A non-uniform inlet channel type thruster

Abstract

The present invention relates to a non-uniform inlet channel type thruster, which comprises a duct. A stator assembly is installed at the front part inside the duct, and a rotor assembly is installed at the rear part. The duct is a through pipe body that is larger at the front and smaller at the rear, and comprises a pipe body 1 and a pipe body 2 that are connected front and rear. The pipe body 1 is symmetric about the left and right, and the pipe body 2 is an axisymmetric rotating body. The distance between the top surface of the pipe body 1 and the axis of the pipe body 2 is less than the distance between the bottom surface of the pipe body 1 and the axis of the pipe body 2; the stator assembly is located inside the pipe body 1, and the rotor assembly is located inside the pipe body 2; the stator assembly includes a stator hub, and stator blades are installed at intervals along the circumferential direction on the outer wall surface of the stator hub. The density of the stator blades distributed on the upper part of the outer wall surface of the stator hub is greater than that of the lower part; thus, the duct and the stator assembly together form a non-uniform inlet channel, so that the non-uniform incoming flow is converted into a uniform fluid through the non-uniform inlet channel and then flows into the rear rotor assembly, making the overall thruster have a smaller unsteady excitation force and a higher propulsion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater thrusters, and in particular to a non-uniform inlet duct type thruster. Background Art

[0002] For underwater vehicles such as submarines, torpedoes, and AUVs, acoustic stealth performance is one of the important performance indicators. Propeller noise is one of the three major noise sources of underwater vehicles. According to the spectral characteristics, it can be divided into low-frequency line spectrum noise, low-frequency broadband noise, and medium-high frequency noise. Among them, the low-frequency line spectrum noise is mainly caused by the direct radiation noise of the propeller blades due to the periodic unsteady excitation force caused by the spatial non-uniformity of the propeller inlet flow. Due to its high energy and slow attenuation, the low-frequency line spectrum noise is extremely easy to be detected and captured. In addition, the unsteady excitation force is also transmitted through the shafting to cause the coupled vibration of the thruster-shaft-underwater vehicle, thereby radiating noise. Therefore, it is crucial to control the unsteady excitation force of the thruster.

[0003] Compared with a propeller, a conventional pump-jet thruster has certain advantages in noise reduction and efficiency improvement due to the characteristics that the stator can make the incoming flow uniform, etc. However, for underwater vehicles such as submarines, in addition to the axisymmetric main body, there are also upper decks, conning towers, bow rudders or fairwater rudders, and stern appendages for maneuvering control, so that the flow field in front of the stator is circumferentially non-uniform. The existing conventional pump-jet thruster stator is circumferentially uniformly distributed. After the incoming flow in front passes through the stator with circumferentially uniform arrangement for modulation, the uniformity of the rotor inlet flow is improved, but it is still a circumferentially non-uniform flow field. Therefore, the conventional pump-jet thruster will still be subject to a certain unsteady excitation force, and there is room for further reducing the unsteady excitation force and increasing the propulsion efficiency. Summary of the Invention

[0004] The applicant of the present invention aims at the above-mentioned disadvantages in the existing production technology and provides a non-uniform inlet duct type thruster with a reasonable structure, so that the non-uniform incoming flow is converted into a uniform fluid through the non-uniform inlet duct and then flows into the rear rotor assembly, making the overall thruster have smaller unsteady excitation force and higher propulsion efficiency.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A non-uniform inlet channel type thruster, comprising a duct. A stator assembly is installed at the front part in the axial direction inside the duct, and a rotor assembly is installed at the rear part in the axial direction inside the duct. The duct is a through pipe body structure with a larger front part and a smaller rear part, including a pipe body one and a pipe body two that are connected front and back along the axial direction. The pipe body one is symmetric left and right, and the pipe body two is an axisymmetric rotating body. The distance between the top surface of the pipe body one and the axis of the pipe body two is less than the distance between the bottom surface of the pipe body one and the axis of the pipe body two. The stator assembly is located inside the pipe body one, and the rotor assembly is located inside the pipe body two. The stator assembly includes a stator hub, and stator blades are installed at intervals along the circumferential direction on the outer wall surface of the stator hub. The density of the stator blades distributed on the upper part of the outer wall surface of the stator hub is greater than that of the lower part.

