Propulsion device for applying thrust to fluid
By introducing the design of intermediate propulsion elements and guide elements into the propulsion equipment, the problems of high resistance and cavitation phenomena of traditional propellers are solved, and the effects of efficient propulsion and low resistance are achieved.
Patent Information
- Application Number
- CN202380045761.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-19
- Filing Date
- 2023-12-11
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2043-12-11
AI Technical Summary
Traditional spiral thrusters have problems with high rotational resistance, air cavitation, poor vibration and noise, resulting in low energy efficiency and blade wear.
A propulsion equipment is designed, including a central hub and multiple propulsion devices. Each propulsion device is composed of a front propulsion element, a rear propulsion element, a middle propulsion element, an outer guide element and an inner guide element. Through the middle propulsion element and the guide element, Designed to increase thrust and reduce drag.
Efficient propulsion, low resistance, concentrated axial flow, low cavitation and low noise are achieved, improving the overall efficiency and reliability of the propulsion equipment.
Smart Images
Figure CN119343295A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure generally relates to the field of propulsion devices for generating thrust to a fluid. The propulsion devices disclosed herein can be used in various applications, such as for the propulsion of aircraft including marine and airborne aircraft (including drones), and for the generation of forced fluid flow, such as fans, blowers and liquid pumps. Background Art
[0002] Conventional screw propellers generally include a rotating hub and two or more blades fixed to and projecting radially from the hub. The blades are spaced apart to define a spiral similar to a helix.
[0003] Such conventional propellers typically have a high resistance to rotation, resulting in high motor loads and low energy efficiency. Conventional propellers are also subject to cavitation, which in turn can damage the blades, cause undesirable vibrations and generate noise. In addition, such conventional propellers typically exhibit significant slippage, further reducing energy efficiency.
[0004] GB188,206 discloses a propeller, which comprises a hub and a plurality of radially supported main blades fixed to the hub. Each main blade is connected to a first auxiliary blade arranged in front of the main blade and a second auxiliary blade arranged behind the main blade. The tips of the main blade and the auxiliary blade extend radially beyond the connection between the main blade and the auxiliary blade. Summary of the invention
[0005] It is an object of the present invention to provide an enhanced propulsion device for generating thrust to a fluid.
[0006] Another object is to provide an efficient propulsion device.
[0007] Another object is to provide a propulsion device that generates an axial flow with relatively very little separation.
[0008] Yet another object is to provide a propulsion device that exhibits relatively low resistance to the fluid.
[0009] Yet another object is to provide a propulsion device that prevents cavitation.
[0010] Another object is to provide a propulsion device with a relatively low slip ratio.
[0011] In general, unless otherwise expressly defined herein, all terms used in the claims should be interpreted according to their ordinary meaning in the technical field. Unless otherwise expressly stated, all references to "an element, device, component, means, step, etc." should be openly interpreted as referring to at least one instance of an element, device, component, means, step, etc. Unless expressly stated otherwise, the steps of any method disclosed herein do not have to be performed in the exact order disclosed.
[0012] According to a first aspect, the present disclosure provides a propulsion device as claimed in claim 1. The propulsion device is arranged to apply thrust to a fluid. The propulsion device comprises a central hub and at least two propulsion devices. The central hub has a front end and a rear end and is rotatable about a rotation axis extending longitudinally between the front end and the rear end. At least two propulsion devices protrude radially from the hub and are evenly distributed around the circumference of the hub. Each propulsion device comprises a front propulsion element and a rear propulsion element, the front propulsion element extending radially from the front inner end to the front outer end, and the rear propulsion element extending radially from the rear inner end to the rear outer end. The outer guide element extends from the front outer end to the rear outer end at a radial outer guide element distance from the rotation axis, and the inner guide element extends from the front inner end to the rear inner end at a radial inner guide element distance from the rotation axis. An elongated front spacing member and an elongated rear spacing member extend radially from the hub to the inner guide element. At least one intermediate propulsion element is arranged between the front propulsion element and the rear propulsion element and extends radially from the inner guide element to the outer guide element. The longitudinal projections of the front propulsion element, the intermediate propulsion element and the rear propulsion element at least partially overlap. The inner guide element, the front spacing member, the rear spacing member and the outer periphery of the hub define an open space that allows fluid to pass freely.
