KR102456858B1 - Ship propulsion system equipped with flow control module - Google Patents

Abstract

The present invention relates to a ship propulsion system provided with means for controlling the flow of fluid flowing into a propeller by the Coanda effect, and relates to a propeller, a driving module, a rudder, and a fluid installed in front of the propeller and introduced into the propeller a flow control module for controlling the flow, wherein the flow control module is provided with flow control blades protruding laterally from the front of the propeller to both sides of the vessel, and a flow path is formed in the flow control blade along the longitudinal direction, A high-pressure pump extending to the surface of the flow control vane and supplying a high-pressure fluid to the flow path is provided, so that the fluid compressed by the high-pressure pump passes through the flow path and through the surface of the flow control vane toward the propeller. An object of the present invention is to provide a ship propulsion system equipped with a flow control module in which the forward fluid resistance of the propeller is reduced by being injected into the

Description

Ship propulsion system equipped with flow control module

The present invention relates to a ship propulsion system provided with means for controlling the flow of fluid flowing into a propeller by the Coanda effect.

Carbon dioxide is a representative greenhouse gas and is considered the main cause of global warming. In addition, sulfur oxides and nitrogen oxides emitted as exhaust gases after burning petroleum-based fuels in engines such as ships are associated with certain respiratory diseases.

In this regard, 'Seas at Risk' and 'Transport & Environment', which are composed of European environmental groups and non-profit organizations, reduce the speed of ships by 20% to reduce carbon dioxide emissions by 24% and nitrogen A research report was published that included a reduction in the emission of oxides and sulfur oxides. “Just as a car engine achieves maximum fuel economy at its optimum speed, slower moving ships can reduce fuel consumption and reduce gas emissions to the atmosphere,” the report said.

Currently, ships account for 3% of global greenhouse gas emissions, which is equivalent to 1.7 gigatons out of 55 gigatons of total annual emissions, which is a huge amount.

The International Maritime Organization (IMO) estimates that, if measures to reduce greenhouse gas emissions are not implemented, the amount generated by international shipping could increase by 50% to 250% over the next several decades. In this case, carbon emissions from ships are expected to account for 17% of global emissions by 2050.

In this regard, some large shipping companies are said to have begun to slow down ship operations in line with the IMO's goal of reducing gas emissions by at least 50% by 2050.

However, this speed limit inevitably becomes a factor that makes the travel time of the vessel longer. For this reason, most experts say that in order to reduce greenhouse gas emissions for a longer period of time, the development of alternative fuels or new engines and ships should be done in parallel.

In order to significantly improve fuel efficiency or to use eco-friendly fuels in parallel, dual fuels are sometimes used in LNG carriers.

However, significant operational and technical improvements are required to achieve complete decarbonization. According to the scenario to achieve the goals of the IMO GHG initial strategy, transportation efficiency (digitization) is less than about 20%, linear development and efficiency improvement are about 10-15%, and the greenhouse of ships is about 5-20% by machinery. It is possible to reduce gas, and after 2035, it is essential to reduce greenhouse gas by using alternative fuels.

In addition, there is a limit to being replaced by a dual fuel engine using natural gas in a general ship, like an LNG carrier, except for cases in which a normal leakage of natural gas can be used as fuel, such as an LNG carrier.

Therefore, a technology capable of remarkably increasing the efficiency of a marine engine is urgently requested, but at present, the extent to which the efficiency can be increased by improving the technology is insufficient.

Publication No. 10-2020-0059846 (published date: May 29, 2020)

Accordingly, the present invention is to provide a ship propulsion system equipped with a flow control module that minimizes the rotational resistance of the fluid and also suppresses cavitation by using the Coanda effect for the flow of fluid flowing into the propeller and introducing the jet jet flow into the propeller. .

