JPS595678Y2 - Marine reaction fin - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a reaction fin provided upstream of a propulsion screw propeller installed at the stern of a ship.

Generally, a rotational flow in the same direction as the propeller rotation remains behind the propulsion screw propeller installed at the rear of the ship (downstream side), but by installing reaction fins in front of the propeller (upstream side), By providing a rotational flow in the opposite direction to the rotational flow behind the propeller, the rotational energy of the propeller wake can be reduced, and the propulsion efficiency can be increased by that amount.

In conventional reaction fins, the mounting angle of the fin was the same on both port and starboard sides, regardless of the mounting position, in order to provide a rotating flow in the opposite direction to the backward rotating flow of the propeller.

FIG. 1 is a perspective view showing a stern section provided with conventional reaction fins.

Note that the propulsion screw propeller is omitted.

In the figure, 1 is a stern frame, 2 is a rudder, 3 is a shoe piece that supports the rudder 2, and 7 is a boss of a fin formed on the stern frame 1 so as to surround a propeller shaft (not shown). Upper center fin 5A, lower center fin 5B, port side fins 6a, 6b, 6C, starboard side fins 6d, 6e,
6f protrudes radially.

Furthermore, fin reinforcement rings 4 are attached to the tips of these fins.
a and 4b are attached.

These fins are attached at equal inclination angles to the propeller axis 8 in order to give the screw propeller a swirling flow in a direction opposite to the direction of propeller rotation.

For example, when a propeller generates thrust in a direction that moves the ship forward, the direction of rotation is clockwise when viewed from the stern (hereinafter, this will be referred to as a clockwise propeller, and the opposite will be referred to as a counterclockwise propeller).

), the same inclination angle θ as shown in FIG. 2 is given.

The upper center fin 5A has one end attached to the boss 7 and the other end to the stern frame 1, and the lower center fin 5B has one end attached to the boss 7 and the other end to the shoe piece 3. Both fins 5A and 5B are attached to the propeller axis 8. The fin is given an inclination angle θ equal to that of the other fins.

Further, the upper ends of the reinforcing rings 4a, 4b are attached to the stern frame 1, and the lower ends are attached to the shoe beads 3.

FIG. 3 is a diagram showing the flow velocity distribution during propeller operation in a cross section just before the propeller when no reaction fins are installed, as seen from the stern rear.

In the figure, 9 is the propeller blade tip circle, 10 is the propeller boss, and 11
is the hull centerline that symmetrically divides the hull cross section into two.

Further, arrow a is a vector representing a certain amount of flow velocity on a cross section perpendicular to the longitudinal direction of the ship, and curve b is a contour line representing a certain amount of flow speed in the traveling direction.

FIG. 4 is a diagram showing the flow velocity distribution during propeller operation in a cross section just before the propeller when the reaction fins are installed, as seen from the rear of the ship.

Looking at Figure 3, it can be seen that the flow at the propeller position is upward near the bottom and downward near the top.

Therefore, in the case of a clockwise propeller, the starboard side has a rotational flow in the opposite direction to the rotational flow behind the propeller, and the port side has a rotational flow in the same direction as the rotational flow behind the propeller.A reaction fin is provided to provide a rotational flow in the opposite direction to the rotational flow behind the propeller. When the starboard fin 6
d, 6e, and 6f have small angles of attack with respect to the flow, and port side fins 6a, 6b, and 6C have large angles of attack, so as shown in Figure 4, compared to when no reaction fins are installed. , on the starboard side, the direction of the flow hardly changes, and the effect of improving propulsion performance cannot be obtained, and on the port side,
The direction and speed of the flow change dramatically, creating vortices.

In the case of a counterclockwise propeller, the opposite is true; on the starboard side, the angle of attack with respect to the flow is large, causing vortices, etc., and on the port side, the angle of attack with respect to the flow is small, and the effect of improving propulsion performance cannot be obtained.

Therefore, conventional reaction fins have the following drawbacks.

(1) Even if reaction fins are installed, not only is it not possible to expect much improvement in propulsion efficiency, but it may even become a factor in increasing the drag.

(2) The propeller excitation force becomes larger than when no reaction fins are installed, which increases the hull vibration.

(3) Cavillation of the propeller will be greater than when no reaction fins are installed, and the propeller will be damaged.

The present invention was proposed with the aim of eliminating the above-mentioned drawbacks, and in order to give a rotational flow in the opposite direction to the propeller rotation direction to the flow flowing into the propeller for propulsion at the stern of the ship. In a reaction fin having a plurality of fins projecting approximately radially around the propeller axis, the plurality of fins are shaped to have a substantially constant inclination angle with respect to the propeller axis from the root to the tip without twisting, and , a ship characterized in that when the propeller rotates in a direction that moves the ship forward, the inclination angle of the fin on the side where the blade tip of the propeller descends is larger than the inclination angle of the fin on the side where the propeller blade tip rises. We provide reaction fins for

According to the reaction fin of the present invention, the angle of attack of each fin is adjusted so that the angle of attack of each fin is the most suitable angle of attack for changing the flow along the hull surface at the stern in the direction opposite to the rotational direction of the propeller blade at each position. By setting the inclination angles of the fins to the propeller axis appropriately, it is possible to effectively reduce the rotational flow generated in the wake of the propeller and greatly improve propulsion efficiency, and the fins also reduce the flow near the stern. It is not disturbed and does not cause an increase in resistance.

Therefore, an increase in the propeller excitation force and the resulting vibration of the ship body is not caused, and the occurrence of cavitation in the propeller blades can be reduced.

Furthermore, in the device of this invention, each fin has a shape in which the angle of inclination with respect to the propeller axis is almost constant from the root to the tip, and there is no twist, making it extremely easy to set the inclination angle when manufacturing the fins and attaching them to the boss. It has the advantage of being easy.

