RU157049U1 - WATER BODY WITH AIR BED AT THE BOTTOM - Google Patents

Abstract

A displacement vessel with an air cavity on the bottom, having a recess in the bottom to form a single air cavity with a wave profile, starting from a redan in the bow and bounded by skegs along the sides and a stern vault in the form of an inclined plate, and the cavity of the recess is in communication with a source of high pressure air, and inside the recess there are longitudinal keels that limit the lateral movement of air, and transversely located visors in the form of inclined plates following each other downstream, characterized in that behind each visor there is an inclined plate with an opening angle against the flow, the length of which along the flow is a value that ensures the conjugation of the visor with the bottom surface inside the recess to reduce the flow separation intensity behind the visor, while the trailing edge of the said inclined plate adjoins the bottom, and the bow is located at a height of 0.70-0.95 of the height of the trailing edge of the visor, behind which an inclined plate is installed.

Description

The utility model relates to shipbuilding and relates to the design of displacement vessels with an air cavity on the bottom, providing a decrease in hydrodynamic resistance and improving the operational characteristics of the vessel.

A vessel with an air gap under the bottom is known, comprising a recess made in the bottom, which is limited by the bow red, side keels and aft inclined plane and is divided into separate sections by longitudinal keels and transverse visors located along the entire width of the recess and located along the stream along the recess, and an air source high pressure, communicated with the cavity of the bottom of the vessel to create and maintain air spaces formed behind the transverse visors - artificial cavities (Copyright certificate in the USSR №1145587 from 30.04.1994 till application №3664908 / 11 of 29.09.1983) - The prototype. The main element of the device is a bottom recess, inside of which an air gap is created - a single cavity with a wave profile. The longitudinal keels installed inside the recess divide this cavity into sections, restricting the lateral movement of air and thereby increasing the lateral stability of the vessel. The transverse visors provide the possibility of creating an air cavity with a wave profile in the recess during the movement of the vessel, preventing its destruction.

However, when a ship moves in conditions of severe excitement, a single air cavity is destroyed, and in the case of a ship with a significant initial trim, this cavity cannot form at all. As a result, at the bottom of the vessel inside the recess the flow becomes detached, accompanied by a separation of the flow behind the visors, which leads to a sharp increase in the resistance to movement of the vessel. As a result, the efficiency of using the device to improve the economic characteristics of the vessel is sharply reduced. In such cases, the hydrodynamic resistance of the vessel with the device for creating an air cavity becomes even higher than that of a traditional vessel. A particularly sharp increase in the resistance of a vessel with a cavity occurs when the source of air supply under the bottom fails.

In addition, with the above unfavorable modes of movement of the vessel, the transverse visors do not provide for the creation of a single air cavity with a wave profile in the recess and cannot prevent its destruction.

When a vessel moves in ice, there is a danger that fragments of finely chipped or grated ice, as well as ice porridge, can be carried by a stream of water into the spaces between the transverse visors and the bottom of the recess, which will lead to an additional increase in the overall resistance to movement of the vessel. Stuck debris can also clog the air inlets.

The objective of the proposed utility model is to improve the operational characteristics and increase the economic efficiency of a displacement vessel with an air cavity on the bottom due to a decrease in its hydrodynamic resistance when moving with a significant initial trim, as well as in the case of the destruction of a single air cavity under conditions of intense waves or when leaving building an air supply source under the bottom.

This is achieved by the fact that in a displacement vessel with an air cavity on the bottom, having a recess in the bottom for the formation of a single air cavity with a wave profile, starting from the redan in the bow and limited to the skegs along the sides and the aft arch in the form of an inclined plate, and the cavity of the recess is communicated with an air source of high pressure, and longitudinal grooves are placed inside the recess, limiting the transverse movement of air, and transversely arranged visors in the form of inclined plates following one after another down the sweat Ku, in the utility model for each visor mounted inclined plate with an opening angle against the flow, the length along which the flow amounts to providing interfacing with the bottom surface of the cap within the recess for reducing the separated flow hood. In this case, the trailing edge of the said inclined plate is adjacent to the bottom inside the recess, and the bow is located at a height of 0.70-0.95 of the height of the trailing edge of the visor, behind which the inclined plate is installed.

The installation of an inclined plate behind each visor allows, due to a smoother pairing of the visor with the bottom surface inside the recess, to reduce the intensity of flow separation in the event of destruction or absence of an air cavity, and thereby reduce the hydrodynamic resistance of the vessel.

The essence of the proposed utility model is illustrated by drawings, where:

- in FIG. 1 schematically shows a displacement vessel with an air cavity on the bottom (side view);

- in FIG. 2 is a section AA in FIG. one;

- in FIG. 3 - transverse visor with an inclined plate.

The numbers and letter abbreviations in the figures indicate:

1 - the bottom of the vessel;

2 - a notch in the bottom of the vessel for the formation of a single air cavity with a wave profile;

3 - a single air cavity with a wave profile;

4 - redan;

5 - pipeline;

6 - source of forced air supply;

7 - longitudinal keel;

8 - transverse visor;

9 - inclined plate;

10 - direction of air movement;

OP - the main plane of the vessel.