A ship propulsion system equipped with a flow control module according to the present invention for achieving this object includes a propeller installed at the rear of the ship, a driving module for driving the propeller, a rudder installed behind the propeller, and the propeller It includes; a flow control module installed in the front for controlling the flow of fluid flowing into the propeller, wherein the flow control module is provided with flow control blades protruding from the front of the propeller to both sides of the vessel to the side, the flow control blades A flow path is formed in the longitudinal direction and extends to the surface of the flow control blade, and a high-pressure pump for supplying a high-pressure fluid to the flow path is provided. The forward fluid resistance of the propeller is reduced by spraying in the form of a jet jet stream through the propeller.

Here, the flow path may preferably be composed of a tunnel formed elongated in the longitudinal direction of the flow control blade, and a slit formed from the tunnel to the surface of the flow control blade.

In this case, the slit is formed in a curved shape, and the center of curvature of the curved shape is preferably located in front of the slit with respect to the forward direction of the ship.

In this case, the surface portion of the flow control blade adjacent to the inlet of the slit is preferably a proximity guide surface formed by cutting a portion in a direction in which the angle between the jet jet flow injected through the slit and the surface of the flow control blade decreases. can be formed.

Also, the cross-sectional area of the slit is preferably smaller than the cross-sectional area of the tunnel.

In particular, the slit is preferably sprayed onto the upper surface of the flow control blade, and the flow blade may be inclined in a direction in which the upper surface faces the front side of the vessel.

Meanwhile, the high-pressure pump is preferably installed inside the ship, and the flow control module includes a fluid inlet pipe connecting the outside of the ship and the high-pressure pump so that the surrounding fluid is sucked into the high-pressure pump, and the high pressure compressed by the high-pressure pump. Further comprising a high-pressure water supply pipe for injecting the fluid of the tunnel, the fluid inlet formed in a portion where the fluid inlet pipe is exposed on the surface of the ship may be installed in front of the flow control wing.

Alternatively, the high-pressure pump is installed inside the ship, and the flow control module includes a fluid inlet pipe connecting the outside of the ship and the high-pressure pump so that the surrounding fluid is sucked into the high-pressure pump, and the high-pressure fluid compressed in the high-pressure pump. It further includes a high-pressure water supply pipe for injecting into the tunnel, preferably, the fluid inlet formed in a portion where the fluid inlet pipe is exposed to the surface of the ship may be installed in front of the propeller.

The ship propulsion system equipped with the flow control module according to the present invention uses the Coanda effect for the flow of fluid flowing into the propeller, so that the jet jet flow is introduced into the propeller, thereby minimizing the rotational resistance of the fluid and also suppressing cavitation. .

1 is a conceptual diagram of the principle of the Coanda effect;
2 is a schematic diagram of a ship propulsion system according to the present invention;
3 is a horizontal cross-sectional view of FIG. 2 ;
Fig. 4 is a schematic diagram showing a modified embodiment of Fig. 2;
Fig. 5 is a horizontal cross-sectional view of Fig. 4;
6 is a perspective view of a flow control vane;
7 is a cross-sectional view of the incision line shown in FIG. 6;
8 is a partially enlarged view of FIG. 7;
9 (a) (b) (c) is a cross-sectional view of the modified embodiment of FIG.

The specific structural or functional descriptions presented in the embodiments of the present invention are merely exemplified for the purpose of describing the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described herein, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

A ship propulsion system equipped with a flow control module according to an embodiment of the present invention includes a propeller 4 installed at the aft of the ship 1 as shown in FIG. 2, and a driving module for rotationally driving the propeller 4 ( not shown), a rudder 3 , and flow control modules 10 and 20 .

Since the propeller 4 can adopt any propeller as a propulsion mechanism of the normal ship 1, there is no particular limitation in material or shape.

The driving module (not shown) is a device for rotationally driving the propeller 4 . Since any device for rotating the propeller 4 of the ship 1 can be adopted, a conventional diesel engine or a dual fuel engine used in the latest LNG carriers may also be applied, and an electric motor may also be applicable.

