An asymmetrically structured annular propeller and a vehicle

Abstract

The application provides an asymmetric annular propeller and a vehicle, and belongs to the propeller field.The blade comprises a front section, a rear section and a transition section, the transition section is connected between the free ends of the front section and the rear section and makes the blade form an annular shape, in the radial section of the annular propeller, a circle is drawn with the center axis as the center, the circle intersects with the leading edge and the trailing edge at two points, the distance between the two points is the width of the blade, the maximum distance between the outer contour of the transition section and the center axis along the radial direction of the annular propeller is the radius of the blade, and the width or the radius of at least two blades is different.The thickness, the width and the rotating radius of the annular blade are changed, the design parameters are changed, the annular propeller has the asymmetry, the asymmetric annular propeller structure can disperse the line spectrum noise at the blade frequency and the double blade frequency to multiple frequencies, the line spectrum noise of the annular propeller at a single frequency is greatly reduced, and the noise reduction performance of the annular propeller is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of propeller, in particular to an annular propeller with asymmetric structure and a vehicle. BACKGROUND

[0002] As an important power component of ships and underwater submersibles, the performance of the propeller is directly related to the propulsion efficiency, noise level and navigation stability of the ship and underwater submersible. The closed structure of the tail end of the blade of the annular propeller can suppress the movement of the fluid from the pressure surface to the suction surface, thereby suppressing the tip vortex and weakening the hub vortex, achieving the purpose of improving the propulsion efficiency and reducing the flow noise.

[0003] The annular propeller disclosed in Chinese patent CN115892412 is composed of a propeller shaft and a plurality of annular blades arranged around the propeller shaft. However, this annular propeller has two problems. First, the structure of the annular blades of the current annular propeller can be regarded as two blades of a traditional propeller connected at the blade tip. This causes the blade to produce another line spectrum noise at twice the blade frequency in addition to the line spectrum noise at the blade frequency when the blade rotates. Second, the annular blades of the propeller are still the same, resulting in a mirror-symmetric structure of the annular propeller relative to the rotation axis of the propeller shaft, which also causes a significant increase in the blade frequency line spectrum noise. SUMMARY

[0004] Therefore, the present application provides an annular propeller with asymmetric structure and a vehicle to solve the problem that the current annular propeller produces line spectrum noise at the blade frequency and twice the blade frequency, thereby affecting the noise reduction performance of the annular propeller.

[0005] The technical scheme of the present application is as follows: The present application provides an annular propeller with asymmetric structure, comprising a hub with a central axis as the rotation axis of the annular propeller, and a plurality of blades arranged around the central axis on the outer peripheral wall of the hub. The blade comprises a front section, a rear section, and a transition section. The direction of the annular propeller towards the downstream is the first direction, the rear section and the front section are spaced apart along the first direction, one end of each of the rear section and the front section is connected to the outer peripheral wall of the hub and the other end extends away from the hub, and the transition section is connected between the free ends of the front section and the rear section to form a ring with the blade. The rotation direction of the annular propeller is the second direction, the side edge of the front section along the second direction is the leading edge, and the side edge of the rear section facing away from the second direction is the trailing edge. In the radial cross-section of the annular propeller, a circle is drawn with the central axis as the center and the circle intersects the leading edge and the trailing edge at two points. The distance between the two points is the width of the blade. The maximum distance between the outer contour of the transition section and the central axis in the radial direction of the annular propeller is the radius of the blade. The width or radius of at least two blades is different.

[0006] On the basis of the above technical scheme, preferably, the connecting positions of the front section and the rear section with the hub outer peripheral wall are front root section and rear root section respectively, the maximum width of the front root section or the rear root section blade profile along the chord line is the thickness of the blade profile, the thickness of the front root section or the rear root section blade profile is the blade thickness, and the width, radius or thickness of the at least two blades are different.

[0007] Further preferably, the width, radius or thickness of each blade is adjusted so that the centers of gravity of each blade are uniformly arranged around the central axis.

[0008] Further preferably, the thickness of the front root section blade profile of the same blade is the same as the thickness of the rear root section blade profile.

[0009] Further preferably, when the radii of the two blades are the same, the greater the width of one blade is, the greater the thickness of the other blade is.

[0010] Further preferably, when the widths of the two blades are the same, the greater the radius of one blade is, the greater the thickness of the other blade is.