Next, one embodiment of the device of the present invention will be described based on the drawings.

In Figures 5 to 8, reference numeral 17 denotes a boss surrounding the propeller shaft 20, which is shaped into the stern frame and is fixed to the stern frame from the boss 17 along the hull center plane, including an upper center fin 15A, a lower center fin 15B, and a starboard side fin. 16
d, 16 e, 16 f, port side fin 16 a,
16 b and 16 C are provided to protrude radially.

14 is a fin reinforcing ring to which the tips of each fin are connected, and 19 is a screw propeller attached to the tip of the propeller shaft 20.

Figure 5 is a view of the action fin attached to the stern section seen from the rear of the ship, Figure 6 is a sectional view taken along line VI-Vl in Figure 5, and Figures 7 and 8 are Vll-- in Figure 6. VI
It is a sectional view along the I line and the ■■-■ line.

In FIGS. 7 and 8, αe and αb are the starboard side fin 18e and the port side fin 16b with respect to the propeller axis 18.
At an inclination angle of The magnitude of the inclination angle a with respect to the propeller axis 18 is set so that it has an angle.

That is, for example, in the case of a clockwise propeller, each fin has a leading edge (
(upstream side tip) The inclination angle is given to point to the right side with respect to the propeller axis 18, but as shown in Figs. 7 and 8, the port side fins 13a, 13b, 13C have a small inclination angle and Side fins 13d, 13e, 13f
increases the tilt angle.

For a counterclockwise propeller, do the opposite.

Further, the inclination of each fin with respect to the propeller axis 1B is constant from the root to the tip, and there is no twist, and the tip is fixed to the reinforcing ring 14 and the root to the boss 17.

In addition, as shown in Fig. 5, the reinforcing ring 14 is opened forward by an appropriate angle β in order to obtain an optimal angle of attack with respect to the flow at the stern, and in some cases, the position on the circumference may be adjusted by β. You can change the size of.

In such a device, each fin changes its inclination angle depending on its position, and the angle of attack is optimal for changing the flow in the direction opposite to the propeller rotation direction without disturbing the water flow. When the wheel rotates and the ship sails,
The flow passing through each fin is undisturbed and is redirected in the opposite direction to the propeller rotation direction.
9.

For example, in the case of a clockwise propeller, the starboard side fin 13d,
The inclination angle of 13e and 13f is the port side fin 13a and 13.
The angles of inclination are larger than those of b and 13c, and this makes them the optimal angles of attack for the flow, so the updraft on the starboard side can be directed upward and the updraft on the port side can be directed downward without disturbing the flow. , it is possible to most effectively generate a flow in the direction opposite to the rotation axis direction of the propeller 19 while keeping the resistance of each fin small.

In the case of a counterclockwise propeller, contrary to the case of a clockwise propeller, the inclination angle of the port side fin is made larger than that of the starboard side fin to most effectively generate a flow in the opposite direction to the propeller rotation direction. Can be done.

In addition, since each fin has a shape with no twist, the angle of inclination is substantially constant from the root to the tip, it is extremely easy to manufacture the fin and set the angle of inclination when attaching it to the boss 17.

In addition, the fin reinforcing limb 14 is also opened forward by an appropriate angle β, and in some cases, the size of β is adjusted depending on the position on the circumference, so the angle of attack is optimal for the flow at the stern. Do not cause an increase in resistance.

In this way, this device can remove the rotational force behind the propeller 19 without increasing the hull resistance.
Not only can propulsion efficiency be significantly increased, but propeller excitation force and hull vibration are reduced.

It also reduces propeller cavitation.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the stern of a ship equipped with conventional reaction fins, FIG. 2 is an explanatory view showing the inclination angle of the fins with respect to the propeller axis 8 in the above device, and FIGS. 3 and 4. Figure 5 is a flow velocity distribution diagram during propeller operation at the position just before the screw propeller when reaction fins are not installed and when reaction fins are installed, Figure 5 is an elevational view of the reaction fin of the present invention seen from the stern rear, and Figure 6 is a diagram of the flow velocity distribution during propeller operation. FIG. 5 is a cross-sectional view taken along the line VI--VI, and FIGS. 7 and 8 are cross-sectional views taken along the -Vtt line and the ■1-■ line in FIG. DESCRIPTION OF SYMBOLS 1... Stern frame, 2... Rudder, 3... Shoe piece, 4 a, 4 b, 14-7in reinforcing ring, 15A, 15A... Upper center fin, 15 B
, 15 B...Lower center fin, 6a, 6b,
6C, 16a, 16b, 16C-- Port side fin, 6d, 6e, 6 f, 16d, 16e
, 16f... Starboard side fin, 7, 17... Fin boss, 8, 18... Propeller axis, 9... Propeller blade tip circle, 10... Propeller boss, 11... Hull center Line, 19...screw propeller, 20...pro-hetero shaft.

Claims (1)

[Scope of utility model registration request] A reaction system equipped with multiple fins that protrude almost radially from the propeller axis upstream of the screw propeller in order to provide a rotating flow in the opposite direction to the propeller rotation direction to the flow flowing into the stern propulsion screw propeller. In the fin, the plurality of fins have a shape in which the angle of inclination with respect to the propeller axis is substantially constant from the root to the tip, and there is no twist, and the direction in which the propeller moves the ship forward is such that when the propeller rotates, the tip of the blade of the propeller descends. A reaction fin for a ship, characterized in that the angle of inclination of the fin on the side where the tip of the propeller blade rises is larger than the angle of inclination of the fin on the side where the tip of the propeller blade rises.