The rudder (3) is also called a rudder and corresponds to the steering device of the ship (1). The rudder 3 may be manufactured in a streamlined form for a smooth steering action, and a separate small propeller may be built inside so that additional thrust can be exerted due to the rudder 3 . In addition to the rudder shape shown in Figs. 2 or 4, a rudder having a propeller mounted on the lower end and steered together with the propeller may be adopted. (not shown) In this case, the propeller's The direction of propulsion may also be varied (not shown). And, although the rudder 3 shown in FIG. 2 is supposed to be installed under the transom 2, the installation position of the rudder 3 must be the transom ( 2) It is not limited to the lower part.

The flow control modules 10 and 20 are installed in front of the propeller 4 and serve to control the flow of fluid flowing into the propeller 4 when the ship 1 advances. In the flow control modules 10 and 20, as shown in FIG. 2, flow control blades 20 manufactured in the shape of a wing protruding laterally on both front sides of the propeller 4 are installed one at a time on one side.

In particular, the flow control vane 20 has flow paths 21 and 22 formed along the longitudinal direction therein, leading to the surface of the flow control vane 20, and a high-pressure pump 11 is installed inside the stern of the vessel 1, , the surrounding fluid is compressed by the high-pressure pump 11 and then transferred along the flow paths 21 and 22 and ejected in the form of a jet jet stream HW from the surface of the flow control vane 20 .

The flow control vane 20 is disposed so that the jet jet stream HW is sprayed toward the propeller 4 . Thereby, the fluid flow that is injected from the flow control blade 20 and is directed toward the propeller 4 in the form of a jet jet flow HW flows toward the front of the propeller 4, so that the normal propeller absorbs the surrounding fluid and A phenomenon in which significant driving force is consumed to form a rotational flow of the fluid in the process of pushing backward is prevented, and the rotational driving force required to drive the propeller 4 can be reduced, so that the driving efficiency is improved.

In addition, since the direction in which the jet jet stream HW is ejected from the flow control vane 20 is toward the rear of the vessel 1, the jetting of the jet jet stream HW generates its own thrust by itself and The propulsion efficiency is further improved, and the sound and durability of the propeller 4 are further improved by dispersing the cavitation generated on the surface of the propeller 4 as the flow consisting of the jet injection flow (HW) flows into the propeller 4, and Accidents can be prevented.

The flow paths 21 and 22 formed in the flow control vane 20 are more specifically, as shown in FIG. 6 , a tunnel 21 and a tunnel 21 formed long in the longitudinal direction of the flow control vane 20 . ) to the surface of the flow control vane 20 is composed of a slit (22). The high-pressure fluid compressed by the high-pressure pump 11 is transferred to the tunnel 21 as shown in FIGS. 2 to 5 , and the high-pressure fluid introduced into the tunnel 21 passes through the tunnel 21 and passes through the slit 22 . In the course of passing, the flow rate is rapidly increased as the cross-sectional area passed through is reduced, and the fluid ejected from the surface of the flow control vane 20 through the end of the slit 22 is ejected in the form of a jet jet stream (HW).

At this time, the shape of the slit 22 is directed in the direction in which the end is as close to the surface of the flow control vane 20 as possible, as can be seen in the cross-sectional view shown in FIG. 7 . In particular, the slit 22 is formed in a curved shape, and the center of curvature of the curved shape is located in front of the slit 22 with respect to the forward direction of the ship 1 . That is, referring to FIG. 7 , since the forward direction of the ship 1 is to the left, the curve forming the shape of the slit 22 is formed in a shape that expands toward the forward direction of the ship 1 .

As such, when the slit 22 is formed in a form that rotates based on any one center of curvature, the jet jet flow HW ejected through the slit 22 has centrifugal force due to acceleration, and thus the jet jet flow ( HW) proceeds in close contact with the surface of the flow control blade.

