A ducted propeller with weakened tip gap vortex and method of use

Abstract

The application provides a ducted propeller with weakened tip gap vortex and a use method thereof, which comprises a groove on an inner wall of a pipe body; a blade tip is located in the groove; a skin is arranged on the inner wall of the pipe body; a first ring assembly is located between the pipe body and the skin; an inner wall of the first ring assembly is bonded to the skin, the first ring assembly has the ability to deform and change the inner diameter and drives the skin to elastically stretch or contract outside the first ring assembly, and adjusts the distance between the part of the skin bonded to the inner wall of the first ring assembly and the blade tip; the first ring assembly deforms and changes the inner diameter, thereby driving the skin to stretch or contract, adjusting the distance between the inner wall of the first ring assembly and the skin and the blade tip, controlling the fluid amount flowing through the tip gap by reducing the tip gap as much as possible but not completely eliminating the tip gap, controlling the vortex core formed after the fluid flows through the tip gap to be small, and avoiding the fluid from transferring through other parts of the blade under the action of the pressure difference between the two sides of the blade.

Description

Technical Field

[0001] This invention relates to the field of duct propeller technology, and more particularly to a duct propeller that weakens tip gap vortices and its method of use. Background Technology

[0002] A ducted propeller consists of a propeller and an externally mounted cylindrical guide tube. As a form of underwater propulsion, it is widely used in surface ships and underwater vehicles. The tiny gap between the duct and the blade tip of a ducted propeller is called the tip gap. During propeller operation, a suction zone forms in front of the blade, and a pressure zone forms behind it. Under the influence of this pressure difference, fluid flows along the blade tip through the tip gap towards the suction zone. Upon entering the suction zone, it interacts with the low-pressure fluid, generating high-intensity vortices called tip gap vortices. This flow is called tip gap flow (TLV). The tip gap of a ducted propeller contains complex flows, with vortices of various sizes alternately shedding off. These unstable tip gap vortices not only affect the propeller's efficiency but also easily cause erosion damage to the propeller itself. Furthermore, the presence of tip gap vortices easily leads to cavitation in the low-pressure region of the vortex core, forming cavitation bubbles. The generation of cavitation bubbles directly increases the noise during propeller operation.

[0003] Chinese patent CN113158376A discloses a rectangular groove vortex-eliminating structure, design, and processing method for the inner wall of a pump-jet propeller duct. It involves creating an annular groove inside the duct, positioning the propeller blade tips within the groove. When the propeller rotates and generates tip gap vortices, these tip vortices are generated within the groove. The groove's inner wall disrupts and dissipates these vortices and the outflow, reducing the radial velocity gradient of the propeller, dispersing radial free vortices, and decreasing the outflow velocity and the pressure difference between the tip pressure and suction surfaces, thus reducing vortex intensity. However, this design increases the tip gap distance. A larger tip gap distance results in a stronger tip gap vortex. Even with the dissipation effect of the groove's inner wall, complex separation vortices are still generated, negatively impacting propulsion efficiency and noise levels.

[0004] Therefore, minimizing the tip gap as much as possible to reduce the adverse effects of tip gap vortices is an important issue in the research and design of duct propellers. Summary of the Invention

[0005] In view of this, the present invention proposes a ducted propeller that weakens tip gap vortices and its usage method, in order to solve the problem that current ducted propellers cannot adjust the tip gap, and therefore it is difficult to weaken the adverse effects of tip gap vortices.

[0006] The technical solution of the present invention is implemented as follows: The present invention provides a ducted propeller that weakens tip gap vortex, including a tube body with grooves formed on its inner wall around the tube body axially; a blade disposed in the tube body and rotating around the tube body axially with the blade tip located in the groove; a skin laid on the inner wall of the tube body and having elastic tensile properties; and a first ring assembly sleeved in the groove and located between the tube body and the skin; wherein, the inner wall of the first ring assembly is bonded to the skin, the first ring assembly has the ability to deform and change its inner diameter, and drives the part of the skin outside the first ring assembly to elastically stretch or contract, and adjusts the distance between the part of the skin bonded to the inner wall of the first ring assembly and the blade tip.