The proposed vessel with an air gap on the bottom 1 (Fig. 1) contains a recess 2 for the formation of the air gap - a single air cavity 3 with a wave profile. The recess is made at the bottom of the vessel and begins with redan 4. The vessel also contains a forced air supply 6, connected by pipelines 5 with a cavity of recess 2 to create a single air cavity 3. Under the recess 2, longitudinal keels 7 are placed parallel to the diametrical plane, limiting lateral movement air along the bottom of the recess 2 (Fig. 2), as well as transversely arranged visors 8, following each other downstream along the length of the recess 2. Behind each visor 8, an inclined plate 9 is installed with a solution angle of into the stream (Fig. 3). The length of the plate 9 along the flow is a value that allows the visor 8 to pair with the surface of the bottom inside the recess 2 to reduce the intensity of separation of the flow behind the visor 8. The trailing edge of the inclined plate 9 is adjacent to the bottom inside the recess 2, and the bow is located at a height of 0.70-0.95 the height of the trailing edge of the visor 8, behind which this inclined plate is mounted. A small ledge, the height of which is 0.05-0.30 the height of the trailing edge of the visor 8, provides the formation of a separate air cavity. The gap between the trailing edge of the visor 8 and the leading edge of the inclined plate 9 serves to release air in the direction 10 from the pipeline 5 to the air cavity 3.

The operation of the device is as follows.

When the vessel is moving in quiet water or with little disturbance, the air from the forced supply source 6 through a piping system 5 is supplied to the redan 4 and to the transverse visors 8 to create an air gap in the form of an artificial cavity 3. The supplied air is held in the zone of reduced liquid pressure arising behind the redan 4 and the transverse visors 8, as a result of which, after the redan 4 and each transverse visor 8, a system of separate air cavities following each other is formed. Due to the supplied air, the lengths of the individual caverns gradually increase over time, reaching their limiting values, equal to the distances between the lower edges of the transverse peaks at the operational speed of travel 8. When the tail parts of the air caverns reach the lower edges of the transverse peaks 8, they are combined into a single air cavity 3 with wave profile. Ensuring the best integration of individual caverns into a single air cavity 3 is achieved for various modes of operation of the vessel by the corresponding volume of air supply into the cavity of the recess 2 and by choosing the appropriate location and dimensions of the transverse visors 8. At this point, the pressure in the single cavity 3 increases, as a result of which the amplitude of the wave profile the surface of the cavity 3 also decreases — the air-water interface — departs from the transverse visors 8, which no longer come into contact with water.

In the case when the ship is moving in conditions of severe excitement with significant keel or roll, a single air cavity 3 is destroyed. When the vessel is moving with a large initial trim, it may not form at all. As a result, this will lead to an increase in the friction resistance on the surface of the bottom of the recess 2. In addition, behind the redan 4 and behind the transverse visors 8, the flow breaks off, which also leads to a sharp increase in the hydrodynamic resistance. Thus, as a result of the destruction or absence of the air cavity 3, the total resistance to the movement of the vessel increases sharply, which becomes even higher than the total resistance of a similar vessel without a notch on the bottom, which leads to an increase in the power consumed by the vessel and, consequently, to a deterioration in the performance of the vessel with a notch for air cavity. In this case, to reduce the intensity of the flow separation behind the visors 8, inclined plates 9 are installed behind them, which provide a smooth flow due to the visor pairing with the bottom surface inside the recess 2. Moreover, the trailing edge of the inclined plate 9 abuts the bottom inside the recess 2, and the bow is located at a height of 0.70-0.95 of the height of the trailing edge of the visor 8, behind which the inclined plate 9 is installed. As a result, the flow separation behind the transverse visors 8 is reduced and, as a result, the hydrodi the resistance of the vessel, its operational characteristics are improved, and its economic efficiency increases when moving in conditions of strong waves or with a large initial trim.

When the vessel moves in ice, the inclined plate 9 will prevent debris from finely chipped or grated ice, as well as ice porridge, into the space bounded by the transverse visor 8 and the bottom of the recess 2, thereby preventing the increase of the hydrodynamic resistance of the vessel and keeping the openings of the air supply system 5 open.

The proposed vessel with an air cavity on the bottom allows to improve its operational characteristics and increase economic efficiency when moving in ice, as well as in conditions of intense waves or with a significant initial trim due to the reduction of its resistance in the event of the destruction of a single air cavity or in case of failure of the supply source air under the bottom, which compares favorably with the prototype.

Claims (1)

A displacement vessel with an air cavity on the bottom, having a recess in the bottom for the formation of a single air cavity with a wave profile, starting from the redan in the bow and limited by the skegs along the sides and the stern arch in the form of an inclined plate, the cavity of the recess communicating with the air source of high pressure, and inside the recess there are longitudinal keels limiting the transverse movement of air, and transversely arranged visors in the form of inclined plates following each other downstream, characterized in that each visor has an inclined plate with a solution angle against the flow, the length of which along the flow is a value that ensures the visor to interface with the surface of the bottom inside the recess to reduce the intensity of flow separation behind the visor, while the trailing edge of the inclined plate is adjacent to the bottom and the bow is at a height , component 0.70-0.95 of the height of the trailing edge of the visor, behind which an inclined plate is installed.

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