A device for removing bubbles from the reverberation box wall in a cavity pulsating pressure measurement test

Abstract

The present invention provides a device for removing bubbles on the wall of a reverberation box in a cavity pulsation pressure measurement test. The device comprises a first propeller, a first motor, a first motor housing, a second propeller, a second motor, a second motor housing, a third propeller, a third motor, a third motor housing, a bracket, and a power supply. The first propeller is connected to the first motor, the first motor is located inside the first motor housing, the second propeller is connected to the second motor, the second motor is located inside the second motor housing, the third propeller is connected to the third motor, the third motor is located inside the third motor housing, the first propeller, the first motor and the first motor housing are located on the left side of the bracket, the second propeller, the second motor and the second motor housing are located on the right side of the bracket, the third propeller, the third motor and the third motor housing are located in the middle and rear part of the bracket, and the positive and negative poles of the power supply are connected to the first motor, the second motor and the third motor via a cable. The device can effectively remove bubbles attached to the wall of the reverberation box.

Description

Technical Field

[0001] The invention relates to a device for removing bubbles on the wall surface of a reverberation box in a cavity pulsation pressure measurement test, and belongs to the field of acoustic measurement. Background Art

[0002] Currently, when measuring pore pressure fluctuations in gravity-type, low-noise water tunnels, a common problem is the generation of numerous small bubble clusters on the walls of the reverberation chamber after it is filled with tap water. This is primarily due to the temperature difference between the reverberation chamber wall and the tap water. Because bubbles are acoustically absorbing structures, when the hydrodynamic noise generated by the flow-excited pore radiates into the reverberation chamber, the bubbles absorb the hydrodynamic noise. The hydrodynamic noise received within the reverberation chamber is the reverberation effect caused by multiple reflections from the walls. Because the hydrodynamic noise is absorbed by the bubbles on the walls, the reverberation effect is weakened, resulting in a low signal-to-noise ratio (SNR) of the received signal. Furthermore, the hydrodynamic noise generated by the pore fluid oscillations affects the pore fluid oscillation process, namely, the acoustic-fluid coupling process. The weakening of the reverberation chamber's reflection effect also weakens the acoustic-fluid coupling effect, thereby affecting the accurate measurement of the pore pressure fluctuations.

[0003] In the past, degassing the walls of a reverberation chamber relied solely on time. Over time, these bubbles would rise to the surface and exit the chamber, typically requiring two weeks. With the accelerating pace of scientific research, such a long wait for bubble removal was untenable. Furthermore, due to the chamber's large volume—approximately 36 cubic meters when filled with water—heating and other methods of degassing were impractical. Furthermore, the chamber's walls and floor were not insulated, resulting in very rapid heat dissipation.

[0004] Therefore, developing a device for quickly removing bubbles from the reverberation chamber wall is one of the key equipment for accurately measuring cavity pulsating pressure and hydrodynamic noise. Summary of the Invention

[0005] The purpose of the present invention is to provide a device for removing bubbles on the wall of a reverberation box in a cavity pulsation pressure measurement test, wherein the device can effectively remove bubbles attached to the wall of the reverberation box.

[0006] The objective of the present invention is achieved as follows: it includes a first propeller, a first motor, a first motor housing, a second propeller, a second motor, a second motor housing, a third propeller, a third motor, a third motor housing, a bracket, a power supply, and a cable. The first propeller is connected to the first motor, the first motor is located inside the first motor housing, the second propeller is connected to the second motor, the second motor is located inside the second motor housing, the third propeller is connected to the third motor, the third motor is located inside the third motor housing, the first propeller, the first motor and the first motor housing are located on the left side of the bracket, the second propeller, the second motor and the second motor housing are located on the right side of the bracket, the third propeller, the third motor and the third motor housing are located in the middle and rear part of the bracket, the power supply is connected to the positive and negative poles of the first motor through a cable, the power supply is connected to the positive and negative poles of the second motor through a cable, and the power supply is connected to the positive and negative poles of the third motor through a cable.

