Pump-jet propeller

Abstract

The invention relates to a pump jet propeller which comprises an annular guide pipe, a first stator, a rotor and a propeller hub, the first stator, the rotor and the propeller hub are all arranged in the annular guide pipe, the first stator is close to the tail edge of the annular guide pipe, the first stator and the rotor are connected with the propeller hub, and the first stator is connected with the inner wall of the annular guide pipe. The tail edge of the annular guide pipe is provided with a plurality of sawtooth assemblies which are arranged at intervals in the circumferential direction of the annular guide pipe, the sawtooth assemblies are located between every two adjacent stator blades, each sawtooth assembly comprises at least one sawtooth structure, and the first stator comprises a plurality of stator blades; the rotor is used for rotating and generating water power, so that the pump-jet propeller generates forward thrust; the sawtooth assembly is used for disturbing the wake flow field of the pump-jet propeller to conduct vibration and noise reduction, and the problems that due to a continuously-distributed sawtooth structure, the thrust loss is large, and the noise reduction effect is poor can be solved.

Description

Technical Field

[0001] The present application relates to the field of ship propulsion technology, and in particular to a pump-jet propulsion device. Background Art

[0002] Pump-jet propulsion, as a high-efficiency, low-noise combined propulsion device, is becoming the main mechanical propulsion device for underwater equipment. Pump-jet propulsion is mainly composed of an annular duct and a rotor and stator inside the duct.

[0003] As underwater equipment continues to develop in the direction of high speed and silence, more stringent requirements are also placed on the performance of pump-jet propulsion. As the main working component of underwater equipment, the hydrodynamic performance and noise performance of pump-jet propulsion significantly affect the rapidity and acoustic stealth of underwater equipment. Therefore, it is of great significance to improve the performance control such as the hydrodynamic performance and noise performance of the propeller. At present, the performance control methods of pump-jet propulsion mainly focus on the structural improvement of the pump-jet rotor, duct, and stator. Among them, the method of applying a bionic structure to the trailing edge of the duct has the advantage of convenient processing and manufacturing compared with other methods.

[0004] However, the above-mentioned pump-jet propulsion system has the problem that the hydrodynamic performance and noise performance cannot be regulated at the same time. Summary of the invention

[0005] Based on this, it is necessary to provide a pump-jet propulsion system that can take into account both the regulation of hydrodynamic performance and noise performance in order to address the above-mentioned technical problems.

[0006] In a first aspect, the present application provides a pump-jet propeller, comprising: an annular duct, a first stator, a rotor and a hub, wherein the first stator, the rotor and the hub are all arranged inside the annular duct, the first stator is close to the trailing edge of the annular duct, the first stator and the rotor are connected to the hub, the first stator is connected to the inner wall of the annular duct, the trailing edge of the annular duct is provided with a plurality of sawtooth assemblies arranged at intervals along the circumference of the annular duct, the sawtooth assembly is located between two adjacent stator blades, the sawtooth assembly includes at least one sawtooth structure, and the first stator includes a plurality of stator blades;

[0007] A rotor, configured to rotate and generate hydrodynamic force so that the pump-jet propeller generates forward thrust;

[0008] The sawtooth assembly is used to interfere with the wake field of the pump-jet propulsor to reduce vibration and noise.

[0009] In one embodiment, each sawtooth assembly is arranged at equal intervals along the circumference of the trailing edge of the annular duct, and the coverage area of ​​the sawtooth assembly is the area between the suction surface of one of the two adjacent stator blades and a preset position, and the preset position is a position determined according to the middle position between the two adjacent stator blades.

[0010] In one embodiment, the number of the sawtooth assemblies is equal to the number of stator blades.

[0011] In one embodiment, the height of the sawtooth structure does not exceed 0.1 times the chord length of the annular duct, and does not exceed the axial distance between the trailing edge of the first stator and the trailing edge of the annular duct.

[0012] In one embodiment, the ratio of the height of the sawtooth structure to the width of the sawtooth structure is not less than 2 and not greater than 4.

[0013] In one of the embodiments, the pump-jet propulsor further includes a second stator, which is disposed inside the annular duct, and is respectively connected to the hub and the inner wall of the annular duct, and is away from the trailing edge of the annular duct.

[0014] In one of the embodiments, surfaces of the annular duct, the first stator, the rotor and the second stator are provided with sliding surfaces.

[0015] In one embodiment, the sliding lengths of the sliding surfaces corresponding to the annular duct, the first stator, the rotor and the second stator are the same or different.

[0016] In one embodiment, the slip length is 20 -500 between.

[0017] In one embodiment, the slip surface includes at least one of a carbon-based coating surface and a fluorine-containing coating surface.

