RU2553516C2 - Destruction of ice cover - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to ice destruction for making passages in ice fields. Proposed process is based on two effects to be brought on ice fields: irradiation with high-power laser radiation and straining of ice by ice breaker hull. Laser units are installed at ice breaker with their focusing devices are directed downward, onto ice cover. To make the cutouts in ice field it is irradiated starting from the field edge and proceeded in lines parallel with ice breaker heading. The destruction of ice cover is performed in said lines of cutouts at strain developed by ice breaker hull in motion.

EFFECT: accelerated process, lower strain at ice breaker hull.

2 cl, 8 dwg

Description

 1. The technical field

The invention relates to methods for destroying ice cover to open a passage through an ice field, to ship equipment and to an icebreaker for implementing the method.

2. The level of technology

There is a method of destroying the ice cover using the devices of patent No. RU 2245275 B63B 35/08, which uses a laser system located on the bottom of the vessel with an air cushion for applying notches transverse to the direction of the vessel’s movement on the ice to create a light-hydraulic impact on the ice and to destroy it by resonance method. EFFECT: increasing the destruction efficiency of ice.

The disadvantage is the applicability of the method only for a hovercraft and the need to create a bending-gravitational wave.

There is also a method of ice destruction by the resonance method with the transfer of laser radiation energy into the ice layer (VV Bogorodsky, VP Gavrilo, O.A. Nedoshivin. Ice destruction. Methods, technical means. L .: Gidrometeoizdat, 1983).

The disadvantage is the restriction of the application of the method only in a thin layer of ice in the presence of a resonant wave.

It is known to use laser radiation to crack ice on aircraft surfaces - US patent No. 4900891, NKI 219 / 121.6, 1990 and US patent No. 5823474, NKI 244 / 134E, 1998. In known patents - US No. 6206325, NKI 244 / 134E , 2001 and Canada No. 2222881, MKI H02G 7/16, 1998 for this purpose use laser radiation with a wavelength in the range of 10-11 μm, corresponding to the absorption region of radiation by ice, and ice chipping occurs.

The disadvantage is the use on aircraft surfaces and local action on thin layers, which does not allow the destruction of ice on large massifs.

A known method of ice cover destruction according to patent No. KR 20090094924 (A) "ICE BREAKER WITH A HIGH POWER LASER" dated 09.09.2009, B63B 35/08, in which an ice-breaking high power laser located on the nose of the icebreaker is used to break the ice, making cracks in ice when the laser beam irradiates ice, thereby reducing the impact on the bow and increasing the speed of the icebreaker.

A disadvantage of the known technical solution is that with its help it is impossible to provide an icebreaker with wide channels for piloting large-sized vessels and destroy thick massive ice fields.

The well-known "Method of destruction of the ice cover" according to patent No. 2463200 RU dated 04.15.2011, which uses irradiation of the ice cover with powerful laser radiation along the voltage concentration lines created by an icebreaker running over a whole ice field. This method involves operations such as loading the ice cover with a rolling icebreaker body, determining stress concentration lines in the ice cover, focusing the laser radiation on the stress concentration lines, evaporating the ice with focused laser radiation on these lines, evaporating the ice to a depth, and breaking the ice cover.

"Method of ice cover destruction" according to patent No. 2463200 RU of 04.15.2011 was adopted as a prototype as a method closest in its technical essence to the essence of the invention.

The disadvantage of this method of destruction of the ice cover is:

- the need to create special equipment for the implementation of operations to continuously determine the line of stress concentration in the ice sheet, to continuously direct the laser beam to these lines and to scan focused laser radiation along these lines,

- a large length of stress concentration lines that exceeds the icebreaker path length, as a result of which the scanning of these lines by a laser beam should be carried out at a speed significantly exceeding the speed of the icebreaker, which at a fixed laser power leads to a decrease in the linear density of the laser radiation energy distribution along the scan line.

3. Disclosure of invention

The aim of the invention is to reduce the scope of operations of the action of high-power laser radiation on the ice sheet to reduce the ice load on the icebreaker body when it moves in a continuous ice field and the formation of a channel for piloting, as well as increasing the linear density of the laser energy distribution along the ice line irradiation line, by reducing the length of these lines and the speed of movement along them to the length of the path traveled by the icebreaker, and its speed, respectively.

This goal is achieved by changing the sequence of operations affecting the ice cover of the mechanical load of the icebreaker running onto the ice and the energy of powerful laser radiation.