[0007] Based on the above technical solutions, preferably, the first ring assembly includes several arc-shaped segments, which are spaced apart around the tube body axially and form a ring, with the inner walls of all segments bonded to the skin; several movable parts are arranged around the tube body axially between the inner wall of the tube body and the arc-shaped segments; wherein, the several arc-shaped segments move synchronously relative to the tube body along the radial direction of the tube body and change the inner diameter of the first ring assembly; one end of the movable part is inserted into the inner wall of the tube body and the other end abuts against the surface of the arc-shaped segment, and the movable part moves relative to the tube body along the radial direction of the tube body and causes the arc-shaped segments to move synchronously.

[0008] More preferably, a groove is formed on the surface of the arc-shaped section facing the inner wall of the tube, and the groove is hemispherical or semi-elliptical; a ball head is provided on the end of the movable part that abuts against the arc-shaped section, and the ball head is inserted into the groove and abuts against the inner surface of the groove.

[0009] More preferably, the first ring assembly further includes an elastic element, with its two ends respectively connected to the surface of the middle part of the movable part and one end of the arc-shaped segment; wherein, when the movable part moves toward the inner wall of the tube, the skin elastically contracts and causes the arc-shaped segment to move synchronously with the movable part, and the elastic element holds the arc-shaped segment and prevents the ball head from dislodging from the groove.

[0010] More preferably, the plurality of movable parts include a first movable member and a second movable member; the first movable member and the second movable member are disposed at both ends of the arc-shaped segment along the axial direction of the pipe body, and the end of the first movable member or the second movable member away from the pipe body abuts against the surface of the arc-shaped segment; the first movable member moves toward the inner wall of the pipe body relative to the second movable member, or the second movable member moves toward the inner wall of the pipe body relative to the first movable member, or the first movable member and the second movable member move toward each other simultaneously, so that the extension direction of the inner wall surface of the arc-shaped segment intersects the axial direction of the pipe body.

[0011] More preferably, the two ends of the arc segment extending along the axial direction of the pipe are configured as deformation parts. The deformation parts are made of shape memory alloy material. The deformation parts deform with temperature changes and have an initial state and at least one deformation state. When the deformation parts are heated and deformed, they switch to the deformation state, causing the corresponding arc segment end to rotate toward the inner wall of the pipe and causing the extension direction of the inner wall surface of the arc segment to intersect with the axial direction of the pipe, and pushing the first movable member or the second movable member to move toward the inner wall of the pipe.

[0012] More preferably, it also includes a power supply, which is disposed inside the tube and has a positive and a negative terminal; a switching switch; wherein the negative terminal of the power supply is electrically connected to one end of the two deformable parts simultaneously; the switching switch is disposed between the positive terminal of the power supply and the two deformable parts, and the switching switch selectively connects the positive terminal of the power supply to the other end of one of the deformable parts or disconnects the power supply.

[0013] Based on the above technical solutions, preferably, it also includes a second ring assembly and a third ring assembly, both of which are disposed between the tube body and the skin and are located at both ends of the groove along the axial direction of the tube body; wherein, the inner walls of the second ring assembly and the third ring assembly are tightly attached to the skin, and both the second ring assembly and the third ring assembly have the ability to deform and change their inner diameter. The second ring assembly and the third ring assembly deform synchronously and drive the part of the skin outside the groove to elastically stretch or contract, and adjust the depth of the groove.

[0014] Secondly, the present invention also provides a method for using a ducted propeller that weakens tip gap vortices. The method, employing the aforementioned ducted propeller, includes the following steps: Step 1, the first ring assembly deforms and its inner diameter decreases relative to the tube body, causing the skin to elastically contract and reducing the distance between the portion of the skin adhered to the inner wall of the first ring assembly and the blade tip; Step 2, the first ring assembly deforms and its inner diameter increases relative to the tube body, causing the skin to elastically stretch and increasing the distance between the portion of the skin adhered to the inner wall of the first ring assembly and the blade tip; Step 3, the first ring assembly deforms and its inner diameter differs at both ends of the tube body, with the inner diameter of the first ring assembly increasing or decreasing proportionally along the axial direction of the tube body, so that the extension direction of the inner wall surface of the first ring assembly intersects the axial direction of the tube body.