[0018] The pump-jet propeller comprises an annular duct, a first stator, a rotor and a hub. The first stator, the rotor and the hub are all arranged inside the annular duct. The first stator is close to the trailing edge of the annular duct. The first stator and the rotor are connected to the hub. The first stator is connected to the inner wall of the annular duct. The trailing edge of the annular duct is provided with a plurality of sawtooth assemblies arranged at intervals along the circumference of the annular duct. The sawtooth assembly is located between two adjacent stator blades. The sawtooth assembly includes at least one sawtooth structure. The rotor is used to rotate and generate hydrodynamic force so that the pump-jet propeller generates forward thrust. The first stator includes a plurality of stator blades. The sawtooth assembly is used to interfere with the wake flow field of the pump-jet propeller to reduce vibration and noise. By arranging a plurality of sawtooth assemblies arranged at intervals along the circumference of the annular duct on the trailing edge of the annular duct, and making the sawtooth assembly located between two adjacent first stators, the non-continuously distributed sawtooth assemblies on the trailing edge of the annular duct can improve the problems of large thrust loss and poor noise reduction effect caused by the continuously distributed sawtooth structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic structural diagram of a pump-jet propulsion device in one embodiment;

[0021] Figure 2 is a schematic structural diagram of a pump-jet propulsion device in another embodiment;

[0022] Figure 3 A schematic diagram of the sawtooth aspect ratio of a pump-jet propulsor in one embodiment;

[0023] Figure 4 A schematic diagram of a curve showing the influence of a sawtooth structure on a thrust coefficient in one embodiment;

[0024] Figure 5 A schematic diagram of a curve showing the effect of a sawtooth structure on propulsion efficiency in one embodiment;

[0025] Figure 6 A schematic diagram of a curve showing the effect of a sawtooth structure on a change in sound pressure level in an xy vertical plane in one embodiment;

[0026] Figure 7 A schematic diagram of a curve showing the effect of a sawtooth structure on a change in sound pressure level in an xz vertical plane in one embodiment;

[0027] Figure 8 A schematic diagram of a curve showing the effect of a sawtooth structure on a change in the total sound pressure level in an xy vertical plane in one embodiment;

[0028] Fig. 9 Schematic diagram of a curve showing the effect of a sawtooth structure on a change in the total sound pressure level in the xz vertical plane in one embodiment;

[0029] Fig.10 A schematic diagram of a curve showing the influence of the coupling between the sawtooth structure and the sliding surface on the thrust coefficient in one embodiment;

[0030] Fig.11 A schematic diagram of a curve showing the effect of the coupling between the sawtooth structure and the sliding surface on the propulsion efficiency in one embodiment;

[0031] Fig.12 A schematic diagram of the effect of the coupling between the sawtooth structure and the sliding surface on the change in the sound pressure level in the xy vertical plane in one embodiment;

[0032] Fig.13A schematic diagram of the effect of the coupling between the sawtooth structure and the sliding surface on the change in the sound pressure level in the xz horizontal plane in one embodiment;

[0033] Fig.14 A schematic diagram of the effect of the coupling between the sawtooth structure and the sliding surface on the change in the total sound pressure level in the xy vertical plane in one embodiment;

[0034] Fig.15 Schematic diagram of the effect of the coupling between the sawtooth structure and the sliding surface on the change of the total sound pressure level in the xz vertical plane in one embodiment;

[0035] Fig.16 It is a schematic diagram of comparing the pump jet noise performance under the small sawtooth working condition in one embodiment;

[0036] Fig.17 It is a schematic diagram for comparing the pump jet noise performance under large sawtooth conditions in one embodiment.

[0037] Description of reference numerals:

[0038] Pump-jet propeller 01; annular duct 10;

[0039] stator blades 20; rotor 30;

[0040] Hub 40; Sawtooth assembly 50;

[0041] Sawtooth structure 500 ; Second stator 60 . DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0043] Pump-jet propulsion, as a high-efficiency, low-noise combined propulsion device, is becoming the main mechanical propulsion device for underwater equipment. Pump-jet propulsion is mainly composed of an annular duct and a rotating blade cascade (rotor) and a fixed blade cascade (stator) in the duct.

[0044] As underwater equipment continues to develop in the direction of high speed and silence, more stringent requirements are also placed on the performance of pump-jet propulsion. In terms of hydrodynamic performance, the annular duct, stator and rotor will all generate thrust, and the stator and rotor will generate torque, which will affect the propulsion efficiency of the pump-jet propulsion. In terms of flow noise performance, the duct and stator mainly contribute broadband noise, while the rotor mainly contributes line spectrum noise. Therefore, the regulation of the duct, stator and rotor will affect the hydrodynamic performance and flow noise performance of the pump-jet propulsion.

[0045] At present, the performance control methods of pump-jet propulsion mainly focus on the structural improvements of the pump-jet rotor, annular duct, and stator, such as adding end rings to the rotor blade tips, applying grooves to the inner wall of the annular duct, setting the trailing edge of the annular duct or stator as a porous medium, and applying a bionic structure to the trailing edge of the duct. However, since the above structures will have an adverse effect on the hydrodynamic performance while reducing the pump-jet noise, it is difficult to simultaneously control the pump-jet hydrodynamics and flow noise performance. Among them, the method of applying a bionic structure to the trailing edge of the annular duct has the advantage of convenient processing and manufacturing compared to other methods, and therefore has the possibility of further improvement. However, the above-mentioned pump-jet propulsion has the problem that the hydrodynamic performance and noise performance cannot be controlled at the same time. The present application aims to provide a new type of pump-jet propulsion to solve the above problems.

[0046] After introducing the background technology of the pump-jet propulsion device provided in the embodiment of the present application, the following focuses on introducing the pump-jet propulsion device proposed in this solution.

