Small aircraft body noise characteristic test system and method

Abstract

The invention discloses a system and a method for testing noise characteristics of a small aircraft body. The system comprises a water inlet pipe, a mute water pump, a liquid flowmeter, a water outlet pipe, a porous horizontal mounting rod, a Y-shaped water outlet, an underwater aircraft, an aircraft fixing rod, a hydrophone and signal processing equipment, the water inlet pipe is connected with the mute water pump, the mute water pump is connected with the liquid flow meter, and the water outlet pipe is connected with a water outlet pipe connector of the Y-shaped water outlet. A Y-shaped water outlet is fixedly connected with the porous horizontal mounting rod through a Y-shaped water outlet fixing rod, and meanwhile, the head of the underwater vehicle is pushed into the Y-shaped water outlet; the underwater vehicle is fixed on the porous horizontal mounting rod through the two sets of vehicle fixing rods; and the porous horizontal mounting rod is used for fixing the underwater vehicle on the lifting rotary table for the underwater acoustic measurement equipment. The device has the navigational speed simulation capability and can separate the vibration noise and the fluid noise of the aircraft body.

Description

Technical Field

[0001] This invention belongs to the field of vibration and noise measurement technology for small underwater vehicles, and relates to a testing system and method for the noise characteristics of a small underwater vehicle, particularly a testing method and system for the noise characteristics of a small underwater vehicle with speed simulation capabilities. Background Technology

[0002] Underwater vehicles need to carry acoustic detection equipment to complete specific detection tasks. With the development of technology, the acoustic detection frequency of underwater vehicles has begun to develop towards low frequencies of 10kHz and below. However, the vibration noise of the vehicle itself and the fluid noise are concentrated within 10kHz. Therefore, the noise suppression capability of the vehicle itself will severely limit the detection performance of the acoustic detection payload. Small underwater vehicles generate self-noise during navigation. Self-noise mainly includes two types: vibration noise generated by the high-speed rotation of the vehicle's propeller and motor, and fluid noise during navigation.

[0003] Propulsion system noise includes vibration noise generated by propeller rotation and motor rotation; the higher the speed and the higher the rotational speed, the greater the noise. Hydrodynamic noise is also affected by speed; the higher the speed of the vessel, the stronger the noise. To suppress the vibration noise and fluid noise of the vessel itself, it is necessary to first analyze and process the noise signal characteristics received by the hydrophone to formulate corresponding interference suppression strategies. In existing technologies, when measuring the vibration noise and fluid noise of the vessel itself during dynamic navigation, the signal received by the hydrophone is a superposition of the two noise signals, making it impossible to independently separate the two noises for targeted analysis. Furthermore, dynamic navigation testing requires finding a quiet water area free of surrounding vessels, resulting in low test organization and implementation efficiency and high test costs. Conversely, using conventional independent hydrophone external monitoring methods cannot accurately obtain the interference characteristics of the vessel relative to the receiving hydrophone.

[0004] CN119197735A discloses a real-time self-measurement evaluation method for underwater radiated noise of a vessel. This method measures the noise radiated by the vessel during dynamic navigation, rather than measuring the vibration transmission of the vessel itself, and cannot separate fluid noise. To reduce the interference of vessel vibration noise on acoustic hydrophones, a tail-towed receiver method is currently commonly used. However, tail-towed receivers significantly reduce the ease of use of the equipment.

[0005] Therefore, determining the method for separating and measuring the interference characteristics induced by the change in speed of the two types of vehicle noise is a challenging technical issue that urgently needs to be addressed. This will help further improve the signal detection capability and low-frequency detection capability of underwater high-speed mobile detection equipment. Summary of the Invention

[0006] The embodiments of the present invention provide a small aircraft body noise characteristic testing system and method with speed simulation capability, which solves the difficulty of independently separating the two interference noises when measuring the vibration noise and fluid noise of the aircraft body during dynamic navigation using traditional technical means.