[0015] Thirdly, the present invention also provides a method for using a ducted propeller that weakens the tip gap vortex. The method using the above-mentioned ducted propeller includes the following steps: Step four, the second ring assembly and the third ring assembly deform synchronously and reduce the inner diameter of the second ring assembly and the third ring assembly relative to the tube body, thereby causing the skin to stretch elastically and increasing the depth of the groove; Step five, the second ring assembly and the third ring assembly deform synchronously and increase the inner diameter of the second ring assembly and the third ring assembly relative to the tube body, thereby causing the skin to contract elastically and reducing the depth of the groove.

[0016] The ducted propeller with reduced tip gap vortex and its method of use according to the present invention have the following advantages over the prior art: (1) The present invention deforms the first ring component and changes its inner diameter, thereby causing the skin to stretch or contract, thereby adjusting the distance between the inner wall of the first ring component and the skin on it and the blade tip. By minimizing the tip gap as much as possible without completely eliminating the tip gap, the amount of fluid flowing through the tip gap is controlled, and the fluid is controlled to form a smaller vortex core after flowing through the tip gap. At the same time, the fluid is prevented from being transferred through other parts of the blade under the action of the pressure difference on both sides of the blade, thereby weakening the strength of the tip gap vortex.

[0017] (2) The present invention uses several arc segments to form a ring of the first ring component. The arc segments move synchronously to realize the change of the inner diameter of the first ring component. When the skin is laid on several arc segments, the problem of the skin surface being sunken due to lack of support can be avoided. At the same time, the end of the movable part uses a ball head to abut against the groove of the arc segment. When the arc segment moves and the abutment position between the arc segment and the end of the movable part shifts, the ball head can still abut against the groove to prevent the movable part from leaving the arc segment. The ball head end of the movable part can also make effective contact with the arc segment to maintain the support effect.

[0018] (3) The two ends of the arc segment of the present invention are respectively abutted by different movable parts. By adjusting the relative position of the two movable parts, the surface of the arc segment is tilted to the axis of the tube body, thereby changing the size of the space area on both sides of the blade to control the pressure difference formed on both sides of the blade, thereby achieving the purpose of weakening or enhancing the tip gap vortex intensity.

[0019] (4) The present invention sets the deformation part at both ends of the arc segment to be made of shape memory alloy material. The deformation part will expand in volume due to heat, thereby extending one end of each arc segment at the same time and increasing the inner diameter of the ring formed.

[0020] (5) The present invention provides a second ring assembly and a third ring assembly on the tube body located at both ends of the groove. The second ring assembly and the third ring assembly also have the ability to deform and adjust the inner diameter, thereby changing the inner diameter of the inner space of the guide tube and adjusting the depth of the groove, thereby adjusting the length of the blade tip located in the groove. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1This is a side sectional view of the duct propeller of the present invention; Figure 2 This is a side sectional view of step three of the duct propeller of the present invention; Figure 3 This is a side sectional view of another embodiment of step three of the duct propeller of the present invention; Figure 4 For the present invention Figure 3 Enlarged view of point A in the middle; Figure 5 For the present invention Figure 4 Enlarged view of point B in the middle; Figure 6 This is a front view of the duct propeller of the present invention; Figure 7 This is a front view of step one of the duct propellers of the present invention.

[0023] In the diagram: 1. Pipe body; 101. Groove; 2. Blade; 3. Skin; 4. First ring assembly; 41. Arc segment; 411. Deformation part; 42. Movable part; 421. First movable part; 422. Second movable part; 43. Elastic part; 401. Groove; 5. Power supply; 6. Switch; 7. Second ring assembly; 8. Third ring assembly. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] like Figure 1 As shown, combined with Figure 2 and Figure 4 The present invention provides a ducted propeller for reducing tip gap vortices, comprising: The tube body 1 has grooves 101 axially formed on its inner wall. Both ends of the tube body 1 are open, serving as the fluid inlet and outlet, respectively. Although the tube body 1 is depicted as a straight cylindrical shape in the accompanying drawings, in actual aircraft, it can also be conical, drum-shaped, or bottleneck-shaped. The specific shape of the tube body 1 does not affect the implementation of this design. The function of the grooves 101 is to weaken the tip gap vortex.

[0026] The blade 2 is disposed inside the tube body 1 and rotates axially around the tube body 1, with its tip located within the groove 101. The blade structure of the blade 2 on the propeller section of the ducted propeller is such that the shape of the blade 2 is a helical twist at a certain angle. Therefore, the flow direction after the tip gap vortex is generated is actually along the tangential direction of the blade tip tip. Some current ducted propellers position the blade tip 2 within the groove 101, thereby generating the tip gap vortex within the groove 101. The weakening of the tip gap vortex is achieved through the destructive and dissipative effects of the inner wall of the groove 101.