[0047] In one embodiment, Figure 1 As shown, a pump jet propulsor 01 is provided, which includes an annular duct 10, a first stator, a rotor 30 and a hub 40. The first stator, the rotor 30 and the hub 40 are all arranged inside the annular duct 10. The first stator is close to the trailing edge of the annular duct 10. The first stator and the rotor 30 are connected to the hub 40. The first stator is connected to the inner wall of the annular duct 10. The trailing edge of the annular duct 10 is provided with a plurality of sawtooth assemblies 50 (see FIG. 5 ) arranged at intervals along the circumference of the annular duct 10. Figure 2 ), the sawtooth assembly 50 is located between two adjacent stator blades 20, the sawtooth assembly 50 includes at least one sawtooth structure 500, and the first stator includes a plurality of stator blades 20;

[0048] The rotor 30 is used to rotate and generate water power so that the pump-jet propeller 01 generates forward thrust;

[0049] The sawtooth assembly 50 is used to interfere with the wake field of the pump-jet propulsor 01 to reduce vibration and noise.

[0050] The annular duct 10 is a quasi-annular structure with unequal radii at both ends, wherein the end with a smaller radius is the trailing edge of the annular duct 10 , and the end with a larger radius is the non-trailing edge of the annular duct 10 .

[0051] Generally, the pump-jet propulsor 01 may include only one stator or two stators; when the pump-jet propulsor 01 includes only one stator, the stator may be close to the trailing edge of the annular duct 10 and disposed on the hub 40, or may be far away from the trailing edge of the annular duct 10 and disposed on the hub 40; and, when the pump-jet propulsor 01 includes two stators, the two stators may be respectively close to the trailing edge position of the annular duct 10 and the non-trailing edge position of the annular duct 10, and disposed on the hub 40.

[0052] Further, when the stator in the pump-jet propeller 01 is arranged near the trailing edge of the annular duct 10, the rotor 30 is far away from the trailing edge of the annular duct 10 and is arranged on the hub 40. When the stator in the pump-jet propeller 01 is far away from the trailing edge of the annular duct 10, the rotor 30 is near the trailing edge of the annular duct 10 and is arranged on the hub 40. In the case where the pump-jet propeller 01 includes two stators, one near the trailing edge of the annular duct 10 and one near the non-trailing edge of the annular duct 10, the rotor 30 is located between the two stators and is arranged on the hub 40. When the motor drives the rotor 30 to rotate, water flows in from the non-trailing edge of the annular duct 10, thereby generating huge hydrodynamic force. The rotation of the rotor 30 generates forward thrust, thereby causing the pump-jet propeller 01 to generate forward thrust.

[0053] The first stator in the pump-jet propulsor 01 provided in the embodiment of the present application is a stator close to the trailing edge of the annular duct 10, one end of the first stator is fixed to the inner wall of the annular duct 10, and the other end of the first stator is fixed to the hub 40 to ensure that the annular duct 10, the first stator and the hub 40 are fixed and do not move.

[0054] It should be noted that a first stator is provided in the pump-jet propulsor 01 to recover the rotational energy in the wake of the rotor 30 and improve the overall efficiency of the pump-jet propulsor 01, but its noise is relatively high. In addition, the blades of the first stator are subjected to a force opposite to the incoming flow, generating thrust and having the function of balancing the torque.

[0055] See also Figure 2 The trailing edge of the annular duct 10 is provided with a plurality of sawtooth assemblies 50 arranged at intervals along the circumference of the annular duct 10. The sawtooth assembly 50 is located between two adjacent stator blades 20, and the sawtooth assembly 50 includes at least one sawtooth structure 500. The sawtooth assembly 50 has the advantages of simple structure and convenient processing. It should be noted that the sawtooth assembly 50 should be obtained by removing material on the basis of the original annular duct 10, rather than by adding material to the trailing edge on the basis of the original annular duct 10. The reason is that the method of removing material can ensure a higher structural strength and avoid the situation where the sawtooth assembly 50 oscillates under a larger hydrodynamic load caused by the added sawtooth assembly 50, thereby causing a surge in noise.

[0056] The pump-jet propulsor provided in the embodiment of the present application, by providing a plurality of sawtooth assemblies arranged at circumferential intervals along the annular duct on the trailing edge of the annular duct, and making the sawtooth assemblies located between two adjacent stator blades, the non-continuously distributed sawtooth assemblies on the trailing edge of the annular duct can improve the problems of large thrust loss and poor noise reduction effect caused by the continuously distributed sawtooth structure.

[0057] In one embodiment, the arrangement area of ​​the sawtooth assembly 50 needs to be further restricted. The sawtooth assemblies 50 are arranged at equal intervals along the circumference of the annular duct 10, and the coverage area of ​​the sawtooth assembly 50 is the area between the suction surface of one of the two adjacent stator blades 20 and the preset position. The preset position is a position determined according to the middle position between the two adjacent stator blades 20.

[0058] The first stator includes a plurality of stator blades 20 , each of which includes a convex curved surface and a concave curved surface, and the suction surface of the stator blade 20 is the convex curved surface of the stator blade 20 .

[0059] Generally, the center position between the two stator blades 20 in the first stator can be determined first, and a sawtooth assembly 50 can be set between the center position between the two stator blades 20 and the suction surface of any one of the two stator blades 20. It should be noted that the sawtooth assemblies 50 are arranged at equal intervals along the circumference of the trailing edge of the annular duct.

[0060] The pump-jet propulsor provided in the embodiment of the present application improves the problems of large thrust loss and poor noise reduction effect caused by the continuous distributed sawtooth structure by setting a sawtooth assembly between any two stator blades of the first stator, so as to interfere with the wake field of the pump-jet propulsor to reduce vibration and noise.

