JP3073490B1 - Duct propeller device - Google Patents

Abstract

A conventional duct propeller has not been able to maximize the effects of a duct. SOLUTION: This is a duct propeller device comprising a straightening plate 6 projecting forward from a duct front edge 1a at a lower end of a duct 1 in a duct propeller projecting downward from a ship bottom. Due to the presence of the current plate 6, the inflow angle into the duct 1 increases, and the duct generates a larger thrust. It is preferable to arrange a plurality of flow holes 9 in the current plate 6 because the water pressure is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ducted propeller which is driven to protrude downward from the bottom of a ship, and which is used for propulsion and position holding of the ship.

[0002]

2. Description of the Related Art Hitherto, a turning thruster has been frequently used for a main propulsion unit or an auxiliary propulsion unit of a ship, and among them, a propeller is provided with a duct disposed in a duct for guiding a water flow generated by its rotation. A propeller is known (for example, Japanese Utility Model Unexamined Publication No. Sho 61-62698: Conventional Example 1). In this method, a deflector is provided at the upper part of a duct so that a water flow spouted from the duct by the deflector is prevented from flowing along a bottom outer plate.

[0003] On the other hand, there is also known an up-and-down type swiveling thruster which is stored in the hull when not in use and protrudes downward from the bottom of the hull when in use.
No. 69599: Conventional example 2). In this method, a bottom plate is provided at the lower end of the thruster, and the bottom plate covers the opening of the hull when the thruster is stored, so that the bottom of the hull is made smooth to avoid an increase in hull resistance.

[0004]

In the prior art 1, a deflector is provided above the duct so that the water flowing out of the duct does not follow the bottom of the ship. It does not improve efficiency. Since the flow of water introduced into the duct is not primarily focused on, there is a limit to the improvement of duct efficiency.

[0005] The prior art 2 merely provides a bottom plate at the lower end of the thruster so as to function as an opening lid. In addition, since a duct is basically not provided, it is irrelevant to the present application in which the propulsion performance is improved by the duct.

In any case, the conventional duct propeller has not been able to maximize the effects of the duct.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a duct propeller projecting downward from the bottom of a ship and protruding downward or laterally of the duct and at least forward of a leading edge of the duct. Rectifier plate,
To form a long airfoil flow field
This is a duct propeller device characterized in that:

Thus, as will be described later, the flow field having a long airfoil shape is formed between the current plate and the duct, thereby increasing the thrust. Due to the presence of the current plate, the inflow angle (attack angle) into the duct increases, and the duct generates a larger thrust. The flow plate itself becomes a flow field that generates thrust.

In this case, there are the following modes. In a plan view, the current plate is formed as a current plate protruding in a curved or polygonal shape ahead of the front edge of the duct. In a plan view, the current plate is a circular or polygonal current plate extending from the center near the front edge of the duct to the area including the duct propeller. A grid-shaped rib is erected on the upper surface of the current plate, and the current plate is attached to the duct using the grid-shaped rib. When viewed from the front, the rectifying plate is a rectifying plate shaped almost along the duct. A distribution plate with multiple flow holes. A plurality of holding members for holding the current plate on the duct propeller side, including a support member extending obliquely downward and forward from a pod containing a power transmission mechanism of the propeller. A straightening plate provided with an arc-shaped guide plate at least at a peripheral edge of a front edge portion.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a propeller with a duct protruding from a ship bottom S provided with a current plate of the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a plan view of the current plate itself.

As shown in these figures, in a front view, a circular duct 1 is held via a mounting member 3 on a strut 2 which is suspended to the center. A sheath-like pod 5 having a built-in power transmission mechanism for transmitting a driving force to the propeller 4 is provided below the strut 2, and a rear end thereof extends into the duct to form a boss 5a, and the boss 5a is attached to the boss 5a.
Are projected radially. The cross section of the duct 1 has an airfoil shape, and the tip of the propeller 4 extends to near the inner surface of the duct 1.

Below the duct 1, a flat plate-shaped current plate 6 is provided in contact with the lower end of the duct 1. This current plate 6
At least, the duct 1 projects horizontally forward from the front edge 1a. The current plate 6 projects in a curved shape (or may project in a polygonal shape) and straightens the water flow flowing into the duct 1. The current plate 6 is usually provided with the duct 1 as shown in FIG.
And has a radius R (diameter D) extending to a position including the pod 5 and the duct 1 (shown by projection of a thin line).
The current plate may not be a disk but may be a polygon.

Since the current plate has such a size, the following operation and effect can be obtained. In other words, the duct propeller device of FIG. 1 is made as a single unit, and is stable on the ground before installation in a factory or installation. It can be left sitting. In addition, as described later, this is to obtain a flow field that forms a long airfoil.

On the upper surface 6a of the current plate 6, reinforcing ribs 7 projecting upward are arranged in a lattice pattern. The reinforcing ribs 7 are used to attach the current plate 6. That is, substantially triangular holding members 8 are vertically provided at two places on both sides of the duct 1, and the lower ends of the holding members 8 are in contact with the reinforcing ribs 7, overlap and are fixedly fixed by bolt nuts. . A holding member 8 is also provided at the center position of the duct 1 and hangs obliquely downward and forward, and the lower end thereof is fixedly joined to the reinforcing rib 7. The holding members 8 are all flat plates (flat blades), but may have a rectifying effect to enhance the function of the propeller. Further, the center holding member 8a may have a wing cross section having a twist that generates a rotational flow in a direction opposite to the rotational flow generated by the propeller rotation. Then, the rotational energy can be recovered, and the propulsion efficiency can be increased.

