A variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform and method

Abstract

The application provides a variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform and experimental method, which comprises a deep water pool, a variable buoyancy test bench, a model receiving and releasing bearing device, a test model and a data acquisition and display module. The variable buoyancy test bench is fixed at the bottom center of the deep water pool; the model receiving and releasing bearing device is fixed to the bottom of the variable buoyancy test bench; the test model is slidably and detachably installed on the variable buoyancy test bench; and the data acquisition and display module is fixed on the variable buoyancy test bench. The core technology of the application is to replace the traditional propulsion device with the variable buoyancy propulsion device, to exclude the interference of the wake flow and the hydrodynamic noise generated by the propulsion device on the flow field and the noise, to establish the direct relationship between the flow velocity and the flow resistance and the flow noise generated by the vehicle shell, to obtain the low signal-to-noise ratio flow resistance and flow noise signals, and to accurately evaluate the drag reduction and noise reduction performance of the underwater vehicle shell and the surface structure thereof.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of fluid drag reduction and noise reduction, and particularly relates to a variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform and a test method. BACKGROUND

[0002] Improving the maneuvering performance and acoustic stealth performance of a ship is an important research content for the development of marine equipment, and test research is one of the main methods for fluid drag reduction and noise reduction research. Therefore, it is currently an essential work to develop a fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform capable of accurately measuring fluid drag and noise signals, cultivate high-quality talents in the field of fluid drag reduction and noise reduction, and conduct high-precision fluid drag reduction and noise reduction tests.

[0003] Currently used fluid drag reduction and noise reduction test devices mainly include a circulating water tunnel, a towing tank and a gravity water tunnel. For the circulating water tunnel and the towing tank, they can provide flow field conditions close to actual working conditions, but an external propulsion system (such as a water pump for the circulating water tunnel and a towing vehicle for the towing tank) is needed to provide power during operation. In actual application, it is difficult to eliminate the influence of the propulsion system, resulting in a large amount of environmental noise in the measured fluid drag and noise results. For the gravity water tunnel, the internal fluid moves under the action of gravity, is relatively quiet and eliminates the influence of the propulsion system, but a large amount of water needs to be pumped into the water tower (or water tank) during the test preparation stage, which consumes a large amount of energy. Therefore, it is very important to design a fluid drag and noise test device that eliminates the interference of the propulsion system and has low energy consumption for the study of the drag and noise performance of a vehicle at medium and high speeds. SUMMARY

[0004] The application aims to provide a variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform and a test method.

[0005] The application achieves the above-mentioned purpose by the following technical solutions.

[0006] A variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform comprises a deep water pool, a variable buoyancy test bench, a model launching and receiving bearing device, a test model and a data acquisition and display module. The variable buoyancy test bench is fixed to the center of the bottom of the deep water pool. The test model is installed on a guide rail in the frame of the variable buoyancy test bench. The model launching and receiving bearing device is used for launching and receiving the test model. The test model generates variable buoyancy by means of a counterweight, and moves along the guide rail in the deep water pool at an adjustable speed. The data acquisition and display module is fixed to the variable buoyancy test bench and is used for acquiring fluid drag, noise signals and vortex distribution information in the flow field.

[0007] The model retraction and bearing device comprises a retraction servo device and a bearing release device, the guide rail is installed on the bearing release device, the bearing release device is installed at the center of the variable buoyancy test bench base plate, and the retraction servo device is installed on the base plate of the variable buoyancy test bench.

[0008] Further, the variable buoyancy test bench is an overall frame of a variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform, comprising a test bench main body and a guide rail.

[0009] Further, the bearing release device comprises a bearing release device shell, a push rod motor, a sliding block and a clamping arm; the bearing release device shell is fixed at the bottom of the variable buoyancy test bench base plate, the push rod motor is fixed in the bearing release device shell, the sliding block is detachably connected with the push rod motor, the sliding block is slidably connected with the model bearing release device shell, and the sliding block slides along the bearing release device shell under the action of the push rod motor; one end of the clamping arm is rotatably connected with the sliding block, the other end is free, and the clamping arm rotates around the bearing release device shell.

[0010] Further, the test model surface is provided with a sample to be measured, and the test model comprises a buoyancy cabin shell, an electronic cabin and a throw load cabin shell, a throw load battery, a permanent magnet, a power coil and a load; the buoyancy cabin shell and the electronic cabin and the throw load cabin shell are fixedly connected, and are sealed by a sealing ring; the throw load battery is fixed in the electronic cabin and the throw load cabin shell, the permanent magnet is fixedly connected with the electronic cabin and the throw load cabin shell, the power coil is wound outside the permanent magnet, and the load is adsorbed on the lower surface of the permanent magnet wound with the power coil.