[0013] By providing an intermediate propulsion element in the propulsion device, which extends from an inner guide element radially arranged at a certain distance from the hub, the propulsion device provides an additional thrust generating surface at the peripheral part of the propulsion device. The thrust generating area arranged at the peripheral part of the propulsion device provides greater thrust and less axial and tangential drag than the blade area in the central part of a conventional screw propeller. Therefore, the intermediate propulsion element improves the efficiency of the propulsion device by increasing the thrust while maintaining low drag. In a propulsion device, the inner and outer guide elements extending longitudinally between all the propulsion elements reduce radial flow and promote the generation of axial flow. Therefore, the axial component of the flow generated by the propulsion device is increased while keeping the lateral separation of the flow low. This also helps to improve the efficiency of the propulsion device. The outer and inner guide elements also increase the rigidity of the propulsion device, thereby making the propulsion element relatively thin and reducing vibrations. The outer guide element also reduces cavitation at the peripheral part of the propulsion element, thereby reducing wear of the propulsion element as well as noise and other vibrations.
[0014] The propulsion device has been shown to exhibit high efficiency, low drag, highly concentrated axial flow and small lateral separation, low degree of cavitation, and low levels of noise and other vibrations in both axial and circumferential directions.
[0015] In an embodiment of the propulsion device, the longitudinal projections of the front propulsion element, the middle propulsion element and the rear propulsion element completely overlap, which further reduces the axial resistance.
[0016] The length of the axial projection of the chord of the front propulsion element, the rear propulsion element and the intermediate propulsion element can be substantially constant. Therefore, the axial projection of the propulsion element presents a rectangular or diamond shape. In this way, while keeping the chord short, the area of the effective propulsion element can be large. This in turn increases the thrust while minimizing cavitation.
[0017] The maximum chord of the front propulsion element, the rear propulsion element and the intermediate propulsion element can be a short chord. Such a short chord is defined by the NACA standard nomenclature. Thus, the propulsion element exhibits a relatively short extension in the circumferential direction in the effective area radially outside the inner guide element, which reduces cavitation.
[0018] The inner guide element distance (IG) may be at least 40% of the outer guide distance (OG). This means that the distance between the intermediate propulsion element and the axis of rotation is large enough to provide a large thrust relative to the resistance.
[0019] The outer guide element may protrude rearwardly from the rear outer end. The protruding portion of the outer guide element then provides a so-called wing, which effectively reduces cavitation.
[0020] The outer guide element and the inner guide element can have a substantially constant longitudinal cross section which bulges outwards. This reduces the circumferential resistance.
[0021] The outer guide element and the inner guide element can have a substantially constant longitudinal cross section which is concave inwards. This further reduces the circumferential resistance.
[0022] The convex curvature radius or the concave curvature radius may be substantially equal to the radial distance from the rotation axis to the corresponding outer guide element and inner guide element. This also reduces the circumferential resistance.
[0023] The distance between the leading edge and the trailing edge of each of the front propulsion element, the rear propulsion element and the intermediate propulsion element can be substantially constant. This also makes the effective propulsion element area larger while keeping the chord relatively short.
[0024] The front spacing member and the rear spacing member may be longitudinally aligned.
[0025] The front spacing member and the rear spacing member may be arranged to extend radially from the front inner end and the rear inner end to the hub, respectively.
[0026] Each propulsion device may comprise a plurality of intermediate propulsion elements, preferably two or three intermediate propulsion elements. The advantage of arranging the effective propulsion element area at the periphery of the propulsion device is thereby further enhanced.
[0027] Propulsion equipment may include:
[0028] Two propulsion devices spaced 180° apart from each other in the circumferential direction; or
[0029] Three propulsion devices spaced 120° apart in the circumferential direction; or
[0030] Four propulsion devices spaced 90° apart in the circumferential direction; or
[0031] Five propulsion devices spaced 72° apart in the circumferential direction; or
[0032] Six thrusters spaced 60° apart from each other in the circumferential direction.