[0007] As a further improvement of the above technical solution:

[0008] The cross-section of the duct gradually contracts and decreases from front to back, forming a smooth wall surface with a larger front opening and a smaller rear opening.

[0009] The cross-section of the pipe body one is composed of two upper and lower semi-elliptical shapes. The upper and lower semi-elliptical shapes share the horizontal axis length (X). The ratio (Y / X) of the vertical axis length (Y) to the horizontal axis length (X) of the semi-elliptical shape is between 0.8 and 1.2.

[0010] The duct is relatively fixed to the stator assembly. Each stator blade is arranged in a helical inclination direction relative to the stator hub in the axial direction. The inner end of the stator blade is connected to the outer wall surface of the stator hub, and the outer end of the stator blade is connected to the inner wall surface of the duct. The rotor assembly is rotatably installed at the rear end of the stator assembly.

[0011] The stator blades are densely arranged in the area where the left and right sides are each deflected by 40° (α) directly above the stator hub.

[0012] The total number of the stator blades is 9 - 30, and the stator blades are symmetrically arranged left and right with respect to the stator hub.

[0013] The rotor assembly includes a rotor hub, and rotor blades are evenly arranged at intervals on the outer circumferential surface of the rotor hub. Flow deflectors are provided on the outer wall surface of the stator hub on both sides of the trailing edge of the root of each rotor blade.

[0014] The gaps between the outer ends of each rotor blade and the inner wall surface of the pipe body two are the same, and the inner ends of the rotor blades are fixedly connected to the rotor hub. The total number of the rotor blades is 5 - 21.

[0015] Each rotor blade is helically installed relative to the outer wall surface of the rotor hub, and the flow deflector is located at the rear of the helical extension line of the rotor blade.

[0016] The profile values and installation positions of the fairings located at the pressure side of the rotor blades are the same, and the profile values and installation positions of the fairings located at the suction side of the rotor blades are the same; the height (h) of a single fairing is 1%-4% of the radius of the rotor blade.

[0017] The beneficial effects of the present invention are as follows:

[0018] The structure of the present invention is compact and reasonable, and it is convenient to operate. By setting the conduit as an asymmetric structure with a relatively short upper half and arranging the stator blades of the stator assembly in an asymmetric form with a denser upper part and a sparser lower part, it fits the circumferentially non-uniform flow field in front of the stator. When the non-uniform oncoming flow passes through the conduit and the stator assembly, it is converted into a relatively uniform fluid, and then flows into the rotor, thereby improving the inflow uniformity of the propeller rotor, reducing the high-order quantities related to the number of rotor blades in the rotor inflow, making the propeller have smaller unsteady excitation forces and higher propulsion efficiency, achieving further noise reduction and efficiency increase, and greatly contributing to ensuring the quietness and speed of underwater vehicles such as submarines;

[0019] The fairings are arranged on both sides of the trailing edge of the root of the rotor blade. Through the interaction between the fairings and the root vortices at the root of the rotor blade, the root vortices are weakened or even eliminated, thereby reducing the energy damage of the propeller and increasing the efficiency by 1%-3%. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the present invention.

[0021] Figure 2 It is a front view of the conduit of the present invention.

[0022] Figure 3 It is Figure 2 a right view of

[0023] Figure 4 It is a side view of the stator assembly of the present invention.

[0024] Figure 5 It is a schematic structural diagram of the rotor assembly of the present invention.

[0025] Figure 6 It is Figure 5 a partial enlarged view of point A in

[0026] Wherein: 1, conduit; 2, stator assembly; 3, rotor assembly;

[0027] 11, pipe body one; 12, pipe body two;

[0028] 21, stator blade; 22, stator hub;

[0029] 31, rotor blade; 32, fairing; 33, rotor hub. Detailed Embodiments

[0030] The following describes the specific implementation manners of the present invention in conjunction with the accompanying drawings.