In particular, in this case, due to the Coanda effect, the jet jet stream HW is maintained in a laminar form until it leaves the flow control vane 20 . Here, a section in which the jet jet flow HW maintains the shape of the flow on the surface of the flow control vane 20 due to the Coanda effect will be referred to as a Coanda flow section C.

The Coanda effect refers to a phenomenon in which a fluid flows along the curvature of a curved surface instead of in a straight line when a fluid flows in contact with a curved surface. If the ping-pong ball is placed on the top of the nozzle of the hair dryer in a state where the hair dryer is arranged to spray warm air vertically upward, the phenomenon that the ping-pong ball does not bounce off and stays in the vertical upper part of the nozzle is caused by the Coanda effect when the hair dryer is operated. will be.

The principle by which the Coanda effect occurs is illustrated in FIG. 1 . As shown in (a) of FIG. 1, when the jet jet flow (HW) is generated toward the right, the surrounding air due to the Bernoulli principle is the result of lowering the pressure around the jet jet flow (HW) due to the high-speed flow. As they gather toward the jet stream HW, the jet jet stream HW maintains a straight and laminar flow state.

However, when there is a wall around the jet jet flow (HW) as shown in FIG. 1 (b), the pressure from the ambient air is applied only from the opposite direction of the wall surface, so the jet jet flow (HW) proceeds in close contact with the wall surface. As such, the Coanda effect refers to a phenomenon in which the jet jet stream (HW) adheres to the wall surface due to the pressure of the surrounding air continues without being separated from the wall surface or turning into a vortex.

As shown in FIG. 2 , the flow control vane 20 may be installed so that the upper surface is inclined toward the front of the vessel 1 . Since the jet jet stream HW ejected from the slit 22 proceeds at high speed along the upper surface of the flow control blade 20 due to the Coanda effect, lift force is formed in the flow control blade 20 in the direction toward the upper surface. . Therefore, since the ship 1 receives a forward force due to an increase in lift in addition to an increase in thrust according to the action and reaction law of the jet injection flow HW itself, thrust can be further increased.

A cross-section of a portion indicated by line AA′ in FIG. 6 is shown in FIG. 7 . In FIG. 7 , the direction in which the jet jet flow HW is directed is a direction toward the rear of the vessel 1 . At the point where the jet jet stream HW is ejected from the distal end of the slit 22, a portion indicated by a hatched line in FIG. 8 is cut so that the jet jet stream HW is closer to the surface of the flow control vane 20. By forming the Anda guide surface 23 , the injection direction of the jet jet stream HW is further in close contact with the surface of the flow control blade 20 , so that the Coanda effect can be more smoothly generated.

Since the cross-sectional area of the slit 22 is formed smaller than the cross-sectional area of the tunnel 21 as described above, the high-pressure fluid supplied to the tunnel 21 enters the slit 22 and the pressure decreases according to Bernoulli's law and the flow rate When this rapidly increases and is ejected from the end of the slit 22, it is ejected in the form of a jet jet stream HW. As can be seen from the conceptual diagram of FIG. 1, this jet jet flow (HW) is in close contact with the surface of the flow control vane 20 until it leaves the flow control vane 20 due to the pressure of the surrounding fluid and flows at a high speed, so Coanda flow It is formed in a section (C).

On the other hand, the high-pressure pump 11 sucks the fluid in the lower part of the vessel 1 and compresses it. More specifically, as shown in FIG. 2 , the high-pressure pump 11 may be installed inside the vessel 1 . However, in some cases, it may be installed outside the stern of the ship 1 or on the surface of the stern.

At this time, the flow control modules 10 and 20 are provided with a fluid inlet pipe 12 connecting the outside of the vessel 1 and the high pressure pump 11 so that not only the flow control vanes 20 but also the surrounding fluid is sucked into the high pressure pump 11 . and a high-pressure water supply pipe 13 for injecting the high-pressure fluid compressed by the high-pressure pump 11 into the tunnel 22 .