[0033] Further objects and advantages of the propulsion device according to the first, second and third aspects will be apparent from the following description of exemplary embodiments and from the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Aspects and embodiments will now be described by way of example and with reference to the accompanying drawings, in which:
[0035] Figure 1 is a perspective view of a propulsion device according to a first embodiment.
[0036] Figure 2a to Figure 2c They are Figure 1 Side, front and rear views of the propulsion device shown.
[0037] Figure 3 is a perspective view of a propulsion device according to a second embodiment.
[0038] Figure 4 is a perspective view of a propulsion device according to a third embodiment. DETAILED DESCRIPTION
[0039] Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.
[0040] However, these aspects can be embodied in a variety of different forms and should not be considered as limiting; on the contrary, these embodiments are provided by way of example to make this disclosure comprehensive and complete and to fully convey the scope of all aspects of the invention to those skilled in the art. Throughout the description, the same numerals represent the same elements.
[0041] Figures 1 to 4 The propulsion devices shown are all intended for propulsion of marine vehicles. Other non-illustrated embodiments within the scope of the present disclosure may be used for other applications, such as for propulsion of aircraft including drones or for generating forced fluid flows, such as fans, blowers and pumps.
[0042] according to Figure 1 to Figure 2c The marine propulsion device of the illustrated embodiment comprises a central hub 10 which is rotatable about a central axis of rotation A. In the illustrated embodiment, the hub 10 is arranged to allow exhaust gases from an outboard or inboard engine (not shown) to pass through the interior of the hub. The hub is tapered end, tapering from a front end 11 to a rear end 12. The hub 10 has a central hole 13 extending longitudinally from the front end 11 to the rear end 12. A cylindrical internal spline sleeve member 14 extends through the center of the hole 13. The sleeve member 14 is fixed to the inner wall of the hole 13 by four radial struts 15, so that an annular channel for exhaust gas is formed in the hole 13 around the sleeve member 14.
[0043] The propulsion device further comprises two propulsion devices 20, which are fixed to the outer peripheral surface of the hub 10 and are spaced 180 degrees apart. The two propulsion devices are identical, and for simplicity, only one will be described below.
[0044] Each propulsion device 20 comprises a front propulsion element 30, a rear propulsion element 40 and an intermediate propulsion element 50. The front propulsion element 30 has a front inner end 31 and a front outer end 32. Correspondingly, the rear propulsion element 40 has a rear inner end 41 and a rear outer end 42.
[0045] The outer guide element 60 extends parallel to the rotation axis A from the front outer end 32 to the rear outer end 42. The outer guide 60 is arranged at a radial outer guide element distance OG from the rotation axis A. The outer guide element 60 protrudes axially a short distance behind the rear propulsion element 40 to form a wing 61 protruding rearwardly.
[0046] The inner guide element 70 extends parallel to the axis of rotation A, from the front inner end 31 to the rear inner end 41. The inner guide element 70 is fixed to the outer periphery of the hub by means of an elongated front spacing member 35 and an elongated rear spacing member 45. The spacing members 35, 45 each extend radially from the hub to the inner guide element 70. In the embodiment shown, the front spacing member 35 forms a radially inward extension of the front propulsion element 30, and the rear spacing member forms a radially inward extension of the rear propulsion element 40. However, in other embodiments not shown, the spacing members may be arranged at other longitudinal positions of the inner guide element, as long as the spacing members keep the inner guide element 70 at a radial distance from the hub 10.
[0047] The inner guide element 70 is arranged at a radial inner guide element distance IG from the rotation axis A. The inner guide element distance IG is shorter than the outer guide distance OG, but greater than the maximum outer diameter of the hub 10. That is, the inner guide element 70 is arranged radially between the outer periphery of the hub and the outer guide element 60. In the embodiment shown, the inner guide element distance IG is about 60% of the outer guide element distance OG. Preferably, the inner guide element distance IG is 40% to 75% of the outer guide element distance OG.
