JP2005112257A - Propeller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a propeller for which a cavitation is reduced without increasing the blade area, and at the same time, of which the propeller efficiency is increased. <P>SOLUTION: For this propeller blade 1A, in a propeller which is used for a ship, a flap 11 which is formed to have a specified blade length β and a specified blade angle α is provided in a rear edge side specified region 5 on the propeller rear edge h side from a specified position (0.6R) on the blade root section side to the blade distal end (1.0R) side. Also, a distal end side specified region 7 from a specified position (0.7R) on the blade root side to the blade distal end (1.0R) side is formed into a shape wherein a pitch ratio is reduced by a specified straight line distribution or a specified curved line distribution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a propeller capable of reducing cavitation generated by rotation without increasing the blade area.

  Generally, a ship is provided with a propeller at the lower rear end of the hull, and the propulsion of the ship is obtained by rotating the propeller. This propeller has a blade shape with a streamline cross section in the rotation direction.

FIG. 5 is a diagram showing a conventional general propeller. In FIG. 5, when the propeller blade 1 is the rotation center O of the boss 3, the length of the radius d of the boss 3 is substantially determined from the length from the rotation center O to the tip end of the radius R. It has a deducted length.
In the propeller blade 1 having such a shape, the thickness of the blade cross section gradually increases from the tip of the propeller (tip of radius R) toward the blade root. In addition, the thickness of the blade cross section of the propeller blade 1 is gradually increased from the front edge f toward the blade vertical line and gradually decreased toward the rear edge h, and the back surface is relatively straight. Is formed. That is, the blade surface of the propeller blade 1 is formed in a so-called streamlined cross section.

In the conventional propeller blade 1 having such a blade cross section, when designing a propeller with severe cavitation, it is necessary to increase the blade area more than usual, and as a result, the propeller efficiency is deteriorated.
Cavitation is generally a phenomenon in which a low-pressure part of a liquid flowing at high speed evaporates and vapor pockets are formed in a very short time, which collapses and disappears in a very short time. Say. When this occurs, the performance of the fluid device deteriorates, the fluid device vibrates, noise is generated, and erosion occurs. Since the propeller of a ship also rotates underwater, it is known that cavitation occurs around the propeller depending on the shape of the propeller, the rotation speed of the propeller, and other conditions.

Therefore, another conventional propeller has been proposed in which the wing shape is devised to suppress cavitation so as not to reduce the propeller efficiency.
In this other conventional propeller, the thickness of the trailing edge side of the blade cross section is made thicker in the predetermined region near the boss side than the conventional one, and in the predetermined region on the tip side far from the boss, the blade cross section is on the leading edge side. The radius is made smaller than the conventional one (see Patent Document 1).
According to the propeller having such a blade shape, even if the occurrence of cavitation is suppressed by reducing the rotation speed, the propeller efficiency is not lowered without increasing the diameter of the propeller.
The description and drawings of Japanese Patent Laid-Open No. 2000-79897.

However, according to other conventional propellers described above, the thickness of the trailing edge of the blade cross section is set to be thicker than that of the conventional one in a predetermined region near the boss side, so the blade area is reduced in order to reduce cavitation. The conventional method, which is to be dealt with by increasing from the conventional one, is adopted as it is, and the purpose of reducing cavitation without increasing the blade area cannot be achieved. Further, when the blade area is increased, there is a disadvantage that the propeller efficiency is deteriorated as a result.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a propeller that reduces cavitation without increasing the blade area and does not reduce propeller efficiency.

In order to achieve the above object, a propeller according to a first aspect of the present invention is a propeller used in a ship, wherein a predetermined blade length is provided in a predetermined region on a trailing edge side of a propeller trailing edge from a predetermined position on a blade root side to a blade tip side. In addition, a flap formed at a predetermined blade angle is provided, and the pitch ratio is reduced by a predetermined linear distribution or a predetermined curve distribution in a predetermined region on the tip side from a predetermined position on the blade root side to the blade tip side. It is characterized in that it is formed in the shape.
According to a second aspect of the present invention, in the propeller according to the first aspect of the present invention, the flap provided in the predetermined region on the trailing edge side is 0.6 R to 0 when the radius from the center of the boss to the tip of the propeller is R. In the region up to 0.7R, flaps are gradually formed, and in the region from 0.7R to 0.95R, α is the flap blade angle, β is the flap blade length, and L is the total propeller blade length. In addition, a flap is formed in the range of 0.05 L ≦ β ≦ 0.15 L, 1 [degree] ≦ α ≦ 3 [degree], and gradually flaps toward the tip in the region of 0.95R to 1.0R. It is characterized by being formed in a shape that eliminates this.
According to a third aspect of the present invention, in the propeller according to the first aspect of the present invention, the predetermined region on the tip side is a predetermined position on the blade root side when the radius from the center of the boss to the tip of the propeller is R. .7R to blade tip 1.0R are linearly formed into a shape with a reduced pitch ratio at a constant ratio, or formed into a shape with a predetermined curve distribution with a reduced pitch ratio. It is characterized by this.

