JP5244341B2 - Marine propulsion device and design method for marine propulsion device - Google Patents

Description

  The present invention relates to a marine vessel propulsion apparatus and a marine vessel propulsion apparatus design method that are installed in a marine vessel such as a dredger, a trawler, and the like that has a large thruster load and requires a large thrust.

  A work vessel such as a dredger or trawler, which has a large thruster load and requires a large thrust, is provided with a nozzle that surrounds the screw propeller and has a wing-shaped cross section. A propulsion device using a thrust generated by a propeller is employed (see, for example, Patent Document 1).

  This nozzle-equipped propulsion device (nozzle propeller) is used in ships that require a large propulsive force especially at low speeds. In recent years, the cross-sectional shape of the nozzle has been improved for the purpose of improving the performance of the nozzle-equipped propulsion device. Development itself has also been carried out (for example, see Patent Document 2). In particular, this type of development is often aimed at improving bollard thrust, which is a force that pulls an object when the ship is stationary.

  Since these nozzle propellers generate a large thrust not only in the nozzle but also in the propeller, cavitation (cavity phenomenon) is likely to occur on the back of the wing of the propeller, causing vibration problems and the inner surface of the nozzle near the wing tip. May cause cavitation erosion. For this reason, the inner surface of the nozzle may be formed of a stainless steel material having excellent erosion resistance performance instead of an iron material.

  As one countermeasure against cavitation erosion, in the case of a normal propeller without a nozzle, a propeller shape with a skew angle is employed to control the occurrence of cavitation. However, the propeller efficiency becomes worse as the skew amount of the propeller blade is increased. Therefore, in the prior art, as shown in FIGS. 9 to 11, the propeller blade 20 </ b> X having no skew and a rake distribution is used as the nozzle propeller, and the center of the propeller blade 20 </ b> X is used. The position Pc and the center position Nc of the chord length of the nozzle 30 are arranged to coincide with each other. In the figure, Tmax indicates the maximum blade thickness of the propeller blade.

  Further, it is known that the skew angle that can reduce the vibration force caused by the propeller is generally 20 degrees or more, and preferably 60 degrees or less at the maximum. However, as a new nozzle propeller, when a skew propeller blade having a skew angle of 20 degrees or more is employed in the nozzle propeller and a nozzle propeller that does not exist in the prior art is developed, the following problems arise.

  That is, when the propeller blades 20Y and 20Z having a skew angle α of 20 degrees or more as shown in FIGS. 12 and 14 are simply adopted in the nozzle propeller, as shown in FIGS. 13 and 15, the propeller blades are used. Since the center position Pc of the chord length at the tip (tip) position 21 of 20Y and 20Z is behind the center position Nc of the chord length of the nozzle 30, the efficiency as a nozzle propeller is significantly reduced. For this reason, the result is the reverse of the request to improve efficiency as much as possible.

In particular, in order to improve the thrust in the bollard state and the propulsion efficiency at the time of sailing, a nozzle having a different airfoil from the conventional 19A airfoil (dotted line C) as shown in FIG. In the case of a nozzle propeller that employs B), the cylindrical surface portion of the nozzle inner surface (the straight portion between P1 and P2) also tends to become narrower, so that the front and rear positions of the tip of the propeller blade are The impact on performance will be greater. In the case of these nozzles having a narrow cylindrical surface portion, if the center position of the tip of the propeller blade is shifted rearward, it may be displaced from the cylindrical surface portion. Therefore, the problem of the relative position in the front-rear direction becomes an important problem when a skew propeller is adopted as the nozzle propeller.
JP-A-57-994 JP 2006-90750 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a marine vessel including a propeller wing and a nozzle that is disposed around the propeller wing and has an airfoil cross-sectional shape. For a marine propulsion device (screw type nozzle propeller), a method for designing a marine vessel propulsion device and a marine vessel propulsion device capable of reducing the vibration force caused by the propeller and improving the propulsion efficiency during bollard pull and navigation Is to provide.

