JPS58492A - Device for improving propulsion efficiency of ship - Google Patents

Abstract

PURPOSE:To enhance the propulsion efficiency of a propeller and at the same time reduce the manufacturing cost of the device by a structure wherein the setting angle of fins located at the side, at which the blade of the propeller moves upward, are rendered to be constant, resulting in effectively generating rotating currents. CONSTITUTION:The fins 12a2 and 12b2 located at the side, at which the blade of the propeller moves upward, are fitted in such a manner that the trailing edge of the fin is lower than the leading edge and the setting angle of the fin is kept constant throughout the entire length of the fin. The fins with constant setting angle can generate the rotating currents with opposite rotating direction to that caused by the blades of the propeller as effective as the fins twisted toward their tips can do. Consequently, the enhancement of the propulsion efficiency of the propeller and the reduction of the manufacturing cost of said device are resulted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for improving the propulsion performance of a ship.

Figures 1 and 2 show a structure in which a plurality of fins are attached to the front of the propeller in the stern of a normal l-axis, single-rudder vessel, and a rotational flow in the opposite direction to the rotation of the propeller is applied to the flow flowing into the propeller. This cancels the rotational flow behind the propeller and improves propulsion efficiency. This figure shows a first example of a conventional ship propulsion performance improvement device, and the fins mentioned above are generally called reaction fins.

In the first conventional ship propulsion performance improvement device shown in FIGS. 1 and 2, 1 is a hull, 1 is a bottom, 2 is a propeller; 3 is a propeller boss; 4 is a rudder; 5 is an upper rudder support member; 6 is a rudder handle, 7 is a shoe piece, 8 is a propeller cap, and 9 is a propeller shaft.The rear end of the coaxial shaft 9 is connected to the propeller 2, and the front end of the coaxial shaft 9 is connected to a prime mover (not shown). 10 is the stern boss (hereinafter referred to as the boss),
Same boss l.

It is fixed to frames 11a and 11b.

11a is an upper stern frame, 11b is a lower stern frame +12a, 12b.

12c, 12d, 12e, and 12f are reaction fins, and 13 is a load waterline.

Below is a case where propeller 2 rotates clockwise.

In Figure 2, 7 (n 12a, 12b).

12C, 12dt12e, and 12f will be explained. Note that when the propeller 2 rotates counterclockwise, it is opposite to when it rotates clockwise.

Figure 2 is an enlarged cross-sectional view taken along the nm line in Figure 1, Figure 3 is a side view from the port side, Figure 4 is a cross-sectional view taken along the line W-M in Figure 3, and Figure 5 is a cross-sectional view taken along the line W-M in Figure 3.
The figure is a V-V cross-sectional view of Figure 3, Figure 6 is a side view from the starboard side of Figure 2, Figure 7 is a cross-sectional view taken along ■-■ of Figure 6, and Figure 8 is a ■-■ of Figure 6. −■ It is a sectional view.

Note that the front and rear designations in FIG. 9 represent the front and rear sides of the hull 1, and α represents the mounting angle with respect to the propeller shaft centerline 14.

The mounting angle is the angle between the wing side of the fin and the center line of the propeller shaft.

Further, 14 indicates the center line of the propeller shaft.

Fins 12a, 12b, and 12c protrude radially from a boss 10 concentric with the propeller shaft 9.

12 d t 12 e s 12 'The installation angle α of the starboard side fins 12d, 12e, and 12f is.

The boss 10 is twisted so that it gradually becomes larger from the attachment root to the tip. on the other hand.

The mounting angle α of the port side fins 12a, 12k) and 12C is:
The boss 10 is twisted so that it gradually becomes smaller from the attachment root to the tip.

Generally, the flow distribution at the reaction fin mounting position is shown in FIG. 9. Note that 15 in Figure 2 is the rotation trajectory of the propeller tip, and the numerical value is the flow velocity V in the propeller axial direction.
It represents the ratio between x and ship speed ■, and a curve is a line connecting the lines with the same ratio. Further, the arrows are border torque indicators representing flow velocity components and directions in the ship width direction and the ship depth direction.

As seen in FIG. 9, the flow velocity Vx in the propeller axial direction increases as the distance from the boss 10 increases.