The present invention has the following effects.
(1) Since a flap formed at a predetermined blade length and a predetermined blade angle is provided in a predetermined region on the trailing edge side of the propeller trailing edge side, lift increases.
(2) Since the tip-side predetermined region from the predetermined position on the blade root side to the blade tip side has a predetermined linear distribution or a predetermined curve distribution with a reduced pitch ratio, the blade cross-sectional area is increased. Therefore, cavitation can be reduced, and a decrease in propeller efficiency can be prevented.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1 to 4 are for explaining a propeller according to the best mode for carrying out the present invention. FIG. 1 is a diagram showing a propeller according to the best mode for carrying out the present invention. FIG. 2 is an explanatory diagram for explaining various performances according to the dimensions of the flap formed on the propeller trailing edge h side of the propeller according to the best mode for carrying out the present invention in comparison with the conventional one. FIG. 3 is a characteristic diagram for explaining the setting of the pitch ratio of the predetermined region on the tip side of the propeller according to the best mode for carrying out the present invention in comparison with the conventional one. FIG. 4 is an explanatory diagram for explaining the relationship between the pressure distribution and the cavitation related to the blade section of the propeller according to the best mode for carrying out the present invention in comparison with the conventional one. In the best mode for carrying out the present invention, the same components as those in the conventional propeller are denoted by the same reference numerals and described.

  1A is a view showing the entire propeller, FIG. 1B is a view showing the entire blade section of a predetermined portion, and FIG. 1C is an enlarged view of the trailing edge of the blade section. FIG. In FIG. 3, the horizontal axis represents the pitch ratio, and the vertical axis represents the position (r / R) relative to the propeller radius R of the distance r from the rotation center O of the propeller blade cross-section leading edge f. In FIG. 4, the dotted line shows the pressure distribution by the propeller according to the present invention, and the solid line shows the pressure distribution by the conventional propeller.

  1A, 1B, and 1C, a propeller blade 1A according to the best mode for carrying out the present invention is a blade from a predetermined position (0.6R) on the blade root side of the propeller. A flap 11 formed at a predetermined blade width β and a predetermined blade angle α is provided in a predetermined region 5 on the trailing edge side of the propeller trailing edge h up to the tip (1.0R) side, and on the blade root side of the propeller The tip-side predetermined region 7 from the predetermined position (0.7R) to the blade tip (1.0R) side is formed in a shape in which the pitch ratio is reduced by a predetermined linear distribution or a predetermined curve distribution. .

Next, the blade angle α and the blade length β of the flap 11 will be described in more detail. The blade angle α of the flap 11 is an angle formed by the back surface 11k of the flap 11 with respect to the horizontal line Y of the propeller blade 1A, as shown in FIG. The blade length β of the flap 11 is a distance from the trailing edge h of the propeller blade 1A to a predetermined position on the blade center axis side. Moreover, the code | symbol L is a blade | wing length (blade width) including the flap 11 of the propeller blade | wing 1A, as shown in FIG.1 (b).
Under such conditions, the blade angle α and the blade length β of the flap 11 are
0.05L ≦ β ≦ 0.15L (1)
1 [degree] ≦ α ≦ 3 [degree] (2)
The value given by.

  That is, in the propeller blade 1A according to the best mode for carrying out the present invention, the flap 11 provided in the predetermined region 5 on the trailing edge side is from the rotation center O of the boss 3 as shown in FIG. When the radius to the propeller tip is R, flaps are gradually formed in the region from 0.6R to 0.7R, and α is the blade angle of the flap in the region from 0.7R to 0.95R. When β is the flap blade length and L is the total blade length of the propeller, the flap is formed within the range of 0.05 L ≦ β ≦ 0.15 L, 1 [degree] ≦ α ≦ 3 [degree]. In addition, in the region from 0.95R to 1.0R, the flap is gradually eliminated toward the tip (1.0R).

