CN114750913A - Propeller structure for reducing cavitation - Google Patents

Propeller structure for reducing cavitation Download PDF

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Publication number
CN114750913A
CN114750913A CN202210555151.8A CN202210555151A CN114750913A CN 114750913 A CN114750913 A CN 114750913A CN 202210555151 A CN202210555151 A CN 202210555151A CN 114750913 A CN114750913 A CN 114750913A
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Prior art keywords
propeller
airfoil
blade
blades
hub
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CN202210555151.8A
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朱秋阳
段旭鹏
赵涛
刘官涛
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Shenzhen Weidu Intelligent Technology Co ltd
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Shenzhen Weidu Intelligent Technology Co ltd
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Priority to CN202210555151.8A priority Critical patent/CN114750913A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/26—Blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/18—Propellers with means for diminishing cavitation, e.g. supercavitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/20—Hubs; Blade connections
    • B63H1/22—Hubs; Blade connections the blades being foldable

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Hydraulic Turbines (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

The embodiment of the invention discloses a propeller structure for reducing cavitation phenomena, which comprises a propeller hub and blades, wherein the blades are arranged on the propeller hub in a foldable manner and are respectively provided with a propeller tip end and a propeller root end; along the oar root end extremely the direction at oar pointed end, the paddle has a plurality of cross-section in proper order, the shape of a plurality of cross-section gradually changes. The technical problems that in the prior art, due to the design of blades of a folding propeller structure for power mode switching, the appearance adaptation of a folding function specific structure and the power efficiency requirement under the appearance adaptation are difficult to meet simultaneously are solved.

