RU2588562C1 - Device for breaking down ice cover - Google Patents

Abstract

FIELD: shipbuilding.

SUBSTANCE: invention relates to underwater vessels which break down ice using a resonance method. Device for ice breaking consists of a submarine vessel, capable of moving under ice cover and excite therein resonance flexural-gravity waves. Vessel has in water-flow channels between its strong and light two impellers, cross-sections of which are located perpendicular to longitudinal axis of vessel, they are located one after another and have in top parts open sections, impellers can rotate in opposite directions. Blade impellers at end of open channel sections are able to deviate, that is,can be held down to inner surface of impellers, for a time equal to time of approach to closed sections of next blades, after which they return into initial position. Blades of front and rear impellers are bent in directions opposite to direction of their rotation, and blades of rear impeller are further inclined to its rotation axis. Impellers are also configured to periodically with frequency of resonance flexural-gravity waves start and stop its rotation during time equal to half-period of said waves.

EFFECT: higher efficiency of ice breaking.

1 cl, 4 dwg

Description

The invention relates to the field of shipbuilding, in particular to submarines destroying ice cover by the resonance method, i.e. by excitation in the ice sheet of resonant flexural-gravitational waves (IGW) (1. Kozin VM Resonance method of destruction of the ice sheet. Inventions and experiments. - Moscow: Publishing House "Academy of Natural Sciences". 2007. - 355 p. ISBN 978- 5-91327-017-7).

A technical solution is known (2. RU2240252 C2, 02.28.2002), in which it is proposed to destroy the ice cover by an underwater vessel by creating from the rotation of the impeller located in the upper part of the vessel's hull an area of increased pressure under the arising top of the IHV.

The disadvantages of this solution are: the presence on the hull of the protruding part in the form of an impeller, which increases the resistance of water and, consequently, reduces its speed; the cumbersome design of the impeller beyond the dimensions of the housing; low working capacity of the solution due to the hydrodynamic imperfection of its implementation (the absence of the targeted, i.e. focused, effect of the generated hydrodynamic forces on the top of the IGW) and, accordingly, the insufficient height of the excited IGV.

The essence of the invention consists in the development of a device installed in the hull of the vessel and increasing the height of the IHV, excited when the vessel moves under ice cover.

The technical result obtained by carrying out the invention is to increase the thickness of destructible ice.

The essential features characterizing the invention.

Restrictive: a device for the destruction of ice cover, consisting of an underwater vessel, capable of driving resonant IHV in it under the ice cover and using a rotating impeller located in the upper part of the ship’s hull, an area of increased pressure under the ice cover at the location of the top of the IHV.

Distinctive: on the vessel, two impellers are installed between the strong and light hulls of the water-flowing channels, the cross sections of which are perpendicular to the longitudinal axis of the vessel, they are located one after the other and have open sections in the upper parts, the impellers can rotate in opposite directions, and impeller blades at the moment of completion of passage of open sections of channels by them - deviate, i.e. press against the inner surface of the impellers for a time equal to the approach time to the closed sections of the next blades, then return to their original position, the blades of the front and rear impellers are bent in the directions opposite to the directions of their rotation, and the blades of the rear impeller are additionally inclined to the axis of its rotation, the impellers also have the ability to periodically start and stop their rotation with a frequency of resonant flexural-gravitational waves over a period equal to the half-period of these waves.

It is well known that during the rotational motion of a medium, centrifugal forces will inevitably act on its mass. This obvious pattern can be used to increase the efficiency of ice cover destruction by the resonance method using the proposed device. To do this, these forces should be directed below the top of the excited IGW, which will increase the hydrodynamic pressure in this area, i.e. increase the height of the IHV.

It is known from the course of hydraulics that if the fluid rotates by an impeller, the blades of which are bent in the directions opposite to the direction of their rotation (for example, as with the impeller of a centrifugal pump), then centrifugal forces will have only a radial direction. If the impeller blades are additionally inclined to the axis of its rotation (for example, like the blades of a ship’s propeller), then the axial components of the flow will be added to the radial, circumferential (due to the twisting of the liquid), i.e. water will flow under the ice. If this axial flow is directed under the basin of the IHV, then the pressure in this region will decrease.

