ENERGY-SAVING ARRANGEMENT FOR TWIN-SCREW SHIPS

Abstract

In order to create an improved arrangement to reduce the propulsion-power requirement of a twin-screw ship comprising a first propeller and a second propeller and a first guiding device and a second guiding device, wherein, in the forward direction of the watercraft, the first guiding device is arranged in front of the first propeller, and the second guiding device is arranged in front of the second propeller, wherein the first propeller and the second propeller are attached to a first propeller shaft and to a second propeller shaft, and wherein the first propeller shaft defines a first propeller axis and the second propeller shaft defines a second propeller axis, the first guiding device and the second guiding device each comprise at least one fin, which extends from the propeller axes, wherein the fin of the first guiding device and of the second guiding device extend outwardly to the sides of the watercraft respectively.

Claims

1. Arrangement for reducing the propulsion-power requirement of a twin-screw ship, comprising a first propeller and a second propeller and comprising a first guiding device and a second guiding device, wherein, in the forward direction of the watercraft, the first guiding device is arranged in front of the first propeller, and the second guiding device is arranged in front of the second propeller, wherein the first propeller and the second propeller; are attached to a first propeller shaft and to a second propeller shaft, wherein the first propeller shaft defines a first propeller axis and the second propeller shaft defines a second propeller axis, wherein the first guiding device and the second guiding device each comprise at least one fin, which extends from the propeller axes, wherein the fin of the first guiding device and of the second guiding device extends outwardly towards the sides of the watercraft respectively.

2. Arrangement according to claim 1, wherein the first guiding device and the second guiding device each comprise at least one fin.

3. The arrangement according to claim 1, wherein the at least two fins of the first and second guiding devices are at an angle to each other, wherein the at least two fins of the guiding devices are attached in the area of shaft bearings, in particular on shells of stern tubes designed to support the first and second propeller shafts of the watercraft, or are attached to a watercraft hull.

4. The arrangement according to claim 1, wherein at least one fin of the guiding devices is set up to generate a pre-swirl when the first and second propellers are flown, wherein the pre-swirl is generated by the respective guiding device in an inflow region of the propellers which has no or a reduced pre-swirl generated by at least one asymmetrical skeg.

5. Arrangement according to claim 1, wherein the fin having a length, wherein the length of the fin corresponds to 65% to 110% of a propeller radius of the propellers, preferably 80% to 110%, particularly preferred 90% to 105%, mostly preferred 100%.

6. Arrangement according to claim 2, wherein the at least two fins of the first and second guiding devices are connected to each other by a connecting bar.

7. The arrangement according to claim 6, wherein the connecting bar is arranged along a length of the fins considered between 30% and 70% of the length of the fins, preferably between 45% and 55%, being particularly preferred, centred at 50% of the length of the fins.

8. The arrangement according to claim 6, wherein the connecting bar is shaped straight or curved along a length and/or width of the connecting bar.

9. Arrangement according to claim 1, wherein each of the guiding devices comprises exactly two fins.

10. Arrangement according to claim 1, wherein the propellers are designed as counter-rotating propellers, wherein the first guiding device is arranged on an impinging side of the first propeller, and the second guiding device is arranged on an impinging side of the second propeller.

11. Arrangement according to claim 1, wherein the guiding devices are positioned essentially mirror-symmetrical to each other with respect to a vertical plane of symmetry of the watercraft.

12. Arrangement according to claim 1, wherein at least one fin has a constant or changing profiling and/or position along its length.

13. Watercraft, in particular a twin-screw ship, comprising an arrangement for reducing the propulsion-power requirement of a twin-screw ship, comprising a first propeller and a second propeller and comprising a first guiding device and a second guiding device, wherein, in the forward direction of the watercraft, the first guiding device is arrange in front of the first propeller, and the second guiding device is arranged in front of the second propeller, wherein the first propeller and the second propeller are attached to a first propeller shaft and to a second propeller shaft, wherein the first propeller shaft defines a first propeller axis and the second propeller shaft defines a second propeller axis, wherein the first guiding device and the second guiding device each comprise at least one fin, which extends from the propeller axes, wherein the fin of the first guiding device and of the second guiding device extends outwardly towards the sides of the watercraft respectively.

Description

[0042] A plurality of exemplary embodiments of the invention are explained in more detail below on the basis of the drawings. The figures show:

[0043] FIG. 1 an exemplary simulation of the pre-swirl around propellers of a twin-screw ship,

[0044] FIG. 2a a perspective illustration of an arrangement according to the invention in accordance with a first embodiment,

[0045] FIG. 2b perspective illustrations of an arrangement according to the invention in accordance with a second embodiment,

[0046] FIG. 3 rear view of the arrangement according to the invention in accordance with the second embodiment.

[0047] FIG. 1 shows an exemplary simulation of the pre-swirl in the area of propellers 20, 21 of a twin-screw ship 100, which are shown as an example in FIG. 2a and FIG. 3. The simulation shows a cross-sectional area of an inflow or in the direction of propellers 20, 21 of flowing water with a corresponding pre-swirl distribution. A pre-swirl around a first propeller axis 22 and around a second propeller axis 23 of a watercraft 100 designed as a twin-screw ship is shown.