[0011] Further preferably, the chord line of the front root section blade profile and the chord line of the rear root section blade profile are both inclinedly arranged relative to the central axis, the chord line of the front root section blade profile has a bank angle relative to the central axis, the bank angle of the chord line of the front root section blade profile is preset to be 0°, the bank angle of the chord line of the rear root section blade profile is 180°, and the bank angle of the chord line of the blade profile at the radius position of the transition section is 90°.

[0012] Further preferably, a straight line that simultaneously passes through the midpoint of the chord line of the front root section blade profile and the central axis along the radial direction of the annular propeller is preset as a first axis, a straight line that simultaneously passes through the midpoint of the chord line of the rear root section blade profile and the central axis along the radial direction of the annular propeller is preset as a second axis, and the included angle between the first axis and the second axis is an acute angle; the included angle between the first axis and the second axis is adjusted to change the width of the blade.

[0013] On the basis of the above technical scheme, preferably, the number of blades is a prime number.

[0014] On the other hand, the application also provides a vehicle that sails in water or underwater and uses the above-mentioned annular propeller with an asymmetric structure, and the number of annular propellers with an asymmetric structure used is at least one.

[0015] The annular propeller with an asymmetric structure and the vehicle of the application have the following beneficial effects relative to the prior art:

[0016] (1) The present application changes the thickness, width and rotation radius of the annular blade, so that the different blades of the annular propeller have asymmetry, and the asymmetric annular propeller structure can disperse the line spectrum noise at the blade frequency and the double blade frequency to multiple frequencies, thereby greatly reducing the line spectrum noise of the annular propeller at a single frequency, and improving the noise reduction performance of the annular propeller.

[0017] (2) The present application adjusts the thickness, width and rotation radius of each blade, so that the center of gravity of each blade can still be uniformly distributed around the hub center axis, ensuring that the overall center of gravity of the annular propeller also falls on the hub center axis, thereby ensuring the balance and stability of the propeller operation.

[0018] (3) The present application designs the front and rear of the same blade with different roll angles, and the front and rear have a misalignment angle relative to the center axis of the hub, avoiding the mirror symmetry of the blade itself relative to an axis, and further improving the noise reduction performance of the annular propeller. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 is a perspective view of the annular propeller of the present application;

[0021] Figure 2 is a side view of the annular propeller of the present application;

[0022] Figure 3 is a front view of the annular propeller of the present application;

[0023] Figure 4 is a front view of another embodiment of the annular propeller of the present application;

[0024] Figure 5 is a leaf section view of the front and rear roots of the annular propeller of the present application;

[0025] Figure 6 is a characteristic spectrum diagram of the annular propeller of the present application, wherein a is the characteristic spectrum of the annular propeller with symmetric annular structure, and b is the characteristic spectrum of the annular propeller with asymmetric annular structure.

[0026] In the figure: 1, hub; 101, center axis; 2, blade; 21, front section; 22, rear section; 23, transition section; 201, leading edge; 202, trailing edge; 203, front root; 204, rear root; 205, first axis; 206, second axis. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, combined Figure 2 and Figure 6 The present invention provides an annular propeller with an asymmetric structure, comprising a hub 1 and blades 2.

[0029] The central axis 101 of the hub 1 is the rotation axis of the annular propeller.

[0030] A plurality of blades 2 are arranged on the outer circumferential wall of the hub 1 around a central axis 101. The blades 2 include a front section 21, a rear section 22, and a transition section 23. With the annular propeller facing downstream as the first direction, the rear section 22 and the front section 21 are spaced apart along the first direction. One end of each of the rear section 22 and the front section 21 is connected to the outer circumferential wall of the hub 1, and the other end extends away from the hub 1. The transition section 23 connects between the free ends of the front section 21 and the rear section 22, forming the blades 2 into a ring shape. With the annular propeller's rotational direction as the second direction, the side edge of the front section 21 along the second direction is the leading edge 201, and the side edge of the rear section 22 facing away from the second direction is the trailing edge 202.