[0061] In one embodiment, the number of sawtooth assemblies 50 is equal to the number of stator blades 20. Generally, the first stator of the pump-jet propulsor 01 provided in the embodiment of the present application has 13 stator blades 20, that is, 13 sawtooth assemblies 50 are arranged in the circumferential direction of the trailing edge of the annular duct 10.

[0062] The pump-jet propulsor provided in the embodiment of the present application can adaptively improve the problems of large thrust loss and poor noise reduction effect caused by the continuous distributed sawtooth structure by setting a number of sawtooth components equal to the number of stator blades, so as to interfere with the wake field of the pump-jet propulsor to reduce vibration and noise.

[0063] In one embodiment, the height of each sawtooth structure 500 needs to be limited. Figure 2 and Figure 3The height of the sawtooth structure 500 does not exceed 0.1 times the chord length of the annular duct 10 , and does not exceed the axial distance between the trailing edge position of the first stator and the trailing edge position of the annular duct 10 .

[0064] The trailing edge position of the first stator is the outer edge position of each stator blade 20 in the first stator, and the outer edge position is the trailing edge position close to the annular duct 10 .

[0065] The pump-jet propulsor provided in the embodiment of the present application further limits the height of the sawtooth structure, providing a data basis for manufacturing the sawtooth structure, thereby achieving interference with the wake field of the pump-jet propulsor to reduce vibration and noise.

[0066] In one embodiment, it is also necessary to limit the relationship between the height of each sawtooth structure 500 and the width of the sawtooth structure 500, see Figure 3 , a ratio of the height of the sawtooth structure 500 to the width of the sawtooth structure 500 is not less than 2 and not greater than 4.

[0067] It should be noted that each sawtooth structure 500 can be a triangular-like structure, for example, a triangle with a ratio of height to width of 2-4, or a sine shape with a ratio of height to width of 2-4, or other shapes with a ratio of height to width of 2-4, and the embodiments of the present application are not limited thereto.

[0068] The pump-jet propulsor provided in the embodiment of the present application further limits the ratio between the height of the sawtooth structure and the width of the sawtooth structure, providing a data basis for manufacturing the sawtooth structure, thereby achieving vibration reduction and noise reduction by interfering with the wake field of the pump-jet propulsor.

[0069] In one embodiment, see Figure 1 The pump-jet propulsor 01 also includes a second stator 60, which is disposed inside the annular duct 10. The second stator 60 is respectively connected to the hub 40 and the inner wall of the annular duct 10, and the second stator 60 is far away from the trailing edge of the annular duct 10.

[0070] One end of the second stator 60 is connected to the hub 40, and the other end is connected to the inner wall of the annular duct 10, so that the second stator 60 fixedly connects the hub 40 to the annular duct 10. In addition, the second stator 60 is provided in the pump-jet propeller 01 to provide pre-spin for the rotor 30, improve the working conditions of the rotor 30, thereby improving the propulsion efficiency of the rotor 30, and effectively reducing the radiation noise.

[0071] The pump-jet propeller provided in the embodiment of the present application is provided with a second stator to provide a basis for further noise reduction.

[0072] In one embodiment, the surfaces of the annular duct 10, the first stator, the rotor 30 and the second stator 60 in the pump-jet propulsor 01 are all provided with sliding surfaces.

[0073] In the embodiment of the present application, a slip surface is arranged on the surfaces of the annular duct 10, the first stator, the rotor 30 and the second stator 60 in the pump-jet propulsor 01, so that the fluid in contact with the surface generates a certain slip speed when flowing through the surface, thereby reducing the velocity gradient near the wall surface, thereby reducing the shear stress and friction resistance at the fluid-solid interface. At the same time, the slip can change the pressure distribution on the surfaces of the annular duct, the first stator, the second stator and the rotor, reduce the pressure difference resistance, and increase the lift of the cross-sectional airfoil, thereby increasing the overall thrust and efficiency of the pump-jet propulsor and achieving an improvement in the pump-jet water dynamics performance.

[0074] Optionally, a sliding surface may be provided only on the surface of the annular duct 10 of the pump-jet propulsor 01, or a sliding surface may be provided only on the surface of the first stator of the pump-jet propulsor 01, or a sliding surface may be provided only on the surface of the rotor 30 of the pump-jet propulsor 01, or a sliding surface may be provided only on the surface of the second stator 60 of the pump-jet propulsor 01, or a sliding surface may be provided on the surface of the annular duct 10 and the first stator of the pump-jet propulsor 01, or a sliding surface may be provided on the surface of the annular duct 10 and the rotor 30 of the pump-jet propulsor 01, or a sliding surface may be provided on the surface of the annular duct 10 and the second stator of the pump-jet propulsor 01. A sliding surface is provided on the surface of the rotor 60, or a sliding surface is provided on the surface of the first stator and the rotor 30 of the pump-jet propulsor 01, or a sliding surface is provided on the surface of the first stator and the second stator 60 of the pump-jet propulsor 01, or a sliding surface is provided on the surface of the rotor 30 and the second stator 60 of the pump-jet propulsor 01, or a sliding surface is provided on the surface of any three of the annular duct 10, the first stator, the rotor 30 and the second stator 60 of the pump-jet propulsor 01, or a sliding surface is provided on the surface of the annular duct 10, the first stator, the rotor 30 and the second stator 60 of the pump-jet propulsor 01. It should be noted that the embodiment of the present application does not limit the setting position of the sliding surface.