[0011] Further, the data acquisition and display module comprises a pressure sensor, a hydrophone and a PIV test system; the pressure sensor is arranged in the interior of the guide rail; the hydrophone and the PIV test system are fixed to the inner sides of the two vertical supports opposite to the main body of the variable buoyancy test bench respectively.

[0012] A variable buoyancy propelling fluid drag reduction and noise reduction teaching and scientific research comprehensive test method, the specific steps are as follows:

[0013] 1) The construction of the test bench frame

[0014] The variable buoyancy test bench main body is fixed to the center of the bottom of the deep water pool, the load release device is fixed to the center of the bottom plate of the variable buoyancy test bench main body, the guide rail is fixed to the center of the upper surface of the load release device, the PIV test system and the hydrophone are fixed to any two vertical supports arranged opposite to the main body of the variable buoyancy test bench, the pressure sensor is fixedly connected with the guide rail, the winding and unwinding servo device is fixedly connected with the bottom plate, and a certain height of water is added in the deep water pool; the sample to be tested is installed on the surface of the test model, and the steel wire rope is connected between the winding and unwinding servo device and the test model;

[0015] 2) Start the experiment

[0016] Start the winding and unwinding servo device, tighten the steel wire rope, make the test model sink, make the load release device in the load bearing working condition, and fix the test model; reverse the model winding and unwinding servo device, and loosen the steel wire rope;

[0017] When the drag and noise test is carried out:

[0018] Make the model load release device in the release working condition, release the test model, the test model floats up, use the pressure sensor to monitor the time when the test model reaches each sensor, calculate the test model floating speed through the distance between adjacent sensors and the time difference, use the hydrophone to test the hydrodynamic noise, and use the PIV test system to observe the fluid boundary layer on the surface of the sample to be tested.

[0019] Further, the buoyancy borne by the test model is:

[0020] F 浮 =ρ 液 gV 排

[0021] Wherein, g is the acceleration of gravity; is the displacement volume of the test model; the gravity of the test model itself is:

[0022] G=ρ 固 gV 固

[0023] Wherein, is the volume of the solid part in the test model; therefore, in order to ensure F浮 G, in the preferred case (p 液 = 1000 kg / m 3 ; p 固 = 7850 kg / m 3 ), there is the following relationship:

[0024] V 排 = 7.85V 固

[0025] The beneficial effects of the present application are:

[0026] 1. The test model in the present application comprises a buoyancy chamber, an electronic chamber and a throw-off chamber, wherein the buoyancy chamber provides constant buoyancy, the electronic chamber is used to control the outward throw-off of the throw-off chamber, the gravity experienced by the test model is adjusted through the throw-off, so as to control the size of the propulsive force experienced by the test model, and further control the movement speed of the test model.

[0027] 2. The present application uses variable buoyancy propulsion composed of the electronic chamber and the throw-off chamber to replace the traditional propulsion device, eliminates the interference of the propulsion system, and can obtain purer flow resistance and flow noise signals. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of a variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive experiment platform;

[0029] Figure 2 is a structural schematic diagram of a model retraction servo device (top view);

[0030] Figure 3 is a structural schematic diagram of a model retraction servo device (front view);

[0031] Figure 4 is a structural schematic diagram of a test model;

[0032] Figure 5 is a schematic diagram of a model bearing release device bearing working condition;

[0033] Figure 6 is a schematic diagram of a model bearing release device release working condition;

[0034] Figure 7 is a schematic diagram of a variable buoyancy test bench support body;

[0035] Figure 8 is a schematic diagram of a guide rail cross section.

[0036] In the figure, 1-steel wire rope; 2-PIV test system; 3-deep water pool; 4-variable buoyancy test bench main body; 5-guide rail; 6-test model; 7-sample to be tested; 8-hydrophone; 9-load bearing release device; 10-winding and unwinding servo device; 11-winding motor; 12-winding shaft coupling; 13-winding nut; 14-winding guide rod; 15-winding bearing; 16-winding bearing; 17-shaft sleeve; 18-winding and unwinding servo device shell; 19-I-beam winding wheel; 20-winding shaft; 21-winding shaft coupling; 22-winding motor; 23-winding wheel; 24-buoyancy cabin shell; 25-sealing ring; 26-electronic cabin and throw-off cabin shell; 27-throw-off battery; 28-permanent magnet; 29-coil; 30-load; 31-supporting arm; 32-sliding block; 33-push rod motor; 34-load bearing release device shell; 35-vertical support I; 36-vertical support II; 37-top frame; 38-vertical support III; 39-vertical support IV; 40-bottom plate; 41-pressure sensor. DETAILED DESCRIPTION

[0037] The application will be further described below with reference to the drawings.

