Low noise underwater synthetic jet actuator generator

Abstract

The application provides a low-noise underwater synthetic jet exciter generating device, which comprises a first cavity, a sound insulation ring, a second cavity, a gas release valve, a base, a vibration rod, an electromagnetic exciter, a support rod, a first damper, a first base, a second damper, a second base, one end of the sound insulation ring is connected with the first cavity, the other end of the sound insulation ring is connected with the second cavity, the gas release valve is installed outside the second cavity, the bottom of the second cavity is bonded with the base, one end of the base is connected with the vibration rod, the other end of the vibration rod is connected with the electromagnetic exciter, one end of the electromagnetic exciter is connected with the support rod, the other end of the support rod is connected with the first damper, the other end of the first damper is connected with the first base, the other end of the first base is connected with the second damper, and the other end of the second damper is connected with the second base; the device amplifies the oscillation generated by the electromagnetic exciter by using different cavity area ratios, improves the strength and speed of the suction and ejection flow, and is a novel underwater synthetic jet exciter.

Description

TECHNICAL FIELD

[0001] The present application relates to a low-noise underwater synthetic jet actuator generating device, belonging to the field of acoustic measurement. BACKGROUND

[0002] Synthetic jet is a common active flow control technology in high-speed aerodynamics, which causes the change of macro flow by perturbing the flow near the wall surface, so as to achieve the purpose of flow control. The structure of synthetic jet actuator has the forms of vibrating diaphragm, single-cavity vibrating diaphragm, double-cavity vibrating diaphragm, etc. These vibrating diaphragms are driven by excitation voltage to perform periodic reciprocating motion, so that the fluid is "sucked in" and "blown out" from the cavity opening, increasing the kinetic energy of the fluid in the boundary layer near the wall surface, and effectively suppressing the separation of the boundary layer. Since the mass of the sucked and blown fluid is zero in a cycle, but the momentum is not zero, the synthetic jet technology is also called zero-mass jet technology.

[0003] In recent years, it is a research hotspot to use synthetic jet technology to control the flow of underwater vehicles and thus reduce the hydrodynamic noise. However, the synthetic jet actuator cannot be directly used in water as in air, because the fluid loaded by the vibrating diaphragm in air is air, which has very low density and belongs to non-conductive medium, so the vibrating diaphragm of the synthetic jet actuator does not have to consider the problems of pressure resistance and electric leakage. Since water is a heavy fluid, the vibrating diaphragm of the synthetic jet actuator applied in water must have good strength to bear the static pressure of the fluid. At the same time, water is a weak conductive medium, and the insulating property of the vibrating diaphragm must be considered. In addition, the vibrating diaphragm will generate a specific frequency sound wave in water when it vibrates with a low-frequency sine wave, which will destroy the acoustic stealth performance of the submarine.

[0004] In summary, it is a key problem to design and manufacture a synthetic jet actuator that can be used in water, which is urgently needed in the research process of using synthetic jet to suppress hydrodynamic noise. SUMMARY

[0005] The purpose of the present application is to provide a low-noise underwater synthetic jet actuator generating device, which uses different cavity area ratios to amplify the oscillation generated by the electromagnetic actuator, and improves the strength and speed of the suction and blowing flow. It is a new type of underwater synthetic jet actuator.

[0006] The purpose of the present application is achieved by comprising a first cavity, a sound insulation ring, a second cavity, a gas release valve, a base, a vibration rod, an electromagnetic exciter, a support rod, a first damper, a first base, a second damper, a second base, one end of the first cavity is connected with the sound insulation ring, the other end of the sound insulation ring is connected with the second cavity, the gas release valve is installed outside the second cavity, the bottom of the second cavity is bonded with the base, one end of the base is connected with the vibration rod, the other end of the vibration rod is connected with the electromagnetic exciter, one end of the electromagnetic exciter is connected with the support rod, the other end of the support rod is connected with the first damper, the other end of the first damper is connected with the first base, the other end of the first base is connected with the second damper, and the other end of the second damper is connected with the second base.

[0007] Further, the first cavity is a cylindrical shell structure, and the front end of the first cavity is open; the second cavity is a cylindrical shell structure, the front part of the second cavity is provided with a circular hole, and the bottom is an extremely thin stainless steel plate; the inner diameter of the first cavity is equal to the inner diameter of the sound insulation ring and the inner diameter of the circular hole in the front part of the second cavity.

[0008] Further, the sound insulation ring is a double-layer cylindrical shell structure, and is made of polytetrafluoroethylene, and the interlayer is filled with rubber particles and lead particles.

[0009] Further, the gas release valve is installed on the side or the bottom of the second cavity, and the gas in the second cavity is completely discharged by using the gas release valve.

[0010] Further, the base is a thin cylindrical structure, and the middle part is a threaded through hole.

[0011] Further, the vibration rod is a quenched screw rod.