[0027] The skin 3 is laid on the inner wall of the tube 1 and has elastic tensile properties. The skin 3 is made of highly elastic silicone rubber or highly elastic fiber, such as methyl vinyl silicone rubber or polyether ester elastic fiber. The two ends of the skin 3 are generally fixed to the inner wall of the tube 1 and located at both ends of the tube 1. The skin 3 is located in the middle of the fixed ends and can be elastically stretched or contracted.

[0028] Although this embodiment has a groove 101 on the inner wall of the tube body 1, which has the ability to weaken the tip gap vortex, the mechanism of tip gap flow and the vortices it generates are extremely complex. The tip gap leakage vortex will be weakened or even disintegrated under the action of the groove 101, but it is difficult to ensure that other types of vortices generated by the disintegration of the tip gap leakage vortex, such as tip gap separation vortices, will continue to have adverse effects. Therefore, this embodiment seeks a method that can minimize the tip gap as much as possible, thereby weakening the generation intensity of the tip gap vortex to the greatest extent. As a means to solve the above problems, the first ring assembly 4 is sleeved in the groove 101 and located between the tube body 1 and the skin 3. Therefore, the position of the first ring assembly 4 along the axial direction of the tube body 1 is consistent with that of the blade 2. Since in this embodiment, the skin 3 needs to be recessed inward and enter the groove 101, the inner wall of the first ring assembly 4 is adhered to the skin 3, so that the first ring assembly 4 drives the skin 3 to be recessed. In this embodiment, the first ring assembly 4 has the ability to deform and change its inner diameter. When the inner diameter of the first ring assembly 4 changes, the degree of indentation of the recessed part formed by the skin 3 at the part of the first ring assembly 4 will also change, thus causing the skin 3 to stretch or contract elastically. Since the inner diameter of the first ring assembly 4 changes, the distance between the part of the skin 3 bonded to the inner wall of the first ring assembly 4 and the tip of the blade 2 will also change, that is, the tip gap is adjusted.

[0029] It should be noted that adjusting the size of the tip gap is one of the methods to control the intensity of the tip gap vortex. However, the tip gap flow generated by the propeller rotation and its mechanism are extremely complex. The tip gap vortex cannot be effectively weakened by simply reducing or increasing the tip gap. Therefore, the purpose of this embodiment is to provide a duct structure with a variable tip gap, which will help to study the correlation between the tip gap size and the intensity of the tip gap vortex.

[0030] exist Figure 6 In a preferred embodiment shown, combined with Figure 7 The first ring component 4 includes an arc-shaped segment 41 and a movable part 42.

[0031] In this configuration, several arc-shaped segments 41 are spaced apart axially around the tube body 1 and form a ring, with their inner walls tightly attached to the skin 3. Each arc-shaped segment 41 can be considered as dividing a ring with a small inner diameter into several segments, with each segment 41 moving radially backward to form a new ring. The new ring has a larger inner diameter, but the arc-shaped segments 41 forming it are disconnected. Therefore, the arc-shaped segments 41 can move synchronously relative to the tube body 1 radially and change the inner diameter of the first ring assembly 4.

[0032] Several movable parts 42 are axially arranged around the inner wall of the tube body 1 between the inner wall of the tube body 1 and the arc-shaped segment 41. One end of the movable part 42 is inserted into the inner wall of the tube body 1, and the other end abuts against the surface of the arc-shaped segment 41. The movable part 42 moves radially relative to the tube body 1 and moves the arc-shaped segment 41 synchronously. The movable part 42 serves to support the arc-shaped segment 41 and push the arc-shaped segment 41 to move. Generally, movable parts 42 are provided at both ends of the arc-shaped segment 41 along its arc. When the arc-shaped segment 41 moves back and forth, it can be found that the position where the end of the movable part 42 contacts the surface of the arc-shaped segment 41 will shift. This means that if the connection position between the end of the movable part 42 and the arc-shaped segment 41 is fixed, it will hinder the arc-shaped segment 41 from moving radially along the tube body 1. Therefore, in this embodiment, the end of the movable part 42 abuts against the arc-shaped segment 41; when the arc-shaped segment 41 moves, the end of the movable part 42 can slide on the surface of the arc-shaped segment 41, thereby changing the contact position with the arc-shaped segment 41. Without hindering the movement of the arc-shaped segment 41, it can still play an effective supporting and pushing role.