  In order to achieve the above object, a marine propulsion device according to the present invention is provided with a propeller wing, and a marine propulsion device that is disposed so as to surround the propeller wing and has a nozzle-shaped cross-sectional shape. The propeller blade is formed in a propeller shape having a skew angle of 20 degrees or more and 60 degrees or less, and the center position of the chord length at the tip position of the propeller blade is 42% behind the nozzle cord length from the front edge of the nozzle And 55% behind the nozzle cord length.

  As shown in FIG. 12, when the propeller blade is viewed from the front, the skew angle is indicated by an opening angle α from the center of the propeller blade of a curve connecting the center position of the chord length, and the conventional nozzle propeller Then, as shown in FIG. 9, in the case of a general propeller blade without a nozzle, it is usually about 10 degrees. As the skew angle is increased, the effect of reducing the excitation force due to cavitation generated in the propeller blades is increased. However, since the propeller efficiency is reduced, the skew angle is determined within a practical range. In the case of a normal nozzle propeller, 20 degrees to 30 degrees is often adopted.

  Further, the above range from the front edge of the nozzle regarding the arrangement of the center position of the chord length at the tip position of the propeller blade is the result of the experiment as shown in FIG. 7 in consideration of the shape of the nozzle as shown in FIG. It was obtained from

  The center position of the chord length at the tip position of the propeller blade is disposed within a range between 42% rearward of the nozzle cord length and 55% rearward of the nozzle cord length from the front edge of the nozzle. Such a configuration can be realized.

  In the marine vessel propulsion device, the position of the propeller blade attached to the propeller boss is such that the center position of the chord length at the tip position of the propeller blade is 42% behind the nozzle cord length from the front edge of the nozzle and the nozzle The propeller blade is positioned at a position between 55% rearward of the chord length, or the central position of the chord length at the tip position of the propeller vane is 42 of the nozzle cord length from the front edge of the nozzle. The propeller blade is formed as a propeller shape in which the rake distribution of the propeller blades is changed so that the position is located within the range between% rear and 55% rear of the nozzle cord length. The rake is a line connecting points where the vertical plane passing through the center of the propeller boss and the cross section of each radial position of the propeller blade intersect. The normal rake represents how the propeller wings collapse in the front-rear direction.

  Further, the marine vessel propulsion device design method of the present invention for achieving the above object includes a skew type propeller blade having a skew angle of 20 degrees or more and 60 degrees or less, a propeller blade arranged so as to surround the blade, and the blade A method of designing a marine propulsion device including a nozzle having a cross-sectional shape, the relative position between the center position of the chord length at the tip position of the propeller blade and the center position of the chord length of the nozzle In this relation, the center position of the chord length at the tip position of the propeller blade is disposed between 42% to 55% of the nozzle cord length from the front edge of the nozzle. .

  Further, in the above-described marine propulsion device design method, the position of the propeller blade attached to the propeller boss is such that the center position of the chord length at the tip position of the propeller blade is the nozzle cord length from the front edge of the nozzle. The central position of the chord length at the tip position of the propeller blade is 42 to the nozzle code length from the front edge of the nozzle. % At the tip position of the propeller blade by forming it as a propeller shape with a modified rake distribution of the propeller blade so that it is located within the range between% rear and 55% rear of the nozzle cord length The central position of the chord length is disposed within a range between 42% rearward of the nozzle cord length and 55% rearward of the nozzle cord length from the front edge of the nozzle.

  According to the marine vessel propulsion device and the marine vessel propulsion device design method of the present invention, when a skew type propeller is used, not only can the bollard state and the propulsion efficiency during cruising be improved, but also the vibration force caused by the nozzle propeller. Can be reduced.

  Hereinafter, a marine vessel propulsion device and a marine vessel propulsion device design method according to embodiments of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 6, skew-type nozzle propellers 1 </ b> A, 1 </ b> B, and 1 </ b> C that are marine propulsion devices according to the embodiment of the present invention include a propeller blade 20 </ b> A fixed to a propeller boss 10, and the propeller The nozzle 30 is disposed so as to surround the blade 20A and has an airfoil cross-sectional shape.

