Fluid drag reduction effect testing device and method for realizing bionic surface structure transformation

Abstract

The present invention discloses a fluid drag reduction effect test device and method for realizing bionic surface structure transformation, the device comprises a water circulation system, a drag reduction effect test device, a surface structure transformation device and a bionic structure test board; the drag reduction effect is judged by setting the surface structure transformation device on the bionic structure test board and testing the drag reduction time by magnetic on-off. The present invention can realize drag reduction test of pit convex hull models with different depths and curvatures and different groove depths and groove structure model transformations, has a simple structure, convenient data collection, and can effectively and intuitively reflect the drag reduction effects of various models, and is easy to operate.

Description

Technical Field

[0001] The invention relates to the field of testing frictional resistance between fluid and solid, and in particular to a fluid drag reduction effect testing device and method for realizing bionic surface structure transformation. Background Art

[0002] When a fluid flows on a solid surface, frictional resistance will be generated on its surface. In the fields of ocean navigation, pipeline transportation, etc., the power of the pump group is mainly used to overcome the frictional resistance between the fluid and the wall. The surface frictional resistance of conventional surface ships accounts for about 50% of the total resistance, and the surface frictional resistance of underwater vehicles even accounts for more than 70% of the total resistance. According to theoretical calculations, under certain conditions of power and energy, assuming that the resistance of the underwater vehicle is reduced by 10%, its cruising speed and range can be increased by about 3.57% at the same time. Therefore, the research on drag reduction technology can save a lot of energy and improve capacity utilization. At present, the research on drag reduction technology is mainly divided into non-smooth surface drag reduction, microbubble drag reduction, wall vibration drag reduction, polymer additive drag reduction and bionic jet drag reduction. Among them, non-smooth surface drag reduction has a good drag reduction effect through simulation research on the characteristics of some organisms, and it is green and environmentally friendly, with great research significance and value.

[0003] In recent years, studies have found that many biological surface structures are non-smooth. For example, the skin of sharks and dolphins is distributed with many rib-like scale structures. These groove structures can change the structure and velocity distribution of the turbulent layer on the skin surface of sharks when swimming. The groove drag reduction surface is inspired by the shark skin shield scales with excellent swimming ability. In addition, pits and convex hulls are also an important type of grooves, which are inspired by the pits or convex hull structures on the surface of soil animals. There are similar structures on the surfaces of fish scales and humpback whale fins. By studying the influence of pit and convex hull drag reduction elements on the drag reduction performance of pipelines, it is found that the highest drag reduction rate of pits and convex hulls can reach 33.57%. Inspired by this, the non-smooth biological structure characteristics of different biological surfaces are optimized and simulated, and then these simulated and optimized characteristics are put into the experiment, and comparative experiments are set to explore the drag reduction effect that these different biological characteristics can achieve. In order to solve the diversity of experimental characteristics, it is very important to design and invent a small, simple, economical experimental device that can measure the drag reduction effect of different groove shapes and pit and convex surfaces. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a fluid drag reduction effect testing device and method that realizes bionic surface structure transformation, which can be used to measure the friction between fluid and solid, and can evaluate the drag reduction effect of different groove shapes and pits and convex hulls.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A fluid drag reduction effect test device for realizing bionic surface structure transformation, the device comprising a water circulation system, a drag reduction effect test device, a surface structure transformation device and a bionic structure test plate;

[0007] The water circulation system comprises a test pipeline, and pipeline upper covers are arranged at both ends of the upper part of the test pipeline, and both ends of the bionic structure test plate are slidably connected between the pipeline upper covers;

[0008] The drag reduction effect test device includes a main control platform, a conversion switch, a timer, a support plate, a support frame, a pressure-controlled switch, a force transmission baffle, a magnet and an electromagnet; the electromagnet is integrated at the bottom of the main control platform, and the electromagnet is connected to the pipeline upper cover plate; the conversion switch and the timer are installed on the main control platform; one end of the support plate is fixedly connected to the main control platform, and the other end is fixedly installed on the pipeline upper cover plate through the support frame; the magnet is fixed on the end of the bionic structure test plate close to the electromagnet, the force transmission baffle is fixed on the end of the bionic structure test plate away from the electromagnet, and the surface structure transformation device is fixed on the bionic structure test plate and is located between the magnet and the force transmission baffle;

[0009] The pressure-controlled switch is fixed on a side of the pipeline upper cover plate close to the force transmission baffle;

[0010] The conversion switch is used to simultaneously control the demagnetization of the electromagnet and the timing of the timer, and the voltage-controlled switch is used to implement a signal for the timer to stop timing.