[0007] To solve the above-mentioned technical problems, the embodiments of the present invention adopt the following technical solutions:

[0008] A method for testing the noise characteristics of a small underwater vehicle with speed simulation capability mainly comprises an inlet pipe 1, a silent water pump 2, a liquid flow meter 3, an outlet pipe 4, a multi-hole horizontal mounting rod 6, a "Y"-shaped water outlet 7, an underwater vehicle 8, a vehicle fixing rod 9, and a signal processing device 12. The inlet pipe 1 is connected to the silent water pump 2; the silent water pump 2 is connected to the liquid flow meter 3; the outlet pipe 4 is connected to the outlet pipe connector 7-4 of the "Y"-shaped outlet 7; the "Y"-shaped outlet 7 is fixedly connected to the multi-hole horizontal mounting rod 6 through the "Y"-shaped outlet fixing rod 10; at the same time, the head of the underwater vehicle 8 is pushed into the "Y"-shaped outlet 7; the underwater vehicle 8 is fixed to the multi-hole horizontal mounting rod 6 through two sets of vehicle fixing rods 9; the multi-hole horizontal mounting rod 6 is fixed to the underwater vehicle 8 on the lifting and turning platform 5 for the underwater acoustic measurement equipment through the adapter flange 11; the signal transmission cable 8-4 connects the underwater vehicle 8 and the signal processing equipment 12.

[0009] The inner diameters of the inlet pipe 1, the liquid flow meter 3, the outlet pipe 4, and the outlet pipe connector 7-4 are all equal.

[0010] The outlet end of the “Y”-shaped water outlet 7 is equipped with four fine-tuning screws 7-3. By adjusting the four fine-tuning screws 7-3, the underwater vehicle 8 can be ensured to be in the middle position of the “Y”-shaped water outlet 7.

[0011] Preferably, to simulate the fluid noise at different speeds of the aircraft while it is stationary, it is necessary to ensure that the inlet and outlet flow velocities of the "Y"-shaped outlet 7 are consistent. Assuming the inner pipe radius of the outlet pipe joint 7-4 is... The inner pipe radius of the outlet of the "Y"-shaped outlet 7 is The radius of the outer shell of underwater vehicle 8 is ,but That is, the cross-sectional area of ​​the inner pipe of the water outlet joint 7-4 is equal to the cross-sectional area of ​​the water outlet after the underwater vehicle 8 is propelled into the "Y"-shaped water outlet 7.

[0012] The “Y”-shaped water outlet 7 can be configured in various ways depending on the structural characteristics of the underwater vehicle 8 and the location of the receiving hydrophone.

[0013] Preferably, for the underwater vehicle 8 with the receiving hydrophone located at the head, if the head of the underwater vehicle 8 has a pointed structure, the outlet structure of the "Y"-shaped water outlet 7 must be conformal to the head of the underwater vehicle 8; if the head of the underwater vehicle 8 has a flat structure, the top of the outlet of the "Y"-shaped water outlet 7 needs to have a certain buffer distance from the head of the underwater vehicle 8; for the underwater vehicle 8 with the receiving hydrophone located at other parts (not at the head), after the "Y"-shaped water outlet 7 has a certain buffer distance, the water outlet pipe can be able to wrap around it.

[0014] Preferably, when measuring the fluid noise interference characteristics of the receiving hydrophone, different output power of the silent water pump 2 can be adjusted to simulate different sailing speeds of the aircraft, thereby obtaining the fluid noise interference characteristics of the receiving hydrophone at different sailing speeds of the aircraft.

[0015] Preferably, when measuring the vibration and noise interference characteristics of the receiving hydrophone under different speeds of the underwater vehicle 8, the vibration and noise interference characteristics of the receiving hydrophone under different speeds can be obtained by adjusting the rotational speed of the propulsion motor 8-3.

