JPH08192795A - Marine side thruster having water flow guiding member - Google Patents

Abstract

PURPOSE: To properly guide a water flow generated by actuation of an impeller, particularly in a tunnel penetrating through the hull in a marine side thruster. CONSTITUTION: An impeller 3 is provided in an almost central part of a tunnel 2 penetrating in the horizontal direction in a hull end part under the water surface, and water flow guiding members 4 and 4 are respectively arranged between the impeller 3 and both end parts of the tunnel. The respective water flow guiding members 4 and 4 are formed in an almost truncated cone shape formed so as to gradually increase an inside flow cross section toward the impeller 3, and are arranged and supported so as to have the same central axis with the impeller 3 and so that its outer peripheral surface is separated from an inner peripheral surface of the tunnel 2. Therefore, a water flow 6 flowing in a large radius part of an impeller blade becomes fast and a water flow 7 flowing in a small radius part becomes slow, and generation of cavitation in an impeller blade tip part having large peripheral speed is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side thruster equipped at the end of a hull (the bow or the stern) to improve the maneuverability of a ship.

[0002]

2. Description of the Related Art There is a conventional side thruster as shown in FIG. 3, in which a cylindrical tunnel 2 is formed at the end of the hull perpendicularly to the center plane of the hull and penetrating both sides, and at the center thereof. Is provided with an impeller 3. The impeller 3 pushes the water in the tunnel 2 outward on the port side or outward on the starboard side so that the turning force of the ship can be obtained.

[0003]

Generally, in the side thruster, a variable pitch type impeller 3 having a reference pitch of zero is used so that the thrust of the same magnitude can be produced in the starboard direction and the port side direction. By changing the pitch angle as necessary, the direction of thrust is adjusted to either the port or port direction, or the magnitude of thrust is adjusted.

The change of the pitch angle is carried out around the eccentric axis oriented in the direction perpendicular to the rotation axis of the impeller 3.
Therefore, the pitch angle is θ (constant from blade root to blade tip)
When expressed by, the pitch ratio p is expressed by the equation [1].

## EQU1 ## p = π (r / R) tan θ where r is the radius coordinate, R is the impeller radius, and the pitch ratio of the blade cross section at each radial position is large in the blade portion where the radius is large, and where the radius is small. It becomes smaller in the wing part of.

The pitch ratio corresponds to the angle of attack of the blade cross section during operation, and in the conventional method in which the flow velocity distribution of the water flow 5 flowing in with the operation of the impeller 3 is uniform, the angle of attack and the circumference of the blade part having a large radius are measured. As the speed increases, the thrust distribution at the blade tip also increases, causing problems such as vibration, noise, and erosion due to cavitation in that portion.

[0006] The present invention is intended to solve the above problems, by changing the flow velocity distribution of the water flow flowing into the impeller in the tunnel in the marine side thruster,
Cavitation, etc. can be prevented by increasing the flow velocity at the tip of the impeller blade, that is, at a large radius, and decreasing the flow velocity at a small radius to prevent an excessive angle of attack at the blade tip. Another object of the present invention is to provide a marine side thruster with a water flow guide member.

[0007]

In order to achieve the above-mentioned object, a side thruster for a ship with a water flow guide member of the present invention comprises:
A marine side thruster consisting of a cylindrical tunnel that is formed so as to penetrate laterally at the end of the hull below the water surface, and an impeller that is concentrically disposed and supported at approximately the center in the longitudinal direction of the tunnel. In, the water flow guide member is provided between both ends of the tunnel and the impeller, and the water flow guide member gradually increases the internal flow cross-section toward the impeller. It is characterized in that it is formed so as to have the same central axis as the impeller, and is disposed and supported so as to separate its outer peripheral surface from the inner peripheral surface of the tunnel.

[0008]

In the above-mentioned marine side thruster with a water flow guide member of the present invention, the water flow guide member having a substantially truncated cone shape
The flow velocity distribution of the water flow flowing into the impeller in the tunnel becomes faster in the part where the radius of the impeller is large and becomes slower in the part where the radius is small. As a result, it is possible to eliminate the excessive angle of attack of the impeller blades and avoid the occurrence of cavitation and the like due to the excessive angle of attack as in the past.

The water flow passing through the impeller has a large flow velocity along the inner peripheral surface of the tunnel and a low flow velocity along the central axis of the tunnel, but this water flow is made uniform by the water flow guide member on the other side. Since it is jetted from the tunnel opening as it is converted, the thrust for maneuvering can be efficiently obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A ship side thruster with a water flow guide member according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a horizontal sectional view of a ship equipped with the side thruster, and FIGS. FIG. 3B is an explanatory view showing the effects of impeller blades in comparison between the conventional side thruster (a) and the side thruster (b) of the present invention.