Description

Propeller structure for reducing cavitation
Technical Field
The embodiment of the invention relates to the technical field of hydrodynamic fluid mechanics design, in particular to a propeller structure for reducing cavitation.
Background
At present, propeller structures of water wing plates are all formed by combining columnar propeller rods and shovel-shaped propeller blades. The blade usually has a special streamline shape, namely, the section shape of the blade can be synchronously changed along with the continuous change of the distance between the blade and a blade rod so as to increase the power efficiency on the basis of a conventional blade.
However, when the shape adaptation of a specific structure and the power efficiency requirement under the shape adaptation need to be met, for example, in a folding propeller structure for switching power modes, each blade can be folded based on the rotation of a hub, the existing conventional streamline blade design cannot be adapted to the hub in shape, contact collision is easily caused, the modified streamline blade shape has limited help for improving the power efficiency, the propulsion power is limited, the energy consumption is improved, and the propeller cannot exert the optimal performance.
Disclosure of Invention
The embodiment of the invention aims to provide a propeller structure for reducing cavitation, which is used for solving the problem that the existing blade design of a folding propeller structure aiming at power mode switching is difficult to simultaneously meet the requirements of appearance adaptation of a folding function specific structure and power efficiency under the appearance adaptation.
In order to achieve the above object, an embodiment of the present invention provides a propeller structure for reducing cavitation, including a hub and blades, where the blades are arranged on the hub in a foldable manner, and each blade has a blade tip end and a blade root end;
along the oar root end extremely the direction at oar pointed end, the paddle has a plurality of cross-section in proper order, the shape gradual change in a plurality of cross-section, just the geometric information in a plurality of cross-section does in proper order:
Figure BDA0003654637600000021
Figure BDA0003654637600000031
c is the chord length of the section airfoil, namely the maximum connecting line length between two end points of the section airfoil, D is the outer diameter of the propeller, and c/D is the ratio of the two；t0Is the maximum thickness of the sectional airfoil, i.e. the maximum thickness of the airfoil in the direction of the normal of the chord length c of the sectional airfoil, t0The/c is the ratio between the two, and refers to the relative thickness value of the section airfoil; p is a pitch, namely the distance passed by the plane where the blades are located after the propeller rotates for one circle in a non-flowing medium, and P/D is the ratio of the P to the D and refers to a speed advancing coefficient; pitch is a blade angle, namely a twist angle of the blade, and refers to an included angle between a straight line where a section airfoil chord length c of the blade is located and a rotating plane where the blade is located, and the included angle changes with the change of the propeller radius; skew is that the side oblique angle is not changed; rake is a longitudinal inclination angle which is gradually increased from the oar root end to the oar tip end, so that after the paddles are folded, a plurality of groups of paddles are close to each other as much as possible.
On the basis of the above technical solution, the present invention is further explained as follows:
in a further aspect of the present invention, an edge corner of the paddle root end is rounded.
As a further aspect of the present invention, the paddle tip is a flat head, and an edge corner of the paddle tip is rounded.
As a further aspect of the present invention, the blade airfoil formed from the root end to the tip end is an NACA65A0xx series airfoil, xx is a percentage of a section airfoil thickness to a section airfoil chord length, and the airfoil family to which the blade belongs is a laminar flow airfoil.
As a further scheme of the present invention, the two side end surfaces of the blade respectively have a pressure surface and a suction surface in one-to-one correspondence, the pressure surface and the suction surface are oppositely disposed, and the suction surface is a smooth convex outer surface.
As a further scheme of the invention, the two blades are arranged and are uniformly positioned at one end side part of the hub.
As a further aspect of the present invention, an installation groove is formed at one end of the hub, two blades are rotatably disposed in the installation groove, respectively, and the blades are folded, closed, or extended based on the installation groove of the hub.
As a further aspect of the present invention, the folding movement track of the paddle root end is disposed at an interval from the outer edge of the mounting groove, and when the blade is folded, folded or extended based on the hub, the paddle root end is adapted to the outer edge of the mounting groove without contact.
As a further aspect of the present invention, the propeller has a pitch, the pitch is a distance covered by one rotation of a plane in which the propeller is located in a non-flowing medium, and a ratio between the pitch and an outer diameter of the propeller is a feed rate coefficient.
The ratio of the section airfoil chord length to the outer diameter of the propeller and the advance speed coefficient are gradually changed along the direction from the propeller root end to the propeller tip end.
Along the direction of oar root end to oar tip, the ratio between the section wing section chord length and the screw propeller external diameter is for increasing earlier afterwards reduces.
The gradual change sequence of the acceleration coefficient is firstly reduced, then increased and then reduced.
In a further aspect of the invention, the diameter of the hub is 0.04m, the outer diameter of the propeller is 0.14m, and the radius of the propeller is 0.07 m.
The embodiment of the invention has the following advantages:
1. the blade airfoil is designed into a laminar flow airfoil and a special parameter similar-Kaplan flat-head propeller, so that the power efficiency of the propeller in practical application can be effectively ensured under a special working condition, the laminar flow area is enlarged, the resistance is lower, the blade can avoid a higher pressure peak value, cavitation is not easy to occur, and an excellent cavitation-free effect is achieved; and in a folded state, the blades can be close to each other as much as possible, and the underwater resistance of the blades is small.
2. Through shortening oar root end length and having adjusted oar root end appearance, when the paddle folded to draw in or extend based on the propeller hub, can effectively realize contactless adaptation between the outer fringe of oar root end and mounting groove to carry out slick and sly processing to the oar point, with this reduced daily use and collided with the damage that brings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.
The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.