[0007] Furthermore, the front of the blade of the first propeller is aligned with the front of the blade of the second propeller and is located at the front of the bracket, and the third propeller is located at the rear of the bracket. The direction of the jet generated by the first propeller and the second propeller is 180 degrees different from the direction of the jet generated by the third propeller.

[0008] Furthermore, the first propeller is a copper four-blade propeller, and a copper ring is connected to the edge of the propeller. The inner surface of the ring is smooth, and the outer diameter of the ring changes exponentially, with the maximum value in the middle of the outer part of the ring.

[0009] Furthermore, the first motor is a DC motor, and the rotating shaft of the DC motor is directly connected to the propeller shaft of the first propeller; the first motor housing is a cylindrical housing made of stainless steel, and the first motor is placed inside the shell. The shaft of the first motor is watertight using a grid ring at the front end cover, and there is a cable outlet at the rear end cover to supply power to the first motor.

[0010] Furthermore, the second propeller is a copper four-blade propeller, and a copper ring is connected to the edge of the propeller. The inner surface of the ring is smooth, and the outer diameter of the ring changes exponentially, with the maximum value in the middle of the outer part of the ring.

[0011] Furthermore, the second motor is a DC motor, and the rotating shaft of the DC motor is directly connected to the propeller shaft of the second propeller; the second motor housing is a cylindrical housing made of stainless steel, and the second motor is placed inside the shell. The shaft of the second motor is watertight using a grid ring at the front end cover, and there is a cable outlet at the rear end cover to supply power to the second motor.

[0012] Furthermore, the third propeller is a copper seven-blade propeller, and a copper ring is connected to the edge of the blades, and the inner and outer surfaces of the ring are smooth.

[0013] Furthermore, the third motor is a DC motor, and the rotating shaft of the DC motor is directly connected to the propeller shaft of the third propeller; the outer shell of the third motor is a cylindrical shell made of stainless steel, and the third motor is placed inside the shell. The shaft of the third motor is watertight using a grid ring at the front end cover, and there is a cable outlet at the rear end cover to supply power to the third motor.

[0014] Furthermore, the bracket is made of a hollow stainless steel tube, the left side of the bracket is a circular ring, the circular ring is fixed to the first motor housing by welding technology, the middle part of the bracket is a circular ring, the circular ring is fixed to the third motor housing by welding technology, the right side of the bracket is a circular ring, the circular ring is fixed to the second motor housing by welding technology, the circular ring on the left side of the bracket, the circular ring in the middle of the bracket and the circular ring on the right side of the bracket are horizontally connected by a small rod, and a vertical long rod is fixed on the circular ring in the middle of the bracket for operating the bracket.

[0015] Furthermore, the power supply is a 24V DC power supply.

[0016] Furthermore, the cable is a two-strand insulated cable.

[0017] Compared with the prior art, the present invention has the following advantages: first, the jet generated by the propeller of the first propeller and the second propeller is used to blow away the bubbles on the wall of the reverberation box. Under the action of the jet, the bubbles will break away from the wall of the reverberation box and quickly float to the surface of the water in the reverberation box and be discharged; second, when the first propeller and the second propeller generate the jet, they can also accelerate the disturbance of the water in the reverberation box, thereby accelerating the precipitation of bubbles suspended in the water of the reverberation box and attached to the surface of tiny floating particles, reducing the sound attenuation caused by the bubbles in the water of the reverberation box and improving the measurement accuracy of the radiated sound power in the reverberation box; third, the first propeller and the second propeller can also accelerate the disturbance of the water in the reverberation box when generating the jet, thereby accelerating the precipitation of bubbles suspended in the water of the reverberation box and attached to the surface of tiny floating particles, reducing the sound attenuation caused by the bubbles in the water of the reverberation box and improving the measurement accuracy of the radiated sound power in the reverberation box. The propulsion efficiency of the propeller is lower than that of the third propeller, so that the thrust generated by the first and second propellers can be balanced by the thrust of the third propeller alone. That is, the jet generated by the third propeller can offset the thrust generated by the first and second propellers, thereby reducing the deviation effect of the bracket away from the wall of the reverberation box and reducing the difficulty of adjusting the position of the bracket; finally, the jet generated by the third propeller can be diffused to other positions in the reverberation box, which also accelerates the disturbance of the water in the reverberation box, thereby causing the bubbles suspended on the surface of the tiny floating particles to precipitate quickly, reducing the influence of the bubbles on the measurement of the cavity pulsation pressure test.