FIG. 10 is a vector diagram of the flow in a portion of the port side fin in FIG. 2 that is relatively close to the boss 10, and FIG. 11 is a vector diagram of the flow in a portion of the fin that is relatively close to the tip of the fin.

In Figure 2, 16 is the flow velocity component perpendicular to the fins, 17 is the flow size, and 18 is the flow velocity component in the propeller axial direction Vx, θ
indicates the angle of attack with respect to the fin ρ flow. As seen in Figures 10 and 11, the angle of attack for the fin flow is 0.
The tip of the fin is smaller than the base of the fin attachment.

When the propeller 2 rotates and the hull 1 travels in a fluid exhibiting the above-mentioned flowing hot water distribution, the reaction fins 12a, 12b, 12c, 1 provided in front of the propeller
2d.

The flow is changed by 12e and 12f in a direction opposite to the rotation of the propeller and flows into the propeller 2. Therefore, the rotational flow remaining behind the propeller is reduced, and the propulsion efficiency is increased accordingly.

At that time, the starboard side fins 12d and 12e.

12, f is twisted so that the mounting angle α is larger at the tip than at the mounting root. Thus the fins 12d, 12e of stream 17.

Since the angle of attack 0 with respect to 12f is approximately the same from the attachment root to the tip, a rotational flow in the opposite direction to the propeller rotation direction is effectively generated.

On the other hand, the port side fin 12a H12b +12C is
The mounting angle a is twisted such that the mounting angle a is smaller at the tip than at the mounting root. Therefore, the fins 12a of the stream 17
, 12b.

Since the angle of attack 0 with respect to 12C gradually decreases from the attachment root to the tip, a rotational flow in the direction opposite to the propeller rotation is not effectively generated.

Therefore, it has been found that with the first example of the conventional ship propulsion performance improving device, the propulsion efficiency due to the reaction fin effect cannot be sufficiently increased. The inventors discovered the above-mentioned drawbacks 1 and conducted experiments to further improve the propulsion efficiency, and the ship propulsion performance-L shown in FIGS. 12 to 15 was
We have already developed a device and filed an application.

FIG. 12 shows a conventional second cross section corresponding to the nn cross section in FIG.
FIG. 13 is a sectional view of the example ship propulsion performance improvement device, and FIG. 13 is a side view from the port side.

14 is a sectional view taken along line XIV-XIV in FIG. 13, and FIG. 15 is a sectional view taken along line xv-xv in FIG. 13.

In Figures 12 to 15, + 12al' 112
b+ + 12Ci + 12cl, t 12e+
't12f+ are fins attached radially to the boss 10.

Same phi: / 12al'+ I2b, t t2c,,
12dl + 12e+ ) 12f, all of which gradually become larger from the fin attachment root toward the tip.

In the conventional marine propulsion performance improvement device of the second example configured as shown in FIG. 2, when the propeller 2 rotates clockwise, the water flowing into the reaction fin is
2d, , 12e,.

As in the case of 12f, port side fins 12a1, 12b
Even in the case of 1°12C6, the mounting angle α gradually increases from the fin mounting root to the tip.

The angle of attack θ with respect to the water flow is approximately the same from the fin attachment root to the tip. Therefore, the port side fin 12al H
12bl+! L2eiJKfu-tp te 1 Enki right・'
Similar to the side fins ``2d+ + 12e, t 12f, a rotational flow in the direction opposite to the propeller rotation is effectively generated and flows into the propeller, so the propulsion efficiency of the 9 ship propulsion performance improvement device is equal to that of the conventional ship propulsion 19a. , 19b,
19C, 19d, 19e, 19f.

This is a third example of a conventional ship propulsion performance improvement device in which the reaction fins are reinforced to prevent vibration. Further, the reinforcing material may be attached not only to the center of the fin but also to the tip of the fin as shown in the figure.

However, in the ship propulsion performance improvement devices of the second and third examples of the first fixed conventional ship propulsion performance improvement device, the mounting angle α of the fins on both sides of the fins with respect to the propeller shaft 9 gradually increases from the fin mounting root to the tip. Because of its twisted shape, the production cost was extremely high.