[0011] Further, the surface structure transformation device is a concave-convex transformation device, which includes a housing 1, a concave-convex telescopic rod, a concave-convex telescopic control console, a concave-convex telescopic rod control assembly, an annular support ring, an annular divergent spring, a circular magnetic particle-containing covering film, an upper annular roller and a lower annular roller;

[0012] The bottom of the shell protrudes outward and is fixed on the bionic structure test board. A plurality of circles of concave-convex telescopic rods are arranged inside the shell, and each concave-convex telescopic rod has a set of telescopic rod control components. The bottom end of each circle of concave-convex telescopic rods is fixedly connected to an annular support ring, and the annular support ring is made of magnetic material; the circular magnetic particle-containing covering film covers the surface of all annular support rings from the bottom, and a circle of annular divergent springs extending radially is installed on the periphery of the circular magnetic particle-containing covering film; one end of the annular divergent spring is fixed on the circular magnetic particle-containing covering film, and the other end is fixed on the bionic structure test board; an upper annular roller and a lower annular roller are respectively installed on the upper and lower surfaces of the circular magnetic particle-containing covering film and the corresponding positions of the circular opening at the bottom of the shell, so that the circular magnetic particle-containing covering film can be smoothly extended when the annular support ring extends inward or outward.

[0013] Further, the concave-convex telescopic rod control assembly includes a sleeve, a main gear, a left drive gear, a right drive gear, an upper bearing, a lower bearing, a high-precision motor 1 and a high-precision motor 2. The main gear is installed on the concave-convex telescopic rod through a threaded connection. A sleeve is installed on the upper and lower ends of the main gear respectively. The end of the sleeve is supported on the concave-convex telescopic control console. The upper bearing and the lower bearing are respectively sleeved on the sleeve to fix the main gear; the high-precision motor 1 and the high-precision motor 2 are respectively fixed on the concave-convex telescopic control console and are located on the left and right sides of the concave-convex telescopic rod. The left drive gear and the right drive gear are respectively connected to the high-precision motor 1 and the high-precision motor 2, and both are meshed with the main gear;

[0014] The left driving gear and the right driving gear rotate simultaneously and stably to drive the main gear to rotate, so that the concave and convex telescopic rod is extended and retracted through the action of the thread.

[0015] Furthermore, a concave-convex control panel is installed on the concave-convex telescopic control console, and a concave-convex USB access port and a concave-convex gear change button are integrated on the concave-convex control panel.

[0016] Further, the surface structure transformation device is a groove transformation device, which includes a second housing, a groove telescopic rod, a groove telescopic rod control assembly, a rectangular support sheet, a rectangular magnetic particle-containing covering film, a rectangular divergent spring, an upper rectangular roller, and a lower rectangular roller;

[0017] The bottom of the second shell protrudes outward and is fixed on the bionic structure test board. A plurality of rows of groove telescopic rods are arranged inside the second shell. Each groove telescopic rod has a set of groove telescopic rod control components. The lower end of each row of groove telescopic rods is fixedly connected to a rectangular support sheet, and the rectangular support sheet is made of magnetic material; the rectangular magnetic particle-containing covering film covers all rectangular support sheets from the bottom, and a circle of rectangular divergent springs extending radially is installed on the periphery of the rectangular magnetic particle-containing covering film; one end of the rectangular divergent spring is fixed on the rectangular magnetic particle-containing covering film, and the other end is fixed on the bionic structure test board; upper and lower surfaces of the rectangular magnetic particle-containing covering film and the corresponding positions of the rectangular opening at the bottom of the second shell are respectively installed with an upper rectangular roller and a lower rectangular roller, so that the rectangular magnetic particle-containing covering film can be smoothly extended as the rectangular support sheet extends inward or outward.

[0018] Furthermore, the groove telescopic rod control assembly and the concave-convex telescopic rod control assembly have the same structure and composition.

[0019] Furthermore, a slide groove is provided inside the pipeline upper cover plate, and a plurality of grooves are provided inside the slide groove, and the bionic structure test plate slides along the slide groove relative to the pipeline upper cover plate, and waterproof sealing is achieved through the grooves.

[0020] Furthermore, the water circulation system includes a large water tank, a main pipeline, an electromagnetic flowmeter, a test pipeline, an auxiliary pipeline, a rectifier grid 1, a rectifier grid 2, a small water tank, a power pipeline, a return pipeline, a water pump, a frequency converter and a motor; the large water tank, the main pipeline, the rectifier grid 2, the test pipeline, the rectifier grid 1, the auxiliary pipeline, the small water tank and the return pipeline are connected in sequence, one end of the power pipeline is connected to the large water tank, and the other end is connected to the water outlet of the water pump, and one end of the return pipeline is connected to the water inlet of the water pump; the water pump is driven by the motor, and the flow rate is adjusted by the frequency converter.

