A pump interstitial gap flow elimination device based on an inner rotor embedded ring design

Abstract

The application relates to a pump-jet gap flow elimination device based on a rotor embedded ring design and relates to the field of ship vibration noise technology equipment, and comprises a pump-jet propeller guide pipe, the inside of the pump-jet propeller guide pipe is coaxially connected with a pump-jet propeller rotor, the outer side of the pump-jet propeller rotor is coaxially fixedly connected with a rotor blade tip sleeve ring, the inner diameter of the rotor blade tip sleeve ring is larger than the inner diameter of the pump-jet propeller guide pipe, a guide pipe inner ring cavity is arranged at the position of the inner side wall of the pump-jet propeller guide pipe relative to the rotor blade tip sleeve ring, and the rotor blade tip sleeve ring is located in the guide pipe inner ring cavity. The application has the advantages that pump-jet propeller flow-induced vibration and gap cavitation noise caused by gap flow can be eliminated.

Description

Technical Field

[0001] This application relates to the field of ship vibration and noise technology equipment, and in particular to a pump-jet gap flow elimination device based on a rotor embedded ring design. Background Technology

[0002] Pump-jet propulsion is a combined propulsion device characterized by high propulsion efficiency, good operational performance, and low noise levels. It consists of an annular duct, stator, and rotor. Due to the requirements of the International Maritime Organization (IMO)'s "International Ship Noise Control Regulations" and "Guidelines for Reducing Underwater Noise of Commercial Ships," ships should not cause excessive noise pollution to their surroundings during navigation. Pump-jet propulsion has significant advantages in noise reduction, making its application in this area extremely valuable. This has created a great demand for the research and development of pump-jet propulsion, especially research on its noise characteristics.

[0003] There is a gap between the rotor blade tip and the inner wall of the duct in the pump-jet propulsion unit. When the flow field passes through the blade tip gap, due to the relative motion between the blade tip and the duct wall and the pressure difference between the rotor thrust surface and the back surface, eddies and leakage flow will be formed at the blade tip gap. On the one hand, the complex eddies will induce vortex-induced vibration and gap cavitation. On the other hand, the large pressure pulsation will also aggravate the vibration of the duct and rotor and transmit it to the hull, causing strong stern coupled vibration noise, which affects the acoustic performance of the ship in many ways. Summary of the Invention

[0004] In order to eliminate flow-induced vibration and gap cavitation noise in pump-jet propulsion caused by gap flow, this application provides a pump-jet gap flow elimination device based on rotor embedded ring design.

[0005] This application provides a pump-jet gap flow elimination device based on a rotor embedded ring design, which adopts the following technical solution:

[0006] A pump-jet interstitial flow elimination device based on a rotor embedded ring design includes a pump-jet propulsion duct. A pump-jet propulsion rotor is coaxially rotatably connected inside the pump-jet propulsion duct. A rotor blade tip collar is coaxially fixedly connected to the outer side of the pump-jet propulsion rotor. The inner diameter of the rotor blade tip collar is larger than the inner diameter of the pump-jet propulsion duct. An inner ring cavity is formed on the inner sidewall of the pump-jet propulsion duct at a position relative to the rotor blade tip collar. The rotor blade tip collar is located within the inner ring cavity of the duct.

[0007] Optionally, the diameter of the inner annular cavity of the duct is larger than the outer diameter of the rotor blade tip collar.

[0008] Optionally, the pump-jet propulsion duct is provided with a damping layer on the side wall of the inner annular cavity of the duct, and the damping layer is spaced apart from the outer side wall of the rotor blade tip collar.

[0009] Optionally, the inner diameter of the inner annular cavity of the duct is the same as the inner diameter of the rotor blade tip collar.

[0010] Optionally, an empty annular cavity is provided on both sides of the inner annular cavity of the duct, the empty annular cavity is connected to the inner annular cavity of the duct, and the line connecting the two empty annular cavities is set along the axial direction of the pump-jet propulsion duct.

[0011] Optionally, the length of the rotor blade tip collar along the axis of the pump-jet propulsion duct is greater than the length along the axis of the pump-jet propulsion duct at the connection point between the pump-jet propulsion rotor and the rotor blade tip collar.

[0012] Optionally, the pump-jet propulsion rotor includes a central shaft, with rotor blades fixedly connected to the outer side wall of the central shaft. Multiple rotor blades are arranged circumferentially along the outer side wall of the central shaft, and the outer sides of the multiple rotor blades are fixedly connected to the inner side wall of the rotor blade tip collar.

[0013] Optionally, the pump-jet propulsion duct is provided with a pump-jet propulsion stator, and the pump-jet propulsion stator and the pump-jet propulsion rotor are arranged coaxially.