[0016] Preferably, when measuring the characteristics of fluid noise interference and navigation vibration noise interference experienced by the receiving hydrophone, the propulsion motor 8-3 and the silent water pump 2 can be started simultaneously. By adjusting the speed of the propulsion motor 8-3 and the output power of the silent water pump 2, the comprehensive interference characteristics of fluid noise and vibration noise of the pointed receiving hydrophone 8-1 under different speeds of the underwater vehicle 8 can be obtained.

[0017] Preferably, the inlet pipe 1 is a flexible water pipe to prevent the vibration noise of the silent water pump 2 from being transmitted through the outlet pipe 4.

[0018] Compared with existing underwater dynamic navigation tests, the advantages of this invention include:

[0019] (1) Existing technologies require finding a quiet water area with no surrounding ships; otherwise, the test process is easily affected by external conditions, the test organization and implementation efficiency is low, and the test cost is high. This invention can be tested in an anechoic pool and the vibration noise interference received by the receiving hydrophone can be measured under the condition that the vehicle is stationary.

[0020] (2) In the prior art, the signal received by the receiving hydrophone is a superposition of vibration noise and fluid noise interference signals, and it is impossible to independently separate various noises for targeted analysis. The present invention uses a silent water pump and a liquid flow meter to simulate the liquid flow characteristics during the dynamic navigation process of the aircraft. Therefore, the receiving hydrophone can obtain the fluid noise interference characteristics when the aircraft is stationary, which can further improve the acoustic detection capability of the receiving hydrophone installed on the aircraft body.

[0021] (3) Since the vehicle is fixed on the lifting and turning platform of the underwater acoustic measurement equipment, the vibration noise interference received by the receiving hydrophone can be measured under static conditions without fluid noise interference.

[0022] (4) Under static conditions, the present invention can obtain the comprehensive interference characteristics of fluid noise and vibration noise of the receiving hydrophone at different speeds of the underwater vehicle by adjusting the speed of the propulsion motor and the output power of the silent water pump. The test is relatively convenient. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the navigation noise test of the small aircraft of the present invention;

[0024] Figure 2 This is a cross-sectional view of the small aircraft navigation noise testing device of the present invention;

[0025] Figure 3 This is a schematic diagram of the installation of the "Y"-shaped water outlet for adapting to a pointed-nose aircraft according to the present invention.

[0026] Figure 4 This is a schematic diagram of the installation of the "Y"-shaped water outlet for adapting to a flat-headed aircraft according to the present invention.

[0027] The reference numerals in the figure are as follows:

[0028] 1. Inlet pipe; 2. Silent water pump; 3. Liquid flow meter; 4. Outlet pipe; 5. Lifting and rotating platform; 6. Multi-hole horizontal mounting rod; 7. "Y" type outlet, 7-1 pointed "Y" type outlet, 7-2 flat "Y" type outlet, 7-3 fine-tuning screw, 7-4 outlet pipe connector; 8. Underwater vehicle, 8-1 pointed hydrophone receiver, 8-2 flat hydrophone receiver, 8-3 propulsion motor, 8-4 signal transmission cable; 9. Vehicle fixing rod; 10. "Y" type outlet fixing rod; 11. Adapter flange; 12. Signal processing equipment. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and specific examples.

[0030] Example 1

[0031] like Figure 1As shown, a small underwater vehicle noise characteristic testing system with speed simulation capability mainly consists of an inlet pipe 1, a silent water pump 2, a liquid flow meter 3, an outlet pipe 4, a multi-hole horizontal mounting rod 6, a "Y"-shaped water outlet 7, an underwater vehicle 8, a vehicle fixing rod 9, and a signal processing device 12. The inlet pipe 1 is connected to the silent water pump 2; the silent water pump 2 is connected to the liquid flow meter 3; the outlet pipe 4 is connected to the outlet pipe connector 7-4 of the "Y"-shaped outlet 7; the "Y"-shaped outlet 7 is fixedly connected to the multi-hole horizontal mounting rod 6 through the "Y"-shaped outlet fixing rod 10; at the same time, the head of the underwater vehicle 8 is pushed into the "Y"-shaped outlet 7; the underwater vehicle 8 is fixed to the multi-hole horizontal mounting rod 6 through two sets of vehicle fixing rods 9; the multi-hole horizontal mounting rod 6 is fixed to the underwater vehicle 8 on the lifting and turning platform 5 for the underwater acoustic measurement equipment through the adapter flange 11; the signal transmission cable 8-4 connects the underwater vehicle 8 and the signal processing equipment 12.