  As shown in FIG. 1, the propeller blades 20A, 20B, 20C are formed in a propeller shape having a skew angle α of 20 degrees or more and 60 degrees or less. If the skew angle α is smaller than the lower limit of 20 degrees, the effect of reducing the vibration force caused by cavitation generated in the propeller blades is small, and the normal nozzle propeller is used in the range of 20 degrees to 30 degrees. If it is necessary to reduce the force, a larger skew angle is adopted. However, if it is larger than the upper limit of 60 degrees, the propeller efficiency is extremely lowered, so that it is not practical. In addition, the solid line 22 in a figure is a line which shows the center position of the chord length for every radial direction.

  At the same time, as shown in FIGS. 2, 3, and 5, the central position Pc of the chord length at the position of the tip 21 of the propeller blades 20 </ b> A, 20 </ b> B, 20 </ b> C is changed from the leading edge Nf of the nozzle 30 to the nozzle cord length Ln ( In a range Ra between 42% rear Na of the front edge Nf and rear edge Ne) and 55% rear Nb of the nozzle cord length Ln, in other words, 8% Ln forward of the center position Nc of the front-rear position of the nozzle 30 It is arranged in the range Ra between the position Na and the position Nb 5% Ln behind the center position Nc.

  In the nozzle propeller 1A according to the first embodiment shown in FIG. 2, when the central position Pc of the chord length at the tip position of the propeller blade 20A is simply arranged in the same manner as in the prior art (FIG. 2) The propeller blade 20 </ b> A is attached to the propeller labs 10 so that the propeller blade 20 </ b> A is moved forward rather than the dotted line. With this forward arrangement, the center position Pc of the chord length at the position of the tip 21 of the propeller blade 20A is arranged within the range Ra.

  The range Ra relating to the arrangement of the central position Pc of the chord length at the position of the tip 21 of the propeller blade 20A is the result of the experiment shown in FIG. 7 in consideration of the nozzle shape (A, B, C) as shown in FIG. It was obtained from the examination of the above. FIG. 7 shows that the propeller efficiency (propeller efficiency) (KTT / 10KQ) is high in the range Ra. This KTT is the thrust coefficient (thrust coefficient) of the total thrust acting on the nozzle and propeller of the nozzle propeller, and KQ is the torque coefficient of the propeller.

  Further, in the nozzle propeller 1B of the second embodiment shown in FIG. 3, as shown in FIG. 4, the propeller blade 20B is formed as a propeller shape having a rake distribution in which the rake at the propeller tip position is a negative value. In the nozzle propeller 1B of the second embodiment, as shown in FIG. 4, in the propeller radial direction, only a part of the propeller blade (in FIG. 4, a part outside of about 0.7 times the propeller radius) is raked. (Rake) is set to the negative (-) side. In the figure, Tmax indicates the maximum blade thickness.

  Further, in the nozzle propeller 1C of the third embodiment shown in FIG. 5, as shown in FIG. 6, the propeller blade 20C is formed as a propeller shape having a rake distribution in which the rake at the propeller tip position is a negative value. 6, the rake distribution is provided almost entirely in the propeller radial direction, and the rake (Rake) is set to be positive (+) inside the propeller blade (inside of about 0.85 times the propeller radius in FIG. 6). The rake is on the negative (−) side on the outside. With this configuration, as shown in FIG. 5, the amount of forward protrusion is reduced, so that the propeller boss length can be shortened compared to the nozzle propeller blades 1A and 1B of FIGS. Arise.

  The marine propulsion device design method of the present invention is a design method for designing the nozzle propellers 1A, 1B, 1C of the first to third embodiments, and is performed as follows.

  First, the skew type propeller blades 20A, 20B, and 20C are formed as skew type propeller blades having a skew angle of 20 degrees to 60 degrees. A nozzle 30 having an airfoil cross-sectional shape is disposed so as to surround the propeller blades 20A, 20B, and 20C.