The essence of the invention lies in the fact that, in contrast to the prototype in this method, the ice cover is first exposed to laser radiation, and then it is loaded with the mechanical load of a colliding icebreaker.

Moreover, three laser systems are placed on the icebreaker (Fig. 1), the focusing devices of which are oriented downward on the ice sheet. Moreover, one device is placed in the diametrical plane in front of the icebreaker’s nose, the second and third are symmetrically to the icebreaker’s diametrical plane at a distance of 1.3 times the ice thickness from the icebreaker’s waterline in its widest part and on the line perpendicular to the diametrical plane between the icebreaker’s nose and its stem.

Moreover, the linear density of energy distribution of laser radiation along the line of irradiation of the ice sheet is regulated by the speed of the vessel.

Moreover, the speed of the vessel is selected depending on the thickness of the ice cover.

Moreover, the movement of the icebreaker begins in clean water, while moving the laser beams along three parallel lines with a selected speed of the vessel and parallel to the direction of movement of the vessel, and not along the lines of stress concentration.

Moreover, they act with laser radiation on the edge of the ice sheet and, as the vessel moves, the ice evaporates along lines parallel to the direction of movement of the icebreaker to the depth of splitting.

Moreover, the ice cover is loaded with an icebreaker running over its edge and the ice field is split along the notch lines, forming a channel the width of which exceeds the icebreaker’s maximum width by 2.6 thicknesses of ice.

The technical result consists in reducing the number of operations and equipment needed to implement the method, in reducing the length of the irradiation lines and the speed of the laser beam along these lines to the speed of the icebreaker, thereby increasing the linear density of the laser energy distribution along the ice line irradiation line , in reducing the ice load on the ship's hull, in the formation of a channel for guiding vessels of the correct form, the width of which exceeds the maximum width of the icebreaker by 2.6 tons ins ice.

4. Drawings

The proposed technical solution is illustrated by diagrams and photographs of experiments on the development of ice destruction technologies shown in FIG. 1-8.

In FIG. Figure 1 shows the "Layout of the laser installations on the ship and the interaction of the Laser Installations - Icebreaker" system with the ice field. " This circuit in FIG. 1 discloses the basic principles for placing the focusing devices of laser systems on a ship and the sequence of operations with the ice field of the Laser Systems - Icebreaker system.

In FIG. 1 marked the following items:

- positions 1, 2, 3 - focusing devices of laser systems,

- positions 4, 5, 6 - irradiation lines (cut lines) of the ice sheet,

- position 7 - laser beam installation No. 1,

- position 8 - laser beams of installations No. 2, 3,

- position 9 - the central cut of the ice field,

- position 10 - side cuts of the ice field,

- position 11 - the edge of the ice field,

- position 12 - icebreaker,

- position 13 - the diametrical plane of the vessel,

- position 14 - waterline of the vessel,

- position 15 - the direction of movement of the icebreaker at a speed V,

- position 16 - ice field.

The photographs shown in FIG. 2 and 4, demonstrate separate experiments on cutting large ice masses with a laser beam, during which the fundamental possibility of cutting thick ice masses with powerful laser radiation was confirmed for the first time.

In FIG. 2 presents photographs illustrating “The effect of laser radiation with a power of 30 kW on a large-sized ice massif of sizes 1000 × 500.500 mm ³ ”.

In FIG. Figure 3 presents the "Design of an experiment for cutting an ice array of 1000 × 500.500 mm ³ by laser radiation with a power of 30 kW, λl = 1.07 μm, F = 550 mm, ω ₀ = 25 μm", which shows the kinematics of the interaction of a laser beam with an ice array during full-scale experiments on cutting ice with high-power laser radiation.

In FIG. 4 are photographs illustrating “Cutting an ice cube 500 × 500 × 500 mm ³ : a) a laser beam in a vertical plane to the ice surface, b) the final phase of the cutting process”.

The photographs in FIG. 5-8 show the most typical episodes of model experiments on assessing the effect of various methods of notching an ice field on the magnitude of the ice load on the icebreaker hull.

In FIG. Figure 5 presents “Modeling of notches of the ice cover over its entire thickness (1.5 m) along three lines parallel to the course of the vessel”.

In FIG. Figure 6 shows the “channel shape in the absence of incisions”.

In FIG. 7 presents the "channel Shape in the presence of lateral incisions."

In FIG. 8 also presents "Channel shape in the presence of lateral incisions."

