The invention relates to a fast sea-going ship with a double hull which features a waterjet drive comprising at least one pump assembly for generating the water jet and at least one drive motor for the pump assembly.
The object of the invention is to provide a fast sea-going ship, e.g. a frigate or a destroyer, but also a ferry or a megayacht, with a drive system which offers significant advantages over the known drive systems. The main advantage is to be the avoidance of the exhaust plume. In addition the invention is designed to reduce the space required for the drive. The intention is also, in conjunction with a propeller drive, to provide redundancy which for example will allow warships to keep going after sustaining a heavy hit.
These objects are achieved by locating the pump assembly and its drive motor outside the stern area of the ship, partly using the space in the double hull.
The new arrangement in accordance with the invention makes it advantageously possible without any great outlay to direct exhaust gases underneath the ship, so that these dissipate in the water. Using a part of the double hull produces a low-profile layout for the waterjet and its drive motor while still obtaining a good waterjet exit angle.
Waterjets for driving fast sea-going ships are known from the latest
Internet pages of Rolls-Royce under the title “Rolls-Royce- the force in marine solutions”1, Page 7.
Here the individual components of the drive system are located in the stern section of the ship, as is also known from speedboats with waterjets and has long been normal in large shipbuilding for propeller drives. For reasons of effectiveness the waterjets are essentially located so that the jet is freely emitted, i.e. over water. This type of arrangement is however not suitable for achieving the objects in accordance with the invention.
There is a provision in the embodiment of the invention for the pump assembly and its drive motor to be located in the rear area of the middle of the ship. Locating the system rear amidships means that the water jet is able to contribute to the distribution of the exhaust gas in the water. Of particular advantage is the breakup and fine distribution of the exhaust gas bubbles when the ship is traveling fast. Because of the deep introduction into the water they do not rise to the surface until they are well behind the stern of the ship. Here they rise up into the ship's wake.
In a further embodiment of the invention there is provision for the drive motor for the pump assembly to be an electric motor, with this electric motor especially featuring partly HTSL windings. Usually the pump assemblies of waterjets will be driven directly by diesel engines or gas turbines. This would be possible in the midships area of any large ship. It is however of particular advantage for the ability to control and accommodate the waterjet if the drive is an electric motor.
In a further major embodiment of the invention there is provision for the drive motor for the pump assembly to feature an armature with HTSL windings. An armature of the electric motor with HTSL windings allows a particularly small design of motor. In this case a large air gap between armature and stator windings is possible. This provides favorable conditions for a shockproof embodiment of the motor which is very advantageous for warships. In addition the efficiency of the motor compared to conventional electric motors is increased and the very advantageous option of arranging the electric motor within the double hull of the ship is also provided. This in its turn leads to a short shaft between the electric motor and the pump assembly which is essentially arranged outside the double hull of the ship. Overall this produces a waterjet and drive arrangement which is smaller and lighter than conventional versions by an order of magnitude. The technical difficulties which would be produced by having a long shaft are avoided, as is the large space requirement, for example for a diesel direct drive of the waterjet.
In this case there is provision for the pump assembly to be arranged in a single-part or multipart nacelle, especially one which is partly integrated in the double hull. This provides the option of an especially good flow around of the nacelle and entry of the water into the pump assembly. The inflow is especially important when an axial pump or a diagonal/radial pump is used. The underwater silhouette of the ship is advantageously only slightly altered by this.
The waterjet, its nacelle and where necessary its drive motor are advantageously arranged in a special hull section of the ship which is embodied as a double hull module and can be inserted during the building phase of the ship into the double hull. This allows rational prefabrication to be undertaken and the difficulties and costs of retrofitting are avoided. These advantages are also obtained when the waterjets for cargo or passenger ships, where the complete exhaust dissipation into the water is not so significant, are arranged in the stern area.
In a further embodiment of the invention there is provision for the pump assembly to be arranged under a raised part of the ship's lower hull. In this case it is advantageous that by virtue of the small dimensions of the electric motor and its accommodation in the double hull in the raised part that only flattening of the lower hull is required. It is not necessary to make an indentation in the shape of the lower hull.
There are preferably multiple pump assemblies for generating the water jets and these are grouped into pairs. This produces an especially favorable flow design of the small water jet housings which can be arranged entirely below the lower hull or are partly incorporated into the lower hull. This depends on the relevant size of the ship and the projected speed, on which the size of the waterjets depends.