[0012] Further, the first damper is an air spring damper, and the second damper is a rubber spring damper.

[0013] Compared with the prior art, the beneficial effects of the present application are: first, the first cavity, the sound insulation ring and the second cavity constitute the suction and injection mechanism of the synthetic jet actuator, the reciprocating motion is applied to the electromagnetic vibrator at the bottom of the second cavity, the fluid in the first cavity, the sound insulation ring and the second cavity is periodically sucked and injected, the underwater synthetic jet is realized, the bottom of the second cavity is an extremely thin stainless steel plate, the ability of the diaphragm to resist hydrostatic pressure is improved, the pressure bearing problem of the diaphragm in the air is avoided, therefore, it is a new type of underwater synthetic jet actuator; secondly, the bottom area of the second cavity is much larger than the area of the opening of the first cavity, the opening of the first cavity amplifies the fluid oscillation generated at the bottom of the second cavity, so that the suction and injection effect caused by the reciprocating motion of the electromagnetic vibrator at the bottom of the second cavity is amplified at the opening of the first cavity, thereby forming a suction and injection effect with larger amplitude at the opening of the first cavity, meeting the momentum requirement of the underwater synthetic jet, that is, the weak oscillation effect at the bottom of the second cavity can form a suction and injection effect with larger amplitude and intensity at the opening of the first cavity; thirdly, the reciprocating motion is generated by the electromagnetic vibrator at the extremely thin stainless steel plate at the bottom of the second cavity to form oscillation excitation, the excitation strength of the electromagnetic vibrator is large, which can meet the high static pressure requirement of heavy fluid, and the oscillation form of the electromagnetic vibrator can be adjusted according to the input signal, so that the synthetic jet actuator can meet the engineering requirements; finally, the underwater synthetic jet actuator generating device can avoid the additional noise interference generated by the diaphragm excitation in the air, because the inside of the first cavity, the sound insulation ring and the second cavity is water, and the outside is air, which belongs to a soft boundary acoustic waveguide and cannot propagate plane waves, plus the small inner diameter of the first cavity, the frequency of the first order normal wave is very high, much higher than the working frequency of the electromagnetic vibrator, which makes the radiated noise signal generated by the excitation of the extremely thin stainless steel plate by the electromagnetic vibrator does not exist in the first cavity, therefore, no additional noise interference is brought to the sound field of the underwater synthetic jet.

[0014] The present application has the advantages that: first, the first damper is an air spring damper, and the second damper is a rubber spring damper, the air spring damper has a very low isolation frequency and can well attenuate the vibration of the electromagnetic vibrator, the rubber spring damper has a large loss factor and strong damping capacity and can further attenuate the vibration of the electromagnetic vibrator, and the damper-base-damper-base structure belongs to a floating raft damping system and can greatly reduce the vibration influence of the electromagnetic vibrator; second, the suction and ejection frequencies of the synthetic jet technology can be adjusted according to the working frequency of the electromagnetic vibrator, because the frequency of the electromagnetic vibrator can be as low as several hertz and as high as several thousand hertz, therefore, the underwater synthetic jet generating device has a very wide frequency adjustment range, and this structure avoids applying voltage to the very thin stainless steel plate and does not need to consider the insulation problem of the conductive medium water; and finally, the air release valve installed outside the second cavity can effectively discharge the gas in the first cavity, the sound insulation ring and the second cavity, and avoids the cavitation and noise effect of the underwater synthetic jet exciter caused by the bubbles mixed in the water during use. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a side view of the underwater synthetic jet generating device with low noise.

[0016] Figure 2 It is a top view of the underwater synthetic jet generating device with low noise.

[0017] Figure 3 It is a schematic view of the sound insulation ring.

[0018] In the figure, 1 is the first cavity, 2 is the sound insulation ring, 3 is the second cavity, 4 is the air release valve, 5 is the base, 6 is the vibration rod, 7 is the electromagnetic vibrator, 8 is the support rod, 9 is the first damper, 10 is the first base, 11 is the second damper, 12 is the second base, 13 is the opening, 21 is the lead particle, and 22 is the rubber particle. DETAILED DESCRIPTION

[0019] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0020] The application comprises a first cavity 1, a sound insulation ring 2, a second cavity 3, a gas release valve 4, a base 5, a vibration rod 6, an electromagnetic exciter 7, a support frame 8, a first damper 9, a first base 10, a second damper 11, and a second base 12.

[0021] The first cavity 1 is a cylindrical shell structure, and has an opening 13 at the top, which is in the shape of a rectangle and serves as an inhalation and ejection port of the synthetic jet.

[0022] The sound insulation ring 2 is a double-layer cylindrical shell structure without a top and a bottom, and is made of polytetrafluoroethylene.