[0018] The benefits of the present invention also lie in: first, the driving motors in the first propeller, the second propeller and the third propeller adopt DC motors, which have the advantage of smooth rotation and no "small fluctuation" interference that exists in the use of AC motors, so that the jet of the propeller is more uniform, the intensity of the pulsating pressure change is improved, and the hydrodynamic noise of the propeller is effectively reduced; secondly, the air layer formed by the first motor housing, the second motor housing and the third motor housing and the gap between the DC motor installed inside and the gap between the two forms a small sound insulation cover. Since the acoustic impedance characteristics of the air layer are very different from the characteristic impedance of the motor housing, and the volume of the sound insulation cover is very small, the frequency of the sound waves passing through it is very high, which can effectively cut off the low-frequency line spectrum interference generated by the first motor, the second motor and the third motor during the rotation process, reducing the impact on the cavity pulsating pressure test measurement process; thirdly, the first propeller and the second propeller The propellers are all four-blade propellers, which have high rigidity and are not prone to generating strong flow-induced noise. In addition, the external circular rings are all convex structures in the middle, which can not only reduce the radiation noise of the propeller itself, but also guide the return flow of the first and second propellers to the reverberation wall, making the flow more divergent and the mixing effect better. In addition, the outer wall of the circular ring of the third propeller is a smooth structure, which can suppress the strong pulsating pressure effect of the edge of the seven-blade propeller, effectively reduce the noise generated by the propeller jet, and thus reduce the influence of the hydrodynamic noise generated by the third propeller on the cavity pulsation pressure test measurement. Finally, during use, the device only needs DC power supply, and the power supply is relatively simple. It can quickly improve the removal process of bubbles on the wall of the reverberation box, greatly shorten the degassing time of the wall of the reverberation box, reduce the background noise caused by bubbles, improve the test efficiency, and reduce the cost expenditure during the cavity pulsation pressure test. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic top view of a device for removing bubbles from the wall of a reverberation box in a cavity pulsation pressure measurement test;

[0020] Figure 2 is the configuration diagram of the first propeller;

[0021] Figure 3 is a cross-sectional view of the edge ring of the first propeller;

[0022] Figure 4 is the configuration diagram of the second propeller;

[0023] Figure 5 is a cross-sectional view of the edge ring of the second propeller;

[0024] Figure 6 This is the configuration diagram of the third propeller;

[0025] Figure 7 is a schematic diagram of the bracket;

[0026] Among them, 1 is the first propeller, 2 is the first motor, 3 is the first motor housing, 4 is the second propeller, 5 is the second motor, 6 is the second motor housing, 7 is the third propeller, 8 is the third motor, 9 is the third motor housing, 10 is the bracket, 11 is the power supply, 12 is the cable, 31 is the grid ring, 61 is the grid ring, 91 is the grid ring, 101 is the ring, 102 is the ring, 103 is the ring, 104 is the small rod, 105 is the small rod, 106 is the long rod, 111 is the ring, 444 is the ring, and 777 is the ring. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The present invention includes a first propeller 1, a first motor 2, a first motor housing 3, a second propeller 4, a second motor 5, a second motor housing 6, a third propeller 7, a third motor 8, a third motor housing 9, a bracket 10, and a power supply 11. The first propeller 1 is connected to the first motor 2, the first motor 2 is located inside the first motor housing 3, the second propeller 4 is connected to the second motor 5, the second motor 5 is located inside the second motor housing 6, the third propeller 7 is connected to the third motor 8, and the third motor 8 is located inside the third motor housing 9. The first propeller 1, the first motor 2 and the first motor housing 3 are located on the left side of the bracket 10, the second propeller 4, the second motor 5 and the second motor housing 6 are located on the right side of the bracket 10, the third propeller 7, the third motor 8 and the third motor housing 9 are located in the middle and rear part of the bracket 10, the power supply 11 is connected to the positive and negative poles of the first motor 1 through a cable 12, the power supply 11 is connected to the positive and negative poles of the second motor 5 through a cable 12, and the power supply is connected to the positive and negative poles of the third motor through a cable 12.

