KR20220013104A - Air lubrication device of ships - Google Patents

Abstract

The present invention relates to an air lubrication system for a ship with high efficiency compared to the case driven by a conventional power generation engine. According to an embodiment of the present invention, an air lubrication system may comprise: a governor connected to a main propulsion shaft connected to a main engine of a ship, and outputting by changing the rotation speed of the main propulsion shaft; one or more air compressors connected to the governor and rotating according to the number of rotation output from the governor to compress and discharge air; an air injector disposed at the bow of the ship and discharging the air discharged from the air compressor to the outside of the ship; and an air supply pipe for supplying the air discharged from the one or more air compressors to the air injector.

Description

Air lubrication system for ships

The present invention relates to an air lubrication system for a ship, and more particularly, to an air lubrication system having high efficiency compared to the case driven by a conventional engine for power generation.

When a ship sails above sea level, wave resistance, viscous resistance and air resistance occur in the hull. To reduce these resistances, most of the ships are designed to be streamlined.

Wave wave resistance is generated perpendicular to all parts of the hull as regular waves are generated in the bow part when the ship advances, and energy loss of the ship occurs. Viscous resistance is caused by the viscosity of water and can be largely divided into surface friction resistance and shape resistance. Among them, the surface friction resistance is caused by the force that prevents the progress of the hull due to the viscosity of the water, which is the adhesion force of the seawater in contact with the submerged hull.

In order to reduce such surface friction resistance, methods such as underwater wing design that minimizes the contact area between seawater and hull, air lubrication boat design and supercavity underwater vehicle design to improve the condition of the bottom and submerged surface of the submerged hull this is used

In addition, as one of the methods for reducing the surface friction resistance, an air lubrication system is used in a way to reduce energy loss due to the viscosity of water by cutting off the surface of the hull with an air layer.

The general air lubrication system has the advantage of being the most environmentally friendly and easy to apply to an actual ship by reducing frictional resistance by reducing the submerged surface area of a ship by arranging an air cavity on the surface of the hull.

1 is a view showing a conventional air lubrication system.

As shown in Figure 1, the air injector 11 is arranged in the bow portion of the hull 20, adjacent to the air injector 11, two air compressors 13, 14 and the air compressors 13, 14 Motors 15 and 16 for driving are arranged. And a switchboard 17 for driving the motors 15 and 16 may be disposed. At this time, an air supply pipe (AP) connecting between the air compressors (13, 14) and the air injectors (11) is provided.

And a power generation engine (GE) is disposed at the stern, and the switchboard 17 receives the power produced by the power generation engine (GE) and distributes it to the motors 15 and 16 . In addition, the main engine (ME) may be arranged in the stern.

In this case, the power generation engine GE may be provided in plurality, and the switchboard SB may manage the power generated by the power generation engine GE. That is, the switchboard SB and the switchboard 17 may be electrically connected.

Although not shown, a device for controlling the air injection discharged through the air injector 11 may be provided as needed.

Republic of Korea Patent Publication No. 10-2020-0063398 (2020.06.05.)

The problem to be solved by the present invention is to provide an air lubrication system for a ship having higher efficiency compared to the case where it is driven by a conventional engine for power generation.

An air lubrication system according to an embodiment of the present invention includes: a governor connected to a main propulsion shaft connected to a main engine of a ship, and outputting by changing the rotation speed of the main propulsion shaft; one or more air compressors connected to the governor and rotating according to the number of revolutions output from the governor to compress and discharge air; an air injector disposed at the bow of the ship and discharging the air discharged from the air compressor to the outside of the ship; And it may include an air supply pipe for supplying the air discharged from the at least one air compressor to the air injector.

The governor may include one or more gears for converting the rotation speed of the main propulsion shaft.

The governor may further include a clutch for blocking output of the converted rotation speed.

It is installed in the one or more air compressors, may further include one or more control valves for controlling the pressure of the air discharged from the one or more air compressors.

It is installed in the air supply pipe, it may further include a temperature controller for controlling the temperature of the air discharged from the one or more air compressors.

Another embodiment of the present invention, in the above-described air lubrication system, further comprising a control unit in which the air injection amount information according to the ship speed of the ship is stored, and the control unit determines a predetermined air injection amount according to the ship speed; determining the pressure of the air compressor according to the air injection amount; determining the rotation speed of at least one of the governor installed on the main propulsion shaft and the governor of the air compressor; and adjusting the pressure of the air injected to the outside of the ship.

According to the present invention, there is an effect of reducing fuel consumption as it is connected to the main propulsion shaft through the governor without using the electric power produced by the power generation engine compared to the prior art.