[0023] The second cavity 3 is a cylindrical shell structure, has a circular hole with the same diameter as the inner diameter of the first cavity 1 at the top, is thickened at the side, and has a thin stainless steel plate with a thickness of 0.5 mm at the bottom.

[0024] The first cavity 1, the sound insulation ring 2, and the second cavity 3 are coaxially bonded together by epoxy resin glue, and the bonding part is ensured to have no gap.

[0025] The gas release valve 4 is an automatic exhaust valve and is placed outside the second cavity 3.

[0026] The base 5 is a thin cylindrical structure made of stainless steel, has a threaded hole in the center of the thin cylinder, and is bonded to the bottom of the second cavity 3 by epoxy resin.

[0027] The vibration rod 6 is a stainless steel screw rod, is quenched, and has one end screwed into the threaded hole of the base 5 and the other end screwed into the front end of the vibration mechanism of the electromagnetic exciter 7.

[0028] The electromagnetic exciter 7 of the present application is a modal exciter of model JZ-40, with maximum output force of 400 N, working frequency of 5 Hz-3000 Hz, maximum displacement of ±8 mm, and weight of 40 kg, which is used as the vibration source for driving the thin stainless steel plate at the bottom of the second cavity 3 in the embodiment.

[0029] The support rod 8 of the present application is a cylindrical rod made of stainless steel, with threads at both ends, which are screwed into the fixing mechanism of the electromagnetic exciter 7, for supporting the electromagnetic exciter 7.

[0030] The first damper 9 of the present application is an air spring damper of model ALJ-51001, with maximum load of 50 kg, which is fixed by a bolt of M10, and is used for damping the electromagnetic exciter 7.

[0031] The first base 10 of the present application is a circular plate made of copper, with through holes in the middle and around the periphery, the through hole in the middle being used for mounting the second damper 11, and the through holes around the periphery being used for mounting the first damper 9.

[0032] The second damper 11 of the present application is a damping spring damper of model ALJ-0102, with maximum load of 80 kg, which is fixed by a bolt of M12, and is used for further damping the electromagnetic exciter 7.

[0033] The second base 12 of the present application is a circular plate made of stainless steel, with through holes at both ends for mounting the second damper 11, and the second base 12 being mounted at the bottom of the working section of the model test.

[0034] The underwater synthetic jet generating device in the embodiment is used for flow control of a scaled SUBOFF model, and the opening 13 of the first cavity 1 is placed at the location where the horseshoe vortex is generated, so that the reduction effect of the hydrodynamic noise can reach 5 dB or more, with frequency of 10 Hz-2 kHz.

Claims

1. A low noise underwater synthetic jet actuator generator device, characterized by: The soundproof ring, the second cavity, the air release valve, the base, the vibration rod, the electromagnetic exciter, the support rod, the first damper, the first base, the second damper and the second base are arranged in sequence. The first cavity is a cylindrical shell structure, and an opening is arranged at the top of the first cavity, and the first cavity has no bottom; the soundproof ring is a double-layer cylindrical shell structure, and has no top and bottom; the second cavity is a cylindrical shell structure, and a circular hole with the same diameter as the inner diameter of the first cavity is arranged at the top of the second cavity, and the outer diameter of the second cavity is larger than that of the first cavity; the inner diameter of the first cavity, the inner diameter of the soundproof ring and the inner diameter of the circular hole at the top of the second cavity are equal, and the first cavity, the soundproof ring and the second cavity are coaxially connected; The air release valve is arranged outside the second cavity, the base is bonded outside the bottom of the second cavity, one end of the base is connected with the vibration rod, the other end of the vibration rod is connected with the electromagnetic exciter, one end of the electromagnetic exciter is connected with the support rod, the other end of the support rod is connected with the first damper, the other end of the first damper is connected with the first base, the other end of the first base is connected with the second damper, and the other end of the second damper is connected with the second base.

2. A low noise underwater synthetic jet actuator generator device according to claim 1, characterized in that: The opening at the top of the first cavity is used for suction and ejection of the synthetic jet; and the bottom of the second cavity is a thin stainless steel plate.

3. A low noise underwater synthetic jet actuator generator device according to claim 1, characterized in that: The soundproof ring is made of polytetrafluoroethylene, and the inner layer of the soundproof ring is filled with rubber particles and lead particles.

4. A low noise underwater synthetic jet actuator generator device according to claim 1, characterized in that: The air release valve is arranged on the side or the bottom of the second cavity, and the air release valve is used to exhaust all the gas in the second cavity.

5. A low noise underwater synthetic jet actuator generator device according to claim 1, characterized in that: The base is a cylindrical structure, and a threaded through hole is arranged in the middle of the base.

6. A low noise underwater synthetic jet actuator generator device according to claim 1, characterized in that: The vibration rod is a quenched screw rod.

7. A low noise underwater synthetic jet actuator generator device according to claim 1, characterized in that: The first damper is an air spring damper, and the second damper is a rubber spring damper.

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