[0014] In summary, this application includes at least one of the following beneficial technical effects:

[0015] 1. Traditional pump-jet propulsion systems exhibit pulsating flow characteristics at the blade tip gap, with a sharp increase in pulsating pressure at the gap. By modifying the rotor blade tip and the inner wall of the duct at the gap in traditional pump-jet propulsion systems, a collar structure is added to the blade tip and embedded into the annular cavity structure of the duct inner wall, eliminating the pressure pulsation peak at the original gap measuring point. This solution, through modifying the gap structure, effectively eliminates gap flow field pulsation and gap leakage flow without affecting propulsion efficiency, thereby significantly reducing rotor blade tip gap cavitation and propulsion vibration noise caused by gap flow, and effectively improving the acoustic performance of pump-jet propulsion systems. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a pump-jet gap flow elimination device based on a rotor embedded ring design in an embodiment of this application.

[0017] Figure 2 This is a cross-sectional view of a pump-jet gap flow elimination device based on a rotor embedded ring design in an embodiment of this application.

[0018] Figure 3 This is a schematic diagram of the rotor blade tip collar of a pump-jet gap flow elimination device based on rotor embedded ring design in an embodiment of this application.

[0019] Explanation of reference numerals in the attached drawings: 1. Pump-jet propulsion duct; 11. Inner annular cavity of the duct; 12. Empty annular cavity; 2. Pump-jet propulsion stator; 3. Pump-jet propulsion rotor; 31. Central shaft; 32. Rotor blade; 4. Rotor blade tip collar. Detailed Implementation

[0020] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0022] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0023] This application discloses a pump-jet gap flow elimination device based on a rotor-embedded ring design. (Refer to...) Figure 1 , Figure 2 A pump-jet interstitial flow elimination device based on rotor embedded ring design includes a pump-jet propulsion duct 1, which is an annular structure. A pump-jet propulsion stator 2 is disposed inside the pump-jet propulsion duct 1, and a pump-jet propulsion rotor 3 is disposed on one side of the pump-jet propulsion stator 2. The pump-jet propulsion rotor 3 is rotatably connected to the pump-jet propulsion duct 1, and the pump-jet propulsion rotor 3 is coaxially disposed with the pump-jet propulsion duct 1.

[0024] The pump-jet propulsion rotor 3 includes a central shaft 31, which is coaxially arranged with the pump-jet propulsion duct 1. Rotor blades 32 are fixedly connected to the outside of the central shaft 31, and multiple rotor blades 32 are equidistantly arranged along the side wall of the central shaft 31.

[0025] Reference Figure 2 , Figure 3 A rotor blade tip collar 4 is coaxially arranged on the outside of the pump-jet propulsion rotor 3. The rotor blade tip collar 4 is an annular structure, and the inner sidewall of the rotor blade tip collar 4 is fixedly connected to the outer sidewall of all rotor blades 32.

[0026] An inner annular cavity 11 is formed on the inner wall of the pump-jet propulsion duct 1 at a position relative to the rotor blade tip collar 4. The interior of the inner annular cavity 11 is in communication with the interior of the pump-jet propulsion duct 1. The rotor blade tip collar 4 extends into the interior of the inner annular cavity 11, and the diameter of the inner annular cavity 11 is larger than the diameter of the outer wall of the rotor blade tip collar 4, so that there is a gap between the position of the pump-jet propulsion duct 1 relative to the outer wall of the inner annular cavity 11 and the outer wall of the rotor blade tip collar 4.

[0027] Damping coating is applied to the outer wall of the pump-jet propulsion duct 1 relative to the inner annular cavity 11 of the duct, with a gap between the damping coating and the outer wall of the rotor blade tip collar 4. By applying the damping coating, it can be ensured that the rotor blade tip collar 4 will not collide with the pump-jet propulsion duct 1 relative to the inner annular cavity 11 of the duct when the cumulative deformation and vibration amplitude of the rotor blade 32 does not exceed 9% of the diameter.

[0028] The inner wall diameter of the rotor blade tip collar 4 is the same as the inner wall diameter of the pump-jet propulsion duct 1.

[0029] The inner wall of the pump-jet propulsion duct 1 has two empty annular cavities 12 on both sides along the axial direction of the pump-jet propulsion duct 1, relative to the inner annular cavity 11 of the duct. The empty annular cavities 12 are in relative communication with the interior of the inner annular cavity 11. The side wall of the empty annular cavity 12 facing away from the rotor blade tip collar 4 is spaced apart from the outer side wall of the rotor blade tip collar 4.

[0030] The length of the rotor blade tip collar 4 along the axial direction of the pump-jet propulsion duct 1 is greater than the length along the axial direction of the connection point between the rotor blade 32 and the rotor blade tip collar 4.