[0021] A method for testing the fluid drag reduction effect by realizing bionic surface structure transformation is implemented based on the above-mentioned device, and the method specifically comprises the following steps:

[0022] (1) The bottom of the surface structure transformation device is set to form a smooth plane, and the conversion switch is turned to the center position. At this time, the electromagnet is energized to generate magnetism and attract the magnet. The bionic structure test board is pressed against the electromagnet under the action of magnetic force;

[0023] (2) The conversion switch is turned from the center to the right. At this time, the electromagnet is quickly demagnetized, the timer starts timing, and the bionic structure test plate moves to the right under the action of fluid friction until the force transmission baffle touches the pressure-controlled switch. The pressure-controlled switch transmits a closing signal to the timer. At this time, the time is recorded as t1;

[0024] (3) resetting the surface structure changing device to another structure and performing the test according to the same process, and the timer is set to t2 at the end of the test;

[0025] (4) The drag reduction effect is determined based on t=t2-t1. The larger t is, the better the drag reduction effect is.

[0026] The beneficial effects of the present invention are as follows:

[0027] (1) The present invention can realize drag reduction tests on pit-convex hull models with different depths and curvatures and different groove depths and groove structure model transformations, and can simultaneously perform combined tests on different pit-convex hull and groove models, and can also perform drag reduction tests on a single pit-convex hull or groove model to meet test needs.

[0028] (2) The present invention realizes measurement through an electromagnet and a timer, and finally reflects the drag reduction effect through time. The method is simple and clear, easy to operate, and can intuitively reflect the drag reduction effect of the surface of the test plate with different structures.

[0029] (3) In the testing process of the present invention, water is used as the fluid medium, and water is recycled through the power supply device and the mainstream circulation pipeline, which saves resources and is environmentally friendly and pollution-free;

[0030] (4) The present invention has low cost, small footprint, low noise, simple structure, convenient data collection, and can effectively and intuitively reflect the drag reduction effect of various models, and is quick and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the test device structure;

[0032] Figure 2 is a schematic diagram of a concave-convex hull transformation device;

[0033] Figure 3 is a schematic diagram of a concave-convex telescopic rod control assembly;

[0034] Figure 4 A magnified view of the annular divergent spring;

[0035] Figure 5 is a cross-sectional view of a groove conversion device;

[0036] Figure 6 It is a schematic diagram of the bottom structure of the annular support ring and the rectangular support piece;

[0037] Figure 7 A magnified view of the connection between the bionic structure test plate test and the pipeline upper cover plate; DETAILED DESCRIPTION

[0038] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] like Figure 1 As shown, the fluid drag reduction effect testing device for realizing bionic surface structure transformation of the present invention comprises a water circulation system, a convex hull and concave pit transformation device, a groove transformation device, a drag reduction effect testing device and a bionic structure test board 23.

[0040] The water circulation system includes a main test pipeline and a power supply device. The power supply device includes a water pump 14, a motor 13, and a frequency converter 12. The mainstream test pipeline includes a large water tank 2, a main pipeline 27, an electromagnetic flowmeter 28, a test pipeline 20, a secondary pipeline 17, a rectifier grid 1 18, a rectifier grid 2 26, a small water tank 16, a power pipeline 3, and a return pipeline 15. The drag reduction effect test device includes a main control platform 4, a conversion switch 5, a timer 6, a support frame 7, a support plate 8, a pressure-controlled switch 21, a force transmission baffle 22, a magnet 24, and an electromagnet 25. The concave-convex conversion device 9 includes a concave-convex telescopic rod 9-1, a concave-convex telescopic control console 9-2, a concave-convex USB access port 9-3, a concave-convex gear change button 9-4, a concave-convex control panel 9-5, an annular support ring 9-6, an inner annular roller 9-7, an outer annular roller 9-8, a circular magnetic particle-containing covering film 9-9, an annular divergent spring 9-10, a shell 9-11 and an internal telescopic rod control assembly.

[0041] The groove changing device 11 includes a groove telescopic rod 11-1, a groove telescopic control console 11-2, a groove USB access port 11-3, a groove gear change button 11-4, a groove control panel 11-5, a rectangular support sheet 11-6, an inner rectangular roller 11-7, an outer rectangular roller 11-8, a rectangular magnetic particle covering film 11-9, a rectangular divergent spring 11-10, a second shell 11-11, and an internal telescopic rod control assembly.