The waterjets are advantageously inclined both horizontally and also under some circumstances vertically in relation to the longitudinal axis of the ship or the horizontal plane. The inclination is advantageously around 4 to 7 degrees, thus being very small. This produces especially favorable flow conditions under the hull which allow the waterjets and, in accordance with the invention, also electrical rudder propellers on the stern to be operated with a good level of efficiency. The ship can thus be driven with just the rudder propellers and also with just the waterjets and preferably with a combination of these two drive components.
This especially if the waterjets are pointed slightly outwards. The arrangement of the pump assemblies advantageously partly follows the slope of the hull of the ship. This makes for a particularly good distribution of the exhaust gases.
For advantageous introduction of the exhaust gases into the water there is provision in this case for each pump assembly on a water exit side to feature a coaxial exhaust nozzle segment (KADS) for mixing the ship's exhaust into the water jet. Thus it is possible to introduce the ship's exhaust into the flow underneath the ship without exhaust compressors having to be used. At the same time a good distribution of the exhaust in the water is ensured.
The drive motor of the pump assembly advantageously obtains its electrical energy from a gas turbine generator set which is especially accommodated in an energy generation module. This energy generation module can advantageously be well protected from shocks so that, together with an individual shock-protected positioning of the generators in the energy generation module, a high level of shock proofing is produced for the entire drive for warships. The waterjet drive can also be embodied to be very shockproof, since all bearings can be embodied with shock protection and the individual parts are made of high-impact materials.
In this case there is advantageous provision for the gas turbine generator set to be arranged above the pump assembly. This produces, in the aft part of the middle of the ship, low down and thereby well protected, an energy generation system for powering the ship which can be embodied to be highly stable. Of further advantage here is that it is possible for the gas turbine exhaust line to be of a short design to let it flow into the coaxial exhaust gas nozzle segment (KADS) on the waterjet exit side of the pump assembly. The exhaust gas pressure losses are thus minimized. The exhaust line itself can be fed into a vacuum area of the coaxial exhaust gas nozzle segment (KADS), so that there is no significant loss of power of the gas turbine.
In a further embodiment of the invention there is provision for the generator to feature HTSL windings, especially an armature with HTSL windings. This means that the generator to can provide a small design and shock protection levels not previously achieved.
Behind the waterjets jet deflection elements are provided for the water jets, especially jet deflection elements retractable into the double hull, such as swiveling plates. This allows the water jets to be steered which is adapted in a particular way to the spatial arrangement of the waterjets in the body of the ship. This simultaneously produces a favorable flow design for the case where the waterjets are not activated.
The waterjets are advantageously embodied for individual control—this is a simple option provided by using electrical drive motors—and the power regulation of the waterjets is coordinated with the regulation of the power of an additional propeller drive. Thus, at any time, even if the propeller drive fails, both the controllability of the ship—through individual regulation which can be undertaken for each side—and also the overall speed of the ship can be controlled. Overall this produces a survivability capability and a maneuverability capability for the ship not previously known in military shipbuilding and also in civil shipbuilding.
The ship embodied in accordance with the invention advantageously features a propeller drive as well as the waterjets, especially an electrical rudder propeller drive, with the electrical rudder propeller drive preferably obtaining its electrical energy from fuel cells. This produces both for civil ships and for military ships the advantage of full freedom from emissions with fuel cell drive (low speeds) or the unnoticeable emissions for motor (gas turbine) waterjet drive (high speeds). The exhaust wakes and noises which were previously easy to detect (warships) or were annoying (civil ships) completely disappear.
The invention is explained in greater detail on the basis of drawings which show further details also important to the invention.
In
In the hull an auxiliary machine room 10 adjoins the water pump assembly 4. The auxiliary machine room 10, the area of the water pump assembly 4 ship's hull area in which the electric motor 3 is located, together form a hull section which is advantageously installed when the ship is being built.
Further details of an option for accommodating the waterjets in pairs of nacelle are shown in the grid topology in
In
Number | Date | Country | Kind |
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102 24 013.2 | May 2002 | DE | national |
This application is the US National Stage of International Application No. PCT/DE03/01120, filed Apr. 4, 2003 and claims the benefit thereof. The International Application claims the benefits of German application No. 10224013.2 filed May 29, 2002, both of the applications are incorporated by reference herein in their entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE03/01120 | 4/4/2003 | WO | 7/21/2005 |