It is also known (3. Loytsyansky LG, Mechanics of liquid and gas. - M.: Drofa. 2003. - 842 p.) That during the interaction of fluid flows with different velocities, a boundary layer arises at the interface, within the thickness of which - due to the viscosity of the fluid, the velocities in the flows change sharply in the directions transverse to them. Thus, with the oncoming movement of two fluid flows with the same speed and viscosity, which will be created by the proposed device, at their interface, they will mutual inhibition with intense vortex formation. Then, in accordance with Bernoulli’s law, the pressure at this boundary will increase, and as a result, a kind of hydrodynamic barrier (hydrodynamic resistance) will arise that prevents the incoming external flow from flowing through it (in our case, when considering for a better understanding of the reversed motion (see [3]) ), i.e. when the vessel is considered motionless, and the water and ice cover seem to be approaching it, the speed of the external flow will be equal to the speed of the vessel, which will increase the pressure in front of it. In addition, in the path of the external flow at the device’s location between the ship’s hull and the lower surface of the ice sheet, a region of swirling liquid will appear, which will increase the degree of turbulence of not only the boundary layer that occurs on the surface of the vessel itself, but will also lead to turbulence of the entire external flow between his hull and ice. The viscosity of the vessel will increase, which, in turn, will increase the pressure in this area (see [3]).

It is also known (4. D.E. Heysin. Dynamics of ice cover. - L .: Gidrometeoizdat, 1967. - 218 p.) That the application of a periodic dynamic load to the ice cover with a frequency equal to the frequency of resonant IGW significantly increases the deformation of the ice cover in comparison with the same intensity load, but applied stationary. This is explained by the fact that under such influences resonant IGWs arise.

Thus, if under the apex of the IGW arising from the translational movement of the submarine (the main resonant IGV), a period of increased pressure is created periodically with the frequency of the resonant IGV, this will lead to the excitation of additional resonant IGV in the ice sheet.

Obviously, in order to achieve the maximum periodic increase in the amplitude of the total IHV, it is necessary that the exposure time of the forces exciting additional IHV is equal to half the period Τ of the main resonant IHV, the value of which. can be determined by the dependence [4]

, $$T=2\pi \sqrt[6]{D/{\rho }_l\mathrm{<figure-callout\; id="6"\; label="h\; g\; four"\; filenames="00000003.png,00000004.png"\; state="\{\{state\}\}">h\; </figure-callout>}{g}^{\mathrm{four}}{\mathrm{}}^{}}$$

,

where: D is the cylindrical stiffness of the ice plate; ρ _l is the density of ice; h is the thickness of the ice cover; g is the acceleration of gravity.

In this case, when the ice moves up and down from the additional IGWs that have arisen, the forces that excite them will coincide with the directions of ice movement. Thus, the most effective kind of additional build-up of ice cover to the main IGW will arise.

The invention is as follows.

In the ship’s hull, at the most probable location of the IGV peak, two water-flowing channels with open sections in the upper parts are made. Impellers are installed in the channels, which are configured to rotate in opposite directions and equipped with vanes bent in directions opposite to the directions of rotation of the impellers. This shape of the blades, as well as the shape of the blades of the impellers of centrifugal pumps, increases their efficiency. In our case, it creates, at given energy inputs, the maximum centrifugal forces that arise when the impeller is ejected through open sections of water-flowing channels of water masses. The dimensions of the channels and impellers do not exceed the dimensions of the vessel at their location, which, unlike the analogue, does not lead to the appearance of additional resistance in the form of the resistance of the protruding parts. The vertical arrangement of the walls of the channels will provide a strict direction (focused effect) of the ejected water flows, under the top of the IHV. In addition to increasing the pressure under the summit of the IGW due to the centrifugal forces created by the device and the swirling liquid region, its operation due to the proximity of the water flow channels (one after another) will result in hydrodynamic interaction of the water flows excited by the impellers. Rotation of the impellers in opposite directions not only eliminates the occurrence of heeling moment, worsening the transverse stability of the vessel, but also leads to the appearance of a hydrodynamic barrier perpendicular to the direction of movement of the vessel, increasing the efficiency of the proposed device. To ensure that the working volume of the impellers can be filled with outboard water after the masses of water are ejected through open sections of the water-flowing channels due to the centrifugal forces of the blade, they are rejected at the moment they pass the open sections of the channels, i.e. pressed against the inner surface of the impellers. For deflected blades due to water displacement, areas of reduced pressure will appear [3], where outboard water will rush, thereby ensuring the occupancy of these parts of the working volumes of the impellers. After the expiration of the time equal to the approach time to the closed sections of the channels of the next blades, they return to their original position. As a result, the entire working volume of the impellers, except for the open sections of the channels, will be filled with sea water.