[0042] The mainstream test pipeline includes a stopcock 1, a large water tank 2, a main pipeline 27, an electromagnetic flowmeter 28, a test pipeline 20, a secondary pipeline 17, a rectifier grid 1 18, a rectifier grid 2 28, a small water tank 16, a power pipeline 3 and a return pipeline 15.

[0043] Combination Figure 1 As shown, in the water circulation system, the output shaft of the motor 13 is connected to the water pump 14 through a coupling. The motor 13 is a YVP series variable frequency speed regulating three-phase asynchronous motor, and the speed is controlled by the inverter 12. The water inlet of the water pump 14 is connected to the small water tank 16 through the return pipe 15, and the water outlet of the water pump 14 is connected to the large water tank 2 through the power pipe 3. By adjusting the inverter 14, the flow rate of the mainstream pipe 27 can be controlled, thereby controlling the flow rate of the mainstream field.

[0044] The specific structure of the mainstream test pipeline is as follows: the large water tank 2 is placed on the far left, with a cock 1 on it, the power pipeline 3 is connected to the right side above the large water tank 2, and the power pipeline 3 is connected to the liquid outlet of the water pump 14 of the power supply device, and the power pipeline 3 is fixed to the support plate 8 through the fixing plate 10, the liquid inlet of the water pump 14 is connected to the return pipeline 15, and the other end of the return pipeline 15 is connected to the small water tank 16, the bottom right side of the large water tank 2 is connected to the main pipeline 27, and the electromagnetic flowmeter 28 is integrated on the main pipeline 27, and the other end of the main pipeline 27 is connected to the test pipeline 20, and the inlet and outlet of the test pipeline 20 are respectively installed with the rectifier grid 28 and the rectifier grid 18. The outlet end of the test pipeline 20 is connected to the small water tank 16 through the auxiliary pipeline 17, and the small water tank 16 is connected to the liquid inlet of the water pump 14 through the return pipeline 15, forming a water circulation system. During the test, the entire device is filled with liquid by opening the stopcock 1, the water flow power provided by the control power supply device is controlled, and the water flow velocity condition of the test pipe 20 at this time is observed through the electromagnetic flowmeter 28.

[0045] Combination Figure 2 , Figure 3 , Figure 4 , Figure 6The specific structure of the concave-convex package conversion device 9 is as follows: the bottom of the housing 9-10 protrudes outwards and is fixed on the bionic structure test board 23, and a plurality of circles of concave-convex telescopic rods 9-1 are arranged inside the housing. The concave-convex telescopic rod 9-1 is connected to the concave-convex telescopic rod control component inside the housing through the concave-convex telescopic console 9-2, and the telescopic rod control component is as follows: the concave-convex telescopic rod 9-1 is connected to the main gear 9-14 through a thread. A sleeve 9-21 is fixed on the axial surface of the main gear 9-14 by welding, and an upper bearing 9-15 and a lower bearing 9-20 are respectively installed on the upper and lower sides of the sleeve 9-21. The bearing types are all selected as tapered roller bearings. The upper bearing 9-15 and the lower bearing 9-20 fix the main gear 9-14. A left drive gear 9-23 and a right drive gear 9-18 are respectively installed on both sides of the main gear 9-14. The left drive gear 9-23 is connected to the high-precision motor 1 9-12 through the left drive shaft 9-22, and the high-precision motor 1 9-12 is connected to the concave-convex telescopic console 9-2 through the motor fixing rod 1 9-13. The right drive gear 9-18 is connected to the high-precision motor 2 9-17 through the right drive shaft 9-19, and the high-precision motor 2 9-17 is connected to the concave-convex telescopic console 9-2 through the motor fixing rod 2 9-16. The left driving gear 9-23 and the right driving gear 9-18 rotate simultaneously and stably drive the main gear 9-14 to rotate, thereby causing the concave-convex telescopic rod 9-1 to telescope through the action of the thread. The above is the internal telescopic rod control component. The concave-convex telescopic console 9-2 is installed with a concave-convex control board 9-5, and the concave-convex control board 9-5 is integrated with a concave-convex USB access port 9-3 and a concave-convex gear change button 9-4. The bottom of the telescopic rod 9-1 is welded and fixed to the annular support ring 9-6, and the annular support ring 9-6 is made of magnetic material. The surface of the annular support ring 9-6 is covered with a circular magnetic particle-containing covering film 9-9, and a circle of divergent springs 9-10 are integrated on the periphery of the circular magnetic particle-containing covering film 9-9. The divergent springs 9-10 are sealed and connected to the inside of the bionic structure test plate 23. When the annular support ring 9-6 forms a supporting structure, the circular magnetic particle-containing covering film 9-9 changes accordingly, and at the same time drives the annular divergent springs 9-10 to expand and contract, so that the circular magnetic particle-containing covering film 9-9 completes the coating of the annular support ring 9-6. An upper annular roller 9-7 and a lower annular roller 9-8 are respectively installed above and below the corresponding positions of the circular magnetic particle-containing covering film 9-9 and the bottom circular opening, and their function is to play a role in smooth extension when the circular magnetic particle-containing covering film 9-9 extends inward or outward with the annular support ring 9-6.