Further, the propeller blade 1A according to the best mode for carrying out the present invention is configured so that the tip-side predetermined region 7 is moved from a predetermined position (0.7R) on the blade root side as indicated by a dotted line U in FIG. The tip (1.0R) is linearly shaped with a reduced pitch ratio at a constant ratio. Like the conventional propeller blade 1, the blade root side position to the blade tip has a constant pitch ratio. It is formed in a shape different from that configured as it is (see the solid line W in FIG. 3).
In addition, as the propeller blade 1A according to another best mode for carrying out the present invention, the tip side predetermined region 7 is set at a predetermined position (0.7R on the blade root side) as shown by a dotted line V in FIG. ) To the blade tip (1.0R) may be formed in a shape with a predetermined curve distribution and a reduced pitch ratio.

  In the propeller blade 1A according to the best mode for carrying out the present invention as described above, the propeller trailing edge from the predetermined position (0.6R) on the blade root side of the propeller to the blade tip (1.0R) side A flap 11 formed at a predetermined blade width β and a predetermined blade angle α is provided in the h-side trailing edge side predetermined region 5, and the blade tip (from a predetermined position (0.7R) on the blade root side of the propeller) The tip side predetermined region 7 up to the (1.0R) side is formed into a shape with a pitch ratio reduced by a predetermined linear distribution or a predetermined curve distribution. As a result, cavitation can be reduced without increasing the blade area.

  The propeller blade 1A having such a shape is formed as follows. For the wing-shaped propeller blade 1A having the above-described value, a blade sand mold is prepared and nickel aluminum bronze is dissolved and dissolved in the sand mold. Thereafter, the propeller blade 1A can be obtained by cutting with a numerical control (NC) cutting machine and performing a polishing finish.

In the propeller blade 1A according to the best mode for carrying out the present invention, as shown in FIG. 2, when the blade length β of the flap 11 and the blade angle α of the flap 11 are selected, the propeller The operating point J, the thrust coefficient Kt, the torque coefficient Kq, and the propeller efficiency ηo of the blade 1A are values as shown in FIG. For example, when the blade length β = 0.15L and the blade angle α = 2 [degrees], J = 0.726, Kt = 0.171, Kq = 0.0301, and ηo = 0.656. . When the blade length β is set to 0.10 L and the blade angle α is set to 2 degrees, J = 0.726, Kt = 0.171, Kq = 0.0300, and ηo = 0.658. . Further, when the blade length β is set to 0.10 L and the blade angle α is set to 3 degrees, J = 0.726, Kt = 0.171, Kq = 0.0301, and ηo = 0.657. . In addition, when the blade length β is set to 0.05 L and the blade angle α is set to 3 degrees, J = 0.726, Kt = 0.171, Kq = 0.0300, and ηo = 0.659. Become.
On the other hand, in the conventional propeller blade 1, since no flap is formed, the blade length β and the blade angle α of the flap 11 are not set, and J = 0.726 and Kt = 0.171. Kq = 0.0299 and ηo = 0.62.
From the above, it can be seen from the numerical values that in the propeller blade 1A according to the best mode for carrying out the present invention, the efficiency ηo is almost the same as the conventional one and the occurrence of cavitation is suppressed.

These are shown in FIG. 4 as follows. That is, in FIG. 4, the blade cross section of the propeller blade 1A according to the best mode for carrying out the present invention is indicated by a dotted line, and the blade cross section of the conventional propeller blade 1 is indicated by a solid line.
In the case of the blade cross section of the conventional propeller blade 1 shown by the solid line in FIG. 4, the pitch ratio is constant from the blade root side to the tip of the propeller as shown in FIG. As shown in FIG. 4, S (solid line) is incident on the wing at a large angle of attack. As a result, a negative pressure distribution as shown by the solid line in FIG. 4 is formed on the surface M side of the conventional propeller blade 1. This negative pressure distribution causes cavitation in the portion beyond the boiling point shown in FIG.