Fig. 1 is a schematic view of an overall axial structure of a propeller structure for reducing cavitation according to embodiment 1 of the present invention.
Fig. 2 is a schematic projection structure diagram of a propeller structure for reducing cavitation phenomenon in the axial direction of a hub, according to an embodiment of the present invention.
Fig. 3 is a schematic projection structure diagram of a propeller structure for reducing cavitation phenomenon in the radial direction of a hub, according to an embodiment of the present invention.
FIG. 4 is a cross-sectional radial profile of a propeller configuration for cavitation reduction provided by an embodiment of the present invention.
Fig. 5 is a schematic performance curve diagram of a propeller structure for reducing cavitation according to an embodiment of the present invention.
Wherein the reference numerals are:
a hub 1;
the paddle 2: a paddle tip 21, a paddle root end 22, a pressure surface 23, a suction surface 24;
propeller outside diameter D, propeller radius R, cross-section airfoil chord length c, cross-section airfoil thickness t, cross-section airfoil maximum thickness t0The pitch P.
Detailed Description
The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the present specification, the terms "upper", "lower", "left", "right" and "middle" are used for clarity of description only, and are not used to limit the scope of the present invention, and the relative relationship between the terms and the relative positions may be changed or adjusted without substantial technical change.
As shown in fig. 1 to 4, an embodiment of the present invention provides a propeller structure for reducing cavitation, including a cylindrical hub 1 and two blades 2 uniformly arranged on a side portion of one end of the hub 1, wherein an installation groove is formed on one end of the hub 1, and the two blades 2 are respectively rotatably arranged in the installation groove, so as to be capable of being folded, or extended by the blades 2 based on the hub 1, thereby completing the switching of the power propulsion function.
Referring to fig. 1 to 3, the airfoil shape of the blade 2 is a flat-head oar with kaplan, and the blade 2 has a tip end 21 far away from the hub 1 and a root end 22 close to the hub 1, wherein the tip end 21 is flat-head design, and the edge corner of the tip end 21 is set to be a smooth fillet; the oar root end 22 is based on the kaplan oar type, shortens the length of oar root end 22 and adjusts the marginal appearance of oar root end 22, the folding movable track of oar root end 22 with the outer fringe looks interval sets up of mounting groove, when paddle 2 carries out folding on the basis of propeller hub 1 and draws in or extends, there is not contact adaptation between oar root end 22 and the outer fringe of mounting groove, and the marginal bight of oar root end 22 sets up smooth fillet.
Referring to fig. 3, the airfoil of the blade 2 formed from the root end 22 to the tip end 21 is an airfoil of NACA65A0xx series (where xx is the percentage of the section airfoil thickness t to the section airfoil chord length c), and the airfoil family to which the airfoil of the blade 2 belongs is a laminar airfoil.
Referring to fig. 4, two side end surfaces of the blade 2 respectively have a pressure surface 23 and a suction surface 24 in a one-to-one correspondence manner, the pressure surface 23 and the suction surface 24 are oppositely arranged, the suction surface 24 is a smooth convex surface, and the distribution of surface pressure generated by the suction surface 24 when passing through a medium with a predetermined flow velocity is relatively flat, so that on one hand, the laminar flow area is enlarged, and the resistance is lower; on the other hand, a higher pressure peak is avoided, cavitation is not easy to occur, and the propulsion efficiency is ensured, and if the laminar flow airfoil and the suction surface 24 are not arranged, the pressure peak can be greatly expanded, so that cavitation is caused.
With continued reference to fig. 1 to 4, several cross-sectional shapes of the blade 2 gradually change along the direction from the root end 22 to the tip end 21, and the cross-sectional geometrical information of typical positions is shown in the following table:
Figure BDA0003654637600000071
Figure BDA0003654637600000081
where R is the distance between the cross-sectional position and the propeller hub 1, R is the propeller radius, and R/R is the ratio between the two, referring to the real-time position of the cross-sectional position between the tip 21 and root 22 of the propeller. In an embodiment of the present invention, referring to fig. 2, the diameter of the hub 1 is 0.04m, the outer diameter D of the propeller is 0.14m, and the radius R of the propeller is 0.07 m/2.
Referring to FIG. 3, c is the chord length of the sectional airfoil, i.e., the maximum length of the connecting line between the two end points of the sectional airfoil, and c/D is the ratio of the chord length to the maximum length; t is t0Is the maximum thickness of the sectional airfoil, i.e. the maximum thickness of the sectional airfoil in the direction of the normal of the chord length c thereof，t0The/c is the ratio of the two, and refers to the relative thickness value of the airfoil; p is the pitch, namely the distance which the plane of the blade 2 passes after the propeller rotates for one circle in the non-flowing medium, and P/D is the ratio of the two, which is referred to as the advancing speed coefficient. Pitch is a blade angle, that is, a twist angle of the blade 2, and refers to an included angle between a straight line where a section airfoil chord length c of the blade 2 is located and a rotation plane where the blade 2 is located, and the included angle changes with the change of the propeller radius R, and the change rule is the most important factor influencing the working performance of the blade 2. skew is the side bevel angle and rake is the pitch angle. The pitch angle rake gradually increases from the root end 22 to the tip end 21, so that the two blades 2 can be folded as close as possible after the unpowered mode switching blades 2 are folded.
The propeller needs to have large tension and high efficiency, and needs to be specially designed for common working conditions, otherwise, the propeller cannot exert the optimal performance, and cannot convert the motor power into the propulsion power to the maximum extent. The data design provided by the embodiment is applied to a special design that the blades 2 are folded, folded or extended based on the hub 1, and then the power propulsion function is switched, so that the propeller has enough tension at a low forward ratio and the efficiency is maximized at a medium forward ratio and a high forward ratio. The specific performance curve is shown in fig. 5, where KT is the coefficient of tension, KQ is the coefficient of torque, EFFY is the efficiency, and Js is the forward ratio.
As a preferred solution of the present embodiment, besides applying the above-identified geometrical shape to the thickness of the existing propeller blade, it is also within the scope of the present invention to increase the thickness of the blade 2 by a geometrical shape of 0.2mm to 0.4mm over its entire pressure surface 23 and/or suction surface 24.
Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (10)