  The propeller blades 20A, 20B, and 20C have propeller blades 20A, 20B, and 20C in the relationship between the relative position between the center position Pc of the chord length at the position of the tip 21 of the propeller blades 20A, 20B, and 20C and the center position Nc of the chord length of the nozzle 30. The center position Pc of the chord length at the position of the tip 21 is arranged in a range Ra between the front edge Nf of the nozzle 30 and 42% rearward to 55% rearward of the nozzle cord length Ln.

  When the center position Pc is arranged in the range Ra, as shown in FIG. 2, the position where the propeller blade 20A is attached to the propeller boss 30 is moved further forward than in the case of the prior art, so that the center position Pc is within the range. It is set as the position arranged in Ra. Alternatively, as shown in FIGS. 3 to 6, the propeller blades 20 </ b> B and 20 </ b> C are arranged such that the center position of the chord length at the tip position of the propeller blade is 42% behind the nozzle cord length from the front edge of the nozzle and the nozzle cord length. It is formed as a propeller shape in which the rake distribution of the propeller blade is changed so that it is located within the range between 55% rearward, and the central position Pc is not formed rearward with respect to the propeller root, The position Pc is arranged within the range Ra.

  As shown in FIG. 4, the rake distribution may be such that the rake is made negative (−) only at a portion near the tip of the propeller blade 20B (in FIG. 4, a portion outside the propeller radius of about 0.7 times). As shown in FIG. 6, a rake distribution is provided almost entirely in the propeller radial direction of the propeller blade 20C, and the rake is positive on the inside of the propeller blade 20C (inside of about 0.85 times the propeller radius in FIG. 6). On the (+) side, on the outside, the rake is set on the negative (-) side.

  With respect to the propeller radial direction, as shown in FIG. 6, by configuring the inside of the propeller blade 20C so that the rake is on the positive (+) side, as shown in FIG. Therefore, the propeller boss length can be shortened as compared with the nozzle propellers 1A and 1B shown in FIGS.

  According to the marine propulsion device and the marine propulsion device design method described above, a skew-type propeller can be employed to reduce the vibration force caused by the nozzle propeller, and the bollard state and cruising. The propulsion efficiency at the time can be improved.

It is a partial front projection figure which shows the structure of the nozzle propeller which employ | adopted the skew type | mold propeller of 1st Embodiment which concerns on this invention. It is a side view including the nozzle cross section which shows the relative front-back positional relationship of the nozzle and propeller in the structure of the nozzle propeller of 1st Embodiment which concerns on this invention. It is a side view including a nozzle cross section which shows the relative front-and-rear positional relationship of the nozzle and propeller in the structure of the nozzle propeller of 2nd Embodiment which concerns on this invention. FIG. 4 is a diagram showing a rake distribution and a maximum blade thickness distribution of the propeller with respect to the propeller longitudinal direction of the skew type propeller of FIG. 3. It is a side view including a nozzle cross section which shows the relative front-and-rear positional relationship of the nozzle and propeller in the structure of the nozzle propeller of 3rd Embodiment which concerns on this invention. FIG. 6 is a diagram illustrating a rake distribution and a maximum blade thickness distribution of the propeller with respect to the propeller longitudinal direction of the skew type propeller of FIG. 5. It is a figure which shows the relationship between the change of the center position of the blade | wing code | cord | chord length of the propeller chip | tip with respect to a nozzle, and propeller efficiency regarding the front-back direction of a nozzle. It is a sectional side view which shows the shape of a nozzle. It is a partial front projection figure which shows the structure of the nozzle propeller which employ | adopted the propeller without skew of the nozzle propeller of a prior art. FIG. 10 is a side view including a nozzle cross section showing a relative front-rear positional relationship between the nozzle and the propeller in the configuration of the nozzle propeller employing the propeller of FIG. 9. FIG. 10 is a diagram showing a rake distribution and a maximum blade thickness distribution of the propeller in the propeller front-rear direction of FIG. 9. It is a partial front projection figure which shows the structure of the nozzle propeller to which the skew type propeller is applied. FIG. 13 is a side view including a nozzle cross section showing a relative front-rear positional relationship between the nozzle and the propeller in the configuration of the nozzle propeller when the skew type propeller of FIG. 12 is simply applied. It is a partial front projection figure which shows the structure of the nozzle propeller to which the other skew type | mold propeller is applied. FIG. 15 is a side view including a nozzle cross section showing a relative front-rear positional relationship between the nozzle and the propeller in the configuration of the nozzle propeller when the skew type propeller of FIG. 14 is simply applied.

