A coupling drag reduction test device with variable bionic structure

Abstract

The present invention discloses a coupling drag reduction test device of a variable bionic structure, which includes a mainstream supply mechanism, a two-phase jet supply mechanism, a first group of flow control mechanisms, a second group of flow control mechanisms, a bionic structure test plate, and a rectangular test pipe; the mainstream supply mechanism, the first group of flow control mechanisms, and the rectangular test pipe are connected in sequence; the second group of flow control mechanisms, the bionic structure test plate, and the rectangular test pipe are connected in sequence; the bionic structure test plate includes a bionic two-phase jet test plate, a bionic groove test plate, and two moving devices; the bionic two-phase jet test plate is connected to the bionic groove test plate, and a moving device is connected to both sides of the two respectively, and the moving device moves to drive the jet hole on the bionic two-phase jet test plate to deform, and the groove on the bionic groove test plate to deform, thereby realizing coupling drag reduction. The present invention can easily change the size, direction, concave and convex hull, groove shape of the two-phase jet and the optimal drag reduction working conditions under different bionic structures.

Description

Technical Field

[0001] The invention relates to the field of surface drag reduction, and in particular to a coupling drag reduction test device with a variable bionic structure. Background Art

[0002] With the increasing consumption of non-renewable energy and the gradual improvement of human environmental awareness, energy conservation and low-carbon environmental protection are increasingly being highly valued by people all over the world. The resistance of a spacecraft mainly includes friction resistance and shape resistance. According to theoretical analysis and experimental results, when a spacecraft sails at a depth of more than one-third of its body length from the water surface, its friction resistance accounts for 60%-80% of the total resistance. Reducing the friction resistance generated during the movement process has a significant effect on improving the efficiency of ship transportation, saving energy, reducing greenhouse gas emissions, and reducing pollution. Therefore, the study of drag reduction technology is of great significance to ships and other spacecraft.

[0003] Compared with traditional drag reduction technology, scientists have observed in recent years that the surface structures of many organisms such as sharks, pangolins and dung beetles are non-smooth. In the long-term evolution process, the beautiful macroscopic and microscopic structures of these animals are adapted to the living environment and habits of the organisms, and have excellent drag reduction, friction reduction, anti-adhesion and anti-wear properties. At present, bionic jet, bionic groove and bionic pit drag reduction technology are hot topics in the field of fluid drag reduction at home and abroad. This drag reduction method uses the above three drag reduction technologies for testing and research.

[0004] Traditional drag reduction test methods are mostly carried out in water tunnel environments, and the test equipment used is expensive, bulky, difficult to maintain, noisy, and difficult to control test conditions, which has certain limitations in all aspects of the test conditions. Therefore, it is particularly important to provide a convenient and efficient drag reduction test method that uses a simple test device structure and low cost. Summary of the invention

[0005] The present invention aims at reducing the surface drag of underwater navigation devices and solving the problem of complicated current fluid mechanics drag reduction tests, and provides a coupling drag reduction test device with convenient and efficient, multiple test functions and a variable bionic structure.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A coupling drag reduction test device with a variable bionic structure, the device comprising a mainstream supply mechanism, a two-phase jet supply mechanism, a first group of flow control mechanisms, a second group of flow control mechanisms, a bionic structure test plate and a rectangular test pipe;

[0008] The liquid outlet of the mainstream supply mechanism is connected to the liquid inlet of the first group of flow control mechanisms, and the liquid outlet of the first group of flow control mechanisms is connected to the liquid inlet of the rectangular test pipe; the liquid outlet of the two-phase jet supply mechanism is connected to the liquid inlet of the second group of flow control mechanisms, and the liquid outlet of the second group of flow control mechanisms is embedded in the bionic structure test board; the bionic structure test board is fixed on the top of the rectangular test pipe;

[0009] The bionic structure test board includes a bionic two-phase jet test board, a bionic groove test board, and two moving devices; one end of the bionic two-phase jet test board is connected to one end of the bionic groove test board, and the other end of the bionic two-phase jet test board and the other end of the bionic groove test board are respectively connected to a moving device, and the movement of the moving device drives the deformation of the jet hole on the bionic two-phase jet test board and the deformation of the groove on the bionic groove test board, thereby realizing coupled drag reduction.

[0010] Furthermore, the mainstream supply mechanism includes a mainstream inverter, a mainstream motor, a mainstream water pump, and a water tank. The power output end of the mainstream inverter is connected to the power input end of the mainstream motor, the power output end of the mainstream motor is connected to the power input end of the mainstream water pump, the liquid inlet of the mainstream water pump is connected to the water tank through an inlet pipe, and the liquid outlet of the mainstream water pump is connected to the liquid inlet of the first group of flow control mechanisms through an outlet pipe; the speed of the mainstream motor is adjusted by the mainstream inverter, and the mainstream motor drives the mainstream water pump to pump water out of the water tank and into the first group of flow control mechanisms.