In addition, there is an effect that the air compressor can be driven without using a separate switchboard.

1 is a view showing a conventional air lubrication system.
2 is a view showing an air lubrication system of a ship according to an embodiment of the present invention.
3 is a view for explaining a state in which the air compressor and the air injector of the air lubrication system of a ship according to an embodiment of the present invention are connected through an air supply pipe.
4 is a view for explaining a governor of an air lubrication system of a ship according to an embodiment of the present invention.

Hereinafter, specific embodiments for implementing the present invention will be described in detail with reference to the drawings.

In addition, in the description of the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, when it is said that a component is 'connected', 'supported', 'connected', 'supplied', 'transferred', or 'contacted' to another component, it is directly connected, supported, connected, It should be understood that supply, delivery, and contact may occur, but other components may exist in between.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In addition, in the present specification, the expressions of the upper side, the lower side, the side, etc. are described with reference to the drawings, and it is to be noted in advance that if the direction of the corresponding object is changed, it may be expressed differently. For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings, and the size of each component does not fully reflect the actual size.

Also, terms including an ordinal number such as 1st, 2nd, etc. may be used to describe various components, but the components are not limited by these terms. These terms are used only for the purpose of distinguishing one component from another.

The meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and other specific characteristic, region, integer, step, operation, element, component, and/or group. It does not exclude the existence or addition of

2 is a view showing an air lubrication system of a ship according to an embodiment of the present invention. 3 is a view for explaining a state in which an air compressor and an air injector of an air lubrication system of a ship according to an embodiment of the present invention are connected through an air supply pipe, and FIG. It is a figure for demonstrating the governor of a lubrication system.

2 to 4 , the air lubrication system 100 of the present invention discharges air generated using two air compressors to the outside of the hull 200 through the air injector 110 . To this end, the air lubrication system 100 according to the present embodiment includes an air injector 110 , a governor 120 , a first air compressor 130 , a second air compressor 140 , and an air supply pipe (AP). do.

The air injector 110 is provided to discharge the air generated by the first air compressor 130 and the second air compressor 140 to the outside of the hull 200 . At this time, the air injector 110 is installed in the bow portion of the hull 200, the air injector 110, a device for controlling the degree of the injected air may be installed.

At this time, the air injector 110 may be provided with an emergency stop valve 170 for stopping the air being discharged to the air injector 110 . The emergency stop valve 170 may block the discharge of air to the outside of the hull 200 when the air is not normally sprayed, such as when an abnormality occurs in the pressure of the air transferred through the air supply pipe AP. .

The governor 120 is connected to the main propulsion shaft MA connected to the main engine ME, as shown in FIG. 4 .

The governor 120 converts the rotation speed of the main propulsion shaft MA rotated by the main engine ME to match the rotation speed of the first air compressor 130 and the second air compressor 140 . To this end, the governor 120 may include a clutch 122 and a gear 124 .

The clutch 122 is provided to cut off the power when the first air compressor 130 and the second air compressor 140 are not used.

The gear 124 is provided to convert the rotation speed of the main propulsion shaft MA to match the rotation speed of the first air compressor 130 and the second air compressor 140 . One or more gears 124 may be provided to convert the number of rotations, and the gear ratio of the provided gears 124 may be changed as needed.

In this embodiment, it will be described that the governor 120 is provided with four gears 124 , and that the first air compressor 130 and the second air compressor 140 are each provided with two gears 124 . At this time, according to the gear ratio of each gear 124 , the first air compressor 130 and the second air compressor 140 rotate at the corresponding number of revolutions through the two gears 124 , respectively, at the number of revolutions of the main propulsion shaft MA. Convert the number of revolutions so that

In this embodiment, the governor 120 may convert the rotation speed for about 100 rpm of the main propulsion shaft MA to about 1000 rpm to 3000 rpm to fit the first air compressor 130 and the second air compressor 140 . .

At this time, the gear 124 may be shifted continuously, or may be shifted to 2nd or 3rd gear as needed. Alternatively, if necessary, the gear 124 may be fixed to the first gear without shifting.

The first air compressor 130 and the second air compressor 140 are disposed on the output side of the governor 120 , rotate according to the number of rotations converted by the governor 120 to compress air, and release the compressed air. It is discharged through the air supply pipe (AP).

In this embodiment, one of the first air compressor 130 and the second air compressor 140, a centrifugal compressor, a screw, and a positive displacement (Positive Displacement) method may be used.