The rotation of the rear impeller will lead to the appearance, in addition to the radial and circumferential additional axial flow, directed to the aft end of the vessel, i.e. under the first foot of the IHV following the top, which will lead to a decrease in pressure below it. For this, the angle of inclination of the impeller blades to the axis of its rotation (sharp or blunt) is chosen depending on the direction of ω.

In order to reduce the hydrodynamic drag along the axial flow path, the trailing edge of the water flow channel within its open area is rounded. As a result, the pressure under the basin of the IHV will decrease, i.e. the amplitude of the deflection of the ice cover will increase. In addition, the resulting axial flow will create an additional stop for the vessel to the propeller. As a result of the occurrence of regions of increased and reduced pressures that are periodic with resonance IHV under the apex and sole, respectively, a system of additional resonant IHVs will appear, which, overlapping the main resonant IHVs, will periodically increase the height of the total IHVs due to interference. Thus, the operation of the device will provide a higher than the analogue increase in the height of the IHV, which will achieve the claimed technical result.

The invention is illustrated by drawings, where: in FIG. 1 shows a side view of the device; in FIG. 2 and 3 are sections along Α-A and B-B in FIG. one; in FIG. 4 - tear I in FIG. one.

In the hull of the vessel 1 there are two water-flowing channels 2 with open sections 3 (Fig. 1-3). The impellers 4 are installed in the channels 2, the front of which is equipped with blades 5, and the rear - 6. The impellers are able to rotate in opposite directions (Fig. 2, 3). If, when vessel 1 moves with a resonant speed u _p under the ice cover 7, the height of the excited IGV 8 is insufficient to destroy the ice cover, then the impellers begin to rotate at angular speeds ± ω, respectively, which will lead to the release of 2 masses of water through open sections 3 of the flow channels 3 9 and 10 (FIG. 2, 3), which will have both radial components 11 (due to centrifugal forces) and circumferential velocity components 12 (due to the twisting of water in the corresponding channels 2 (FIG. 2, 3)). The flow of water (components 11) due to centrifugal forces will lead to an increase in pressure under the summit of the IGW 8. The circumferential components 12 will cause the formation of a hydrodynamic barrier 13 and the turbulence of the external flow 14. The vanes 15 at the moment they pass through the open sections of 3 channels 2 are rejected, i.e. e. pressed against the inner surface of the impellers 4, which will lead to the appearance of areas of reduced pressure 16 and, consequently, flows of overboard water 17 (Fig. 2, 3). The axial flow 18, arising due to the inclination of the blades 6 of the rear impeller to the axis of its rotation, will lead to the appearance of a reduced pressure region 19 (Figs. 1, 4). The periodic appearance under the sole and apex of the IGV 8, respectively, of the areas of high and low pressure will lead to the excitation of additional resonant IGV 20. As a result of the operation of the device, the height will increase from IGV 8 to IGV 21.

Claims (1)

Device for breaking ice cover, consisting of an underwater vessel capable of generating resonant bending-gravitational waves in it when moving under the ice cover and creating, using a rotating impeller located in the upper part of the ship's hull, an area of increased pressure under the ice cover at the location of the peak -gravity wave, characterized in that on the vessel two impellers are installed between the strong and light hulls of the water-flowing channels, the cross sections of which are perpendicular to the longitudinal axis of the vessel, they are located one after the other and have open sections in the upper parts, the impellers are able to rotate in opposite directions, and the impeller blades are deflected at the moment they pass through the open sections of the channels, i.e. press against the inner surface of the impellers for a time equal to the approach time to the closed sections of the next blades, then return to their original position, the blades of the front and rear impellers are bent in the directions opposite to the directions of their rotation, and the blades of the rear impeller are additionally inclined to the axis of its rotation, the impellers also have the ability to periodically start and stop their rotation with a frequency of resonant flexural-gravitational waves over a period equal to the half-period of these waves.

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