[0075] In one embodiment, the sliding lengths of the sliding surfaces respectively corresponding to the annular duct 10, the first stator, the rotor 30 and the second stator 60 in the pump-jet propulsor 01 may be the same or different.

[0076] It should be noted that the slip surface is measured by the slip length, which is defined as the normal distance corresponding to the zero velocity extending from the slip velocity along the velocity gradient near the wall into the solid.

[0077] In the embodiment of the present application, by arranging a sliding surface with a certain sliding length on the annular duct, the first stator, the rotor and the second stator of the pump-jet propulsor, and arranging a plurality of sawtooth assemblies arranged at intervals in the circumferential direction of the annular duct on the trailing edge of the annular duct, that is, coupling of the discontinuously distributed local sawtooth assemblies with the sliding surface, it is possible to overcome the pump-jet thrust loss caused by the sawtooth structure, significantly improve the hydrodynamic performance of the pump-jet, improve the pump-jet efficiency, and further reduce the pump-jet noise on the basis of the sawtooth structure, thereby showing significant advantages over the prior art.

[0078] In one embodiment, the above-mentioned sliding length is 20 -500 and the slip surface includes at least one of a carbon-based coating surface and a fluorine-containing coating surface.

[0079] It should be noted that the slip surface can be realized by selecting a coating that does not significantly change the surface roughness of the pump spray, such as a carbon-based coating, a fluorine-containing coating, etc., which can be applied to the surface of various pump spray components by spraying or coating, and has the advantages of easy implementation and strong durability.

[0080] Optionally, the following provides two matching relationships between the sizes of sawtooth structures and the sliding surfaces, including: one is a large sawtooth structure, that is, the height of the sawtooth structure is 6 mm, not exceeding 0.1 times the chord length of the annular duct, and not exceeding the axial distance between the trailing edge of the second stator and the trailing edge of the annular duct, and the corresponding sawtooth structure has a width of 3 mm; the other is a small sawtooth structure, the height of the sawtooth structure is half the height of the large sawtooth structure, that is, 3 mm, and the corresponding sawtooth structure has a width of 1.5 mm. Among them, the large sawtooth structure can start from the suction surface of the second stator and be arranged circumferentially along the trailing edge of the annular duct of the pump-jet propulsor, with 4 teeth arranged at each location, 13 locations arranged circumferentially, and a total of 52 teeth. The small sawtooth structure also starts from the suction surface of the second stator and is arranged circumferentially along the trailing edge of the annular duct of the pump-jet propulsor, with 8 teeth arranged at each location, 13 locations arranged circumferentially, and a total of 104 teeth. The sliding surface is set on the duct, the first stator, and the second stator, and the sliding length is set to 100 The pump-jet propulsor with the local sawtooth structure and the sliding surface regulated simultaneously is respectively recorded as “6-3-local-100 ”, “3-1.5-local-100 ”.

[0081] In one embodiment, a "6-3-local-100 ”, “3-1.5-local-100 The simulation results of the pump-jet propulsor are as follows:

[0082] For the pump-jet propulsion system in the above embodiment, a fluid domain is established and a fluid grid is divided to calculate its hydrodynamic and noise performance at the self-propulsion operating point under non-uniform incoming flow. First, SST k- The model performs steady-state flow field calculations. After the calculations are stable, the IDDES method is used for transient calculations. The calculation time step is set to 1 rotation of the pump-jet rotor. Corresponding to the time, the transient calculation time step is 5400 steps (that is, the rotor rotates 15 times). Furthermore, after the IDDES method calculation is stable, the FW-H model is turned on to calculate and collect noise signals, and the collection time step is 5400 steps (the rotor rotates 15 times). After the calculation is completed, the hydrodynamic and noise data of the last 15 weeks are collected for subsequent analysis. Among them, the hydrodynamic performance of the pump-jet propulsion system is mainly measured by the thrust coefficient and propulsion efficiency. The thrust coefficient is the ratio of the thrust exerted on each component and the whole of the pump-jet to the product of the fluid density, the square of the rotation speed, and the fourth power of the diameter. The flow noise performance is measured by the sound pressure level index, that is, the i-th frequency The sound pressure level (SPL) at the location is expressed in the following formula (1):

[0083]

[0084] in, is the reference sound pressure. = 1 10 -6 Pa, represents the i-th frequency The corresponding sound pressure.

[0085] The calculation formula for the overall sound pressure level (OASPL) is as follows:

[0086]

[0087] It should be noted that during the simulation process, the noise receiving point and azimuth angle need to be defined as follows: With the center of the pump-jet propulsor's rotor as the center of the circle, set the noise receiving point on the circumference of the xy vertical plane, xz horizontal plane, and yz cross section 1 m away from the center of the pump-jet propulsor's rotor. Among them, in the xy vertical plane, the positive direction of the x-axis corresponds to the 0° azimuth angle, and the positive direction of the y-axis corresponds to the 90° azimuth angle; in the xz horizontal plane, the positive direction of the x-axis corresponds to the 0° azimuth angle, and the negative direction of the z-axis corresponds to the 90° azimuth angle; in the yz cross section, the negative direction of the z-axis corresponds to the 0° azimuth angle, and the positive direction of the y-axis corresponds to the 90° azimuth angle. It can be seen that the 0° and 90° azimuth angles in the yz cross section correspond to the 90° azimuth angle in the xz horizontal plane and the 90° azimuth angle in the xy vertical plane, respectively. Therefore, the subsequent analysis is mainly carried out in the xy vertical plane and the xz horizontal plane.