[0032] like Figure 2 As shown, to simulate the fluid noise of a vehicle at different speeds under stationary conditions, it is necessary to ensure that the inlet and outlet flow velocities of the "Y"-shaped outlet 7 are consistent. Assume the inner pipe radius of the outlet pipe joint 7-4 is... The inner pipe radius of the outlet of the "Y"-shaped outlet 7 is The radius of the outer shell of underwater vehicle 8 is ,but Specifically, the cross-sectional area of ​​the inner tube of the outlet pipe connector 7-4 is equal to the cross-sectional area of ​​the water outlet after the underwater vehicle 8 is pushed into the "Y"-shaped outlet 7, and the inner tube diameters of the inlet pipe 1, the liquid flow meter 3, the outlet pipe 4, and the outlet pipe connector 7-4 are all equal. Four fine-tuning screws 7-3 are installed at the outlet end of the "Y"-shaped outlet 7. By adjusting these four fine-tuning screws 7-3, the underwater vehicle 8 can be ensured to be in the middle position of the "Y"-shaped outlet 7, while also preventing the "Y"-shaped outlet 7 from shaking.

[0033] like Figure 3 , Figure 4 As shown, the "Y"-shaped water outlet 7 can be configured in various ways depending on the structural characteristics of the underwater vehicle 8 and the location of the receiving hydrophone. For underwater vehicles 8 with the receiving hydrophone located at the head, if the head of the underwater vehicle 8 has a pointed structure, the outlet structure of the "Y"-shaped water outlet 7 must be conformal to the head of the underwater vehicle 8; if the head of the underwater vehicle 8 has a flat structure, the top of the outlet of the "Y"-shaped water outlet 7 needs to have a certain buffer distance from the head of the underwater vehicle 8 to avoid the water flow from the "Y"-shaped water outlet 7 directly impacting the head of the underwater vehicle 8. For underwater vehicles with the receiving hydrophone located in other parts of the underwater vehicle 8 (not at the head), after leaving a certain buffer distance, the water outlet pipe can simply cover it.

[0034] Example 2

[0035] A method for testing the noise characteristics of a small aircraft with speed simulation capabilities, comprising:

[0036] according to Figure 1 The connection method shown connects the various devices. The underwater vehicle 8 is fixed to the lifting and rotating platform 5 of the underwater acoustic measurement equipment through the test fixture. The underwater vehicle is deployed to a certain depth underwater through the lifting and rotating platform 5 of the underwater acoustic measurement equipment. The water outlet pipe 4 is far away from the vehicle under test. The water inlet pipe 1 is a flexible water pipe with a large length and a spiral winding method at the water surface end to avoid the vibration noise of the silent water pump 2 being transmitted through the water outlet pipe 4. When measuring the fluid noise interference characteristics of the pointed hydrophone receiver 8-1, the liquid flow rate is adjusted by regulating the output power of the silent water pump 2, and the liquid flow rate information is accurately obtained using the liquid flow rate meter 3. Since the condition that the cross-sectional area of ​​the inner pipe of the outlet pipe joint 7-4 is equal to the cross-sectional area of ​​the water outlet after the underwater vehicle 8 enters the "Y"-shaped outlet 7 is met, the liquid flow rate value measured by the liquid flow rate meter 3 is equivalent to the flow rate value acting on the pointed hydrophone receiver 8-1. Thus, the flow rate information on the surface of the pointed hydrophone receiver 8-1 can be measured. Based on the fundamental principles of relativity, the fluid noise interference experienced by the hydrophone receiver during the navigation process can be simulated under the condition that the vehicle is stationary. By adjusting different output powers of the silent water pump 2, different navigation speeds of the vehicle can be simulated, thereby obtaining the fluid noise interference characteristics experienced by the hydrophone receiver at different vehicle speeds. When measuring the vibration and noise interference characteristics of the pointed-nose hydrophone 8-1 under navigation vibration, the vibration and noise interference characteristics of the pointed-nose hydrophone 8-1 at different speeds of the underwater vehicle 8 can be obtained by adjusting the rotational speed of the propulsion motor 8-3. When measuring the fluid noise interference and navigation vibration noise interference characteristics of the pointed-nose hydrophone 8-1, the propulsion motor 8-3 and the silent water pump 2 can be started simultaneously. By adjusting the rotational speed of the propulsion motor 8-3 and the output power of the silent water pump 2, the comprehensive interference characteristics of fluid noise and vibration noise of the pointed-nose hydrophone 8-1 at different speeds of the underwater vehicle 8 can be obtained.