[0046] Concave-convex hull model control method: When it is necessary to test the drag reduction effect of a certain convex hull or pit model, firstly, the concave-convex hull model is modeled by computer simulation modeling, and several convex-concave pit models are set and imported into the concave-convex control board 9-5 through the concave-convex USB access port 9-3. Each model corresponds to a concave-convex gear change button 9-4. Press the concave-convex gear change button 9-4 corresponding to the required concave-convex hull model, and the concave-convex control board 9-5 receives the signal and controls the high-precision motor 1 9-12 and the high-precision motor 2 9-17 to operate through the concave-convex telescopic control console 9-2 at the same time. The high-precision motor 1 9-12 and the high-precision motor 2 9-17 control the left drive gear 9-23 and the right drive gear 9-18 to rotate in the same direction through the left drive shaft 9-22 and the right drive shaft 9-19 respectively, so that the main gear 9-14 connected thereto operates, thereby driving the concave-convex telescopic rod 9-1 to telescope through the thread. And the algorithm is used to control the number of revolutions of the high-precision motor 1 9-12 and the high-precision motor 2 9-17 to realize the change of the telescopic amount of the telescopic rod 9-1, and the concave-convex telescopic rod 9-1 is welded on the annular support ring 9-6, and a plurality of concave-convex telescopic rods 9-1 are welded on each annular support ring 9-6, which adopt the same control so that the annular support ring 9-6 can be stably lifted and lowered. The bottom of the entire concave-convex hull conversion device is composed of a plurality of dense annular support rings 9-6. By quantitatively controlling the telescopic amount of the concave-convex telescopic rod 9-1 on each annular support ring 9-6, the telescopic amount of each annular support ring 9-6 is changed, such as the outward telescopic amount of the annular support ring 9-6 of the outermost circle is the smallest, and the telescopic amount of the annular support ring 9-6 of the innermost circle is the largest. The middle plurality of annular support rings 9-6 evenly form a stepped structure to connect the outermost circle and the innermost circle, forming a convex hull support structure we need. Similarly, another concave-convex hull support structure can be formed. Finally, the circular magnetic particle-containing covering film 9-9 on the surface of the pit or convex support structure formed by several annular support rings 9-6 is extended and covered on the support structure and adhered to the surface of the support structure through magnetic adsorption and water pressure to achieve surface sealing and smooth connection of the support structure formed by the annular support rings 9-6, forming a convex or pit structure for test.

[0047] Combination Figure 5 , Figure 6The specific structure of the groove conversion device 11 shown is as follows: the bottom of the second housing 11-11 protrudes outward and is fixed on the bionic structure test board 23, and multiple rows of groove telescopic rods are arranged inside it, and the groove USB access port 11-3 and the groove gear change button 11-4 are integrated on the groove control panel 11-5, and the groove control panel 11-5 is installed on the groove telescopic console 11-2. The groove telescopic rod 11-1 is connected to the groove telescopic rod control assembly inside it through the groove telescopic console 11-2, and the bottom is welded to the rectangular support sheet 11-6, and the surface of the groove telescopic rod 11-1 is also embedded with threads. The installation of the internal telescopic rod assembly is the same as the installation method of the concave-convex telescopic rod 9-1 in the concave-convex package conversion device 9. The surface of the rectangular support sheet 11-6 is covered with a rectangular magnetic particle covering film 11-9, and a rectangular divergent spring 11-10 is embedded and installed on the periphery of the rectangular magnetic particle covering film 11-9. When the rectangular support sheet 11-6 forms a supporting structure, the rectangular magnetic particle covering film 11-9 is extended, and at the same time, the rectangular divergent spring 11-10 is driven to expand and contract, so that the rectangular magnetic particle covering film 11-9 completes the coating of the formed supporting structure. The rectangular magnetic particle covering film 11-9 is also connected to the inside of the bionic structure test plate 23 by sliding sealing. An upper rectangular roller 11-6 and a lower rectangular roller 11-8 are respectively installed above and below the corresponding positions of the rectangular magnetic particle covering film 11-9 and the bottom rectangular opening, and their function is to play a role in smooth extension when the rectangular magnetic particle covering film 11-9 extends inward or outward with the rectangular support sheet 11-6. The main structure of the groove transformation device 11 is similar to that of the concave-convex hull transformation device 9, except that the bottom is designed to be a rectangular support piece 11-6 similar to the shape of a rectangular slice, but is also made of magnetic material. The rectangular support piece 11-6 is controlled by controlling the groove telescopic rod 11-1, and the groove structure is formed by changing the relative position of the rectangular support piece 11-6. The required test groove is formed by covering the rectangular magnetic particle covering film 11-9.