[0033] exist Figure 5In a preferred embodiment shown, since the end of the movable part 42 contacts the arc-shaped segment 41 by abutting, and the arc-shaped segment 41 is pressed against the movable part 42 by the pressure generated by the contraction of the skin 3, the arc-shaped segment 41 does not actually have a stable connection with the movable part 42. The arc-shaped segment 41 can easily slide relative to the movable part 42. Therefore, it is necessary to limit the relative position of the arc-shaped segment 41 and the movable part 42 to a certain extent. In this embodiment, a groove 401 is formed on the surface of the arc-shaped segment 41 facing the inner wall of the tube body 1. The groove 401 is hemispherical or semi-elliptical. A ball head is provided on the end of the movable part 42 that abuts against the arc-shaped segment 41. The ball head is inserted into the groove 401 and abuts against the inner surface of the groove 401. The diameter of the ball head is preferably smaller than the inner diameter of the groove 401. Therefore, when the arc-shaped segment 41 moves, although the position of the end of the movable part 42 on the surface of the arc-shaped segment 41 is shifted, the ball head is still located in the groove 401, which achieves the purpose of the end of the movable part 42 abutting against the surface of the arc-shaped segment 41 and restricting the end of the movable part 42 within the groove 401. The spherical surface of the ball head and the arc surface of the groove 401 can always maintain surface contact rather than point contact.

[0034] exist Figure 5 In a preferred embodiment shown, in order to further improve the contact stability of the arc-shaped segment 41 at the end of the movable part 42, the first ring assembly 4 also includes an elastic element 43.

[0035] The elastic element 43 is connected at both ends to the middle of the movable part 42 and the surface of one end of the arc-shaped segment 41, respectively. When the movable part 42 moves toward the inner wall of the tube body 1, the skin 3 elastically contracts and the arc-shaped segment 41 moves synchronously with the movable part 42. The elastic element 43 holds the arc-shaped segment 41 and prevents the ball head from dislodging from the groove 401. The elastic element 43 can be a spring or a pull rope with elastic extension capability.

[0036] exist Figure 2 In a preferred embodiment shown, combined with Figure 3Besides adjusting the tip gap spacing, controlling and weakening the tip gap vortex can also be achieved by controlling the pressure difference between the front and rear sides of blade 2. The formation of this pressure difference is related to the propeller's rotational speed and also to the ratio of the total fluid volume between the front and rear sides of blade 2. Assuming the area in front of blade 2 is the pressure zone and the area behind it is the suction zone, and that the inner diameters of the tubes 1 in the pressure and suction zones are the same, the pressure difference between the pressure and suction zones is the initial ratio. When the inner diameter of the tube 1 in the pressure zone is smaller than that in the suction zone, the total fluid volume in the pressure zone will be lower than that in the suction zone. This causes a change in the pressure difference between the pressure and suction zones, affecting the intensity of the tip gap vortex. It should be noted that due to the extremely complex mechanism of tip gap flow, current research only reveals that reducing the pressure difference between the pressure and suction zones weakens the intensity of the tip gap vortex. However, the mechanism by which the ratio of the inner diameters of the tubes 1 in the pressure and suction zones affects the change in the pressure difference between the pressure and suction zones remains unclear. The purpose of this embodiment is to provide a means for adjusting the ratio of the inner diameter of the tube body 1 in the pressure zone to the inner diameter of the tube body 1 in the suction zone, thereby contributing to research on methods for reducing the intensity of the tip gap vortex. In this embodiment, several movable parts 42 include a first movable member 421 and a second movable member 422.

[0037] The first movable member 421 and the second movable member 422 are arranged along the axial direction of the tube body 1 at both ends of the arc-shaped segment 41 along the axial direction of the tube body 1, and the end of the first movable member 421 or the second movable member 422 away from the tube body 1 abuts against the surface of the arc-shaped segment 41.