[0037] Finally, the noise interference characteristics under different operating conditions can be analyzed by the data recorded by the signal processing device 12.

[0038] The test method for the combined interference characteristics of fluid noise and vibration noise of the flat-head receiver hydrophone 8-2 or other hydrophones installed in different locations on the underwater vehicle 8 at different speeds is similar to that described above, and will not be repeated here.

Claims

1. A noise characteristic testing system for a small aircraft, characterized in that, Includes an inlet pipe (1), a silent water pump (2), a liquid flow meter (3), an outlet pipe (4), a multi-hole horizontal mounting rod (6), a "Y"-shaped outlet (7), an underwater vehicle (8), a vehicle mounting rod (9), and hydrophones and signal processing equipment (12); among which: The inlet pipe (1) is connected to the silent water pump (2), the silent water pump (2) is connected to the liquid flow meter (3), and the outlet pipe (4) is connected to the outlet pipe joint (7-4) of the "Y"-shaped outlet (7). The "Y"-shaped outlet (7) is fixedly connected to the multi-hole horizontal mounting rod (6) by the "Y"-shaped outlet fixing rod (10), and the head of the underwater vehicle (8) is pushed into the "Y"-shaped outlet (7). The underwater vehicle (8) is fixed on the multi-hole horizontal mounting rod (6) by two sets of vehicle fixing rods (9). The multi-hole horizontal mounting rod (6) is used to fix the underwater vehicle (8) on the lifting and turning platform (5) of the underwater acoustic measurement equipment. The receiving hydrophone is located at the head of the underwater vehicle (8), and the receiving hydrophone is electrically connected to the signal processing equipment (12).

2. The testing system according to claim 1, characterized in that, The inner diameters of the inlet pipe (1), the liquid flow meter (3), the outlet pipe (4), and the outlet pipe connector (7-4) are all equal.

3. The testing system according to claim 1, characterized in that, The outlet end of the "Y"-shaped outlet (7) is equipped with four fine-tuning screws (7-3) along the circumference. By adjusting the four fine-tuning screws (7-3), the underwater vehicle (8) is ensured to be located at the radial center of the "Y"-shaped outlet (7).

4. The testing system according to claim 1, characterized in that, Water outlet pipe connector (7-4) inner pipe radius The inner pipe radius of the "Y"-shaped outlet (7) , the radius of the hull of the underwater vehicle (8) satisfy .

5. The testing system according to claim 1, characterized in that, The "Y"-shaped outlet (7) can be configured in various ways according to the structural characteristics of the underwater vehicle (8) and the location of the receiving hydrophone, including: If the head of the underwater vehicle (8) is a pointed structure, then the outlet structure of the "Y"-shaped outlet (7) is the same as that of the head of the underwater vehicle (8). If the head of the underwater vehicle (8) is a flat-head structure, then the top of the "Y"-shaped water outlet (7) has a certain buffer distance from the head of the underwater vehicle (8).