[0031] In traditional pump-jet propulsion rotors, there is a gap between the blade tip and the inner wall of the duct. When the flow passes through the blade tip gap, eddies and leakage flow are formed. On the one hand, the complex eddies can induce eddy-induced vibration and gap cavitation. On the other hand, the large pressure pulsation can also aggravate the vibration of the duct and rotor and transmit it to the hull, causing strong stern-coupled vibration noise, which affects the acoustic performance of the ship in many ways.

[0032] The rotor embedded ring design method adds a collar structure to the rotor blade tip 32 and embeds the collar structure into the inner wall ring cavity of the duct in the gap. This completely eliminates the gap structure in the pump-jet structure, thereby suppressing vortex-induced vibration and gap cavitation caused by gap flow and reducing propeller vibration noise. At the same time, comparing the propulsion efficiency of the rotor embedded ring design pump-jet propeller and the parent pump-jet propeller, there is no significant difference between the two, that is, this design does not affect the hydrodynamic performance.

[0033] In some embodiments, taking a scaled-down model of a pump-jet propulsion system as an example, the pump-jet propulsion duct 1 in the scaled-down model is 0.177m long, the pump-jet propulsion rotor 3 has a diameter of 0.222m, the pump-jet propulsion rotor 3 has 10 blades, and the pump-jet propulsion stator 2 has 13 blades. The rotor blade 32 has a 90mm axial length at the tip of the bushing (50mm axial length at the blade tip), and extends 20mm forward and backward relative to the blade tip. The thickness of the bushing at the tip of the rotor blade 32 is 2.5mm. The axial length of the inner annular cavity 11 in the duct at the gap is 134mm (including the damping layer), and extends 22.5mm forward and backward relative to the bushing at the tip of the rotor blade 32. The cavity thickness is 19mm (including the damping layer), and the interior is coated with a damping coating with a thickness of 2mm.

[0034] In actual operation, because the rotor blade 32's slightly sleeved ring structure is wider than the inner annular cavity 11 of the duct, the annular cavity opening is completely covered by the rotor blade 32's slightly sleeved ring structure. This eliminates the gap structure and also eliminates the presence of open cavity structures, allowing fluid to flow downstream only through the blades. Simultaneously, under normal operating conditions, the cumulative deformation and vibration amplitude of the rotor blade 32's slightly sleeved ring are less than 9% of the blade diameter. The reserved cavity ensures that the sleeved ring and the annular cavity do not collide. This achieves good vibration reduction and noise reduction effects without causing structural impact or reduced propulsion efficiency.

[0035] In this application, the term "multiple" refers to at least two or more, unless otherwise expressly defined. The terms "installed," "connected," "linked," and "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "linked" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A pump-jet gap flow elimination device based on rotor embedded ring design, characterized in that: The device includes a pump-jet propulsion duct (1), a pump-jet propulsion rotor (3) is coaxially rotatably connected inside the pump-jet propulsion duct (1), a rotor blade tip collar (4) is coaxially fixedly connected to the outside of the pump-jet propulsion rotor (3), the inner diameter of the rotor blade tip collar (4) is larger than the inner diameter of the pump-jet propulsion duct (1), and an inner annular cavity (11) is opened on the inner sidewall of the pump-jet propulsion duct (1) at a position relative to the rotor blade tip collar (4), and the rotor blade tip collar (4) is located inside the inner annular cavity (11) of the duct. The diameter of the inner annular cavity (11) of the duct is larger than the outer diameter of the rotor blade tip collar (4); The pump-jet propulsion duct (1) is provided with a damping layer on the side wall of the inner annular cavity (11) of the duct, and the damping layer is spaced from the outer wall of the rotor blade tip collar (4). Empty annular cavities (12) are respectively opened on both sides of the inner annular cavity (11) of the duct. The empty annular cavity (12) is connected to the inner annular cavity (11) of the duct. The line connecting the two empty annular cavities (12) is set along the axial direction of the pump-jet propulsion duct (1). The inner diameter of the inner annular cavity (11) of the duct is the same as the inner diameter of the rotor blade tip collar (4); The length of the rotor blade tip collar (4) along the axis of the pump-jet propulsion duct (1) is greater than the length along the axis of the pump-jet propulsion duct (1) at the connection position between the pump-jet propulsion rotor (3) and the rotor blade tip collar (4). The pump-jet propulsion rotor (3) includes a central rotating shaft (31), and rotor blades (32) are fixedly connected to the outer wall of the central rotating shaft (31). Multiple rotor blades (32) are arranged circumferentially along the outer wall of the central rotating shaft (31), and the outer side of the multiple rotor blades (32) is fixedly connected to the inner wall of the rotor blade tip collar (4).

2. The pump-jet gap flow elimination device based on rotor embedded ring design according to claim 1, characterized in that: The pump-jet propulsion duct (1) is provided with a pump-jet propulsion stator (2), and the pump-jet propulsion stator (2) and the pump-jet propulsion rotor (3) are coaxially arranged.

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