[0038] As shown in Figs. Figure 1 and Figure 7 , the working principle of the variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform is described in detail.

[0039] Before the flow resistance and flow noise test, the variable buoyancy test bench main body 4 is fixed at the bottom center of the deep water pool 3, the model load bearing release device 9 is fixed at the bottom center of the variable buoyancy test bench main body 4, the guide rail 5 is fixed at the center of the upper surface of the model load bearing release device 9, the PIV test system 2 and the hydrophone 8 are fixed on any two vertical supports oppositely arranged in the variable buoyancy test bench main body 4, the pressure sensor 41 is fixedly connected with the guide rail 5, the model winding and unwinding servo device 10 is fixedly connected with the bottom plate 40, and a certain height of water (or seawater) is added in the deep water pool 3, thereby completing the construction of the test bench frame.

[0040] The sample to be tested 7 is selected according to different test purposes, such as testing the resistance and noise characteristics of the shell, the sample to be tested 7 is a shell with different shapes, or testing the resistance and noise characteristics of the surface structure, the sample to be tested 7 is a surface structure, the sample to be tested 7 is installed on the surface of the test model 6, then the test model 6 is detachably and slidably connected with the guide rail 5, and the model winding and unwinding servo device 10 and the test model 6 are connected through the steel wire rope 1, thereby completing the preparation work before the test.

[0041] The model take-up servo device 10 is started, the steel wire rope 1 is tightened, the test model 6 is sunk, then the model load release device 9 is in the load working condition, the test model 6 is fixed, finally the model take-up servo device 10 is reversed, the steel wire rope 1 is loosened.

[0042] When the resistance and noise test is carried out, the model load release device 9 is in the release working condition, the test model 6 is released, the test model 6 is floated, the time when the test model 6 reaches each sensor is monitored by the pressure sensor 41, the test model 6 floating speed is calculated by the distance between adjacent sensors and the time difference, the hydrodynamic noise is tested by the hydrophone 8, and the fluid boundary layer on the surface of the sample 7 is observed by the PIV test system 2.

[0043] As shown in Figure 2 and Figure 3 , the model take-up servo device 10 comprises a model take-up servo device shell 18, a wire arranging motor 11, a wire arranging shaft 12, a wire arranging guide rod 14, a wire arranging nut 13, a wire arranging wheel 23, a wire arranging bearing 15, an I-shaped take-up wheel 19, a take-up shaft 20, a take-up shaft coupling 21, a take-up motor 22, a shaft sleeve 17 and a take-up bearing 16. In the test preparation stage, the wire arranging motor 11 is started, the wire arranging guide rod 14 is driven to rotate through the wire arranging shaft coupling 12, so that the wire arranging nut 13 moves linearly along the guide rod 14, and then the wire arranging wheel 23 fixedly connected with the wire arranging nut 13 moves linearly. At the same time, the take-up motor 22 is started, the take-up shaft 20 is driven to rotate through the take-up shaft coupling 21, so that the I-shaped take-up wheel 19 rotates, and then the steel wire rope 1 is uniformly arranged on the outer surface of the I-shaped take-up wheel 19 through the wire arranging wheel 23. At this time, the test model 6 is subjected to the downward pulling force provided by the steel wire rope 1, and is sunk in the deep water tank 3. After the test model 6 is sunk to a certain position, the wire arranging motor 11 and the take-up motor 22 are stopped, the test model 6 is fixed by the model load release device 9, then the wire arranging motor 11 and the take-up motor 22 are reversed, the steel wire rope 1 is separated from the I-shaped take-up wheel 19, and freely falls in the model take-up servo device shell 18, so that the test model 6 is not subjected to force, and the preparation work before the experiment is completed.

[0044] As shown in Figure 4As shown, the test model 6 of this invention includes a buoyancy chamber shell 24, an electronics chamber and a jettison chamber shell 26, a jettison battery 27, a permanent magnet 28, an energized coil 29, a load 30, and a sealing ring 25. The load 30 is a magnetic metal block, and the magnetic pole direction of the load 30 is the same as that of the permanent magnet 28. Therefore, when the energized coil 29 is not energized, the load 30 is attracted to the lower surface of the permanent magnet 28. When it is necessary to control the movement speed of the test model 6 by jettisoning, the jettison battery 27 supplies power to the energized coil 29, providing a magnetic field opposite to that of the permanent magnet 28. The magnetic field generated by the energized coil 29 is much greater than that generated by the permanent magnet 28. At this time, the load 30 falls under the action of the magnetic force of the energized coil 29 and its own weight. The overall mass of the test model 6 decreases, the gravity it experiences decreases, and the buoyancy provided by the buoyancy chamber remains unchanged. Therefore, the total propulsion force increases, and the upward speed increases.