[0011] Further, the two-phase jet supply mechanism includes a liquid jet supply mechanism, a gas jet supply mechanism, a two-phase jet conversion device and a jet box; the liquid jet supply mechanism includes a liquid jet frequency converter, a liquid jet motor, and a jet water pump; the gas jet supply mechanism includes a gas jet frequency converter, a gas jet motor, and a jet air pump; the jet box includes a liquid jet inner cavity, a gas jet inner cavity and a conversion device placement cavity that are isolated from each other;

[0012] The power output end of the liquid jet frequency converter is connected to the power input end of the liquid jet motor, the power output end of the liquid jet motor is connected to the power input end of the jet water pump, the liquid inlet of the jet water pump is connected to the water tank through the water inlet pipe, and the liquid outlet of the jet water pump is sealed and connected to the liquid jet inner cavity through the water outlet pipe;

[0013] The power output end of the gas jet frequency converter is connected to the power input end of the gas jet motor, the power output end of the gas jet motor is connected to the power input end of the jet air pump, and the air outlet of the jet air pump is sealed and connected to the gas jet inner cavity through an air guide pipe;

[0014] The two-phase jet conversion device is installed in the conversion device placement cavity;

[0015] The two-phase jet conversion device is composed of multiple groups, each group includes bolts, a DC motor, a DC power supply, a shift switch, a driving gear, a driven gear, and two hoses. The two-phase jet conversion device is rotatably connected to the jet box through bolts, the DC motor is connected to the DC power supply and the shift switch through wires, the driving gear is connected to the output shaft of the DC motor, and the driven gear is connected to the bolts; the two hoses are arranged on the driven gear, and one end of one of the hoses is connected to the liquid jet cavity, and the other end is connected to the second group of flow control components; one end of the other hose is connected to the gas jet cavity, and the other end is connected to the second group of flow control components;

[0016] The DC motor is powered by a DC power supply, and the shift switch controls the forward and reverse rotation of the DC motor. The output shaft of the DC motor drives the driving gear, and the driving gear drives the driven gear, so that the rubber hose of the gas jet and the liquid jet rotates degrees to achieve two-phase jet conversion and simulate different working conditions.

[0017] Further, the first group of flow control mechanisms includes a mainstream jet tube, a mainstream electric ball valve and a mainstream flow meter, the mainstream jet tube integrates the mainstream electric ball valve and the mainstream flow meter, the liquid inlet of the mainstream jet tube is connected to the liquid outlet of the mainstream water pump of the mainstream supply mechanism, and the liquid outlet of the mainstream jet tube is connected to the liquid inlet of the rectangular test pipe;

[0018] The second group of flow control components is composed of multiple groups, each group includes a first jet tube, a jet electric ball valve, a jet flowmeter and a second jet tube. The mortise and tenon of the upper liquid inlet of the first jet tube fits with the liquid outlet of the rubber hose of the two-phase jet supply mechanism, and the first jet tube integrates the jet electric ball valve and the jet flowmeter; the upper liquid inlet of the second jet tube is adhered to the lower liquid outlet of the first jet tube, and the lower liquid outlet of the second jet tube is embedded in the jet hole of the bionic structure test plate.

[0019] Furthermore, the moving device in the bionic structure test board includes a bolt roller bearing, a guide rail, and a mounting plate, wherein the bolt roller bearing is fastened to the top of the rectangular test pipe, the guide rail is fixedly connected to the mounting plate, and the mounting plate is spliced ​​to the bionic two-phase jet test board;

[0020] The bionic two-phase jet test plate comprises a plurality of connecting rods, a permanent magnet, an electromagnet, a sealing plate, a first test plate and a circular rubber surface layer, wherein a permanent magnet is arranged inside the connecting rod, the bottom of the permanent magnet is adhered to the circular rubber surface, the electromagnet is pressed into the sealing plate by interference fit, and every four connecting rods are connected by a rotating shaft to form a jet hole, and each jet hole corresponds to a second group of flow control components; the side edge of the test plate is spliced ​​to the bionic groove test plate through a dovetail groove, and a step seal is formed between the sealing plate and the test plate;

[0021] The bionic groove test plate comprises a plurality of bionic gill cleft rods, a second test plate, a support plate, and a sealing rubber plate. The second test plate and the support plate are respectively connected by hinges, the bionic gill cleft rods are fixedly connected to the second test plate and the support plate, the sealing rubber plate is adhered to the edge of the support plate by an adhesive, and the side edge of the bionic groove test plate is spliced ​​to another moving device by a dovetail groove;