Therefore, the two inventors conducted further experiments from the viewpoint of reducing production costs, and found that on the side where the blades of the propeller rotating in the direction of forward movement of the ship move upward, the mounting angle of the fins relative to the center line of the propeller axis was adjusted to the trailing edge. Even with reaction fins in which the length from the boss attachment point to the tip of the fin is the same on the downhill side, the propulsion efficiency will hardly decrease compared to the propulsion efficiency of the ship propulsion performance improvement device shown in Figures 16 and 17. It became clear.

The present invention was invented based on the results of the above experiments.

In other words, the present invention provides a plurality of screw propellers in front of the stern screw propeller that protrude radially from a boss surrounding the propeller shaft and are formed so as to convert the direction of the flow flowing into the propeller into a direction opposite to the rotating direction of the propeller. In a reaction fin equipped with fins, on the side where the blades of the propeller rotating in the direction of forward movement of the ship move downward, the mounting angle of the fin with respect to the center line of the propeller shaft is set so that the mounting angle of the boss is upward from the trailing edge. From there, twist the fin so that it becomes larger toward the tip of the fin, and on the side where the blade moves upward, adjust the mounting angle of the fin with respect to the center line of the propeller shaft from the mounting part of the boss to the fin in a downward direction from the trailing edge. The purpose is to provide a ship propulsion performance improvement device that can reduce costs while maintaining the propulsion efficiency of conventional ship propulsion performance improvement devices. It is.

The following nine preferred embodiments of the present invention are shown in FIGS. 18 and 1.
This will be explained using an example shown in FIG. Note that in FIGS. 18 and 19, parts equivalent to those in FIGS. 1 to 16 are designated by the same reference numerals.

The two embodiments also show cases in which the propeller rotates clockwise. Therefore, if the propeller is rotating counterclockwise, the opposite is true.

Figure 18 is a cross-sectional view of Figure 19.

A cross-sectional view of this embodiment corresponding to cross section 11 in FIG. 1, No. 19
The figure is a side view seen from the starboard side.

In FIGS. 18 and 19, 12a.

12b is a port side fin, and the same port side fin 12a is
, l 1zb, The mounting angle α with respect to the propeller shaft center line 14 is the same from the mounting root of Habos 1o to the tip of the fin, and it is merely inclined with respect to the propeller shaft center line 14 and is not twisted. . Note that the starboard side fin 12d.

12f is the same fin as shown in FIG. 16 and the like.

In this embodiment configured in this way.

A propeller shaft 9 is rotated by a motor (not shown) inside the ship, and when the propeller 2 rotates to the right due to the rotation of the propeller shaft 9, the ship 1 sails. At that time, the flow of water at the stern is as follows: fin 12az r 12b2t 12't + 1
2'+, the rotation direction is changed to the left and flows into the propeller 2. In this case, the port side fins 12att 12b
t is twisted 3, but the twisted conventional fin 12a,
.

12b, there is no big difference in action and effect. On the other hand, the rotational flow described above reduces the clockwise rotational flow generated behind the propeller 2, increasing the propulsion efficiency.

FIG. 20 compares the reduction in shaft horsepower between the conventional ship propulsion performance improving device and the above-described embodiment of the present invention.

The dotted line in FIG. 20 indicates the embodiment of the present invention.
Regarding the ship propulsion performance improving device shown in FIGS. 16 and 17, the solid line indicates the port side fin in FIG. The results of measuring shaft horsepower based on ship speed for a ship propulsion performance improvement device twisted so that the mounting angle decreases toward the tip are shown below. The horizontal axis in Figure 20 is ship speed.

The vertical axis shows the value obtained by dividing the difference in shaft horsepower between with and without reaction fins by the shaft horsepower without reaction fins. In addition, the dotted line, solid line, and chain line indicated by A (hereinafter,
It's called three lines. ) indicates the rate of decrease in shaft horsepower due to a decrease in rotational flow, and the three lines indicated by B indicate the rate of increase in shaft horsepower resistance due to increased resistance due to the provision of reaction fins. Therefore, the positive elements of the three lines A for increasing propulsion efficiency and the negative elements of the three lines B cancel each other out, resulting in the three lines of the reduction ratio of the shaft horsepower after deducting the increase in resistance of C.

Comparing the three lines in area C in Figure 20.