Here, two embodiments shown in Figs. 2 and 4, respectively, are exemplified for the path through which the ambient fluid is absorbed into the high-pressure pump 11 .

In the embodiment of FIGS. 2 and 3 , the fluid inlet 121 formed while the fluid inlet pipe 12 is in contact with a portion exposed to the surface of the ship is illustrated to be installed in front of the flow control wing 20 . For reference, a bell mouth similar to a trumpet shape may be installed in the fluid inlet 121 so that the fluid can flow more smoothly.

When the fluid inlet 121 is formed in front of the flow control vane 20, the flow control vane 20 moves around the fluid inlet 121 where the water pressure is lowered due to the advance of the vessel 1, so that the vessel 1 is During advancing, the front of the flow control vane 20 has a lower pressure than the rear of the flow control vane 20, so that additional thrust can be obtained while the lift is increased.

Alternatively, as shown in FIGS. 4 and 5 , the fluid inlet pipe 12 sucks the fluid around the propeller 4 , particularly in front of the propeller 4 , and sends it to the high-pressure pump 11 . At this time, the suction of the fluid is possible in the form of suction from the upper or lower front of the propeller 4, or at the same time from the upper and lower portions of the propeller 4, in the embodiment of FIG. 4, around the upper and lower parts of the propeller 4 The high-pressure pump 11 sucks all the fluids at the same time.

When the surrounding fluid is sucked in from the front of the propeller 4, first, the front pressure of the propeller 4 decreases, so that the thrust is increased while the rear pressure of the propeller 4 is relatively increased. Second, as shown in FIG. 5, when the forward pressure of the propeller 4 is reduced, the jet injection flow (HW) according to the Coanda flow formed from the flow control blade 20 is in the form of a Coanda flow to a certain extent along the stern. While being maintained, the jet jet stream (HW) is introduced to the front of the propeller (4).

Because the jet jet stream HW leaving the flow control vane 20, as shown in FIG. 5, is reduced in pressure as the jet jet stream HW has a faster velocity than the ambient fluid pressure relative to the jet jet stream HW. This is because it can continue to be maintained as a Coanda flow.

The fluid flow entering the propeller 4 is uniformly changed due to the jet jet flow HW. In the conventional propeller 4 of the ship 1, the flow of water flowing into the propeller 4 is not uniform, so that the water flowing out to the rear of the propeller 4 causes a rotational motion. As such, in the conventional propeller 4, the rotational driving force is wasted to cause the rotational motion of the water flowing out through the propeller 4, so the efficiency is lowered by that much.

In contrast, in the ship propulsion system according to the embodiment of FIG. 4, the flow of fluid flowing into the propeller 4 becomes uniform, and by minimizing the rotational kinetic energy of water exiting the propeller 4, the resistance to the propeller 4 is minimized. Thus, the rotational driving efficiency of the propeller 4 is increased.

In addition, in the ship propulsion system according to the embodiment of FIG. 2 or FIG. 4, since the jet jet flow (HW) ejected from the flow control blade 20 flows into the front of the propeller 4, generated during the rotation of the propeller 4 There is also an effect that air bubbles are dispersed and the occurrence of cavitation is suppressed. Air bubbles generated by the rotation of the propeller 4 damage the surface of the propeller 4 when the air bubbles are destroyed while moving along the surface of the propeller 4 by a certain interval. At this time, the jet jet stream (HW) suppresses the formation process of air bubbles and the generated air bubbles are separated from the propeller 4 , so that the occurrence of cavitation can be effectively suppressed.

However, such an increase in rotational driving efficiency and suppression of cavitation may be exhibited even if the fluid inlets 121 and 1121 are formed in other parts, rather than the locations of the fluid inlets 121 and 1121 shown in FIGS. 2 to 5 .