In addition, the first air compressor 130 and the second air compressor 140 may be provided with a cross-sectional area adjusting device (not shown) capable of changing the cross-sectional area of the inlet and the outlet, such as a guide vane, at the inlet and the outlet, respectively.

Alternatively, the first air compressor 130 and the second air compressor 140, a device capable of adjusting the internal rotation speed may be installed.

At this time, although it is described that the clutch 122 is disposed on the governor 120 in the present embodiment, the present invention is not limited thereto. If necessary, the clutch 122 may be respectively disposed in the first air compressor 130 and the second air compressor 140 .

The temperature controller 150 is provided to adjust the temperature of the air injected from the first air compressor 130 and the second air compressor 140 . The temperature controller 150 may reduce the change in pressure according to the temperature by adjusting the temperature of the air injected from the first air compressor 130 and the second air compressor 140 .

In addition, in order to control the pressure of the air injected from the first air compressor 130 and the second air compressor 140, a control valve 160 is provided in the first air compressor 130 and the second air compressor 140, respectively. can be installed. For example, the control valve 160 may be connected in parallel to the first air compressor 130 as shown in FIG. 3 .

The air supply pipe AP supplies the air generated by the first air compressor 130 and the second air compressor 140 to the air injector 110 . To this end, the air supply pipe AP may be connected to the first air compressor 130 and the second air compressor 140 , respectively, and may be combined into one supply pipe and connected to the air injector 110 .

In this embodiment, the first air compressor 130 and the second air compressor 140 are disposed at the stern of the hull 200, and the air injector 110 is disposed at the bow of the hull 200. As the air supply pipe ( AP) may be arranged extending from the stern of the hull 200 to the bow.

The air lubrication system 100 according to the present embodiment may inject air by setting an air injection amount according to the ship's speed. To this end, the pressure of the air generated by the first air compressor 130 and the second air compressor 140 may be determined according to the required air injection amount.

Accordingly, the number of rotations output to control the pressure of air generated by the first air compressor 130 and the second air compressor 140 in the governor 120 connected to the main propulsion shaft MA may be adjusted.

In addition, the cross-sectional area adjusting device for changing the cross-sectional area of the inlet and outlet of the first air compressor 130 and the second air compressor 140 is the first air compressor 130 and the second air compressor 140 of the air injected from the pressure can be adjusted.

That is, in this embodiment, the air lubrication system 100 may further include a controller. The controller may adjust the number of gears 124 of the governor 120 to control the number of rotations output from the governor 120 .

In addition, the controller may control a cross-sectional area adjusting device for changing the cross-sectional area of the inlet and the outlet installed in the first air compressor 130 and the second air compressor 140, respectively.

Also, the controller may control the control valve 160 . That is, the controller may control the pressure of the air discharged from the first air compressor 130 and the second air compressor 140 by controlling the control valve 160 .

The controller may control the emergency stop valve 170 . Therefore, when an abnormality occurs in the air pressure in the air supply pipe AP, the emergency stop valve 170 may be controlled to stop the air being injected through the air injector 110 .

Such a controller may be implemented by an arithmetic device including a microprocessor, a memory, and the like, and since the implementation method is obvious to those skilled in the art, further detailed description thereof will be omitted.

The present invention also provides a method of driving an air lubrication system.

In one embodiment, the air lubrication system may include a control unit. The control unit may store information on the optimum air injection amount according to the ship speed.

For example, in the air lubrication system, the control unit determines a predetermined air injection amount according to the ship speed, determines the pressure of the compressor according to the air injection amount, and determines the rotation speed of a governor installed on a propulsion shaft or a governor of the air compressor. Step, and may include the step of adjusting the pressure of the air injected to the outside of the vessel.

In this case, the step of adjusting the pressure of the air may be performed by adjusting the guide vane on the inlet and outlet side and the control valve of the pipe connected to the inlet and the outlet.

Accordingly, the air lubrication system according to the present invention is lubricated with higher efficiency compared to the case where the air lubrication system is driven by a conventional power generation engine, thereby increasing the fuel saving effect.

Example

Example 1: A ship to which an air lubrication system driven by a conventional power generation engine is applied

Although an air injection device that injects air into the bottom of a ship is applied, the fuel consumption in a ship to which an air lubrication system driven by a conventional power generation engine is applied is calculated and shown in Table 1.

At this time, the ME Power is 15187.4 kW, which saves about 10.4% of power compared to the same ship speed, the ME load is 60.3%, the ME SGC is 129.2 g/kWh, and the gas consumed by the ME is 47.1 ton/day. do.