[0022] In the bionic two-phase jet test plate, every four connecting rods form a jet hole, and each jet hole is embedded in a lower end liquid outlet of the second jet tube. The bionic two-phase jet test plate is moved by a moving device, and the jet hole changes the size and direction of the diamond-shaped jet hole due to the change of the position of its four connecting rods; the power supply of the electromagnet is turned on, and the magnetic pole and magnetic force of the electromagnet are changed by adjusting the current direction and size of the electromagnet to attract or repel the permanent magnet, because the bottom of the permanent magnet adheres to the circular rubber surface, thereby realizing the transformation of the bionic pit convex hull and adjusting the diameter and depth of the pit convex hull;

[0023] In the bionic groove test plate, pairs of second test plates form a bionic groove structure, and the arrangement of the bionic gill cleft rods is the structure of shark gill clefts. The bionic groove test plate is moved by a moving device, and the pairs of second test plates are contracted or extended, thereby changing the width and depth of the bionic groove structure and the opening and closing of the bionic gill cleft structure.

[0024] Furthermore, the rectangular test pipe includes a honeycomb, a damping net, a supporting device, a reflux channel and a plurality of speed measuring devices; the liquid inlet of the rectangular test pipe is connected with the liquid outlet of the mainstream jet tube of the first group of flow control mechanisms, the liquid inlet is installed with a honeycomb and a damping net, the liquid outlet of the rectangular test pipe is connected with the liquid inlet of the reflux channel, the liquid outlet of the reflux channel is connected with the water tank of the mainstream supply mechanism, and the supporting device is fixedly connected to both sides of the rectangular test pipe; the speed measuring device is respectively installed on one of the supporting devices, the bionic structure test board and the other supporting device along the water flow direction; the speed measuring device includes a counter-beam photoelectric sensor and a turntable device, and the counter-beam photoelectric sensor is fixedly connected to the turntable device.

[0025] The beneficial effects of the present invention are as follows:

[0026] The present invention uses a bionic structure test plate to reduce the friction resistance between the mainstream field and the contact wall during the flow process, which can reduce energy loss, improve transportation efficiency, save energy, and can easily change the size, direction, and shape of the pits, convex hulls, and grooves of the two-phase jet, and compare the optimal drag reduction conditions under different bionic structures. The device occupies a small area, is low in cost, has a simple structure, and is easy to use. The method for evaluating the drag reduction effect of the bionic structure test plate is simple and intuitive, and the results are reliable. It can also accurately control the two-phase jet velocity and mainstream velocity of the test model, simulate different jet environments, and realize the recycling of water during the test, which is environmentally friendly, energy-saving, and pollution-free. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the present invention;

[0028] Figure 2 It is a front view of the present invention;

[0029] Figure 3 is a top view of the two-phase jet supply mechanism;

[0030] Figure 4 It is a schematic diagram of the structure of a two-phase jet conversion device;

[0031] Figure 5 It is a structural schematic diagram of a bionic structure test board;

[0032] Figure 6 It is a top view of the jet hole size change;

[0033] Figure 7 It is a schematic diagram of the change of bionic pit-convex hull structure;

[0034] Figure 8 It is a schematic diagram of the changes in the bionic groove structure;

[0035] Fig. 9 It is a structural schematic diagram of the speed measuring device. DETAILED DESCRIPTION

[0036] 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.

[0037] Combination Figure 1 and Figure 2 The variable bionic structure coupling drag reduction test device described in the present invention includes a mainstream supply mechanism 1, a two-phase jet supply mechanism 2, a first group of flow control mechanisms 3, a second group of flow control mechanisms 4, a bionic structure test plate 5 and a rectangular test pipe 6.

[0038] The liquid outlet of the mainstream supply mechanism 1 is connected to the liquid inlet of the first group of flow control mechanisms 3, and the liquid outlet of the first group of flow control mechanisms 3 is connected to the liquid inlet of the rectangular test pipe 6; the liquid outlet of the rubber hose of the two-phase jet supply mechanism 2 is connected to the liquid inlet of the second group of flow control mechanisms 4, and the liquid outlet of the second group of flow control mechanisms 4 is embedded in the bionic structure test plate 5; the bolt roller bearing of the bionic structure test plate 5 is fastened to the nut embedded in the top of the rectangular test pipe 6.

[0039] Combination Figure 1 and Figure 2 The mainstream supply mechanism 1 includes a mainstream inverter 1-1, a mainstream motor 1-2, a mainstream water pump 1-3, and a water tank 1-4. The power output end of the mainstream inverter 1-1 is connected to the power input end of the mainstream motor 1-2, and the power output end of the mainstream motor 1-2 is connected to the power input end of the mainstream water pump 1-3. The liquid inlet of the mainstream water pump 1-3 is connected to the water tank 1-4 through an inlet pipe, and the liquid outlet of the mainstream water pump 1-3 is connected to the liquid inlet of the first group of flow control mechanisms 3 through an outlet pipe. The speed of the mainstream motor 1-2 is adjusted by the mainstream inverter 1-1, and the mainstream motor 1-2 drives the mainstream water pump 1-3 to pump water out of the water tank 1-4 and enter the first group of flow control mechanisms 3 through the outlet pipe.