[0029] The front of the blade of the first propeller 1 of the present invention is aligned with the front of the blade of the second propeller 4 and is located in the front of the bracket 10. The third propeller 7 is located in the middle and rear part of the bracket 10. The direction of the jet generated by the first propeller 1 and the second propeller 2 is 180° different from the direction of the jet generated by the third propeller 7.

[0030] The first propeller 1 of the present invention is a copper four-blade propeller, model PC100, with a copper ring 111 connected to the edge of the propeller. The inner surface of the ring 111 is smooth, and the outer diameter of the ring 111 changes exponentially, with the maximum value in the middle of the outer ring 111.

[0031] The first propeller 1 of the present invention is a copper four-blade propeller, model PC100, with a copper ring 111 connected to the edge of the propeller. The inner surface of the ring 111 is smooth, and the outer diameter of the ring 111 changes exponentially, with the maximum value in the middle of the outer ring 111.

[0032] The first motor 2 of the present invention is a DC motor, model XD-3402-2, powered by a 24V DC power supply, and the rotating shaft of the DC motor 2 is directly connected to the propeller shaft of the first propeller 1.

[0033] The first motor housing 3 of the present invention is a cylindrical housing made of stainless steel, in which the first motor 1 is placed. A grid ring 31 is used at the front end cover to make the shaft of the first motor 1 watertight. The grid ring 31 is composed of a sealing ring and an O-ring, also known as a rotary step seal. There is a cable 12 outlet at the rear end cover to supply power to the first motor 1.

[0034] The second propeller 4 of the present invention is a copper four-blade propeller, model PC100, with a copper ring 444 connected to the edge of the propeller. The inner surface of the ring 444 is smooth, and the outer diameter of the ring 444 changes exponentially, with the maximum value in the middle of the outer portion of the ring 444.

[0035] The second motor 5 of the present invention is a DC motor, model XD-3402-2, powered by a 24V DC power supply, and the rotating shaft of the DC motor 5 is directly connected to the propeller shaft of the second propeller 4.

[0036] The second motor housing 6 of the present invention is a cylindrical housing made of stainless steel, in which the second motor 5 is placed. A grid ring 61 is used at the front end cover to make the shaft of the second motor 5 watertight. The grid ring 61 is composed of a sealing ring and an O-ring, also known as a rotary step seal. There is a cable 12 outlet at the rear end cover to supply power to the second motor 5.

[0037] The third propeller 7 of the present invention is a copper seven-blade propeller with a brand of OTHER. A copper ring 777 is connected to the edge of the propeller blade, and the inner and outer surfaces of the ring 777 are smooth.

[0038] The third motor 8 of the present invention is a DC motor, model XD-3402-2, powered by a 24V DC power supply, and the rotating shaft of the DC motor 8 is directly connected to the propeller shaft of the third propeller 7.

[0039] The third motor housing 9 of the present invention is a cylindrical housing made of stainless steel, in which the third motor 8 is placed. A grid ring 91 is used at the front end cover to make the shaft of the third motor 8 watertight. The grid ring 91 is composed of a sealing ring and an O-ring, also known as a rotary step seal. There is a cable 12 outlet at the rear end cover to supply power to the third motor 8.

[0040] The bracket 10 of the present invention is made of a hollow stainless steel tube. The left side of the bracket is a ring 101, which is fixed to the first motor housing 3 by welding technology. The middle part of the bracket is a ring 102, which is fixed to the third motor 8 housing by welding technology. The right side of the bracket is a ring 103, which is fixed to the second motor housing 5 by welding technology. The ring 101 on the left side of the bracket, the ring 102 in the middle of the bracket and the ring 103 on the right side of the bracket are horizontally connected by small rods 104 and 105. There is a vertical long rod 106 on the ring 102 in the middle of the bracket 10 for operating the bracket.