And, in the case of the engine for power generation, since the air compressor for the air lubrication system is operated, the load of each engine for power generation is increased compared to the case of Comparative Example 1, and the consumption of the added gas was calculated with the difference.

In the case of engines for power generation, the SGC according to the load before and after ALS operation of each engine was obtained under 2 sets of operation, and the horsepower was multiplied and subtracted to calculate the additional consumption of 2.1 ton/day.

As a result, the total consumption was calculated as 47.1 + 15.5 + 2.1 = 64.7 ton/day.

Example 2: A ship to which an air lubrication system according to an embodiment of the present invention is applied

Table 1 shows the calculation of fuel consumption in a ship to which the air lubrication system according to an embodiment of the present invention is applied.

Specifically, 15187.3 kW of shaft power is consumed during the operation of the air lubrication system, and 705 (698/0.99) kW of power is added to this to drive the air compressor connected to the governor.

ME Power = 15892.3 kW

ME Load = 63%

ME SGC = 128.6 g/kWh

ME Gas Consumption = 49.0 ton/day

At this time, since there is no change in the engine for power generation, it becomes 15.5 ton/day, and as a result, the total consumption is calculated as 64.5 ton/day.

Comparative Example 1: Ship to which air injection device is not applied

Table 1 shows the fuel consumption in a conventional ship to which an air injection device that injects air into the bottom of the ship is not applied.

At this time, the efficiency was calculated at 18.5 knots, Specific Fuel Gas Consumption (SGC) 129.0 g/kWh at axial horsepower 16950 kW (ME 67% load), ME 67% load, Gas consumption was 52.5 ton/day, In this case, it was assumed that about 15.5 ton/day was consumed.

Experimental example

Comparative Example 1 Example 1 Example 2 Fuel consumption (ton/day) 68.0 64.7 64.5 Fuel consumption reduction rate -- 4.853% 5.588%

As shown in Table 1, in the case of Example 1 to which the conventional air lubrication system is applied, it can be seen that the fuel is reduced by 4.853% compared to Comparative Example 1 to which the air lubrication system is not applied.

In addition, in the case of Example 2 to which the air lubrication system according to an embodiment of the present invention is applied, it can be seen that fuel is further reduced by 0.5% compared to Example 1 to which the conventional air lubrication system is applied.

That is, in the ship to which the air lubrication system according to an embodiment of the present invention is applied, it is not necessary to increase the generator capacity for driving the compressor for the air lubrication system as in the prior art, and the configuration of a separate starter can be omitted, and the supply Since the compressed air for use is sucked in the engine room, the engine room fan (ER FAN) can be used for common use compared to the existing bow area installation.

As described above, the specific description of the present invention has been made by the embodiments with reference to the accompanying drawings, but since the above-described embodiments have only been described with preferred examples of the present invention, the present invention is limited only to the above embodiments. It should not be understood, and the scope of the present invention should be understood as the following claims and their equivalents.

100: air lubrication system
110: air blower
120: governor
122: clutch
124: gear
130: first air compressor
140: second air compressor
150: thermostat
160: control valve
170: emergency stop valve
200: hull
AP: air supply pipe
MA: main propulsion shaft
ME: main engine

Claims (6)

a governor connected to the main propulsion shaft connected to the main engine of the ship, and outputting by changing the rotation speed of the main propulsion shaft;
one or more air compressors connected to the governor and rotating according to the number of revolutions output from the governor to compress and discharge air;
an air injector disposed at the bow of the ship and discharging the air discharged from the air compressor to the outside of the ship; and
and an air supply pipe for supplying the air discharged from the one or more air compressors to the air injector. The method according to claim 1,
The governor is
and one or more gears for converting the number of revolutions of the main propulsion shaft. 3. The method according to claim 2,
The governor is
The air lubrication system further comprising a clutch for blocking output of the converted rotation speed. The method according to claim 1,
The air lubrication system, which is installed in the one or more air compressors, further comprising one or more control valves for controlling the pressure of air discharged from the one or more air compressors. The method according to claim 1,
Installed in the air supply pipe, the air lubrication system further comprising a temperature controller for controlling the temperature of the air discharged from the at least one air compressor. In the air lubrication system according to any one of claims 1 to 5,
Further comprising a control unit in which air injection amount information according to the ship's speed is stored,
determining a predetermined air injection amount according to the ship speed in the control unit;
determining the pressure of the air compressor according to the air injection amount;
determining the rotation speed of at least one of the governor installed on the main propulsion shaft and the governor of the air compressor; and
adjusting the pressure of the air injected to the outside of the vessel;
A method of driving an air lubrication system, comprising:

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