[0031] The above structure is the structural form of all current annular propellers. In the field of propellers, for traditional non-annular propellers, the blade frequency is f BPF =N× f , where N is the number of propeller blades, f is the rotation frequency of the propeller, so the non-annular propeller will generate line spectrum noise at its blade frequency. For the current annular propeller, since the annular structure of its blade 2 is equivalent to the two blades of a traditional propeller connected at the blade tip, its noise spectrum is not only concentrated at the blade frequency, but also at the double frequency of the blade frequency. f BPF Generate another line spectrum noise slightly weaker than the leaf frequency, such as Figure 6the same, and the overall structure of the propeller is mirror-symmetrical or central-symmetrical relative to the central axis, which causes more modes to be generated when the propeller rotates, and further causes the superposition effect of the line spectrum noise at the blade frequency and double blade frequency when the plurality of blades 2 rotate simultaneously.

[0032] Based on the above reasons, the applicant conceives that if the plurality of blades 2 on the propeller hub 1 are different from each other, the overall structure of the propeller is asymmetrical relative to the central axis, which reduces the modes generated when the propeller rotates, and thus the line spectrum noise at the blade frequency and double blade frequency can be weakened.

[0033] Therefore, in the embodiment, the maximum distance between the outer contour of the transition section 23 and the central axis 101 in the radial direction of the annular propeller is the radius of the blade 2, so that the radius of at least two blades 2 is different. The radius of the blade 2 described herein is the rotation radius of the propeller. By making the radius of the two blades 2 different, the propeller forms an asymmetrical structure, and the line spectrum noise at the blade frequency and double blade frequency is dispersed to multiple frequencies

[0034] At the same time, in the radial cross section of the annular propeller, a circle with the central axis 101 as the center is drawn, and the radius of the circle is smaller than the radius of the blade 2. Therefore, the circle intersects the leading edge 201 and the trailing edge 202 at two points, and the distance between the two points is the width of the blade 2, so that the width of at least two blades 2 is different. It should be noted that the blade profile of the front section 21 and the rear section 22 of the annular blade 2 gradually changes along the blade generatrix, so the width of the blade 2 described herein is not a fixed value, but only represents the width of the blade 2 between the two points of intersection when the circle intersects the leading edge 201 and the trailing edge 202. If the radius of the circle changes, the width will also change. The applicant wants to express that by making the width of the two blades 2 different, it means that the size or the outer shape of the two blades 2 is different, and thus the propeller forms an asymmetrical structure.

[0035] By adjusting the width and radius of the different blades 2 arranged on the same propeller hub 1, although the number N of blades 2 of the propeller and the rotation frequency f do not change, but due to the large difference in the size or shape of the different blades 2, the line spectrum noise at the blade frequency and double blade frequency of the propeller is dispersed to multiple frequencies, as shown in b of Figure 6 , and the line spectrum noise at the blade frequency of the propeller is greatly weakened.

[0036] In Figure 5In a preferred embodiment shown, in addition to adjusting the radius and width of the blades 2, the thickness of the blades 2 can also be adjusted to achieve the asymmetric structure of different blades 2, and thus the thickness of the blades 2 needs to be defined. Specifically, the connecting parts of the front section 21 and the rear section 22 of the blades 2 to the outer peripheral wall of the hub 1 are the front root 203 and the rear root 204, respectively, and the maximum width of the blade profile along the chord line of the front root 203 or the rear root 204 is the thickness of the blade profile. The thickness of the front root 203 or the rear root 204 is the thickness of the blade 2, and the width, radius or thickness of at least two blades 2 is different. It should also be noted that the blade profile of the front section 21 and the rear section 22 of the annular blade 2 gradually changes along the generatrix of the blade 2, and the blade profile of the front section 21 and the rear section 22 is a streamlined shape, so the width of different parts of the blade profile is also different. Therefore, the thickness of the blade 2 described here is not a fixed value, but only represents the maximum width of the blade profile at the front root 203 and the rear root 204. The applicant intends to mean that the thickness of the two blades 2 is different, which means that the size or the outer contour shape of the two blades 2 is different, and thus the propeller can form an asymmetric structure.