[0038] The first movable member 421 moves toward the inner wall of the tube 1 relative to the second movable member 422, or the second movable member 422 moves toward the inner wall of the tube 1 relative to the first movable member 421, or the first movable member 421 and the second movable member 422 move toward each other simultaneously. By adjusting the ratio of the distance between the free end of the first movable member 421 and the inner wall of the tube 1 to the distance between the free end of the second movable member 422 and the inner wall of the tube 1, the arc segment 41 is tilted relative to its original state, so that the extension direction of the inner wall surface of the arc segment 41 intersects the axial direction of the tube 1. Thus, when the arc segments 41 form a ring, the inner diameters at both ends of the ring are different. In this case, since the blade 2 is located in the middle of the first ring assembly 4, the blade 2 actually divides the internal space enclosed by the first ring assembly 4 into two parts, and the inner diameters of the two parts of the first ring assembly 4 are different, which causes the pressure difference between the front and rear of the blade 2 to change accordingly.

[0039] exist Figure 4In a preferred embodiment shown, since the arc segment 41 itself is curved, in order to allow the arc segment 41 to undergo tilting deformation under the action of the first movable member 421 and the second movable member 422, the arc segment 41 can be made of a rubber material with elastic deformation properties. However, this makes it difficult to control the degree of deformation of the arc segment 41. Therefore, in this embodiment, the two ends of the arc segment 41 extending along the axial direction of the tube body 1 are set as deformation portions 411. The deformation portions 411 are made of shape memory alloy material. The shape memory alloy material can be a nickel-titanium based alloy, such as titanium-nickel alloy, titanium-nickel-niobium alloy, titanium-nickel-palladium alloy, etc., or it can also be a copper-based alloy or an iron-based alloy.

[0040] The deformable part 411 deforms with temperature changes and has an initial state and at least one deformed state. When the deformable part 411 is heated and deformed, its volume expands. Since other parts of the arc segment 41 do not deform, the deformable part 411 switches to the deformed state, which not only causes the end of the corresponding arc segment 41 to bend and rotate toward the inner wall of the tube 1, but also causes the end of the corresponding arc segment 41 to extend along its arc direction. The ring formed by the deformed arc segments 41 is more like a trumpet shape, rather than the surface of the arc segment 41 remaining flat as shown in the figure. The wall surface of each arc segment 41 also has a certain tilt angle relative to the axis of the tube 1. At the same time, the deformed end of the arc segment 41 will also push the corresponding first movable member 421 or second movable member 422 toward the inner wall of the tube 1.

[0041] exist Figure 4 In a preferred embodiment shown, in order to achieve the purpose of thermal deformation of the deformable part 411, a power supply 5 and a switching switch 6 are also included.

[0042] The power supply 5 is located inside the tube body 1 and has a positive and a negative terminal; the negative terminal of the power supply 5 is electrically connected to one end of the two deformable parts 411.

[0043] A switching switch 6 is located between the positive terminal of the power supply 5 and the two deformation sections 411. The switching switch 6 selectively connects the positive terminal of the power supply 5 to the other end of one of the deformation sections 411 or disconnects the power supply 5. When the switching switch 6 disconnects the power supply 5, the deformation section 411 will not undergo thermal deformation, so the arc segment 41 will not tilt relative to the axial direction of the tube body 1. Therefore, the inner diameters of the two ends of the ring formed by each arc segment 41 are the same. When it is necessary to make the inner diameter of one end of the ring larger than the other end, the switching switch 6 selectively connects the positive terminal of the power supply 5 to the corresponding deformation section 411, so that the deformation section 411 located at that end undergoes thermal deformation, and the arc segment 41 can tilt towards that end.

[0044] exist Figure 4 In a preferred embodiment shown, combined with Figure 2 and Figure 3Since the weakening effect of the pin gap vortex is also related to the depth of the groove 101, this embodiment aims to adjust the depth of the groove 101 when the pin gap remains unchanged, and also includes a second ring assembly 7 and a third ring assembly 8.

[0045] The second ring assembly 7 and the third ring assembly 8 are both disposed between the tube body 1 and the skin 3, and are located at both ends of the groove 101 along the axial direction of the tube body 1, respectively. Since the second ring assembly 7 and the third ring assembly 8 do not form part of the groove 101, their inner walls are tightly attached to the skin 3, allowing the skin 3 to elastically stretch and contract. Both the second ring assembly 7 and the third ring assembly 8 have the ability to deform and change their inner diameter. They deform synchronously, causing the portion of the skin 3 outside the groove 101 to elastically stretch or contract, thus adjusting the depth of the groove 101. The structure of the second ring assembly 7 and the third ring assembly 8 is similar to that of the first ring assembly 4, and they can also have the same adjustment function as the first ring assembly 4 as needed, thereby forming a non-cylindrical shape within the internal space of the duct propeller.