[0041] The power supply of the present invention is a 24V DC power supply, model HY-24V72000, which provides power supply for the first motor 2, the second motor 5, and the third motor 8.

[0042] The cable 12 of the present invention is a double-strand insulated cable with a wire specification of 10 mm2 and a model number of BLXY.

Claims

1. A device for removing bubbles from the wall of a reverberation chamber during a cavity pulsation pressure measurement test, characterized in that: The invention comprises a first propeller, a first motor, a first motor housing, a second propeller, a second motor, a second motor housing, a third propeller, a third motor, a third motor housing, a bracket, a power supply, and a cable. The first propeller is connected to the first motor, the first motor is located inside the first motor housing, the second propeller is connected to the second motor, the second motor is located inside the second motor housing, the third propeller is connected to the third motor, and the third motor is located inside the third motor housing. The first propeller, the first motor and the first motor housing are located on the left side of the bracket, the second propeller, the second motor and the second motor housing are located on the right side of the bracket, the third propeller, the third motor and the third motor housing are located in the middle and rear part of the bracket, the power supply is connected to the positive and negative poles of the first motor through a cable, the power supply is connected to the positive and negative poles of the second motor through a cable, and the power supply is connected to the positive and negative poles of the third motor through a cable; The front of the blade of the first propeller is aligned with the front of the blade of the second propeller and is located at the front of the bracket, and the third propeller is located at the rear of the bracket, and the direction of the jet generated by the first propeller and the second propeller is 180 degrees different from the direction of the jet generated by the third propeller; The first propeller is a four-bladed copper propeller with a copper ring attached to its edge. The inner surface of the ring is smooth, and the outer diameter of the ring changes exponentially, reaching its maximum value in the middle of the ring. The second propeller is a four-bladed copper propeller with a copper ring attached to its edge. The inner surface of the ring is smooth, and the outer diameter of the ring changes exponentially, reaching its maximum value in the middle of the outer ring. The third propeller is a seven-blade copper propeller with a copper ring connected to the edge of the blades. Both the inner and outer surfaces of the ring are smooth.

2. The device for removing bubbles from the wall of a reverberation chamber in a cavity pulsation pressure measurement test according to claim 1, characterized in that: The first motor is a DC motor, and the rotating shaft of the DC motor is directly connected to the propeller shaft of the first propeller; the first motor housing is a cylindrical housing made of stainless steel, and the first motor is placed in the first motor housing. The shaft of the first motor is watertight using a grid ring at the front end cover, and there is a cable outlet at the rear end cover to supply power to the first motor.

3. The device for removing bubbles from the reverberation chamber wall in a cavity pulsation pressure measurement test according to claim 1, characterized in that: The second motor is a DC motor, and the rotating shaft of the DC motor is directly connected to the propeller shaft of the second propeller; the second motor housing is a cylindrical housing made of stainless steel, and the second motor is placed in the second motor housing. The shaft of the second motor is watertight using a grid ring at the front end cover, and there is a cable outlet at the rear end cover to supply power to the second motor.

4. The device for removing bubbles from the wall of a reverberation chamber in a cavity pulsation pressure measurement test according to claim 1, characterized in that: The third motor is a DC motor, and the rotating shaft of the DC motor is directly connected to the propeller shaft of the third propeller; the third motor housing is a cylindrical housing made of stainless steel, and the third motor is placed in the third motor housing. The shaft of the third motor is watertight using a grid ring at the front end cover, and there is a cable outlet at the rear end cover to supply power to the third motor.

5. The device for removing bubbles from the reverberation chamber wall in a cavity pulsation pressure measurement test according to claim 1, characterized in that: The bracket is made of a hollow stainless steel tube. The left side of the bracket is a ring, which is fixed to the first motor housing by welding technology. The middle part of the bracket is a ring, which is fixed to the third motor housing by welding technology. The right side of the bracket is a ring, which is fixed to the second motor housing by welding technology. The ring on the left side of the bracket, the ring in the middle of the bracket and the ring on the right side of the bracket are connected horizontally with a small rod. A vertical long rod is fixed on the ring in the middle of the bracket for operating the bracket.

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