[0048] Groove model control method: Its control principle is roughly similar to that of the concave-convex hull model control method, the main difference lies in the different support structure at the bottom. Figure 5 , Figure 6, groove modeling is performed through simulation modeling, and several groove modes are set and imported into the groove control panel 11-5 through the groove USB access port 11-3. The groove modeling can be mainly designed into a trapezoidal shape and a triangle, etc. By pressing the corresponding groove gear change button 11-4 to start the groove telescopic control console 11-2, the internal telescopic control component controls the telescopic amount of the groove telescopic rod 11-1. The control method of the telescopic control component is the same principle as that of the concave and convex telescopic rod 9-1. The rectangular support sheet 11-6 is in the form of a sheet, similar to a cube slice, and each sheet is a rectangular support sheet 11-6, and each sheet is fitted together. A number of telescopic rods are installed on each rectangular support sheet 11-6, which operate simultaneously to stably control the telescopic amount of each rectangular support sheet 11-6 relative to the bionic structure test plate 23. The bottom of the entire groove transformation device 11 is designed to be composed of dense rectangular support sheets 11-6. By controlling the telescopic amount of the telescopic rods of different rectangular support sheets 11-6, a number of rectangular support sheets 11-6 form a gradient support structure. For example, the number of rectangular support sheets 11-6 in the middle have the highest and equal outward telescopic amount, and the rectangular support sheets 11-6 on both sides have the smallest telescopic amount. The remaining rectangular support sheets 11-6 are evenly connected to the rectangular support sheets 11-6 on both sides and the middle rectangular support sheet 11-6 in turn to form a trapezoidal groove support structure. Figure 5 Similarly, a V-shaped groove support structure can be formed, and finally the rectangular magnetic particle-containing covering film 11-9 is extended along with the support structure, covers the gradient support structure, and adheres to the surface of the support structure through magnetic adsorption and water pressure, so as to achieve a sealing and smooth transition of the surface of the gradient support structure to form the required groove test structure.

[0049] Combination Figure 1 The specific structure of the drag reduction effect test device: the conversion switch 5 and the timer 6 are integrated on the main control platform 4. The conversion switch 5 has three gears. When it is on the left side, the electromagnet and the timer are not working, when it is in the middle, the electromagnet is energized, and when it is on the right side, the timer is timing. The bottom of the main control platform 4 is equipped with an electromagnet 25 and connected to the pipeline upper cover 19 and fixed on its surface through waterproof sealant. When it is not started, it fits with the magnet 24, and the magnet 24 is installed on the leftmost end of the bionic structure test board. The left end of the support plate 8 is welded on the main control platform 4 and fixed by the support rod 7. The lower right end of the support plate 8 is fixed on the pipeline upper cover 19, and a pressure-controlled switch 21 is installed on its left side. A force transmission baffle 22 is installed at the tail end of the bionic structure test board. When the drag reduction effect is tested, the conversion switch 5 is used to simultaneously control the rapid demagnetization of the electromagnet 25 and the timing of the timer 6, and then the pressure-controlled switch 21 is used to realize the signal of the timer to stop timing, and the drag reduction effect is reflected by time.

[0050] Drag reduction effect test method: combined Figure 1When the flow rate is constant, the annular support structure of the pit conversion device 9 and the gradient support structure of the groove conversion device 11 are set to form a smooth plane with the bottom of the bionic structure test board 23, and the conversion switch 5 is turned to the center position. At this time, the electromagnet 25 is energized to generate magnetism and attracts the magnet 24. The bionic structure test board 23 is subjected to the magnetic force and leans against the leftmost end. The conversion switch 5 is turned from the center to the right. At this time, the electromagnet 25 is quickly demagnetized, and the timer 6 starts timing. The bionic structure test board 23 moves to the right under the action of fluid friction, passes through the force transmission baffle 22 until it touches the pressure-controlled switch 21. The pressure-controlled switch 21 transmits a closing signal to the timer 6. At this time, the time is recorded as t1. The annular support structure of the pit conversion device 9 and the gradient support structure of the groove conversion device 11 are retested to set other structures, and the test is carried out according to the same process. The timer 6 counts as t2 after the test. Let t=t2-t1, the larger t is, the better the drag reduction effect is.