Although the dotted line showing the case of the embodiment of the present invention shows that the mounting angle of the port side fin increases toward the tip or the solid line showing the case of action fin, the percentage decrease in shaft horsepower after deducting the increase in resistance is slightly smaller. , the reduction rate of the shaft horsepower after deducting the increase in resistance is significantly larger than the chain line showing the case of a marine propulsion performance improvement device in which the mounting angle of the port side fin decreases toward the tip. Namely.

The propulsion efficiency of this embodiment is approximately equal to the propulsion efficiency of the third conventional ship propulsion performance improvement device shown in FIGS. 16 and 17.

As described above in detail in the above-described embodiments, two parts of the present invention protrude radially from a boss that surrounds the propeller shaft at the front of the stern screw propeller, and direct the direction of the flow flowing into the propeller in the direction of rotation of the propeller. In a reaction fin equipped with a plurality of fins formed to convert in the opposite direction, the center line of the propeller axis of the fin is on the side where the blades of the propeller rotating in the direction of forward movement of the ship move downward. Twist the mounting angle with respect to the center line of the propeller shaft on the side where the blade moves upward by twisting the mounting angle of the fin with respect to the center line of the propeller shaft. is the same from the attachment part of the boss to the tip of the fin in the downward direction of the trailing edge, so that the blade of the propeller rotating in the direction of moving the ship forward moves upward. The propulsive efficiency is increased to the same extent as the reaction fin (Fig. 16), in which the fin on the side has a thickly twisted tip (Fig. 16), and the fin on the side where the wing moves upward does not need to be twisted, so it is easy to work. Therefore, there is an advantage that costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a side view of a conventional marine propulsion performance improvement device showing the first example, Fig. 2 is an enlarged cross-sectional view taken along the i-n line in Fig. 1, Fig. 3 is a side view from the port side, and Fig. 4 is a cross-sectional view taken along the line ■-tv in Figure 3, Figure 5 is a cross-sectional view taken along the line V-V in Figure 3, Figure 6 is a side view from the starboard side in Figure 2, and Figure 7 is a cross-sectional view taken along the line ■- in Figure 6. ■Cross-sectional view,
FIG. 8 is a sectional view taken along the line ■-■ in FIG. 6. Figure 9 is a hot water distribution diagram at the reaction fin installation position, Figure 10 is a vector diagram of the flow in a portion of the fin relatively close to the fin boss, Figure 11 is a vector diagram of flow in a portion relatively close to the tip of the fin, Fig. 12 is an enlarged cross-sectional view of the main parts of a conventional ship propulsion performance improvement device showing a second example, Fig. 13 is a side view from the port side, and Fig. 14 is a W-XI of Fig. 13.
FIG. 15 is a sectional view taken along the line xv-xv in FIG. 13, FIG. 16 is an enlarged sectional view of the main parts of a conventional third example of a ship propulsion performance improvement device, and FIG. 17 is a view from the starboard side. side view,
FIG. 18 is an enlarged sectional view of a main part of an embodiment according to the present invention;
FIG. 19 is a side view of the fin as seen from the starboard side, and FIG. 20 is a graph comparing the reduction ratio of shaft horsepower between the conventional reaction fin and the embodiment of the present invention. 1...Hull +2°''・Propeller 4@@@Rudder 9''''Propeller shaft I Qass boss +11a''I・Upper stern frame, 11b...Lower stern frame 2nd
Figure 6 Figure 9 Figure 10 Figure 12 Figure 16 Figure 17

Claims (1)

[Claims] In front of the screw propeller at the stern, a plurality of fins are provided that protrude radially from a boss surrounding the propeller shaft and are formed so as to convert the direction of the flow flowing into the propeller into a direction opposite to the rotating direction of the propeller. In the reaction fin, on the side where the blades of the propeller rotating in the direction of forward movement of the ship move downward, the mounting angle of the fin with respect to the center line of the propeller axis is adjusted upward from the attachment part of the boss to the fin. Twist so that it becomes larger towards the tip of the fin, and on the side where the blade moves upward, adjust the mounting angle of the fin with respect to the center line of the propeller shaft downward from the mounting part of the boss to the tip of the fin. A ship propulsion performance improvement device characterized by: