Underwater wall surface boundary layer frictional resistance and pressure measuring device

Abstract

The utility model discloses an underwater wall surface boundary layer frictional resistance and pressure measuring device, which belongs to the field of underwater material detection equipment and comprises a universal flow channel assembly, a modular switching frictional resistance and pressure testing system, a transparent acrylic material resistance testing section and a data acquisition system. The general flow channel assembly forms a closed circulation flow channel, and accurate control over the water flow speed is achieved; by replacing the corresponding test cover plate and the force transmission shaft, the test function can be quickly switched; the test sensor has a milliNewton-level resolution, the sampling frequency is greater than or equal to 30 times per second, and the dual-seal design is matched to ensure that the data is accurate and reliable. The device is suitable for sample pieces of various sizes / shapes, the testing process can be observed in real time, the device has the advantages of being compact in structure, convenient to operate, energy-saving and environment-friendly, and reliable data support is provided for resistance reduction design of underwater vehicles and optimization of ocean equipment.

Description

Technical Field

[0001] This utility model relates to the field of underwater material wall boundary layer friction resistance and water flow pressure detection equipment, and in particular to an underwater wall boundary layer friction resistance and pressure measurement device. Background Technology

[0002] As various underwater vehicles and marine equipment continue to develop towards higher efficiency and energy conservation, the need for precise measurement and effective control of the hydrodynamic resistance they experience during operation is becoming increasingly prominent. Frictional resistance accounts for a significant proportion of the total resistance experienced by underwater vehicles, especially in low-speed navigation or viscous flow environments. Reducing surface frictional resistance during underwater navigation plays a crucial role in improving the energy efficiency and overall performance of navigation and transportation processes. For underwater vehicles in particular, reducing surface frictional resistance can effectively extend their underwater endurance. Therefore, achieving accurate measurement of underwater frictional resistance and fluid pressure on material surfaces is of significant engineering importance for the design of efficient drag-reducing surfaces and the optimization of vehicle shape.

[0003] Currently, underwater friction resistance testing methods can be mainly divided into two categories: one is based on numerical simulation, such as using CFD software to perform flow simulation analysis on specific surface structures or material models. However, due to the complexity of actual working conditions, numerical methods can usually only predict the approximate range of resistance, making it difficult to achieve precise quantitative measurement of friction resistance. The other category is to directly measure the friction resistance in the fluid environment through experimental means, such as using water tunnels, circulating water tanks, or towed test devices. Although these experimental methods each have their own characteristics, they also generally suffer from the following shortcomings: the experimental system structure is complex and the cost is high; the stability of the flow field and the repeatability of the experiment are difficult to guarantee; and it is difficult to accurately capture the microscopic changes in friction resistance under high Reynolds number conditions.

[0004] To address the aforementioned issues, developing a compact, stable, and accurate underwater friction resistance and pressure testing platform is of significant theoretical and engineering value. Therefore, this invention proposes an underwater wall boundary layer friction resistance and pressure measurement device. Utility Model Content

[0005] The purpose of this invention is to provide an underwater wall boundary layer friction resistance and pressure measurement device. The device has a compact structure, occupies little space, has modular switching function, can achieve millinewton-level testing accuracy, is compatible with a variety of test samples of different sizes and surface morphologies, can accurately measure the friction resistance and dynamic pressure of material surfaces under dynamic water flow environment, and the testing process can be observed in real time, improving the controllability of the test.

[0006] To achieve the above objectives, this utility model provides an underwater wall boundary layer friction resistance and pressure measurement device, including a universal flow channel assembly, an underwater friction resistance testing system, an underwater pressure testing system, and a device test section;

[0007] The universal flow channel assembly includes a water tank, an inlet pipe, a water flow rate meter, a rigid water pipe, a graduated ball valve, a water pipe reducer, a test device connector, and an outlet pipe. The water tank is connected to the inlet pipe and the outlet pipe respectively. The inlet pipe is connected in series with the water flow rate meter, the rigid water pipe, the graduated ball valve, the water pipe reducer, and the test device connector, and then connected to one end of the test section of the device. The other end of the test section of the device is connected back to the water tank through the outlet pipe to form a closed loop flow channel.

[0008] The underwater friction resistance testing system and the underwater pressure testing system are selected to be installed in the test section of the device. The friction resistance or pressure test can be switched by replacing the corresponding test components. The test section of the device is used to carry the sample to be tested and to supply water flow.

[0009] Preferably, the underwater friction resistance testing system includes a friction resistance testing device cover plate, a resistance testing device force transmission shaft, a first pressure sensor, a test sample, a first sealing ring, and a first sealing strip; the friction resistance testing device cover plate is fixed to the lower part of the testing section of the device by bolts, and the first sealing strip is provided on its circumferential edge, with a through hole in the middle of the cover plate; the resistance testing device force transmission shaft passes through the through hole, one end of which is bolted to the first pressure sensor, and the other end is fixed to the test sample, the first pressure sensor being bolted to the lower part of the friction resistance testing device cover plate; the first sealing ring is pressed between the resistance testing device force transmission shaft and the inner wall of the through hole of the friction resistance testing device cover plate.

[0010] Preferably, the underwater pressure testing system includes a pressure testing device cover plate, a pressure testing device force transmission shaft, a second pressure sensor, a sample to be tested, a second sealing ring, and a second sealing strip; the pressure testing device cover plate is fixed to the lower part of the testing section of the device by bolts, and the second sealing strip is provided on its circumferential edge, with a through hole in the middle of the cover plate; the pressure testing device force transmission shaft passes through the through hole, one end of which is fixed to the second pressure sensor by bolts, and the other end is fixed to the sample to be tested, and the second pressure sensor is fixed to the worktable by bolts; the second sealing ring is pressed between the pressure testing device force transmission shaft and the inner wall of the through hole of the pressure testing device cover plate.

[0011] Preferably, both the first sealing strip and the second sealing strip have a double-layer structure.

[0012] Preferably, the minimum test resolution of both the first pressure sensor and the second pressure sensor is at the millinewton level, and the data sampling frequency is not less than 30 times per second.

[0013] Preferably, the test section of the device is made of transparent acrylic material.

[0014] Preferably, the sample to be tested is detached and fixed to the end of the force transmission shaft of the resistance testing device or the force transmission shaft of the pressure testing device through a sample fixing structure.

[0015] Preferably, it also includes a data acquisition system, which is connected to the first pressure sensor of the underwater friction resistance testing system and the second pressure sensor of the underwater pressure testing system.

[0016] Therefore, the present invention employs the above-mentioned underwater wall boundary layer friction resistance and pressure measuring device, which has the following technical effects:

[0017] (1) The main body of the device in this application is a general flow channel assembly. Only the corresponding test channel cover plate and force transmission shaft assembly need to be replaced to realize the rapid switching of friction resistance and pressure testing functions. No overall equipment modification is required. It is easy to operate and has a wide range of applications.

[0018] (2) Both the first pressure sensor and the second pressure sensor in this application achieve millinewton-level minimum test resolution and data sampling frequency of no less than 30 times per second, which can accurately capture microscopic changes. At the same time, the edge of the test cover is provided with a double-layer sealing strip and a sealing ring is provided between the force transmission shaft and the cover. The double sealing design effectively avoids water leakage, reduces the interference of the external environment on the test results, and improves the accuracy and repeatability of the test results.

[0019] (3) The test sample of this application is installed by a detachable sample fixing structure, which can adapt to material samples of different sizes and surface morphologies and meet diverse testing needs; the test section of the device is made of transparent acrylic material, and the water flow status and sample surface condition can be observed in real time during the test, which makes it easier to grasp the test status and improve the controllability of the test process.

[0020] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of an underwater wall boundary layer friction resistance and pressure measuring device according to the present invention;

[0022] Figure 2 This is a schematic diagram of the underwater friction resistance testing system in an underwater wall boundary layer friction resistance and pressure measuring device of this utility model;

[0023] Figure 3 This is a cross-sectional view of the underwater friction resistance testing system in an underwater wall boundary layer friction resistance and pressure measuring device of this utility model;

[0024] Figure 4 This is a schematic diagram of the underwater pressure testing system in an underwater wall boundary layer friction resistance and pressure measuring device of this utility model;

[0025] Figure 5 This is a cross-sectional view of the underwater pressure testing system in an underwater wall boundary layer friction resistance and pressure measuring device of this utility model;

[0026] Figure 6 This is a schematic diagram of the test sample being fixed on the cover plate of the friction resistance testing device in an underwater wall boundary layer friction resistance and pressure measurement device according to this utility model.

[0027] Figure Labels

[0028] 1. Water flow velocity meter; 2. Rigid water pipe; 3. Graduated ball valve; 4. Workbench; 5. Water pipe reducer; 6. Outlet pipe; 7. Water tank; 8. Inlet pipe; 9. Test device connector; 10. Test section of the device; 11. Cover plate of the friction resistance test device; 12. First pressure sensor; 13. Force transmission shaft of the resistance test device; 14. First sealing strip; 15. First sealing ring; 16. Cover plate of the pressure test device; 17. Second pressure sensor; 18. Force transmission shaft of the pressure test device; 19. Second sealing strip; 20. Second sealing ring; 21. Sample to be tested; 22. Data acquisition system. Detailed Implementation

[0029] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

[0030] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] like Figure 1 As shown, an underwater wall boundary layer friction resistance and pressure measurement device includes a general flow channel assembly, an underwater friction resistance testing system, an underwater pressure testing system, a device test section 10, and a data acquisition system 22.

[0032] The general flow channel assembly includes a water tank 7, an inlet pipe 8, a water flow rate meter 1, a rigid water pipe 2, a graduated ball valve 3, a water pipe reducer 5, a test device connector 9, and an outlet pipe 6. The water tank 7 is connected to both the inlet pipe 8 and the outlet pipe 6. The inlet pipe 8 is connected in series with the water flow rate meter 1, the rigid water pipe 2, the graduated ball valve 3, the water pipe reducer 5, and the test device connector 9, and then connects to one end of the test section 10 of the device. The other end of the test section 10 is connected back to the water tank 7 through the outlet pipe 6, forming a closed loop flow channel. The water tank 7 is used to store fluid. The water flow rate meter 1 detects the water flow velocity in the test channel in real time. The graduated ball valve 3 adjusts the water flow rate to achieve precise control of the water flow velocity during the test. The closed loop flow channel enables the recycling of water flow.

[0033] The underwater friction resistance testing system and the underwater pressure testing system can be optionally installed in the test section 10 of the device. The friction resistance or pressure test can be switched by changing the corresponding test components. The test section 10 is used to carry the sample 21 to be tested and to supply water flow. The test section 10 is made of transparent acrylic material, which facilitates real-time observation of the water flow status and the surface condition of the sample 21 to be tested during the test.

[0034] like Figure 2 , Figure 3 , Figure 6 As shown, the underwater friction resistance testing system includes a friction resistance testing device cover plate 11, a resistance testing device force transmission shaft 13, a first pressure sensor 12, a test sample 21, a first sealing ring 15, and a first sealing strip 14. The friction resistance testing device cover plate 11 is fixed to the lower part of the device testing section 10 by bolts. The first sealing strip 14 is provided in the groove on its circumferential edge. The first sealing strip 14 has a double-layer structure to ensure the sealing performance of the test channel. A through hole is opened in the middle of the cover plate. The resistance testing device force transmission shaft 13 passes through the through hole. One end of the shaft is fixed to the first pressure sensor 12 by bolts, and the other end is fixed to the test sample 21. The first pressure sensor 12 is installed under the friction resistance testing device cover plate 11 by bolts to collect the friction resistance signal generated by the test sample 21 under the action of water flow. A first sealing ring 15 is pressed between the resistance testing device force transmission shaft 13 and the inner wall of the through hole of the friction resistance testing device cover plate 11 to further enhance the sealing performance of this part and prevent water leakage during the test.

[0035] like Figure 4 , Figure 5 , Figure 6As shown, the underwater pressure testing system includes a pressure testing device cover plate 16, a pressure testing device force transmission shaft 18, a second pressure sensor 17, a sample to be tested 21, a second sealing ring 20, and a second sealing strip 19. The pressure testing device cover plate 16 is fixed to the lower part of the device testing section 10 by bolts. The second sealing strip 19 is provided in the groove on its circumferential edge. The second sealing strip 19 has a double-layer structure, and a through hole is opened in the middle of the cover plate. The pressure testing device force transmission shaft 18 passes through the through hole. One end of it is fixed to the second pressure sensor 17 by bolts, and the other end is fixed to the sample to be tested 21. The second pressure sensor 17 is fixed to the worktable 4 by bolts and is used to measure the dynamic pressure on the surface of the sample. A second sealing ring 20 is pressed between the pressure testing device force transmission shaft 18 and the inner wall of the through hole of the pressure testing device cover plate 16 to enhance the sealing performance.

[0036] The test sample 21 is disassembled and fixed to the end of the force transmission shaft 13 of the resistance testing device or the force transmission shaft 18 of the pressure testing device through the sample fixing structure, and ensures that the test sample 21 is located in the water flow channel inside the test section 10 of the device, so that the water flow can flow along the surface of the test sample 21; the test sample 21 can be replaced with different shapes or sizes according to different test requirements to adapt to a variety of test objects.

[0037] The minimum test resolution of the first pressure sensor 12 and the second pressure sensor 17 is at the millinewton level, and the data sampling frequency is no less than 30 times per second to ensure that the test data is stable and reliable. The data acquisition system 22 is connected to the first pressure sensor 12 and the second pressure sensor 17 and is used to record and process the frictional resistance or pressure signals acquired by the sensors.

[0038] Working principle:

[0039] Sufficient test fluid is injected into the water tank 7, and an external power device (such as a water pump) is started to make the water flow from the water tank 7 into the water inlet pipe 8. The water flow rate is adjusted by the graduated ball valve 3, and the water flow velocity meter 1 detects the water flow velocity in the test channel in real time until the preset test flow rate is reached and the water flow state is stabilized.

[0040] Friction resistance test: Water flows along the surface of the sample 21 to be tested, and the resulting friction resistance is transmitted to the first pressure sensor 12 through the force transmission shaft 13 of the resistance testing device. The first pressure sensor 12 collects the friction resistance signal and transmits it to the data acquisition system 22. The data acquisition system 22 records the data at a frequency of not less than 30 times per second and finally outputs the friction resistance data of the surface of the sample 21 to be tested at this flow rate.

[0041] Pressure test: Water flow acts on the surface of the sample 21 to be tested, and the resulting dynamic pressure is transmitted to the second pressure sensor 17 through the force transmission shaft 18 of the pressure testing device. The second pressure sensor 17 collects the pressure signal and transmits it to the data acquisition system 22. After recording and processing, the data acquisition system 22 outputs the dynamic pressure data of the surface of the sample 21 to be tested at this flow rate.

[0042] Multi-condition test: By adjusting the water flow rate through the graduated ball valve 3 to correspond to different test flow rates, repeat the above test steps to obtain the frictional resistance or pressure data of the surface of the sample 21 under different flow rate conditions, and complete the comprehensive measurement of the boundary layer characteristics of the underwater material wall.

[0043] If you need to test different sizes or surface morphologies of the test sample 21, you only need to disassemble the sample fixing structure, replace it with a new test sample 21 and fix it again to carry out the next round of testing. The operation is convenient and efficient.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. A device for measuring the frictional resistance and pressure of the underwater wall boundary layer, characterized in that: This includes general flow channel components, underwater friction resistance testing systems, underwater pressure testing systems and device testing sections; The universal flow channel assembly includes a water tank, an inlet pipe, a water flow rate meter, a rigid water pipe, a graduated ball valve, a water pipe reducer, a test device connector, and an outlet pipe. The water tank is connected to the inlet pipe and the outlet pipe respectively. The inlet pipe is connected in series with the water flow rate meter, the rigid water pipe, the graduated ball valve, the water pipe reducer, and the test device connector, and then connected to one end of the test section of the device. The other end of the test section of the device is connected back to the water tank through the outlet pipe to form a closed loop flow channel. The underwater friction resistance testing system and the underwater pressure testing system are selectively installed in the testing section of the device. The friction resistance or pressure test can be switched by replacing the corresponding test components. The testing section of the device is used to carry the sample to be tested and to supply water flow.

2. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 1, characterized in that: The underwater friction resistance testing system includes a friction resistance testing device cover plate, a resistance testing device force transmission shaft, a first pressure sensor, a test sample, a first sealing ring, and a first sealing strip. The friction resistance testing device cover plate is fixed to the lower part of the testing section of the device by bolts, and the first sealing strip is provided on its circumferential edge. A through hole is opened in the middle of the cover plate. The resistance testing device force transmission shaft passes through the through hole, one end of which is fixed to the first pressure sensor by bolts, and the other end is fixed to the test sample. The first pressure sensor is installed below the friction resistance testing device cover plate by bolts. The first sealing ring is pressed between the resistance testing device force transmission shaft and the inner wall of the through hole of the friction resistance testing device cover plate.

3. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 2, characterized in that: The underwater pressure testing system includes a pressure testing device cover plate, a pressure testing device force transmission shaft, a second pressure sensor, a sample to be tested, a second sealing ring, and a second sealing strip. The pressure testing device cover plate is fixed to the lower part of the testing section of the device by bolts, and the second sealing strip is provided on its circumferential edge. A through hole is opened in the middle of the cover plate. The pressure testing device force transmission shaft passes through the through hole, one end of which is fixed to the second pressure sensor by bolts, and the other end is fixed to the sample to be tested. The second pressure sensor is fixed to the worktable by bolts. The second sealing ring is pressed between the pressure testing device force transmission shaft and the inner wall of the through hole of the pressure testing device cover plate.

4. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 3, characterized in that: Both the first sealing strip and the second sealing strip have a double-layer structure.

5. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 3, characterized in that: The minimum test resolution of both the first and second pressure sensors is at the millinewton level, and the data sampling frequency is no less than 30 times per second.

6. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 1, characterized in that: The test section of the device is made of transparent acrylic material.

7. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 3, characterized in that: The sample to be tested is detached and fixed to the end of the force transmission shaft of the resistance testing device or the force transmission shaft of the pressure testing device through the sample fixing structure.

8. The underwater wall boundary layer friction resistance and pressure measuring device according to claim 1, characterized in that: It also includes a data acquisition system, which is connected to the first pressure sensor of the underwater friction resistance testing system and the second pressure sensor of the underwater pressure testing system.

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