6. The testing system according to claim 5, characterized in that, Corresponding to the pointed or flat-top structure of the underwater vehicle (8), the receiving hydrophone is a pointed receiving hydrophone (8-1) or a flat-top receiving hydrophone (8-2); if the receiving hydrophone is located in a non-head part of the underwater vehicle (8), the top of the "Y"-shaped outlet (7) is left with a certain buffer distance from the head of the underwater vehicle (8) to allow the water outlet pipe to wrap around the "Y"-shaped outlet (7).

7. The testing system according to claim 1, characterized in that: When measuring the fluid noise interference characteristics of the receiving hydrophone, different sailing speeds of the aircraft are simulated by adjusting the different output power of the silent water pump (2), so as to obtain the fluid noise interference characteristics of the receiving hydrophone at different sailing speeds of the aircraft. When measuring the vibration and noise interference characteristics of the receiving hydrophone, the vibration and noise interference characteristics of the receiving hydrophone under different speeds of the underwater vehicle (8) are obtained by adjusting the speed of the propulsion motor (8-3). When measuring the characteristics of fluid noise interference and navigation vibration noise interference of the receiving hydrophone, the propulsion motor (8-3) and the silent water pump (2) are started at the same time. By adjusting the speed of the propulsion motor (8-3) and the output power of the silent water pump (2), the comprehensive interference characteristics of fluid noise and vibration noise of the pointed receiving hydrophone at different speeds of the underwater vehicle (8) are obtained.

8. The testing system according to claim 1, characterized in that, The inlet pipe (1) is made of flexible water pipe to prevent the vibration noise of the silent water pump (2) from being transmitted through the outlet pipe (4).

9. The testing system according to claim 1, characterized in that, The multi-hole horizontal mounting rod (6) fixes the underwater vehicle (8) to the lifting and turning platform (5) of the underwater acoustic measurement equipment through the adapter flange (11).

10. A method for testing the noise characteristics of a small aircraft body, characterized in that, The method, using the testing system as described in any one of claims 1-9, comprises: The underwater vehicle 8 is fixed to the underwater acoustic measurement equipment using a test fixture. The underwater vehicle is then deployed to a certain depth underwater using a lifting and rotating platform, with the water outlet pipe (4) far away from the underwater vehicle (8) to be tested. When measuring the characteristics of the receiving hydrophone affected by fluid noise, the liquid flow rate is adjusted by adjusting the output power of the silent water pump (2), and the liquid flow rate information is accurately obtained by using the liquid flow rate meter (3). The liquid flow rate value measured by the liquid flow rate meter (3) is equivalent to the flow rate value acting on the pointed receiving hydrophone. The fluid noise interference received by the hydrophone during the flight of the aircraft was simulated under the condition that the aircraft was stationary. By adjusting the different output power of the silent water pump (2), the different flight speeds of the aircraft were simulated, so as to obtain the characteristics of fluid noise interference received by the hydrophone under different flight speeds of the aircraft. When the characteristics of vibration and noise interference received by the receiving hydrophone are obtained, the vibration and noise interference characteristics of the pointed receiving hydrophone at different speeds of the underwater vehicle (8) can be obtained by adjusting the speed of the propulsion motor (8-3). When measuring the characteristics of fluid noise interference and navigation vibration noise interference of the pointed receiver hydrophone, the propulsion motor (8-3) and the silent water pump (2) are started at the same time. By adjusting the speed of the propulsion motor (8-3) and the output power of the silent water pump (2), the comprehensive interference characteristics of fluid noise and vibration noise of the pointed receiver hydrophone at different speeds of the underwater vehicle (8) are obtained. Finally, the data recorded by the signal processing device (12) is analyzed to obtain the noise interference characteristics under different operating conditions.

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