[0037] In Figure 1 In a preferred embodiment shown, in order to form an asymmetric structure of different blades 2, the width, radius or thickness of each blade 2 needs to be adjusted, which causes the center of gravity of different blades 2 to be different, resulting in the overall center of gravity of the propeller being offset relative to the central axis 101 of the hub 2. In this case, if the rotation axis and the center of gravity of the propeller are offset when the propeller rotates, not only will the propeller produce great rotational vibration, but it may even be damaged. Therefore, the width, radius or thickness of each blade 2 needs to be adjusted, and the center of gravity of each blade 2 needs to be uniformly arranged around the central axis 101, so that the asymmetric annular propeller structure can maintain the balance and stability of the propeller when rotating. It should be noted that there is a related research on the mathematical expression method of the geometric shape of the annular propeller. Through this mathematical method, the three-dimensional coordinate points of each part of the annular propeller surface can be calculated by the formula under the given geometric elements of the annular propeller (including total axial distance, diameter, hub diameter ratio, number of blades, radius, chord length, pitch, thickness, pitch, skew angle or distance from leading edge to generatrix on blade profile, outside angle, roll angle, vertical angle, blade profile, etc. Distribution along the axial distance), and then these coordinate points can be imported into three-dimensional software to fit the three-dimensional model of the annular propeller. Based on the above research, the applicant determines that the width, thickness and radius of different blades 2 of the annular propeller can be obtained by using the above method, and the position of the center of gravity of each blade 2 can be determined and adjusted according to the three-dimensional model of the annular propeller fitted.

[0038] In Figure 5In a preferred embodiment shown in the figure, the thickness of the front root section 203 profile is the same as the thickness of the rear root section 204 profile, and in the case of adjustable width, thickness and radius of different blades 2, the parameter difference between the front section 21 and the rear section 22 of the same blade 2 is reduced as much as possible, so that the adjustment of the design parameters of different blades 2 can be more accurately controlled.

[0039] In Figure 4 In a preferred embodiment shown in the figure, in order to make the center of gravity of each blade 2 fall on the center axis 101, the radius R of the two blades 2 is the same, and the width L of one blade 2 is greater, then the thickness B of the other blade 2 is greater. Specifically, assuming that the width of one blade 2 is L1 and the thickness is B1, and the other is L2 and B2, then L1>L2, then B1<B2.

[0040] In Figure 3 In a preferred embodiment shown in the figure, in order to make the center of gravity of each blade 2 fall on the center axis 101, the width L of the two blades 2 is the same, and the radius R of one blade 2 is greater, then the thickness B of the other blade 2 is greater. Specifically, assuming that the radius of one blade 2 is R1 and the thickness is B1, and the other is R2 and B2, then R1>R2, then B1<B2.

[0041] In Figure 5 In a preferred embodiment shown in the figure, the chord line of the front root section 203 profile and the chord line of the rear root section 204 profile are both inclined relative to the center axis 101, and the chord line of the front root section 203 profile has a bank angle relative to the center axis 101. In this embodiment, the chord line of the front root section 203 profile is taken as the reference, and compared with the chord line of the rear root section 204 profile and the chord line of the blade profile at the radius position of the transition section 23 of the blade 2, so that the bank angle of the chord line of the front root section 203 profile is preset to 0°, the bank angle of the chord line of the rear root section 204 profile is 180°, and the bank angle of the chord line of the blade profile at the radius position of the transition section 23 is 90°. In this case, the structure of the blade 2 does not form a mirror-symmetrical structure between the front section 21 and the rear section 22, but it can still be a center-symmetrical structure.

[0042] In Figure 4In a preferred embodiment shown in the figure, the first axis 205 is a straight line that passes through the chord midpoint of the front root section 203 profile and the center axis 101 along the radial direction of the annular propeller, the second axis 206 is a straight line that passes through the chord midpoint of the rear root section 204 profile and the center axis 101 along the radial direction of the annular propeller, and the angle between the first axis 205 and the second axis 206 is an acute angle. At this time, the front section 21 and the rear section 22 can be regarded as two front and rear propellers of a tandem propeller. A tandem propeller is a kind of propeller, that is, two propellers of conventional shape are installed on the same tail shaft and can rotate in the same direction at the same time, and the front and rear propellers are separated by a certain distance. In the embodiment, the front section 21 and the rear section 22 have a misalignment angle relative to the two front and rear propellers of the tandem propeller, so that the width of the propeller blade 2 can be changed by adjusting the angle between the first axis 205 and the second axis 206, and the front section 21 and the rear section 22 can also avoid forming a central symmetric structure. In addition, the annular structure of the propeller blade 2 can also have a certain longitudinal inclination, thereby more effectively eliminating the case of forming a symmetric structure of the front section 21 and the rear section 22.