[0048] An asymmetrical shape of a skeg 110 of the watercraft 100 creates areas with an increased pre-swirl 120 and areas with a reduced or non-existent pre-swirl 130. The corresponding arrow lengths illustrate an exemplary measure of pre-swirl, wherein light-shaded areas correspond to reduced pre-swirl and dark-shaded areas correspond to increased pre-swirl with respect to a propeller rotation direction.

[0049] The arrangement shown in FIG. 2a according to the invention 10 comprises guiding devices 30, 31, which are only arranged in areas 130 in which there is no pre-swirl or an unfavourable inflow.

[0050] FIG. 2a shows a perspective illustration of an arrangement according to the invention 10 in accordance with a first embodiment. Arrangement 10 serves to reduce the propulsion-power requirement of the twin-screw ship or watercraft 100. For the sake of clarity, only a second or left side of a stern section of watercraft 100 is shown. In FIG. 3, a stern view of watercraft 100 is shown, which illustrates both sides. FIG. 2a is described with reference to FIG. 3.

[0051] Arrangement 10 comprises a first propeller 20 and a second propeller 21. Furthermore, the arrangement 10 comprises a first guiding device 30 and a second guiding device 31.

[0052] When viewed in the forward direction F of the watercraft 100, the first guiding device 30 is arranged in front of the first propeller 20, and the second guiding device 31 is arranged in front of the second propeller 21.

[0053] The first propeller 20 and the second propeller 21 are attached to a first propeller shaft (not shown) and to a second propeller shaft (not shown), wherein the first propeller shaft defines the first propeller axis 22 and the second propeller shaft defines the second propeller axis 23.

[0054] In the illustrated exemplary embodiment, the first guiding device 30 and the second guiding device 31 each comprise two fins 32, 33, which extend radially from the propeller axes 22, 23. The fins 32, 33 of the first guiding device 30 and of the second guiding device 31 extend outwardly towards the sides of the watercraft 101, 102.

[0055] In particular, the first guiding device 30 extends to a first or right side of the watercraft 101, and the second guiding device 31 extends to a second or left side of the watercraft 102, respectively.

[0056] The two fins 32, 33 of the first and second guiding devices 30, 31 are at an angle A to each another. The two fins 32, 33 of the guiding devices 30, 31 are attached by way of example in the area of shaft bearings 40, in particular, to shells of stern tubes which are designed to support the first and second propeller shafts of the watercraft 100.

[0057] In der FIG. 2b, a perspective illustration of an arrangement according to the invention 10 in accordance with a second embodiment is shown. In particular, in FIG. 2b a side view of the watercraft 100 is shown analogous to FIG. 2a. In contrast to the embodiment that has already been described, the arrangement 10 comprises a connecting bar 50 radially centred between the fins 32, 33.

[0058] The fins 32, 33 have a length L, which corresponds to 100% of a propeller radius of the propellers 20, 21.

[0059] The two radially protruding fins 32, 33 comprise a connecting bar 50 arranged approximately radially in the centre. The connecting bar 50 can structurally reinforce the fins 32, 33. In particular, the fins 32, 33 are mechanically connected to each other by the connecting bar 50.

[0060] In FIG. 3, a stern view of watercraft 100. is shown. Thereby, the entire arrangement 10 is illustrated. The first and second guiding devices 30, 31 extend in the direction of the first and second sides of the watercraft respectively, 101, 102 starting from the shells of the stern tubes and shaft bearings 40, respectively. The direction of rotation of the two propellers is indicated by the two arrows R, which are arranged inwardly at an upper point of rotation, i.e., at a 12:00 o'clock position.

[0061] In the case of propellers 20, 21 rotating inwardly in the direction of arrows R, the two guiding devices 30, 31 are arranged on the outside or on the impinging sides of propellers 20, 21. Based on a view from the rear, the guiding devices 30, 31 are therefore located at 3:00 a.m. and at 9:00 a.m. In such a formation of arrangement 10, the guiding devices 30, 31 are preferably symmetrically arranged with respect to each other with respect to a vertical plane of symmetry S of the watercraft 100.

[0062] Such an arrangement of the guiding devices 30, 31 can be used to achieve particularly high energy savings or fuel reduction, particularly in the case of twin-screw ships.

[0063] Preferably, in addition to the guiding devices 30, 31, no other energy-saving devices comprising fins or nozzles on the watercraft are arranged in the area of propellers 20, 21 or even on rudders.

[0064] FIG. 3 also illustrates the symmetrical structure of arrangement 10 and guiding devices 30, 31. It can also be seen that the connecting piece or the connecting bar 50 is attached approximately in the middle of the fins 32, 33 when viewed along the length L of the fins 32, 33.

REFERENCE LIST

[0065] 100 watercraft/twin-screw ship [0066] 101 first/right side of the watercraft [0067] 102 second/left side of the watercraft [0068] 110 skegs of the watercraft [0069] 120 areas with an increased pre-swirl [0070] 130 areas with a reduced pre-swirl [0071] 10 arrangement [0072] 20 first propeller [0073] 21 second propeller [0074] 22 first propeller axis [0075] 23 second propeller axis [0076] 30 first guiding device [0077] 31 second guiding device [0078] 32 fins of the first guiding device [0079] 33 fins of the second guiding device [0080] 40 shaft bearing [0081] 50 connecting bar [0082] A angle between two fins [0083] F forward direction of travel [0084] L length of a fin [0085] S vertical plane of symmetry of the watercraft [0086] R direction of rotation