[0031] As Figure 1 shown, a non-uniform inflow channel type thruster in this embodiment includes a duct 1. A stator assembly 2 is installed at the front part in the axial direction inside the duct 1, and a rotor assembly 3 is installed at the rear part in the axial direction inside the duct 1. The duct 1 is a through pipe body structure with a larger front and a smaller rear, and includes a pipe body one 11 and a pipe body two 12 that are axially connected front and rear. As Figure 2 and Figure 3 shown, the pipe body one 11 is symmetric about the left and right, and the pipe body two 12 is an axisymmetric rotating body. The distance between the top surface of the pipe body one 11 and the axis of the pipe body two 12 is less than the distance between the bottom surface of the pipe body one 11 and the axis of the pipe body two 12; the stator assembly 2 is located inside the pipe body one 11, and the rotor assembly 3 is located inside the pipe body two 12; as Figure 4 shown, the stator assembly 2 includes a stator hub 22. Stator blades 21 are installed at intervals along the circumferential direction on the outer wall surface of the stator hub 22. The density of the stator blades 21 distributed on the upper part of the outer wall surface of the stator hub 22 is greater than that of the lower part.

[0032] By setting the duct 1 as an asymmetric structure with a relatively short upper half, and arranging the stator blades 21 of the stator assembly 2 in an asymmetric form with a higher density on the upper part and a lower density on the lower part, which fits the circumferentially non-uniform flow field in front of the stator. When the non-uniform incoming flow passes through the duct 1 and the stator assembly 2, it is converted into a relatively uniform fluid, and then flows into the rotor, thereby improving the inflow uniformity of the thruster rotor.

[0033] In this embodiment, the non-axisymmetric rotating pipe body one 11 and the non-uniformly arranged stator blades 21 jointly generate a beneficial interference on the non-uniform incoming flow passing through, convert the non-uniform flow into a uniform flow, reduce the high-order components in the flow field, and then enter the axisymmetric rotating pipe body two 12 in the rear half part of the duct 1 with a suitable wake structure.

[0034] The cross-section of the duct 1 gradually contracts and decreases from front to back, forming a smooth wall surface with a larger opening in the front and a smaller opening in the rear.

[0035] Of course, the cross-sections of the pipe body one 11 and the pipe body two 12 at the connection are matched in shape and size to achieve the connection of the smooth wall surface, so that the flowing fluid is uniform.

[0036] The cross-section of the pipe body one 11 is composed of two upper and lower semi-ellipses. The upper and lower semi-ellipses share the horizontal axis length (X), and the ratio (Y / X) of the vertical axis length (Y) to the horizontal axis length (X) of the semi-ellipse is between 0.8 and 1.2.

[0037] That is to say, as Figure 3As shown, the vertical axis length of the upper semi-ellipse is Y1, and the vertical axis length of the lower semi-ellipse is Y2, where Y1 < Y2. The geometry of the upper semi-ellipse is controlled by Y1 and X, and the geometry of the lower semi-ellipse is controlled by Y2 and X.

[0038] Since the underwater vehicle is symmetric about the left and right but asymmetric about the top and bottom, the nominal stern flow field formed also has the characteristics of being symmetric about the left and right but asymmetric about the top and bottom. Therefore, when the stern flow field with this characteristic flows through the pipe body 11 of the non-axisymmetric rotating body with this characteristic, an interaction occurs, which can better play a rectifying role, improve the uniformity of the non-uniform incoming flow, reduce the unsteady excitation force of the propeller, and improve the propulsion efficiency.

[0039] The conduit 1 is relatively fixed to the stator assembly 2. The individual stator blades 21 are arranged in a helical inclination direction axially relative to the stator hub 22. The inner end of the stator blade 21 is connected to the outer wall surface of the stator hub 22, and the outer end of the stator blade 21 is connected to the inner wall surface of the conduit 1; the rotor assembly 3 is rotatably installed at the rear end of the stator assembly 2.

[0040] The stator blades 21 are densely arranged in the area where the stator hub 22 is deflected 40° (α) to the left and right directly above.

[0041] Of course, the stator blades 21 can be relatively densely arranged evenly within the range of α, or can be relatively densely arranged from top to bottom in a decreasing density; similarly, outside the range of α, the stator blades 21 can be relatively sparsely arranged evenly, or can be arranged non-uniformly along the circumference.