[0051] Combination Figure 7 The device is sealed. The connection and expansion part between the pipeline upper cover plate 19 and the bionic structure test plate 23 is designed to be equipped with a stepped sealing structure with regular geometric shapes. The stepped sealing structure has a longitudinal rectangular groove structure. The stepped sealing structure is arranged around the sliding area of ​​the two to form a sealing groove. When the bionic structure test plate 23 slides, a series of regular throttling gaps and expansion cavities are formed, and a step-by-step throttling effect is generated through the viscous friction of the medium and the conversion of energy, thereby achieving sealing. Similarly, combined with Figure 4 The connecting and extending part between the circular magnetic particle-containing covering film 9-9 and the bionic structure test plate 23 is also designed as a stepped sealing structure with a regular geometric shape. In addition, the connecting and extending part between the rectangular magnetic particle-containing covering film 11-9 and the bionic structure test plate 23 is also of the same structure.

[0052] The working principle of the whole device: when the device is used, first open the stopcock 1 to inject liquid into the large water tank 2, so that the entire mainstream circulation pipeline is filled with liquid, then close the stopcock 1 and adjust the frequency converter 12 in the power supply device to control the speed of the motor 13, realize the control of the water pump operation power, and then complete the control of the flow rate of the mainstream test pipeline, and read it through the electromagnetic flowmeter 28 to set different flow rate conditions in the test pipeline 20. Then, through the concave-convex hull model control method and the groove model control method, the concave-convex hull transformation device 9 and the groove transformation device 11 are transformed, and the test concave-convex hull and groove structure of the bionic structure test plate 23 are controlled. Finally, the drag reduction effect test method is used to evaluate the drag reduction effect of various test concave-convex hulls and grooves.

[0053] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A fluid drag reduction effect testing device for realizing bionic surface structure transformation, characterized in that: The device includes a water circulation system, a drag reduction effect testing device, a surface structure transformation device and a bionic structure test board; The water circulation system comprises a test pipeline, and pipeline upper covers are arranged at both ends of the upper part of the test pipeline, and both ends of the bionic structure test plate are slidably connected between the pipeline upper covers; The drag reduction effect test device includes a main control platform, a conversion switch, a timer, a support plate, a support frame, a pressure-controlled switch, a force transmission baffle, a magnet and an electromagnet; the electromagnet is integrated at the bottom of the main control platform, and the electromagnet is connected to the pipeline upper cover plate; the conversion switch and the timer are installed on the main control platform; one end of the support plate is fixedly connected to the main control platform, and the other end is fixedly installed on the pipeline upper cover plate through the support frame; the magnet is fixed on the end of the bionic structure test plate close to the electromagnet, the force transmission baffle is fixed on the end of the bionic structure test plate away from the electromagnet, and the surface structure transformation device is fixed on the bionic structure test plate and is located between the magnet and the force transmission baffle; The pressure-controlled switch is fixed on a side of the pipeline upper cover plate close to the force transmission baffle; The conversion switch is used to control the demagnetization of the electromagnet and the timing of the timer at the same time, and the voltage-controlled switch is used to realize the signal for the timer to stop timing; The surface structure transformation device is a concave-convex transformation device, which includes a housing 1, a concave-convex telescopic rod, a concave-convex telescopic control console, a concave-convex telescopic rod control assembly, an annular support ring, an annular divergent spring, a circular magnetic particle-containing covering film, an upper annular roller and a lower annular roller; The bottom of the shell protrudes outward and is fixed on the bionic structure test board, and multiple circles of concave-convex telescopic rods are arranged inside the shell, each of which has a set of telescopic rod control components, and the bottom end of each circle of concave-convex telescopic rods is fixedly connected to an annular support ring, and the annular support ring is made of magnetic material; the circular magnetic particle-containing covering film covers the surface of all annular support rings from the bottom, and a circle of annular divergent springs extending radially is installed on the periphery of the circular magnetic particle-containing covering film; one end of the annular divergent spring is fixed on the circular magnetic particle-containing covering film, and the other end is fixed on the bionic structure test board; the upper and lower surfaces of the circular magnetic particle-containing covering film and the circular opening at the bottom of the shell are respectively installed with an upper annular roller and a lower annular roller, so that the circular magnetic particle-containing covering film can be smoothly extended when the annular support ring extends inward or outward; The concave-convex telescopic rod control assembly includes a sleeve, a main gear, a left driving gear, a right driving gear, an upper bearing, a lower bearing, a high-precision motor 1 and a high-precision motor 2. The main gear is installed on the concave-convex telescopic rod through a threaded connection. A sleeve is installed on the upper and lower ends of the main gear respectively. The end of the sleeve is supported on the concave-convex telescopic control console. The upper bearing and the lower bearing are respectively sleeved on the sleeve to fix the main gear; the high-precision motor 1 and the high-precision motor 2 are respectively fixed on the concave-convex telescopic control console and are located on the left and right sides of the concave-convex telescopic rod. The left driving gear and the right driving gear are respectively connected to the high-precision motor 1 and the high-precision motor 2, and both are meshed with the main gear; The left drive gear and the right drive gear rotate simultaneously and stably drive the main gear to rotate, thereby causing the concave and convex telescopic rod to extend and retract through the action of the threads; The surface structure transformation device is a groove transformation device, which includes a second housing, a groove telescopic rod, a groove telescopic rod control assembly, a rectangular support sheet, a rectangular magnetic particle-containing covering film, a rectangular divergent spring, an upper rectangular roller, and a lower rectangular roller; The bottom of the second shell protrudes outward and is fixed on the bionic structure test board. A plurality of rows of groove telescopic rods are arranged inside the second shell. Each groove telescopic rod has a set of groove telescopic rod control components. The lower end of each row of groove telescopic rods is fixedly connected to a rectangular support sheet, and the rectangular support sheet is made of magnetic material; the rectangular magnetic particle-containing covering film covers all rectangular support sheets from the bottom, and a circle of rectangular divergent springs extending radially is installed on the periphery of the rectangular magnetic particle-containing covering film; one end of the rectangular divergent spring is fixed on the rectangular magnetic particle-containing covering film, and the other end is fixed on the bionic structure test board; upper and lower surfaces of the rectangular magnetic particle-containing covering film and the corresponding positions of the rectangular opening at the bottom of the second shell are respectively installed with an upper rectangular roller and a lower rectangular roller, so that the rectangular magnetic particle-containing covering film can be smoothly extended as the rectangular support sheet extends inward or outward.