[0046] like Figure 1 As shown, combined with Figures 2 to 7 The present invention provides a method for using a ducted propeller that reduces tip gap vortices, employing a ducted propeller according to any of the above embodiments, comprising the following steps.

[0047] Step 1: The first ring assembly 4 deforms and its inner diameter decreases relative to the tube body 1, causing the skin 3 to contract elastically and reducing the distance between the part of the skin 3 that is bonded to the inner wall of the first ring assembly 4 and the tip of the blade 2.

[0048] Step 2: The first ring assembly 4 deforms and increases its inner diameter relative to the tube body 1, and the skin 3 is elastically stretched accordingly, increasing the distance between the part of the skin 3 bonded to the inner wall of the first ring assembly 4 and the tip of the blade 2.

[0049] Step 3: The first ring assembly 4 is deformed and the inner diameter of the first ring assembly 4 at both ends of the tube body 1 is different. The inner diameter of the first ring assembly 4 increases or decreases proportionally along the axial direction of the tube body 1, so that the extension direction of the inner wall surface of the first ring assembly 4 intersects the axial direction of the tube body 1, thereby making the inner diameter of the ring body formed by the first ring assembly 4 different at both ends.

[0050] like Figure 1 As shown, combined with Figure 2 and Figure 3 The present invention provides a method for using a ducted propeller that reduces tip gap vortices, employing a ducted propeller according to any of the above embodiments, comprising the following steps.

[0051] Step four: The second ring assembly 7 and the third ring assembly 8 deform synchronously and their inner diameters decrease relative to the tube body 1, thereby causing the skin 3 to stretch elastically and increasing the depth of the groove 101.

[0052] Step 5: The second ring assembly 7 and the third ring assembly 8 deform synchronously and increase their inner diameter relative to the tube body 1, causing the skin 3 to elastically contract and reduce the depth of the groove 101.

[0053] Using the above method, the depth of the groove 101 can be adjusted while keeping the tip gap constant.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A ducted propeller that weakens tip gap vortices, characterized in that, include: The inner wall of the tube (1) has a groove (101) axially formed around the tube (1). The blade (2) is disposed inside the tube body (1) and rotates axially around the tube body (1), with the blade tip located in the groove (101); The skin (3) is laid on the inner wall of the tube (1) and has elastic tensile properties; The first ring assembly (4) is fitted inside the groove (101) and located between the tube body (1) and the skin (3); The inner wall of the first ring assembly (4) is bonded to the skin (3). The first ring assembly (4) has the ability to deform and change its inner diameter and drive the skin (3) to stretch or contract elastically to the part other than the first ring assembly (4), and adjust the distance between the part of the skin (3) bonded to the inner wall of the first ring assembly (4) and the tip of the blade (2). The first ring component (4) includes, Several arc-shaped segments (41) are axially spaced around the tube body (1) and form a ring, with their inner walls all bonded to the skin (3). Several movable parts (42) are axially arranged around the tube body (1) between the inner wall of the tube body (1) and the arc-shaped segment (41); The elastic element (43) is connected at both ends to the surface of the middle part of the movable part (42) and one end of the arc segment (41); Among them, several of the arc segments (41) move synchronously relative to the tube body (1) along the radial direction of the tube body (1) and change the inner diameter of the first ring assembly (4). The arc segments (41) have grooves (401) on the surface facing the inner wall of the tube body (1). The grooves (401) are hemispherical or semi-elliptical. One end of the movable part (42) is inserted into the inner wall of the tube body (1) and the other end abuts against the surface of the arc segment (41). The movable part (42) moves radially relative to the tube body (1) and moves synchronously with the arc segment (41). A ball head is provided on the end of the movable part (42) that abuts against the arc segment (41). The ball head is inserted into the groove (401) and abuts against the inner surface of the groove (401). When the movable part (42) moves toward the inner wall of the tube body (1), the elastic element (43) pulls the arc segment (41) and prevents the ball head from dislodging from the groove (401).