[0045] like Figure 5 and Figure 6 As shown, the model-bearing release device 9 of the present invention includes a support arm 31, a slider 32, a push rod motor 33, and a model-bearing release device housing 34. Before the test begins, the test model 6 is lowered to a certain position under the action of the model deployment and retraction servo device 10, and then the model-bearing release device 9 begins to work. First, the model-bearing release device 9 is in the bearing condition. The slider 32 moves upward along the model-bearing device housing 34 under the action of the push rod motor 33, driving the support arm 31 to rotate, so that the free end of the support arm 31 contacts the lower inner surface edge of the electronic compartment and the jettisoning chamber shell 26 in the test model 6, thereby fixing the test model 6. When the test begins, the model-bearing release device 9 is in the release condition. The slider 32 moves downward along the model-bearing release device housing 34 under the action of the push rod motor 33, driving the support arm 31 to rotate, so that the free end of the support arm 31 leaves the electronic compartment and the jettisoning chamber shell 26 in the test model 6, thereby releasing the test model 6.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A comprehensive experimental platform for teaching and research on variable buoyancy propulsion fluid drag reduction and noise reduction, characterized in that: The device comprises a deep water pool (3), a variable buoyancy test bench, a model loading and releasing device, a test model (6) and a data acquisition and display module; the variable buoyancy test bench is fixed to the center of the bottom of the deep water pool (3); the test model (6) is installed on a guide rail (5) in the variable buoyancy test bench frame; the model loading and releasing device is used for loading and releasing and bearing the test model (6); the test model (6) is moved along the guide rail (5) in the deep water pool (3) at an adjustable speed by means of a variable buoyancy generated by a counterweight; the data acquisition and display module is fixed to the variable buoyancy test bench and is used for acquiring flow resistance, flow noise signals and vortex distribution information in a flow field. The model loading and releasing device comprises a loading and releasing servo device (10) and a bearing releasing device (9); the guide rail (5) is installed on the bearing releasing device (9), which is installed at the center of the bottom plate (40) of the variable buoyancy test bench; the loading and releasing servo device (10) is installed on the bottom plate (40) of the variable buoyancy test bench; the loading and releasing servo device (10) comprises a loading and releasing servo device shell (18), a wire guide rod (14), a wire coupling (12), a wire motor (11), a wire nut (13), a wire wheel (23), a wire bearing (15), an I-shaped wire winding wheel (19), a wire winding shaft (20), a shaft sleeve (17), a wire winding bearing (16), a wire winding coupling (21), a wire winding motor (22) and a steel wire rope (1); the wire motor (11) is fixed inside the loading and releasing servo device shell (18) and is connected with the wire guide rod (14) through the wire coupling (12) and rotates synchronously with the wire guide rod (14); the wire guide rod (14) is a long straight screw rod and is rotatably fixed in the loading and releasing servo device shell (18) through the wire bearing (15); the wire nut (13) is connected with the wire guide rod (14) through threads; the wire wheel (23) is fixedly connected with the wire nut (13); the steel wire rope (1) is wound on the I-shaped wire winding wheel (19) through the wire wheel (23); the I-shaped wire winding wheel (19) is rotatably fixed in the model loading and releasing servo device shell (18) through the wire winding bearing (16); the wire winding coupling (21) is connected with the I-shaped wire winding wheel (19) and the output shaft of the wire winding motor (22) at two ends and rotates synchronously with the I-shaped wire winding wheel (19), the wire winding coupling (21) and the output shaft of the wire winding motor (22); the test model (6) is connected with the loading and releasing servo device (10) through the steel wire rope (1). The test model (6) comprises a buoyancy cabin shell (24), an electronic cabin and a counterweight cabin shell (26); the buoyancy cabin shell (24) and the electronic cabin and the counterweight cabin shell (26) are fixedly connected and are sealed through a sealing ring; the buoyancy cabin provides constant buoyancy; the electronic cabin is used for controlling the counterweight cabin to throw out a counterweight; the gravity borne by the test model is adjusted through the counterweight.