[0042] The total number of the stator blades 21 is 9 - 30, and the stator blades 21 are arranged symmetrically about the left and right relative to the stator hub 22.

[0043] The actual number of the stator blades 21 and the arrangement along the circumference of the stator hub 22 can be determined according to the underwater vehicle and its full appendage structure.

[0044] In practice, due to superstructures such as the conning tower on the underwater vehicle, the upper part of the nominal stern flow field is more uneven. Therefore, arranging the non-uniform stator blades 21 densely in the upper part is beneficial to improving the uniformity of the non-uniform incoming flow to the greatest extent, and since the profile of each stator blade 21 is the same, the production cost can be reduced.

[0045] As Figure 5 shown, the rotor assembly 3 includes a rotor hub 33. Rotor blades 31 are evenly spaced on the outer circumferential surface of the rotor hub 33. Flow deflectors 32 are provided on the outer wall surfaces of the stator hub 22 on both sides of the trailing edge at the root of a single rotor blade 31.

[0046] The fairing 32 is arranged on both sides of the trailing edge at the root of the rotor blade 31. Through the interaction between the fairing 32 and the root vortex at the root of the rotor blade 31, the root vortex can be weakened or even eliminated, thereby reducing the energy damage of the thruster and increasing the efficiency by 1%-3%.

[0047] The gaps between the outer ends of the individual rotor blades 31 and the inner wall surface of the pipe body II 12 are all the same, and the inner ends of the rotor blades 31 are all fixedly connected to the rotor hub 33; the total number of rotor blades 31 is 5-21.

[0048] In practice, the number of rotor blades 31 is determined according to the underwater vehicle and its full appendage structure.

[0049] The profiles of each rotor blade 31 are exactly the same. By interacting with the uniform flow rectified by the duct 1 with suitable accompanying flow and the non-uniform stator assembly 2, the unsteady excitation force on the rotor blade 31 is reduced. At the same time, the circumferentially uniformly arranged rotor blades 31 can reduce the production cost.

[0050] Each individual rotor blade 31 is helically fitted relative to the outer wall surface of the rotor hub 33. The fairing 32 is located at the rear of the spiral extension line of the rotor blade 31. The trailing edge of the fairing 32 is flush with the trailing edge at the root of the rotor blade 31, and the fairing 32 is fixedly connected to the rotor hub 33.

[0051] The profiles and installation positions of the fairings 32 located at the pressure surface of the rotor blade 31 are the same, and the profiles and installation positions of the fairings 32 located at the suction surface of the rotor blade 31 are the same; the height (h) of each individual fairing 32 is 1%-4% of the radius of the rotor blade 31, as Figure 6 shown, effectively ensuring the interaction with the root vortex of the rotor blade 31, thereby effectively weakening or eliminating the hub vortex from the source.

[0052] The working principle of the present invention is as follows:

[0053] Since underwater vehicles such as submarines have, in addition to the axisymmetric main body, appendages such as the upper deck, conning tower, bow rudder or sail rudder, and stern control surfaces for maneuvering control, the flow field in front of the stator of a conventional pump-jet thruster is circumferentially non-uniform. After being modulated by the circumferentially uniform stator, the rotor inflow is still a circumferentially non-uniform flow field.

[0054] According to the characteristics of the nominal stern flow field of the submarine, the duct 1 with suitable accompanying flow and the non-uniform stator assembly 2 are designed specifically. When the non-uniform inflow at the stern of the submarine interacts with the duct 1 with suitable accompanying flow and the non-uniform stator assembly 2, the inflow field of the rotor assembly 3 can be made more uniform, especially the higher-order quantities related to integer multiples of the number of rotor blades 31 are reduced by 20% - 50%, thereby reducing the unsteady excitation force by 20% - 50%.

[0055] In addition, root vortices will be formed at the roots of the rotor blades 31, and the root vortices of each blade will converge to finally form a hub vortex. By specifically designing the flow deflectors 32 at the rear of each rotor blade 31, the root vortices can be weakened or eliminated, thereby weakening or eliminating the hub vortex at the source, reducing energy loss, and increasing the efficiency by 1% to 3%.