2. The ducted propeller for reducing tip gap vortices according to claim 1, characterized in that: The aforementioned movable parts (42) include a first movable element (421) and a second movable element (422); The first movable member (421) and the second movable member (422) are arranged along the axial direction of the tube body (1) at both ends of the arc-shaped segment (41) along the axial direction of the tube body (1), and the end of the first movable member (421) or the second movable member (422) away from the tube body (1) abuts against the surface of the arc-shaped segment (41); The first movable member (421) moves toward the inner wall of the tube body (1) relative to the second movable member (422), or the second movable member (422) moves toward the inner wall of the tube body (1) relative to the first movable member (421), or the first movable member (421) and the second movable member (422) move in opposite directions at the same time, so that the extension direction of the inner wall surface of the arc segment (41) intersects the axial direction of the tube body (1).

3. A ducted propeller for reducing tip gap vortices according to claim 2, characterized in that: The two ends of the arc-shaped segment (41) extending along the axial direction of the tube body (1) are configured as deformation parts (411). The deformation parts (411) are made of shape memory alloy material. The deformation parts (411) deform with temperature change and have an initial state and at least one deformation state. The deformation part (411) is heated and deformed to switch to the deformation state, causing the end of the corresponding arc segment (41) to rotate toward the inner wall of the tube body (1), and causing the extension direction of the inner wall surface of the arc segment (41) to intersect with the axial direction of the tube body (1), and pushing the first movable part (421) or the second movable part (422) to move toward the inner wall of the tube body (1).

4. A ducted propeller for reducing tip gap vortices according to claim 3, characterized in that, Also includes: A power supply (5) is provided inside the tube (1) and has a positive and a negative electrode; Switch (6); The negative terminal of the power supply (5) is simultaneously electrically connected to one end of the two deformable parts (411); The switching switch (6) is located between the positive terminal of the power supply (5) and the two deformable parts (411). The switching switch (6) selectively connects the positive terminal of the power supply (5) to the other end of one of the deformable parts (411) or disconnects the power supply (5).

5. A ducted propeller for reducing tip gap vortices according to claim 1, characterized in that, Also includes: The second ring assembly (7) and the third ring assembly (8) are both disposed between the tube body (1) and the skin (3) and are located at both ends of the groove (101) along the axial direction of the tube body (1); The inner walls of the second ring assembly (7) and the third ring assembly (8) are tightly attached to the skin (3). Both the second ring assembly (7) and the third ring assembly (8) have the ability to deform and change their inner diameter. The second ring assembly (7) and the third ring assembly (8) deform synchronously and cause the part of the skin (3) outside the groove (101) to stretch or contract elastically, and adjust the depth of the groove (101).

6. A method of using a ducted propeller that reduces tip gap vortices, employing the ducted propeller according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: The first ring assembly (4) deforms and reduces the inner diameter of the first ring assembly (4) relative to the tube body (1), and drives the skin (3) to elastically contract, and reduces the distance between the part of the skin (3) that is bonded to the inner wall of the first ring assembly (4) and the tip of the blade (2); Step 2, the first ring assembly (4) deforms and increases the inner diameter of the first ring assembly (4) relative to the tube body (1), and the skin (3) is elastically stretched accordingly, and the distance between the part of the skin (3) bonded to the inner wall of the first ring assembly (4) and the blade tip of the blade (2) is increased; Step 3, the first ring assembly (4) is deformed and the inner diameter of the first ring assembly (4) is different at both ends of the tube body (1). The inner diameter of the first ring assembly (4) increases or decreases proportionally along the axial direction of the tube body (1) so that the extension direction of the inner wall surface of the first ring assembly (4) intersects the axial direction of the tube body (1).

7. A method of using a ducted propeller that reduces tip gap vortices, employing the ducted propeller of claim 5, characterized in that, Includes the following steps: Step four, the second ring assembly (7) and the third ring assembly (8) deform synchronously and reduce the inner diameter of the second ring assembly (7) and the third ring assembly (8) relative to the tube body (1), thereby causing the skin (3) to stretch elastically and increasing the depth of the groove (101); Step 5, the second ring assembly (7) and the third ring assembly (8) deform synchronously and increase the inner diameter of the second ring assembly (7) and the third ring assembly (8) relative to the tube body (1), and the skin (3) elastically contracts accordingly, and the depth of the groove (101) is reduced.

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