5. The implementation of the invention

The basis of the use of laser radiation for ice destruction is the mechanism of thermal absorption of laser radiation in the range of the absorption spectrum of ice (Bogorodsky V.V., Gavrilo V.P., Nedoshivin O.A. Ice destruction. Methods, technical tools. L .: Gidrometeoizdat, 1983 ) When focusing radiation with a density of 15-20 kW / cm ² , ice melts and evaporates the water formed, and an instant ice-water-vapor phase transition occurs. The evaporation rate reaches 1 mm in 0.01 s. (Quantum Electronics, 1994, T. 21, No. 2, S. 137-141). The effect of CO ₂ laser radiation on large drops of phosphoric acid, water, and spherical ice crystals. VK. Rudash). Thus, a hole up to 10 cm deep is formed within a second. With further irradiation, a steam jet expands the inlet in the ice.

TsNII Kurs OJSC together with Astrophysics NTsLSK OJSC conducted research (TsNII Kurs OJSC, scientific and technical report “Development of technologies to reduce ice loads on engineering structures operating on the continental shelf using high-power lasers”, industry number registration No. 100862 dated 05/27/2013) the effects of continuous laser radiation (λ = 1.07 μm) of a 30 kW optical fiber laser with an optical system providing a focal length of 550 mm and a beam diameter in focus of 250 μm on large (1000 × 500 × 500 mm ³ ) m ice assists (Fig. 2).

The experiments showed that the effect of powerful laser radiation on the ice cover does not lead to the formation of cracks and cracking of ice.

When a stationary laser beam acts on the ice surface, a cavity forms, the input diameter of which is twice its depth. In this case, the time of through "burning" to a depth of 500 mm is calculated in tens of seconds.

When the laser beam is oriented downward to the ice surface and the beam moves, starting from the lateral surface of the ice mass, ice evaporates along the beam, a slit is formed (Fig. 3) over the entire thickness of the ice mass (Fig. 4a) and its destruction under the influence of its own weight ( Fig. 4b).

In the course of these experiments, the fundamental ability of high-power lasers to cut ice with a thickness of at least 1 m was first confirmed.

The thickness of the ice being cut is determined by the linear density of the radiation energy distribution along the line of the laser beam along the irradiated ice surface and is nonlinearly related to the characteristics of the laser focusing system. The value of the linear energy distribution density linearly depends on the laser power and is inversely proportional to the speed of movement of the laser beam along the irradiated surface.

The results of the studies determine the necessary order of exposure of the ice to various loads: first, the laser edge is focused on the lateral surface of the ice field edge, and then the incised ice field is loaded with the mechanical load of the incoming icebreaker.

It is known that an increase in pressure on an ice plate leads to an increase in the amplitude of its deflection, and a change in temperature and thickness of ice leads to extreme deflections and to breaking of ice (Kheisin D.E., Dynamics of the ice cover. P .: Gidrometeoizdat, 1967, 216 p. )

Research carried out by TsNII Kurs OJSC together with the Federal State Unitary Enterprise Krylovskiy State Scientific Center (TsNII Kurs OJSC, scientific and technical report “Development of technologies to reduce ice loads on engineering structures operating on the continental shelf using high-power lasers”, industry registration number No. 100862 of 05/27/2013), showed that the preliminary incision of the ice field to its entire thickness (1.5 m in terms of nature) is ahead of the icebreaker in three lines (Fig. 5), two of which are located in the bow of the icebreaker from the left and right sides at a distance of 1-1.3 ice sheet thickness in the widest part of the icebreaker’s hull at the waterline level, and one in front of the icebreaker heading reduces the ice load on its hull from 33% to 40% in the entire range of investigated speeds ( 1-3 knots).

At the same time, the formed channel has, in contrast to the usual one (Fig. 6.), the correct shape (Figs. 7 and 8), and its width exceeds the maximum width of the icebreaker.

The practical implementation of the method is as follows.

Depending on the class of the vessel, the necessary laser power and the parameters of the focusing system are selected.

Depending on the shape of the bow of the vessel, the position of the focusing devices 1-3 of the laser systems (Fig. 1) relative to the bow of the icebreaker is determined and placed on the icebreaker 12. Device 1 is placed in front of the bow of the ship, device 2 and 3 are symmetrically diametrically on the port side and starboard side plane 13 of the icebreaker 12.

Depending on the thickness of the ice sheet 16, a distance is established between the lateral focusing devices 2, 3 of the laser systems and the diametrical plane 13, so that these devices of the laser systems are located at a distance of 1.3 thickness of the ice sheet from the water line 14 in the widest part of the icebreaker body 12 .