2. The variable buoyancy propulsion fluid drag reduction noise reduction teaching and scientific research comprehensive test platform according to claim 1, characterized in that: The variable buoyancy test bench is a whole frame of a variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform, comprising a test bench main body (4) and a guide rail (5); the test bench main body (4) comprises vertical supports I (35), II (36), III (38), IV (39), a top frame (37) and a bottom plate (40), and the guide rail (5) is vertically fixed at the center of the bottom plate (40).

3. The variable buoyancy propulsion fluid drag reduction noise reduction teaching and scientific research comprehensive test platform according to claim 1, characterized in that: The load release device (9) comprises a load release device shell (34), a push rod motor (33), a sliding block (32) and a clamping arm (31); the load release device shell (34) is fixed at the bottom of the variable buoyancy test bench bottom plate (40), the push rod motor (33) is fixed in the load release device shell (34), the sliding block (32) is detachably connected with the push rod motor (33), and the sliding block (33) is slidably connected with the model load release device shell (34), and the sliding block (33) slides along the load release device shell (34) under the action of the push rod motor (33); one end of the clamping arm (31) is rotatably connected with the sliding block (33), and the other end is free, and the clamping arm (31) rotates around the load release device shell (34).

4. The variable buoyancy propulsion fluid drag reduction noise reduction teaching and scientific research comprehensive test platform according to claim 1, characterized in that: The test model (6) is provided with a to-be-tested sample (7) on the surface, and further comprises a throw-off battery (27), a permanent magnet (28), a power coil (29) and a load (30); the throw-off battery (27) is fixed in an electronic cabin and a throw-off cabin shell (26), the permanent magnet (28) is fixedly connected with the electronic cabin and the throw-off cabin shell (26), the power coil (29) is wound outside the permanent magnet (28), and the load (30) is adsorbed on the lower surface of the permanent magnet (28) wound with the power coil (29).

5. The variable buoyancy propulsion fluid drag reduction noise reduction teaching and scientific research comprehensive test platform according to claim 1, characterized in that: The data acquisition and display module comprises a pressure sensor (41), a hydrophone (8) and a PIV test system (2); the pressure sensor (41) is arranged in an array inside the guide rail (5); the hydrophone (8) and the PIV test system (2) are respectively fixed on the inner sides of two vertical supports opposite to each other of the variable buoyancy test bench main body (4).

6. The experimental method of the variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform according to any one of claims 1-5, characterized in that: The specific steps are as follows: 1) construction of the test bench frame The variable buoyancy test bench main body (4) is fixed at the center of the bottom of the deep water pool (3), the load release device (9) is fixed at the center of the bottom plate (40) of the variable buoyancy test bench main body (4), the guide rail (5) is fixed at the center of the upper surface of the load release device (9), the PIV test system (2) and the hydrophone (8) are fixed on any two vertical supports arranged opposite to each other of the variable buoyancy test bench main body (4), the pressure sensor (41) is fixedly connected with the guide rail (5), the winding and unwinding servo device (10) is fixedly connected with the bottom plate (40), and a certain height of water is added in the deep water pool (3); the to-be-tested sample (7) is installed on the surface of the test model (6), and the steel wire rope (1) is used to connect the winding and unwinding servo device (10) and the test model (6); 2) start experiment Start the model launching and recovering servo device (10), tighten the steel wire rope (1), make the test model (6) sink, make the model bearing release device (9) in the bearing working condition, fix the test model (6); Reverse the model launching and recovering servo device (10), loosen the steel wire rope (1); Carry out the resistance and noise test: Make the model bearing release device (9) in the release working condition, release the test model (6), the test model (6) floats up, use the pressure sensor (41) to monitor the time when the test model (6) reaches each sensor, calculate the test model (6) floating speed through the distance between adjacent sensors and the time difference, use the hydrophone (8) to test the hydrodynamic noise, use the PIV test system (2) to observe the fluid boundary layer on the surface of the sample (7) to be tested.

7. The experimental method of the variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform according to claim 6, characterized in that: The buoyancy of the test model (6) is: wherein, is the acceleration due to gravity; is the displacement volume of the test model (6); the self-weight of the test model (6) is: wherein, is the volume of the solid part in the test model (6); therefore, to guarantee , in the preferred case ( ; ), the following relationship exists: 。 8. The experimental method of the variable buoyancy propulsion fluid drag reduction and noise reduction teaching and scientific research comprehensive test platform according to claim 6, characterized in that: The sample (7) to be tested is adjusted according to the test purpose, when testing the resistance and noise characteristics of the shell, the sample (7) to be tested is a shell with different shapes; When testing the resistance and noise characteristics of the surface structure, the sample (7) to be tested is a surface structure with different shapes.

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