  Similarly, in the case of the blade surface of the propeller blade 1A according to the best mode for carrying out the present invention shown by the dotted line in FIG. 4, a predetermined position (0 .7R) to the propeller tip so that the pitch ratio decreases linearly (or the propeller tip from a predetermined position (0.7R) on the blade root side as indicated by reference numeral V in FIG. Therefore, the streamline Sa (dotted line) is incident on the blade with a small angle of attack as shown in FIG. Thereby, a negative pressure distribution as shown by a dotted line in FIG. 4 is formed on the surface M side of the propeller blade 1A according to the best mode for carrying out the present invention.

The negative pressure distribution (dotted line) by the propeller blade 1A according to the best mode for carrying out the present invention is smaller than the negative pressure distribution (solid line) by the conventional propeller blade 1 on the blade leading edge side where cavitation occurs. Therefore, the portion beyond the boiling point can be made small, and the occurrence of cavitation can be reduced.
In other words, the conventional propeller blade 1 has a pressure distribution as shown by the solid line in FIG. 4 and the portion exceeding the boiling point increases and cavitation increases. On the other hand, in the best mode for carrying out the present invention, In the propeller blade 1A, it can be seen that the portion exceeding the boiling point is reduced as shown by the dotted line in FIG. 4 and the cavitation is surely reduced.

As described above, according to the propeller blade 1A according to the best mode for carrying out the present invention, since the blade cross section is formed in the shape as described above, the following effects are obtained.
(1) Since the flap 11 formed at the predetermined blade length β and the predetermined blade angle α is provided in the predetermined region 5 on the trailing edge side of the propeller trailing edge h, the lift increases.
(2) The tip-side predetermined region 7 from a predetermined position (0.7R) on the blade root side to the blade tip (1.0R) side is a predetermined linear distribution or diagram as indicated by a symbol U in FIG. Since the pitch ratio is decreased with a predetermined curve distribution V as indicated by reference numeral 3 in FIG. 3, cavitation can be reduced without increasing the blade area, and a reduction in propeller efficiency can be prevented.
In addition, according to the propeller blade 1A according to the best mode for carrying out the present invention described above, the tip-side predetermined region 7 has been described with a curve as shown by the characteristic V shown in FIG. 3, but is limited to this curve. Instead, any shape may be used as long as the pitch ratio can be reduced at a predetermined reduction rate from a predetermined position on the blade root side toward the blade tip.

It is a figure which shows the propeller which concerns on the best form for implementing this invention. It is explanatory drawing for demonstrating the various performance by the dimension of the flap etc. which are formed in the propeller trailing edge part h side of the propeller which concerns on the best form for implementing this invention compared with a conventional one. FIG. 6 is a characteristic diagram for explaining the setting of the pitch ratio of the predetermined region on the tip side of the propeller according to the best mode for carrying out the present invention in comparison with the conventional one. It is explanatory drawing for demonstrating the relationship between the pressure distribution and cavitation which concern on the blade | wing cross section of the propeller which concerns on the best form for implementing this invention compared with the conventional one. It is a figure which shows the conventional common propeller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A Propeller 3 Boss 5 Rear edge side predetermined area 7 Tip side predetermined area 11 Flap R Propeller radius r Propeller front edge radius α Flap blade angle β Flap blade length

Claims (3)

In propellers used on ships,
A flap formed at a predetermined blade length and a predetermined blade angle is provided in a predetermined region on the trailing edge side of the propeller trailing edge from a predetermined position on the blade root side to the blade tip side, and from a predetermined position on the blade root side. A propeller characterized in that a predetermined region on the tip side to the blade tip side has a shape obtained by decreasing a pitch ratio with a predetermined linear distribution or a predetermined curve distribution.   When the radius from the center of the boss to the tip of the propeller is R, the flap provided in the predetermined region on the trailing edge side is gradually formed in the region from 0.6R to 0.7R. In the region of 0.95R, 0.05L ≦ β ≦ 0.15L, 1 [degree] ≦ when α is the flap blade angle, β is the flap blade length, and L is the total blade length of the propeller. 2. The flap according to claim 1, wherein the flap is formed within a range of α ≦ 3 [degrees], and the flap gradually disappears toward the tip in the region of 0.95R to 1.0R. propeller.   The tip-side predetermined region is linearly constant from 0.7R, which is a predetermined position on the blade root side, to 1.0R, which is the blade tip, where R is a radius from the center of the boss to the tip of the propeller. 2. The propeller according to claim 1, wherein the propeller is formed in a shape with a pitch ratio reduced by a ratio, or formed in a shape with a pitch ratio reduced by a predetermined curve distribution.

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