[0048] The radially outer surface of the outer guide element 60 is convex, and its radius of curvature is substantially equal to the outer guide element distance OG. The radially inner surface of the outer guide element 60 is concave, and its radius of curvature is also substantially equal to the outer guide element distance OG.
[0049] Accordingly, the inner guide element 70 has an outer convex surface and an inner concave surface, both having a radius of curvature substantially equal to the inner guide element distance IG. In this way, the circumferential resistance of the propulsion device is reduced.
[0050] The intermediate propulsion element 50 is longitudinally arranged at the center between the front propulsion element 30 and the rear propulsion element 40 and radially extends from the inner guide element 70 to the outer guide element 60. The intermediate propulsion element 50 has an intermediate inner end 51 fixed to the inner guide 70 and an intermediate outer end 52 fixed to the outer guide 60.
[0051] It can be understood from the above description that the front spacing member 35, the rear spacing member 45, the outer periphery of the hub 10 and the inner guide element 70 define an open space through which a fluid (in this case water) can flow freely without generating any axial or circumferential resistance when the propulsion device rotates.
[0052] The front propulsion element 30, the rear propulsion element 40 and the intermediate propulsion element 50 have substantially the same geometric shape. At each propulsion element 30, 40, 50, the leading edge is arranged substantially parallel to the trailing edge. In addition, the axial projection of the propulsion element is substantially rhombus-shaped. In addition, the widths of the propulsion elements 30, 40, 50, the inner guide element 70 and the outer guide element 60 in the circumferential direction are substantially equal.
[0053] The width of the propulsion element 30, 40, 50 in the circumferential direction can also be expressed by the length of the chord (or chord) extending through the respective propulsion element from the leading edge to the trailing edge and the axial projection of the chord. With the propulsion device according to the present disclosure, the chord and its axial projection can be kept short compared to conventional propellers while still achieving a satisfactory thrust. This is very advantageous, because a short or small chord can reduce the risk of cavitation. It has been shown that the chord of the propulsion element 30, 40, 50 is preferably a so-called short chord or small chord according to the NACA standard nomenclature.
[0054] Figure 3 A second embodiment of a propulsion device is shown, which comprises a hub 110 and three propulsion means 120 distributed along the circumference of the hub 110 and spaced 120° apart.
[0055] Figure 4 A third embodiment of a propulsion device is shown, which comprises a hub 210 and four propulsion means 220 distributed along the circumference of the hub 210 and spaced 90° apart.
[0056] exist Figure 3 and Figure 4 In the illustrated embodiment, the hub 110, 210 and each propulsion device 120, 220 are substantially identical to the hub 110, 210. Figure 1 to Figure 2c The hub 10 and propulsion device 20 shown and described above are the same and will not be described in detail herein.
[0057] In an embodiment not shown, each propulsion device may comprise one or more intermediate propulsion elements arranged between the front propulsion element and the rear propulsion element. In this case too, the intermediate propulsion elements extend radially between an inner guide element arranged at a distance from the hub and an outer guide element extending between the outer ends of the front propulsion element and the rear propulsion element. In this embodiment, each propulsion device comprises active propulsion elements arranged between the inner guide element and the outer guide element, the total number of which is equal to the number of intermediate propulsion elements plus two.
[0058] In another embodiment not shown, each propulsion device may include more than two elongated spacing members to connect the inner guide element to the hub.
[0059] In all the propulsion devices shown and described above, preferably all propulsion elements in the propulsion device are longitudinally aligned and completely overlap each other in the longitudinal direction.
[0060] The above mainly describes various aspects of the present invention in conjunction with several embodiments and examples. However, it is easy for a person skilled in the art to understand that, in addition to the embodiments disclosed above, other embodiments are also possible within the scope of the present invention as defined by the attached patent claims.