[0043] In Figure 1 In a preferred embodiment shown in the figure, the number of propeller blades 2 is a prime number, which can greatly reduce the mode generated by the rotation of the propeller, and the reason is the same as that the number of propeller blades 2 of a conventional non-annular propeller is usually a prime number.

[0044] The aircraft of the present application sails in water or underwater, and adopts the annular propeller with an asymmetric structure of any one of the above embodiments, and the number of annular propellers with an asymmetric structure is at least one.

[0045] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A ringed propeller of asymmetric construction, characterised in that, The application relates to a propeller hub (1) with a central axis (101) as the rotation axis of the annular propeller, a plurality of blades (2) arranged on the outer wall of the hub (1) around the central axis (101), wherein the blades (2) comprise a front section (21), a rear section (22) and a transition section (23), the rear section (22) and the front section (21) are arranged in the first direction, the rear section (22) and the front section (21) are connected to the outer wall of the hub (1) at one end and extend away from the hub (1) at the other end, the transition section (23) is connected between the free ends of the front section (21) and the rear section (22) and forms a ring with the blades (2), the side edge of the front section (21) in the second direction is a leading edge (201), the side edge of the rear section (22) facing away from the second direction is a trailing edge (202), in the radial cross section of the annular propeller, a circle with the central axis (101) as the center and intersecting the leading edge (201) and the trailing edge (202) at two points, and the distance between the two points is the width of the blade (2), the maximum distance between the outer contour of the transition section (23) and the central axis (101) in the radial direction of the annular propeller is the radius of the blade (2), the width or the radius of at least two blades (2) is different, the connection position of the front section (21) and the rear section (22) with the outer wall of the hub (1) is a front root (203) and a rear root (204), the maximum width of the chord of the front root (203) or the rear root (204) section is the thickness of the section, the thickness of the front root (203) or the rear root (204) section is the thickness of the blade (2), the width, the radius or the thickness of at least two blades (2) is different, the width, the radius or the thickness of each blade (2) is adjusted, and the gravity centers of the blades (2) are uniformly arranged around the central axis (101), the thickness of the front root (203) section of the same blade (2) is the same as the thickness of the rear root (204) section, when the radius of two blades (2) is the same, the greater the width of one blade (2) is, the greater the thickness of the other blade (2) is, when the width of two blades (2) is the same, the greater the radius of one blade (2) is, the greater the thickness of the other blade (2) is, the chord of the front root (203) section and the chord of the rear root (204) section are arranged obliquely relative to the central axis (101), the chord of the front root (203) section has a bank angle relative to the central axis (101), the bank angle of the chord of the front root (203) section is 0 DEG, the bank angle of the chord of the rear root (204) section is 180 DEG, and the bank angle of the chord of the transition section (23) at the radius position of the blade (2) is 90 DEG. ​ ​ ​ ​ ​ ​ ​ 2. An asymmetrically configured annular propeller according to claim 1, characterized in that: ​ 3. An asymmetrically configured annular propeller according to claim 2, wherein: ​ 4. An asymmetrically configured annular propeller according to claim 2, wherein: ​ 5. An asymmetrically configured annular propeller according to claim 3, wherein: ​ 6. An annular propeller of asymmetric construction according to claim 3, characterized in that: ​ 7. An asymmetrically configured annular propeller according to claim 2, wherein: ​ 8. An asymmetrically configured annular propeller according to claim 2, wherein: A first axis (205) is preset as a straight line passing through the chord line midpoint of the front root (203) airfoil section and the central axis (101) along the radial direction of the annular propeller, a second axis (206) is preset as a straight line passing through the chord line midpoint of the rear root (204) airfoil section and the central axis (101) along the radial direction of the annular propeller, and the included angle between the first axis (205) and the second axis (206) is an acute angle; the included angle between the first axis (205) and the second axis (206) is adjusted to change the width of the blade (2).

9. An asymmetrically configured annular propeller according to claim 1, wherein: The number of the blades (2) is a prime number.

10. A vehicle characterized by: The annular propeller with the asymmetric structure according to any one of claims 1 to 9 is used for sailing in water or underwater, and the number of the annular propellers with the asymmetric structure is at least one.

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