As shown in FIG. 1, the side thruster of this embodiment also has a cylindrical tunnel 2 formed so as to laterally pass through the end 1 of the hull (main body or stern) under the water surface.
The tunnel 2 is provided with an impeller 3 which is concentrically arranged and supported on the tunnel 2 substantially at the center in the longitudinal direction.

In the present embodiment, the water flow guide members 4, 4 are respectively provided between the both ends of the tunnel 2 and the impeller 3.
4 is attached, and each water flow guide member 4 is an impeller 3
It is formed in a substantially frusto-conical shape so as to gradually increase the internal flow cross-section toward it, has the same central axis as the impeller 3, and separates its outer peripheral surface from the inner peripheral surface of the tunnel 2. It is arranged and supported so that
The water flow guide member 4 is supported by connecting the member 4 to the inner wall of the tunnel 2 by a plurality of radial stays 4a.

Since the side thruster for a ship with the water flow guide member of this embodiment is constructed as described above, the impeller 3
The water flow 5 flowing into the tunnel 2 due to the operation of is changed the flow velocity distribution of the water flow flowing into the impeller 3 by the substantially frustoconical water flow guide member 4, and the fast water flow is generated in the portion where the radius of the impeller blade is large. 6, and a slower water flow 7 occurs at a small radius.

That is, in the case of the present invention shown in FIG. 2 (b), as compared with the conventional case shown in FIG. 2 (a), the velocity of the water flow flowing into the impeller blade at the tip of the impeller blade. v
₁ becomes larger than the conventional speed v, and accordingly, the angle of attack α ₁ becomes smaller than the conventional angle of attack α. As a result, it is possible to eliminate the excessive angle of attack of the impeller blades, and it is possible to avoid the conventional problems such as the occurrence of cavitation due to the excessive angle of attack, vibration, noise, and erosion due to the cavitation.

The water flow passing through the impeller 3 has a high flow velocity along the inner peripheral surface of the tunnel 2 and a low flow velocity along the central axis of the tunnel 2, but this water flow is guided to the other side. Since the flow velocity is made uniform by the member 4 and jetted from the end opening of the tunnel 2, the thrust for maneuvering can be efficiently obtained.

[0016]

As described above in detail, the following effects can be obtained by the marine side thruster with the water flow guide member of the present invention. (1) Due to the substantially frustoconical water flow guide member, the flow velocity distribution of the water flow flowing into the impeller in the tunnel becomes faster at the large radius portion of the impeller blade and slows at the small radius portion of the impeller blade. Excessive angle of attack of impeller blades can be eliminated, causing cavitation due to excessive angle of attack, vibration and noise due to the cavitation.
It becomes possible to avoid problems such as erosion. (2) The water flow passing through the impeller has a high flow velocity along the inner peripheral surface of the tunnel and a low flow velocity along the central axis of the tunnel, but this flow is made uniform by the water flow guide member on the other side. In this way, the jet is ejected from the tunnel opening, so that the thrust for maneuvering can be efficiently obtained.

[Brief description of drawings]

FIG. 1 is a lateral cross-sectional view of a main portion of a ship equipped with a ship side thruster with a water flow guide member according to an embodiment of the present invention.

FIG. 2 (a) is an explanatory view showing a working state of an impeller blade tip of a conventional marine side thruster, and FIG. 2 (b) is an explanatory view showing a working state of an impeller blade tip of a marine side thruster of the present invention. Is.

FIG. 3 is a cross-sectional view of a main part of a ship equipped with a conventional side thruster.

[Explanation of symbols]

 1 Hull end (bow or stern) 2 Tunnel 3 Impeller 4 Water flow guide member 4a Stay 5-7 Water flow

Claims (1)

[Claims] 1. A cylindrical tunnel that is formed so as to penetrate laterally at the end of the hull below the surface of the water, and an impeller that is concentrically disposed and supported at approximately the center in the longitudinal direction of the tunnel. In the marine side thruster, the water flow guide members are respectively provided between both ends of the tunnel and the impeller, and the water flow guide members gradually increase the internal flow cross section toward the impeller. A water flow characterized by being formed into a substantially truncated cone shape and having the same central axis as the impeller and being arranged and supported so as to separate the outer peripheral surface thereof from the inner peripheral surface of the tunnel. Marine side thruster with guide member.