Claims
1. A propulsion device for applying thrust to a fluid, the propulsion device comprising: a central hub (10, 110, 210) having a front end (11) and a rear end (12) and being rotatable about a rotation axis (A) extending longitudinally between the front end (11) and the rear end (12); and At least two propulsion devices (20, 120, 220), the at least two propulsion devices (20, 120, 220) radially protrude from the hub (10, 110, 210) and are evenly distributed around the circumference of the hub (10, 110, 210), wherein each propulsion device (20, 120, 220) comprises: - a front propulsion element (30) extending radially from a front inner end (31) to a front outer end (32), - a rear propulsion element (40) extending radially from a rear inner end (41) to a rear outer end (42), an outer guide element (60) extending from the front outer end (32) to the rear outer end (42) at a radial outer guide element distance (OG) from the rotation axis (A), an inner guide element (70) extending from the front inner end (31) to the rear inner end (41) at a radial inner guide element distance (IG) from the rotation axis (A), - an elongated front spacing member (35) and an elongated rear spacing member (45), the spacing members (35, 45) extending radially from the hub (10) to the inner guide element (60), and - at least one intermediate propulsion element (50), which is arranged between the front propulsion element (30) and the rear propulsion element (40) and extends radially from the inner guide element (70) to the outer guide element (60), wherein the longitudinal projections of the front propulsion element (30), the intermediate propulsion element (50) and the rear propulsion element (40) at least partially overlap, and wherein the inner guide element (70), the front spacing member (35), the rear spacing member (45) and the outer periphery of the hub (10) define an open space allowing a fluid to pass freely.
2. The propulsion device according to claim 1, wherein: The longitudinal projections of the front propulsion element (30), the middle propulsion element (50) and the rear propulsion element (40) completely overlap.
3. A propulsion device according to claim 1 or 2, wherein: The lengths of the axial projections of the chord lines of the front propulsion element (30), the rear propulsion element (40) and the intermediate propulsion element (50) are substantially constant.
4. A propulsion device according to any one of claims 1 to 3, wherein: The maximum chord of each of the front propulsion element (30), the rear propulsion element (40), and the intermediate propulsion element (50) is a short chord defined by extending an angle range of at most 60%.
5. The propulsion device according to any one of claims 1 to 4, wherein: The inner guide distance (IG) is at least 40% of the outer guide distance (OG), and preferably 40% to 75% of the outer guide distance (OG).
6. A propulsion device according to any one of claims 1 to 5, wherein: The outer guide element (60) protrudes rearwardly from the rear outer end (42).
7. A propulsion device according to any one of claims 1 to 6, wherein: The outer guide element (60) and / or the inner guide element (70) have a substantially constant longitudinal cross section that protrudes outward.
8. A propulsion device according to any one of claims 1 to 7, wherein: The outer guide element (60) and / or the inner guide element (70) have a substantially constant longitudinal cross section that is concave inwards.
9. A propulsion device according to claim 7 or 8, wherein: The convex or concave radius of curvature is substantially equal to the radial distance (OG, IG) from the rotation axis (A) to the respective outer guide element (60) and / or inner guide element (70).
10. A propulsion device according to any one of claims 1 to 9, wherein: The distance between the leading edge and the trailing edge of each of the front propulsion element (30), the rear propulsion element (40) and the intermediate propulsion element (50) is substantially constant along the radial extension of the propulsion element (30, 40, 50).
11. A propulsion device according to any one of claims 1 to 10, wherein: The front spacing member (35) and the rear spacing member (45) are longitudinally aligned.
12. A propulsion device according to any one of claims 1 to 11, wherein: The front spacing member (35) and the rear spacing member (45) are arranged to extend from the front inner end (31) and the rear inner end (41) to the radial direction of the hub (10), respectively.
13. A propulsion device according to any one of claims 1 to 12, wherein: Each propulsion device comprises a plurality of intermediate propulsion elements, preferably two or three intermediate propulsion elements.
14. The propulsion device according to any one of claims 1 to 13, comprising: Two propulsion devices (20) spaced 180 degrees apart from each other in the circumferential direction; or Three propulsion devices (120) spaced 120° apart from each other in the circumferential direction; or Four propulsion devices (220) spaced 90° apart from each other in the circumferential direction; or Five propulsion devices spaced 72° apart in the circumferential direction; or Six thrusters spaced 60° apart from each other in the circumferential direction.
Citation Information
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