The flow plate 6 is provided with a large number of circular flow holes 9 in almost the entire area at least in front of the duct 1 so that water can freely flow up and down the flow plate 6. The flow holes 9 allow the water pressure applied to the current plate 6 caused by the water existing below or above the current plate 6 to smoothly escape due to the vertical motion of the ship while the ship is running. As a result, the rigidity and strength of the current plate 6 are reduced, and the structure is simplified.

Although the above-mentioned current plate 6 is an example formed horizontally, a current plate 6A may be formed by bending the current plate to a curvature substantially along the outer periphery of the duct, as shown by a virtual line in FIG. Alternatively, it may be an inverted trapezoidal (polygonal) current plate 6B substantially along the duct. In this case, there is an advantage that the water flow introduced into the duct 1 can be rectified over a wide range.

As shown in FIGS. 4 (a) and 4 (b), an arc-shaped guide plate 10 may be provided on the periphery of the front edge of the current plate 6 in front of the position of the front edge 1a of the duct 1. When a water stream hits the reinforcing ribs 7 erected on the plate 6, a vortex or the like may be generated and the resistance may be increased.

FIG. 5 is an operation and effect diagram of the duct propeller provided with the current plate 6 of the present invention. The following three points can be considered as reasons why the efficiency is improved by the current plate 6.

First, as shown in FIG. 5A, by forming a flow field such that the duct 1 and the flow straightening plate 6 form a long airfoil 11a as shown by a virtual line, the thrust is reduced. It is to increase.

Second, as shown in FIG.
This is because, due to the presence of, the inflow angle (attack angle) into the duct 1 increases, and the duct 1 generates a larger thrust.

Third, as shown in FIG.
This is because the airfoil itself becomes one airfoil 11b, and the lift L acts on the airfoil 11b to form a flow field that generates thrust.

FIG. 6 is a view showing a model test result of a duct propeller device provided with the current plate of the present invention. The vertical axis shows efficiency,
The horizontal axis represents the advance coefficient. The line (thick solid line) is the propeller + duct efficiency when the current plate is provided, and the line (thick dotted line) is the propeller + duct without the current plate.
The line of duct efficiency (thin solid line) is the propeller-only efficiency with a straightening plate (thin dotted line) is the propeller alone efficiency without a straightening plate. In the case of the single efficiency, little difference was observed between the case with and without the current plate. That is, from this, it was found that if the duct was not provided, even if the current plate was provided at the lower end of the thruster, there was no effect of improving the efficiency.

From the comparison with the above, it can be seen that the efficiency is improved by providing the duct.

In comparison with the above, it was found that the efficiency was clearly improved by providing the current plate of the present invention. Up to about 7
%Rose.

[0026]

The present invention is embodied in the form described above and has the following effects.

The current plate maximizes the effect of the duct, increases the thrust, and increases the efficiency as a whole.

In particular, when a flow hole is provided in the current plate,
Since the water pressure is reduced, the structure of the current plate can be simplified.

[Brief description of the drawings]

FIG. 1 is a front view of a duct propeller provided with a current plate of the present invention and protruding from the bottom of a ship.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view of the current plate itself.

FIGS. 4A and 4B are a plan view and a main part view when a guide plate is provided at a front edge of a current plate.

FIGS. 5 (a), (b) and (c) are explanatory diagrams of the operation and effect of the current plate of the present application.

FIG. 6 is a diagram of a model test result of a duct propeller device including a current plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Duct 2 ... Strut 3 ... Mounting member 4 ... Propeller 5 ... Pod 6 ... Rectifying plate 7 ... Reinforcing rib 8 ... Holding member 9 ... Flow hole 10 ... Guide plate

Continued on the front page (72) Inventor Mutsuo Funo 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Kobe Plant (72) Inventor Mitsunobu Hino 3-chome, Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo No. 1 Kawasaki Heavy Industries, Ltd. Kobe Plant (72) Inventor Tatsuya Onodera 3-1-1 Higashi Kawasaki-cho, Chuo-ku, Kobe City, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Kobe Plant (56) References JP-A-59-73390 (JP, A) JP 7-8198 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B63H 5/14-5/16

Claims (8)

(57) [Claims] 1. A duct propeller protruding downward from the bottom of a ship, wherein a straightening plate is provided below or beside the duct, and at least protruding forward from a front edge of the duct.
The flow plate and duct form a long airfoil flow field.
A duct propeller device. 2. The straightening vane, which is formed in a curved or polygonal shape in front of the leading edge of the duct, in a plan view.
The duct propeller device as described. 3. The duct propeller device according to claim 1, wherein the straightening plate is a circular or polygonal straightening plate extending from the center near the front edge of the duct to a range including the duct propeller in plan view. 4. A grid-like rib is erected on the upper surface of the current plate,
The duct propeller device according to any one of claims 1 to 3, wherein the current plate is attached to the duct side using the lattice rib. 5. The duct propeller device according to claim 1, wherein the straightening plate is a straightening plate having a shape substantially along the duct when viewed from the front. 6. A current distribution plate having a plurality of flow holes.
The duct propeller device according to any one of claims 1 to 5. 7. A plurality of holding members for holding the current plate on the duct propeller side, including a support member extending forward and obliquely downward from a pod having a built-in power transmission mechanism of the propeller. A duct propeller device according to the paragraph. 8. The duct propeller device according to claim 1, wherein an arc-shaped guide plate is provided at least on a peripheral edge of a front edge portion of the current plate.