[0088] Furthermore, in order to effectively compare the technical effects of the technical solutions provided in the embodiments of the present application, the hydrodynamic and flow noise performances of the basic pump-jet propulsor model without slip and sawtooth, the pump-jet propulsor model with a continuously arranged sawtooth structure, and the pump-jet propulsor model with a locally arranged sawtooth structure in the present application are compared at the same time. The specific results are as follows (it should be noted that the operating conditions of the pump-jet propulsor model with a locally arranged sawtooth structure in the present application are consistent with the operating conditions of the pump-jet propulsor model with both a locally arranged sawtooth structure and a sliding surface in Example 2):

[0089] Embodiment 1:

[0090] Effect of sawtooth structure on the hydrodynamic performance of pump-jet propulsor Figure 4 and Figure 5 It can be seen that the sawtooth structure causes the thrust of the duct to decrease, thereby causing the total thrust of the pump-jet to decrease, and the larger-sized sawtooth structure causes a larger thrust loss of the duct and the pump-jet as a whole, while the smaller-sized sawtooth structure causes a smaller thrust loss of the duct and the pump-jet as a whole, and the thrust loss caused by the local sawtooth structure is less than the circumferentially continuously arranged sawtooth structure. The continuously arranged sawtooth structures "6-3" and "3-1.5" cause 93.2% and 35.1% thrust losses in the duct, respectively, corresponding to 1.8% and 0.8% overall thrust losses, respectively, while the local sawtooth structures "6-3-local" and "3-1.5-local" cause 57.6% and 12.3% thrust losses in the duct, respectively, corresponding to 1.3% and 0.2% overall thrust losses, respectively. Therefore, the local sawtooth pump-jet has better hydrodynamic performance than the existing continuously arranged sawtooth pump-jet.

[0091] The effect of sawtooth structure on the flow noise performance of pump-jet propulsion can be found in Figure 6 and Figure 7It can be seen that the "3-1.5" sawtooth structure and the "6-3-local" sawtooth structure can significantly reduce the line spectrum sound pressure level of the pump-jet rotor at the 90° azimuth in the xy vertical plane and the xz horizontal plane, reducing the rotor line spectrum sound pressure level by 3.6 dB and 5.7 dB in the xy vertical plane, and by 4.8 dB and 5.2 dB in the xz horizontal plane. The overall line spectrum level of the pump-jet is reduced by 3.9 dB and 4.2 dB in the xy vertical plane, and by 6.3 dB and 6.0 dB in the xz horizontal plane, respectively. The "6-3" sawtooth structure and the "3-1.5-local" sawtooth structure have limited suppression effects on the line spectrum noise of the pump-jet rotor, and the reduction level of the line spectrum sound pressure level is within 1.0 dB.

[0092] The effect of sawtooth structure on the total sound pressure level of pump-jet propulsion can be found in Figure 8 and Fig. 9 It can be seen that at the 90° azimuth in the xy vertical plane, the large sawtooth structures "6-3" and "6-3-local" cause a reduction of 1.7 dB and 1.8 dB in the total duct sound pressure level, respectively, while the small sawtooth structures "3-1.5" and "3-1.5-local" reduce the total duct sound pressure level by less than 0.5 dB; at the 90° azimuth in the xz horizontal plane, the large sawtooth structures "6-3" and "6-3-local" cause a reduction of 2.5 dB and 3.2 dB in the total duct sound pressure level, respectively, while the small sawtooth structures "3-1.5" and "3-1.5-local" reduce the total duct sound pressure level by 1.2 dB and 1.8 dB, respectively. That is, the effect of the sawtooth structure on the total sound pressure level of the duct is stronger in the xz horizontal plane than in the xy vertical plane, and in the xz horizontal plane, the local sawtooth structure shows a noise reduction advantage over the circumferentially continuously arranged sawtooth structure.

[0093] The sawtooth structure also causes a decrease in the total rotor sound pressure level in the xy vertical plane and the xz horizontal plane, see Figure 8 and Fig. 9 At an azimuth angle of 90° in the xy vertical plane, the "3-1.5" sawtooth structure and the "6-3-local" sawtooth structure cause a 1.6 dB and 2.1 dB reduction in the rotor total sound pressure level, respectively, and at an azimuth angle of 90° in the xz horizontal plane, they cause a 2.1 dB and 2.0 dB reduction in the rotor total sound pressure level, respectively. The effects of the "3-1.5-local" sawtooth structure and the "6-3" sawtooth structure on the rotor total sound pressure level are both within 1.0 dB.

[0094] For the total sound pressure level of the pump jet as a whole, see Figure 8 and Fig. 9It can be seen that in the xy vertical plane and the xz horizontal plane, the "6-3-local" sawtooth structure has the largest reduction in the overall total sound pressure level of the pump-jet. At the 90° azimuth in the xy vertical plane and the xz horizontal plane, the "6-3-local" sawtooth structure causes a reduction in the overall total sound pressure level of the pump-jet of about 2.2 dB and 2.6 dB, respectively. The reductions of the other three sawtooth structures are relatively small.

[0095] The above simulation results show that the "6-3-local" sawtooth structure has the best effect in reducing the overall sound pressure level of the pump-jet. In addition, the "6-3-local" sawtooth structure only causes an efficiency loss of about 0.7% in the overall efficiency of the pump-jet, and has a relatively small impact on the hydrodynamic performance of the pump-jet, indicating that the local sawtooth structure has an advantage over the continuous arrangement sawtooth structure in terms of simultaneous regulation of hydrodynamic and flow noise performance, making the pump-jet have relatively better comprehensive performance.