2. The fluid drag reduction effect testing device for realizing bionic surface structure transformation according to claim 1, characterized in that: A concave-convex control panel is installed on the concave-convex telescopic control console, and a concave-convex USB access port and a concave-convex gear position change button are integrated on the concave-convex control panel.

3. The fluid drag reduction effect testing device for realizing bionic surface structure transformation according to claim 2, characterized in that: The groove telescopic rod control assembly has the same structure and composition as the concave-convex telescopic rod control assembly.

4. The fluid drag reduction effect testing device for realizing bionic surface structure transformation according to claim 1, characterized in that: A slide groove is provided inside the pipeline upper cover plate, and a plurality of grooves are arranged inside the slide groove. The bionic structure test plate slides along the slide groove relative to the pipeline upper cover plate, and waterproof sealing is achieved through the grooves.

5. The fluid drag reduction effect testing device for realizing bionic surface structure transformation according to claim 1, characterized in that: The water circulation system comprises a large water tank, a main pipeline, an electromagnetic flowmeter, a test pipeline, an auxiliary pipeline, a rectifier grid 1, a rectifier grid 2, a small water tank, a power pipeline, a return pipeline, a water pump, a frequency converter and a motor; the large water tank, the main pipeline, the rectifier grid 2, the test pipeline, the rectifier grid 1, the auxiliary pipeline, the small water tank and the return pipeline are connected in sequence, one end of the power pipeline is connected to the large water tank, and the other end is connected to the water outlet of the water pump, and one end of the return pipeline is connected to the water inlet of the water pump; the water pump is driven by the motor, and the flow rate is adjusted by the frequency converter.

6. A method for testing the fluid drag reduction effect by realizing bionic surface structure transformation, characterized in that: The method is implemented based on the device described in claim 1, and the method specifically comprises the following steps: (1) The bottom of the surface structure transformation device is set to form a smooth plane, and the conversion switch is turned to the center position. At this time, the electromagnet is energized to generate magnetism and attract the magnet. The bionic structure test board is pressed against the electromagnet under the action of the magnetic force; (2) The conversion switch is turned from the center to the right. At this time, the electromagnet is quickly demagnetized, the timer starts timing, and the bionic structure test plate moves to the right under the action of fluid friction until the force transmission baffle touches the pressure-controlled switch. The pressure-controlled switch transmits a closing signal to the timer. At this time, the time is recorded as t1; (3) resetting the surface structure changing device to another structure and performing the test according to the same process. When the test is finished, the timer is set to t2; (4) The drag reduction effect is determined based on t=t2-t1. The larger t is, the better the drag reduction effect is.

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