On the other hand, although the shape and arrangement of the tunnel 21 and the slit 22 formed in the flow control vane 20 have been described in the form shown in FIG. 7 above, it is not necessarily limited to the form shown in FIG. As shown in (a)(b)(c), it can be implemented in various forms.

9 (a) is an embodiment manufactured in a shape almost similar to that of FIG. 7, but in FIG. HW) may be ejected, and two or more slits 222 may be formed from one tunnel 221 as shown in FIG. 9C .

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

AP: Ambient fluid pressure C: Coanda flow section
SS : Suction side PS : Pressure side
HW: Jet jet flow FD: Forward direction of the vessel
1: ship 2: transom
3: rudder 4: propeller
10: high-pressure water supply part 11: high-pressure pump
12,112: fluid inlet pipe 13: high pressure water supply pipe
20: flow control wing 21,121,221: tunnel
22,122,222: slit 23,123,223: Coanda induction surface
121,1121: fluid inlet

Claims (8)

A propeller (4) installed at the aft of the vessel (1) and;
a driving module for driving the propeller (4);
a rudder (3) installed behind the propeller (4);
It includes; a flow control module installed in front of the propeller (4) to control the flow of fluid flowing into the propeller (4);
The flow control module is provided with flow control blades 20 protruding laterally on both sides of the vessel 1 from the front of the propeller 4,
A flow path is formed in the flow control blade 20 in the longitudinal direction and extends to the surface of the flow control blade 20,
A high-pressure pump 11 for supplying a high-pressure fluid to the flow path is provided,
The fluid compressed by the high-pressure pump 11 is sprayed in the form of a jet jet stream HW toward the propeller 4 through the surface of the flow control vane 20 through the flow path. fluid resistance is reduced,
The flow path is composed of a tunnel 21 elongated along the longitudinal direction of the flow control vane 20, and a slit 22 formed from the tunnel 21 to the surface of the flow control vane 20,
The slit 22 is formed in a curved shape,
A ship propulsion system with a flow control module, characterized in that the center of curvature of the curved surface is located in front of the slit (22) with respect to the forward direction of the ship (1). delete delete According to claim 1,
The surface portion of the flow control blade 20 adjacent to the inlet of the slit 22 has a reduced angle between the jet jet flow HW injected through the slit 22 and the surface of the flow control blade 20 . A ship propulsion system equipped with a flow control module, characterized in that a proximity guide surface formed by cutting a portion in the direction is formed. 5. The method of claim 4,
A vessel propulsion system with a flow control module, characterized in that the cross-sectional area of the slit (22) is smaller than the cross-sectional area of the tunnel (21). According to claim 1,
The slit 22 is sprayed onto the upper surface of the flow control vane 20, and the flow control vane 20 is inclined in a direction in which the upper surface faces the front side of the vessel (1). Vessel propulsion system with control module. According to claim 1,
The high-pressure pump 11 is installed inside the ship 1,
The flow control module includes a fluid inlet pipe 12 connecting the outside of the vessel 1 and the high pressure pump 11 so that the surrounding fluid is sucked into the high pressure pump 11 , and the high pressure compressed by the high pressure pump 11 . Further comprising a high-pressure water supply pipe (13) for injecting the fluid of the tunnel (21),
The fluid inlet 121 formed in the portion where the fluid inlet pipe 12 is exposed to the surface of the vessel 1 is installed in front of the flow control wing 20. system. According to claim 1,
The high-pressure pump 11 is installed inside the ship 1,
The flow control module includes a fluid inlet pipe 12 connecting the outside of the vessel 1 and the high pressure pump 11 so that the surrounding fluid is sucked into the high pressure pump 11 , and the high pressure compressed by the high pressure pump 11 . Further comprising a high-pressure water supply pipe (13) for injecting the fluid of the tunnel (21),
A vessel propulsion system with a flow control module, characterized in that the fluid inlet 1121 formed in a portion where the fluid inlet pipe 12 is exposed to the surface of the vessel 1 is installed in front of the propeller 4 .

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