[0096] Embodiment 2:

[0097] Next, we introduce 100 The dynamic performance of pump water jet under the coupling effect of sliding length and four sawtooth structures, see Fig.10 The application of the sliding interface improves the decrease in the pump water jet dynamics caused by the sawtooth structure, which increases the thrust coefficients of the duct and the rear stator, reduces the drag coefficient of the front stator, increases the torque coefficient of the rear stator, and 100 The coupling of slip length and different sawtooth structures has little effect on the increase of thrust coefficient of the rear stator and the decrease of drag coefficient of the front stator, which are about 20% and 38% respectively. However, the coupling of interface slip and different sawtooth structures has a certain effect on the increase of thrust coefficient of the duct, and the percentage increase of thrust coefficient of the duct has the following relationship, that is, "3-1.5-100 - Local">3-1.5-100 ">6-3-100 - Local">6-3-100 ", corresponding to 217%, 196%, 166% and 132% increase in catheter thrust respectively.

[0098] The increase in the thrust coefficient of the annular duct significantly affects the overall thrust coefficient of the pump-jet, and thus affects the overall propulsion efficiency of the pump-jet. Fig.11 It can be seen that "3-1.5-100 -Partial", "3-1.5-100 ”, “6-3-100 -Local" and "6-3-100 "The four coupling control schemes correspond to 7.7%, 7.4%, 6.9% and 6.4% increases in pump-jet efficiency, respectively, which increase the overall pump-jet propulsion efficiency to 80.7%, 80.4%, 79.8% and 79.4%, respectively. It can be seen that the effects of interface slip and sawtooth structure on the pump-jet water dynamics have a simple superposition relationship, and the interface slip significantly improves the pump-jet water dynamics performance loss caused by the sawtooth structure, which greatly improves the pump-jet water dynamics performance.

[0099] Further, the effect of interface slip and discontinuous sawtooth structure coupling on the flow noise performance of pump-jet propulsion can be found in Fig.12 and Fig.13 , we can know that “3-1.5-100 -Local" and "6-3-100 -local" coupling control scheme has a significant effect on reducing the rotor line spectrum sound pressure level. At the 90° azimuth angle in the xy vertical plane, the rotor line spectrum sound pressure level is reduced by 13.7 dB and 15.3 dB, respectively, and at the 90° azimuth angle in the xz horizontal plane, the rotor line spectrum sound pressure level is reduced by 12.4 dB and 13.8 dB, respectively. At the same time, it causes a significant reduction in the overall line spectrum sound pressure level of the pump jet. The "6-3-100 The coupling control scheme causes the rotor line spectrum sound pressure level to increase by about 1.5 dB, which makes the overall line spectrum sound pressure level of the pump jet show an increase of 1.2 dB and an almost negligible decrease of 0.2 dB in the xy vertical plane and the xz horizontal plane.

[0100] See also Fig.14 and Fig.15 , 100 The total sound pressure level of the duct under the coupling effect of interface slip and four bionic structures is reduced, and the total sound pressure level of the duct corresponding to the coupling of interface slip and different bionic structures is not much different. The reduction of the total sound pressure level of the pump jet duct in the xy vertical plane is in the range of 4.0-4.4 dB, while at the 90° azimuth in the xz horizontal plane, the “3-1.5-100 ” and “6-3-100 -local coupling regulation has a relatively high reduction in the total duct sound pressure level, which is 5.6 dB and 5.2 dB respectively. For the rear stator, 100 Under the coupling effect of interface slip and four bionic structures, the total sound pressure level is reduced to a certain extent, and the reduction is relatively large in the xy vertical plane, with a total sound pressure level reduction of 1.2-2.1 dB at the 90° azimuth, while the reduction is smaller in the xz horizontal plane, with a total sound pressure level reduction of 0.7-1.4 dB at the 90° azimuth. The coupling of interface slip and bionic structure will also have a certain impact on the total sound pressure level of the rotor. Fig.14 , Fig.15 It can be seen that "6-3-100 The coupling control scheme causes the increase of the total sound pressure level of the rotor, while the other three coupling control schemes reduce the total sound pressure level of the rotor, and the "3-1.5-100" coupling of the local sawtooth structure and the sliding surface -Partial", "6-3-100 The "-local" scheme has better control effect, with a reduction effect of 2.8 dB and 2.2 dB in the rotor total sound pressure level at an azimuth angle of 90° in the xy vertical plane, and a reduction effect of 3.0 dB and 2.1 dB in the rotor total sound pressure level at an azimuth angle of 90° in the xz horizontal plane.

[0101] For the overall sound pressure level of the pump jet, the four coupling control schemes all showed a reduction in the total sound pressure level, and the coupling control effect of the local sawtooth structure and the sliding surface was better, "3-1.5-100 -Local" and "6-3-100 The "local" coupling control scheme has a total sound pressure level reduction of 3.7 dB and 3.3 dB at an azimuth angle of 90° in the xy vertical plane, and a total sound pressure level reduction of 4.3 dB and 4.2 dB at an azimuth angle of 90° in the xz horizontal plane. Therefore, 100 Among the coupling control schemes of interface slip and four sawtooth structures, “3-1.5-100 -Local" and "6-3-100 - Local" solution has a lower overall pump spray sound pressure level, "3-1.5-100 "The second is the "6-3-100 "The scheme will have an adverse effect on the overall sound pressure level of the pump jet, indicating the significant advantages of the local sawtooth structure and sliding surface coupling control scheme proposed in the present invention.