Explanation of symbols

1A, 1B, 1C Skew type nozzle propeller (propulsion device for ships)
10 Propellers 20A, 20B, 20C Propeller blades (with skew)
20X propeller wing (no skew)
20Y, 20Z propeller wings (with skew)
21 Tip 22 Line connecting the center of the chord length 30 Nozzle 31 Nozzle outer surface 32 Nozzle inner surface α Skew angle Ln Nozzle code length of nozzle Na 42% Ln behind nozzle front edge (8% Ln forward from nozzle center position) Position of)
Position 55% Ln behind the front edge of the Nb nozzle (position 5% Ln behind the center position of the nozzle)
Nc Nozzle center position Ne Nozzle trailing edge Nf Nozzle leading edge Pc Center position of chord length at tip position of propeller blade Ra Range (between Na and Nb)

Claims (6)

  In a marine propulsion device provided with a propeller blade and a nozzle that is disposed so as to surround the propeller blade and has an airfoil cross-sectional shape, the propeller blade has a skew angle of 20 degrees to 60 degrees. And the center position of the chord length at the tip position of the propeller blade is disposed within a range between 42% behind the nozzle cord length and 55% behind the nozzle cord length from the front edge of the nozzle. A marine vessel propulsion device. The propeller blade is arranged such that the central position of the chord length at the tip position of the propeller blade is within a range between 42% rearward of the nozzle cord length and 55% rearward of the nozzle cord length from the front edge of the nozzle. 2. The marine vessel propulsion device according to claim 1 , wherein the propeller blade is formed in a propeller shape in which the rake distribution of the propeller blades is changed so as to be in a position . In the rake distribution of the propeller blade, the rake is made negative only in a part near the tip of the propeller blade, or the rake distribution is provided almost entirely in the propeller radial direction of the propeller blade, and the inner side of the propeller blade 3. The marine vessel propulsion device according to claim 2 , wherein the rake is made positive and the rake is made negative outside thereof .   A design method for a marine propulsion device comprising a skew type propeller blade having a skew angle of 20 degrees or more and 60 degrees or less, and a nozzle that is disposed so as to surround the propeller blade and has an airfoil cross-sectional shape, In the relationship between the center position of the chord length at the tip position of the propeller blade and the relative position of the center position of the chord length of the nozzle, the center position of the chord length at the tip position of the propeller blade is A marine propulsion device design method, characterized in that the marine vessel propulsion device is disposed between 42% rearward of the nozzle cord length and 55% rearward of the nozzle cord length from the front edge of the nozzle. The propeller blade is arranged such that the central position of the chord length at the tip position of the propeller blade is within a range between 42% rearward of the nozzle cord length and 55% rearward of the nozzle cord length from the front edge of the nozzle. The method for designing a marine vessel propulsion device according to claim 4 , wherein the propeller blade is formed in a propeller shape in which the rake distribution of the propeller blades is changed so as to be in a position . In the rake distribution of the propeller blade, the rake is made negative only in a part near the tip of the propeller blade, or the rake distribution is provided almost entirely in the propeller radial direction of the propeller blade, and the inner side of the propeller blade 6. The method of designing a marine propulsion device according to claim 5 , wherein the rake is made positive and the rake is made negative outside the rake .

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