Focusing devices of 1-3 laser systems are oriented, directing the central 7 and lateral 8 laser beams down.

Depending on the thickness of the ice sheet 16 and taking into account the characteristics of the laser systems, the speed 15 of the vessel 12 is assigned, thus determining the linear distribution density of the laser radiation energy along the scan line of the laser beam.

Turn on laser systems.

The icebreaker 12 begins to move toward the ice field 12, while moving the focusing devices 1-3 of the laser systems and the laser beams 7, 8 in the direction and with the speed of movement 15 of the icebreaker 12. In this case, it is not necessary to carry out the operations of determining the concentration lines of voltage, pointing to these lines laser beam and laser scanning of these lines and the creation of special equipment for their implementation. In this case, the length of lines 4, 5, 6 irradiated by the laser is minimal and coincides with the path length of the icebreaker, and the scanning speed (the speed of the laser beam) coincides with the speed of the vessel.

Laser radiation is applied on the ice field 16, starting from its edge 11, along lines 4-6 parallel to the direction of movement 15 of the vessel 12, first by radiation from the central device 1, and as icebreaker 12 approaches the edge of the ice field 11 by radiation 8 of two lateral focusing devices 2, 3.

The ice is evaporated and cuts 9 (section A-A) and 10 (section B-B) are made in the ice field 16 along lines 4, 5 and 6 to the depth of splitting in front of the icebreaker.

The icebreaker 12, approaching the edge 11 of the notched field 16, runs into it and creates a mechanical load, under the influence of which, when the ultimate strength is reached, the ice cover 16 is destroyed in the thinned layer along the lines 4-6 of incisions 9 and 10, a channel is formed that is wider than the width of the icebreaker .

The technical result achieved by the implementation of the present invention consists in reducing the number of operations and equipment necessary for implementing the method, in reducing the length of the irradiation lines and the laser speed along these lines to the speed of the icebreaker, and thereby increasing the linear distribution density of laser radiation energy along the irradiation line ice cover, in reducing the ice load on the ship's hull, in the formation of a channel for guiding vessels of the correct shape, the width of which exceeds max mal width of the icebreaker.

The proposed method of ice cover destruction is of great economic and defense importance. This invention is aimed at solving one of the urgent problems of the development of hydrocarbon deposits on the Arctic shelf - reducing ice loads on ships and engineering structures operating in the Arctic.

The proposed technical solution can also be applied to reduce ice loads on the supports of mining complexes of various types operating in the Arctic shelf and freezing seas.

Literature

1. Bogorodsky V.V., Gavrilo V.P., Nedoshivin O.A. The destruction of ice. Methods, technical means. L .: Gidrometeoizdat. - 1983. - 232 p.

2. Quantum Electronics, 1994, Volume 21, No. 2, p. 137-141. The effect of CO ₂ laser radiation on large drops of phosphoric acid, water, and spherical ice crystals. VK. Rudash.

3. Heysin D.E. Dynamics of ice cover. P .: Gidrometeoizdat, 1967, 216 p.

4. JSC CRI Kurs, Scientific and Technical Report "Development of Technologies for Reducing Ice Load on Engineering Structures Operating on the Continental Shelf Based on the Use of Powerful Lasers", Industry Registration Number No. 100862 of 05/27/2013

Claims (2)

1. The method of destruction of the ice cover, based on the impact on the ice sheet of powerful laser radiation and loading the icebreaker with ice cover, characterized in that three laser systems are placed on the icebreaker, the focusing device of one installation is placed in the diametrical plane in front of the bow of the vessel, the second and third - port and starboard, symmetrically to the diametrical plane of the icebreaker at a distance of 1.3 ice thickness from the waterline of the vessel in its widest part, depending on the thickness of the ice cover and taking into account x The characteristics of the laser systems select the speed of the vessel, turn on the laser systems and start the movement of the vessel in clean water, moving the laser beams along three parallel lines with the speed of movement and parallel to the direction of movement of the vessel, affect the edge of the ice with laser radiation and evaporate the ice as the vessel moves forward along these lines to the depth of splitting, the notched ice cover is loaded by a ship approaching its edge and the ice field is destroyed along the notch lines, forming a channel whose width th vessel greater width at 2.6 of ice thickness. 2. The method of ice cover destruction according to claim 1, characterized in that the linear density of the laser energy distribution along the ice line irradiation is controlled by the speed of the vessel.

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