1. A propeller structure for reducing cavitation phenomena comprises a propeller hub and blades, and is characterized in that the blades are arranged on the propeller hub in a foldable manner and are respectively provided with a propeller tip end and a propeller root end;
along oar root end extremely the direction at oar point end, the paddle has a plurality of cross-section in proper order, the shape of a plurality of cross-section changes gradually, just the geometric information of a plurality of cross-section does in proper order:
Figure FDA0003654637590000011
Figure FDA0003654637590000021
wherein R is the distance between the cross-sectional position and the hub, R is the propeller radius, and R/R is the ratio between the two, referring to the real-time position of the cross-sectional position between the tip end and the root end of the blade; c is the chord length of the section airfoil, namely the maximum connecting line length between two end points of the section airfoil, D is the outer diameter of the propeller, and c/D is the ratio of the chord length to the outer diameter of the propeller; t is t0Is the maximum thickness of the sectional airfoil, i.e. the maximum thickness of the airfoil in the direction of the normal of the chord length c of the sectional airfoil, t0The/c is the ratio between the two, and refers to the relative thickness value of the section airfoil; p is a pitch, namely the distance passed by the plane where the blades are located after the propeller rotates for one circle in a non-flowing medium, and P/D is the ratio of the P to the D and refers to a speed advancing coefficient; pitch is a blade angle, namely a twist angle of the blade, and refers to an included angle between a straight line where a section airfoil chord length c of the blade is located and a rotating plane where the blade is located, and the included angle changes with the change of the propeller radius; skew is that the side bevel angle is unchanged; rake is a pitch angle, and the pitch angle gradually increases from the paddle root end to the paddle tip end, so that after the paddles are folded, a plurality of groups of paddles are as close as possible.
2. The cavitation reduction propeller arrangement of claim 1,
the edge corner of the oar root end is set as a round angle.
3. The cavitation reduction propeller structure as recited in claim 1 or 2,
the tip of the paddle is a flat head, and the edge corner of the tip of the paddle is a round angle.
4. The cavitation reduction propeller structure of claim 1,
the blade airfoil formed from the blade root end to the blade tip end is an NACA65A0xx series airfoil, xx is the percentage of the thickness of the cross-section airfoil in the chord length of the cross-section airfoil, and the airfoil family to which the blade belongs is a laminar flow airfoil.
5. The cavitation reduction propeller structure of claim 1,
the two side end faces of the paddle are respectively provided with a pressure surface and a suction surface in a one-to-one correspondence mode, the pressure surfaces and the suction surfaces are arranged oppositely, and the suction surfaces are smooth outer convex surfaces.
6. The cavitation reduction propeller arrangement of claim 1,
the number of the blades is two, and the two blades are uniformly positioned on the side part of one end of the hub.
7. The cavitation reduction propeller structure of claim 6,
an installation groove is formed in one end of the propeller hub, the two blades are respectively rotatably arranged in the installation groove, and the blades are folded, folded or extended based on the installation groove of the propeller hub.
8. The cavitation reduction propeller arrangement of claim 7,
the folding movable track of the oar root end with the outer fringe interval of mounting groove sets up, when the paddle is based on the propeller hub is folded and is drawn in or extends, there is not contact adaptation between the oar root end with the outer fringe of mounting groove.
9. The cavitation reduction propeller structure of claim 8,
the propeller is provided with a pitch, the pitch is the distance which is passed by the plane of the propeller in a non-flowing medium through one circle of rotation, and the ratio of the pitch to the outer diameter of the propeller is a speed advancing coefficient;
the ratio of the section airfoil chord length to the outer diameter of the propeller and the advancing speed coefficient are gradually changed along the direction from the propeller root end to the propeller tip end;
along the direction from the propeller root end to the propeller tip end, the ratio of the section airfoil chord length to the propeller outer diameter is increased and then reduced;
the gradual change sequence of the acceleration coefficient is that the acceleration coefficient is reduced firstly, then the acceleration coefficient is increased and then the acceleration coefficient is reduced.
10. The cavitation reduction propeller arrangement of claim 1,
the diameter of the propeller hub is 0.04m, the outer diameter of the propeller is 0.14m, and the radius of the propeller is 0.07 m.
CN202210555151.8A 2022-05-20 2022-05-20 Propeller structure for reducing cavitation Pending CN114750913A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150203181A1 (en) * 2013-12-17 2015-07-23 RingProp Marine Ltd. Marine propellers
CN107150775A (en) * 2016-03-04 2017-09-12 中国科学院沈阳自动化研究所 A kind of foldable propeller set of combination drive underwater robot
CN215622624U (en) * 2021-06-18 2022-01-25 广东逸动科技有限公司 Propeller and marine propeller
CN114476001A (en) * 2022-02-23 2022-05-13 深圳市苇渡智能科技有限公司 Laminar flow airfoil blade structure, application method thereof and propeller
CN217416082U (en) * 2022-05-20 2022-09-13 深圳市苇渡智能科技有限公司 Propeller structure for reducing cavitation phenomenon

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150203181A1 (en) * 2013-12-17 2015-07-23 RingProp Marine Ltd. Marine propellers
CN107150775A (en) * 2016-03-04 2017-09-12 中国科学院沈阳自动化研究所 A kind of foldable propeller set of combination drive underwater robot
CN215622624U (en) * 2021-06-18 2022-01-25 广东逸动科技有限公司 Propeller and marine propeller
CN114476001A (en) * 2022-02-23 2022-05-13 深圳市苇渡智能科技有限公司 Laminar flow airfoil blade structure, application method thereof and propeller
CN217416082U (en) * 2022-05-20 2022-09-13 深圳市苇渡智能科技有限公司 Propeller structure for reducing cavitation phenomenon

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