[0056] The present invention can effectively improve the inflow uniformity of the propeller rotor, reduce the higher-order quantities related to the number of rotor blades in the rotor inflow, and enable the propeller to have smaller unsteady excitation forces and higher propulsion efficiency, achieving further noise reduction and efficiency increase, and greatly contributing to ensuring the quietness and speed of underwater vehicles such as submarines.

[0057] The above description is an explanation of the present invention, not a limitation of the invention. The scope defined by the present invention is referred to the claims, and any form of modification can be made within the protection scope of the present invention.

Claims

1. A non-uniform inlet channel type thruster, comprising a duct (1), a stator assembly (2) is installed at the front part in the axial direction inside the duct (1), and a rotor assembly (3) is installed at the rear part in the axial direction inside the duct (1). Characterized in that: The duct (1) is a through pipe body structure with a larger front and a smaller rear, including a pipe body one (11) and a pipe body two (12) connected in sequence along the axial direction. The pipe body one (11) is symmetrical left and right, and the pipe body two (12) is an axisymmetric rotating body. The distance between the top surface of the pipe body one (11) and the axis of the pipe body two (12) is less than the distance between the bottom surface of the pipe body one (11) and the axis of the pipe body two (12); the stator assembly (2) is located inside the pipe body one (11), and the rotor assembly (3) is located inside the pipe body two (12); the stator assembly (2) includes a stator hub (22), and stator vanes (21) are installed at intervals along the circumferential direction on the outer wall surface of the stator hub (22). The density of the stator vanes (21) distributed on the upper part of the outer wall surface of the stator hub (22) is greater than that of the lower part; the cross-section of the pipe body one (11) is composed of two semi-ellipses, the upper and lower semi-ellipses share the horizontal axis length (X), and the ratio (Y / X) of the vertical axis length (Y) to the horizontal axis length (X) of the semi-ellipse is between 0.8 and 1.2; the stator vanes (21) are densely arranged in the area where the left and right sides of the stator hub (22) are each deflected 40° (α) directly above.

2. A non-uniform inlet channel type thruster according to claim 1, Characterized in that: The cross-section of the duct (1) gradually contracts and decreases from front to back, forming a smooth wall surface with a larger front and a smaller rear opening.

3. A non-uniform inlet channel type thruster according to claim 1, Characterized in that: The duct (1) is relatively fixed to the stator assembly (2). The individual stator vanes (21) are arranged in a spiral inclined direction in the axial direction relative to the stator hub (22). The inner end of the stator vane (21) is connected to the outer wall surface of the stator hub (22), and the outer end of the stator vane (21) is connected to the inner wall surface of the duct (1); the rotor assembly (3) is rotatably installed at the rear end of the stator assembly (2).

4. A non-uniform inlet channel type thruster according to claim 1, Characterized in that: The total number of the stator vanes (21) is 9 - 30, and the stator vanes (21) are arranged symmetrically left and right with respect to the stator hub (22).

5. A non-uniform inlet channel type thruster according to claim 1, Characterized in that: The rotor assembly (3) includes a rotor hub (33), and rotor vanes (31) are evenly arranged at intervals on the outer circumferential surface of the rotor hub (33). Flow deflectors (32) are provided on the outer wall surfaces of the stator hub (22) on both sides of the trailing edge at the root of a single rotor vane (31).

6. A non-uniform inlet channel type thruster according to claim 5, Characterized in that: The gaps between the outer ends of the individual rotor vanes (31) and the inner wall surface of the pipe body two (12) are the same, and the inner ends of the rotor vanes (31) are fixedly connected to the rotor hub (33); the total number of the rotor vanes (31) is 5 - 21.

7. A non-uniform inlet channel type thruster as claimed in claim 5, characterized in that: Each single rotor blade (31) is helically fitted relative to the outer wall surface of the rotor hub (33), and the fluid guide (32) is located at the rear of the helical extension line of the rotor blade (31).

8. A non-uniform inlet channel type thruster as claimed in claim 5, characterized in that: The profile and installation position of the fluid guide (32) located at the pressure surface of the rotor blade (31) are the same, and the profile and installation position of the fluid guide (32) located at the suction surface of the rotor blade (31) are the same; the height (h) of each single fluid guide (32) is 1% - 4% of the radius of the rotor blade (31).

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