. This support strut 131 serves to secure the device 100 to a vessel and to ensure its strength and stability. It generally does not have an airfoil profile.

[0039] Fig. 4 shows a longitudinal section through the arrangement according to the invention. In particular, it shows how the outer fins 120 are attached to the flow guide surface by means of the fin holder 140.

[0040] Fig. 5 shows the attachment of an outer fin 120 in detail. The outer fin 120 is inserted into the fin receptacle 140 and is received thereby in a form-fitting manner. Furthermore, the outer fin 120 is fastened in the fin receptacle 140 by means of bolts 150 running transversely through the fin receptacle 140 and the outer fin 120. Alternatively or additionally, the attachment of the outer fin 120 to the fin receptacle 140 can also be achieved by gluing or welding. For the purpose of better attachment to the fin receptacle, the end of the outer fin facing the fin receptacle is preferably partially made of metal, particularly preferably of iron, steel, copper, bronze, aluminum, titanium, gold or silver, most particularly preferably of steel, aluminum or titanium.In particular, the composite material can contain a non-metallic fiber, and the outer fin made of composite material can have a connecting element at its end facing the flow guide surface, which connecting element comprises a hybrid textile structure made of the non-metallic fiber and the at least one metallic fiber. The metallic fiber can be selected from the group consisting of iron, steel, copper, bronze, aluminum, titanium, gold, and silver, preferably steel, aluminum, and titanium, particularly preferably steel. Preferably, the outer fin further comprises a metallic connecting element that is integrally connected, preferably welded or soldered, to the end of the hybrid textile structure facing the flow guide surface 110. List of reference symbols.

[0041] 100 device

[0042] 110 Flow guide surface

[0043] 120, 120a-120c outer fins

[0044] 130, 130a-130c inner fins

[0045] 131 Support strut

[0046] 140 Fin recording

[0047] 150 bolts

Claims

Claims 1. Device (100) for reducing the propulsion power requirement of a watercraft, in particular a ship, and for arrangement in the flow direction in front of a ship's propeller, comprising: a flow guide surface (110), in particular a nozzle ring or a partial nozzle ring, at least one inner fin (130) protruding from the flow guide surface, wherein the inner fin (130) is attached at one end to the flow guide surface (110) and wherein another end of the inner fin (130) is attached to a watercraft when the device is installed on a watercraft, and at least one outer fin (120) protruding from the flow guide surface, wherein the outer fin (120) is attached at one end to the flow guide surface and wherein another end of the outer fin (120) is designed as a free end, characterized in that the at least one inner fin (120) and / or the at least one outer fin (130) are made of a composite material.

2. Device according to claim 1, wherein the composite material comprises a GFRP, E-composite, E-glass, foam, plastic or carbon fiber and / or wherein the composite material comprises reinforcing non-metallic fibers, in particular Kevlar fibers, glass fibers, basalt fibers, ceramic fibers, aramid fibers or carbon fibers, particularly preferably Kevlar fibers.

3. Device according to claim 1 or 2, wherein the flow guide surface (110) is made of metal, in particular steel, wherein preferably the at least one inner fin (130), particularly preferably all inner fins (130a-d), are made of metal, in particular steel, and wherein preferably the at least one outer fin (120), particularly preferably all outer fins (130a-c), are made of composite material.

4. Device according to one of the preceding claims, wherein the guide surface (110) has at least one fin receptacle (140), in particular made of metal, for mounting the at least one inner fin (130) made of composite material and / or the at least one outer fin (120) made of composite material.

5. Device according to claim 4, wherein the at least one fin receptacle (140) is designed as a socket into which an end region of the at least one inner fin (130) and / or of the at least one outer fin (120) is inserted and connected thereto.

6. Device according to one of the preceding claims, wherein the at least one inner fin (130) made of composite material and / or the at least one outer fin (120) made of composite material is connected to the flow guide surface and / or the fin receptacle (140) by bolting (150), gluing and / or welding.

7. Device according to one of the preceding claims, wherein the composite material comprises a non-metallic fiber and wherein the at least one inner fin (130) made of composite material and / or the at least one outer fin (120) made of composite material has, at its end facing the flow guide surface (110), a connecting element which comprises a hybrid textile structure made of the non-metallic fiber and at least one metallic fiber.

8. Device according to claim 7, wherein the hybrid textile structure has a longitudinal extent along the longitudinal direction of the at least one inner fin (130) and / or the at least one outer fin (120) and wherein a gradient with respect to the material composition runs along the longitudinal extent of the hybrid textile structure, such that the hybrid textile structure is formed from 50% to 100% of the metallic fiber at its end facing the flow guide surface (110) and from 50% to 100% of the non-metallic fiber at its other end.

9. Device according to claim 7 or 8, wherein the metallic fiber is selected from the group consisting of iron, steel, copper, bronze, aluminum, titanium, gold and silver, preferably steel, aluminum and titanium, particularly preferably steel.

10. Device according to one of claims 7 to 9, wherein the connecting element has a metallic connecting element which is integrally connected, preferably welded or soldered, to the end of the hybrid textile structure facing the flow guide surface (110).

11. Device according to one of the preceding claims, wherein the at least one outer fin (120) is continued through the flow guide surface (110) as an inner fin (130), wherein the inner fin (130) is preferably made of steel.

12. Arrangement for a ship comprising: a device (100) according to one of the preceding claims; a propeller with a propeller shaft; a rudder arranged downstream of the propeller in the direction of flow, characterized in that the device is arranged upstream of the propeller in the direction of flow and at least partially encloses the propeller shaft.

13. A ship having an arrangement according to claim 12.

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