[0102] At this point, the technical advantages of the technical solution proposed by the present invention are basically clear. The total sound pressure level and the corresponding line spectrum sound pressure level of the pump-jet propulsion system under the effects of interface slip and the four bionic structures of "3-1.5", "6-3", "3-1.5-local", "6-3-local" and the coupling between the two. Fig.16 and Fig.17 It can be seen that among the nine control schemes of only interface slip control, only sawtooth structure control, and the coupling control of the two, “3-1.5-100 -Partial", "6-3-100 -local" coupling control scheme has lower overall pump-jet sound pressure level and line spectrum sound pressure level, and the "6-3-100 -local" coupling control scheme has the lowest line spectrum sound pressure level. Further, it can be seen from the following Table 1 that "3-1.5-100 -Local" and "6-3-100 The "local" coupling control scheme significantly improves the propulsion efficiency of the pump-jet, with efficiency improvements of 7.7% and 6.8% respectively compared to the basic pump-jet.

[0103] Table 1 Comparison of pump water jet dynamic performance under different control schemes

[0104]

[0105] Therefore, “3-1.5-100 -Local" and "6-3-100 - Local" coupling control schemes have significantly improved the water dynamics and flow noise performance of the pump jet, which has significant technical advantages compared to the shortcomings of the continuous arrangement of sawtooth structures in the prior art, which cause the water dynamics of the pump jet to decrease and the noise reduction effect to be limited. In addition, compared with the continuous arrangement of sawtooth structures in the prior art, the local bionic structure proposed in the present invention can significantly reduce the processing time and processing cost due to the removal of less material, and has less impact on the overall mechanical properties of the pump jet conduit. The realization of the sliding surface can be achieved in the form of coating or spray coating, which has the advantages of convenient implementation and strong durability.

[0106] From the above analysis, it can be seen that compared with the prior art, the beneficial effect of the present invention is that the new type of pump-jet propulsor proposed in the present invention can reduce the loss of pump-jet water power performance caused by the continuous distributed sawtooth structure while further improving the noise reduction effect of the sawtooth structure. Furthermore, the pump-jet propulsor coupled with the local sawtooth structure and the sliding surface proposed in the present invention allows the improvement and regulation of the pump-jet water power performance and the flow noise performance to be taken into account, and the improvement effect is significant, which has significant technical advantages over the prior art. In addition, the technical solution proposed in the present invention can reduce processing time and processing costs, and has less impact on the overall mechanical properties of the annular duct of the pump-jet propulsor, and has broad application prospects in the fields of surface ships, underwater navigation bodies, etc.

[0107] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0108] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A pump-jet propulsion system, characterized in that: The pump-jet propulsor comprises an annular duct, a first stator, a rotor and a hub, wherein the first stator, the rotor and the hub are all arranged inside the annular duct, the first stator is close to the trailing edge of the annular duct, the first stator and the rotor are connected to the hub, the first stator is connected to the inner wall of the annular duct, the trailing edge of the annular duct is provided with a plurality of sawtooth assemblies arranged at intervals along the circumference of the annular duct, the sawtooth assembly is located between two adjacent stator blades, the sawtooth assembly comprises at least one sawtooth structure, and the first stator comprises a plurality of the stator blades; The rotor is used to rotate and generate hydrodynamic force so that the pump-jet propeller generates forward thrust; The sawtooth assembly is used to interfere with the wake field of the pump-jet propulsor to reduce vibration and noise.

2. The pump-jet propeller according to claim 1, characterized in that: Each of the sawtooth assemblies is arranged at equal intervals along the circumference of the trailing edge of the annular duct, and the coverage area of ​​the sawtooth assembly is the area between the suction surface of one of the two adjacent stator blades and a preset position, and the preset position is a position determined according to the middle position between the two adjacent stator blades.

3. The pump-jet propeller according to claim 1 or 2, characterized in that: The number of the sawtooth assemblies is equal to the number of the stator blades.

4. The pump-jet propeller according to claim 1 or 2, characterized in that: The height of the sawtooth structure does not exceed 0.1 times the chord length of the annular duct, and does not exceed the axial distance between the trailing edge of the first stator and the trailing edge of the annular duct.

5. The pump-jet propeller according to claim 4, characterized in that: The ratio of the height of the sawtooth structure to the width of the sawtooth structure is not less than 2 and not more than 4.

6. The pump-jet propeller according to claim 1, characterized in that: The pump-jet propulsor also includes a second stator, which is arranged inside the annular duct, and the second stator is respectively connected to the hub and the inner wall of the annular duct, and the second stator is far away from the trailing edge of the annular duct.

7. The pump-jet propeller according to claim 6, characterized in that: Surfaces of the annular duct, the first stator, the rotor, and the second stator are provided with sliding surfaces.

8. The pump-jet propeller according to claim 7, characterized in that: The sliding lengths of the sliding surfaces respectively corresponding to the annular duct, the first stator, the rotor and the second stator are the same or different.

9. The pump-jet propeller according to claim 8, characterized in that: The slip length is 20 -500 between.

10. The pump-jet propulsion device according to any one of claims 7 to 9, characterized in that: The slip surface includes at least one of a carbon-based coating surface and a fluorine-containing coating surface.

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