[0040] Combination Figure 1 to Figure 4 The two-phase jet supply mechanism 2 includes a liquid jet supply mechanism, a gas jet supply mechanism, a two-phase jet conversion device 2-10 and a jet box 2-11. The liquid jet supply mechanism includes a liquid jet frequency converter 2-1, a liquid jet motor 2-2, and a jet water pump 2-3, and the gas jet supply mechanism includes a gas jet frequency converter 2-5, a gas jet motor 2-6, and a jet air pump 2-7. The jet box 2-11 includes a mutually isolated liquid jet inner cavity 2-4, a gas jet inner cavity 2-8 and a conversion device placement cavity.

[0041] The power output end of the liquid jet frequency converter 2-1 is connected to the power input end of the liquid jet motor 2-2, the power output end of the liquid jet motor 2-2 is connected to the power input end of the jet water pump 1-3, the liquid inlet of the jet water pump 2-3 is connected to the water tank 1-4 through the water inlet pipe, and the liquid outlet of the jet water pump 2-3 is sealed and connected to the liquid jet inner cavity 2-4 through the water outlet pipe; similarly, the power output end of the gas jet frequency converter 2-5 is connected to the power input end of the gas jet motor 2-6, the power output end of the gas jet motor 2-6 is connected to the power input end of the jet air pump 2-7, and the air outlet of the jet air pump 2-7 is sealed and connected to the gas jet inner cavity 2-8 through the air guide tube; the two-phase jet conversion device 2-10 is installed in the conversion device placement cavity.

[0042] The two-phase jet conversion device 2-10 is composed of multiple groups, each group includes a bolt 2-10-1, a DC motor 2-10-2, a DC power supply 2-10-3, a shift switch 2-10-4, a driving gear 2-10-5, and a driven gear 2-10-6. The two-phase jet conversion device 2-10 is rotatably connected to the jet box 2-11 through the bolt 2-10-1, and the DC motor 2-10-2 is connected to the DC power supply 2-10-3 and the shift switch 2-10 through an electric wire. -4, the driving gear 2-10-5 is connected to the output shaft of the DC motor 2-10-2 through a key, and the driven gear 2-10-6 is connected through an interference fit bolt 2-10-1; two hoses 2-9 are arranged on the driven gear 2-10-6, and one end of one of the hoses 2-9 is connected to the liquid jet cavity 2-4, and the other end is connected to the second group of flow regulating controls 4; one end of the other hose 2-9 is connected to the gas jet cavity 2-8, and the other end is connected to the second group of flow regulating controls 4.

[0043] The speed of the liquid jet motor 2-2 is adjusted by the liquid jet frequency converter 2-1, and the liquid jet motor 2-2 drives the jet water pump 1-3 to pump the water in the water tank 1-4 into the liquid jet inner cavity 2-4 through the water outlet pipe; similarly, the speed of the gas jet motor 2-6 is adjusted by the gas jet frequency converter 2-5, and the gas jet motor 2-6 drives the jet air pump 2-7 to introduce the compressed air into the gas jet inner cavity 2-8 through the air guide pipe; the DC motor 2-10-2 is powered by the DC power supply 2-10-3, and the shift switch 2-10-4 controls the forward and reverse rotation of the DC motor 2-10-2, and the output shaft of the DC motor 2-10-2 drives the driving gear 2-10-5, and the driving gear 2-10-5 drives the driven gear 2-10-6, so that the rubber hose 2-9 of the gas jet and the liquid jet rotates 180°, realizing the two-phase jet conversion and simulating different working conditions.

[0044] Combination Figure 1and Figure 2 The first group of flow control mechanisms 3 includes a mainstream jet tube 3-1, a mainstream electric ball valve 3-2 and a mainstream flow meter 3-3. The mainstream jet tube 3-1 integrates the mainstream electric ball valve 3-2 and the mainstream flow meter 3-3. The liquid inlet of the mainstream jet tube 3-1 is connected to the liquid outlet of the mainstream water pump 1-3 of the mainstream supply mechanism 1, and the liquid outlet of the mainstream jet tube 3-1 is connected to the liquid inlet of the rectangular test pipe 6; the second group of flow control components 4 includes a first jet tube 4-1, a jet electric ball valve 4-2, a jet flow meter 4-3 and a second jet tube 4-4. The tongue and groove of the upper liquid inlet of the first jet tube 4-1 is connected to the two-phase jet supply The tenons of the liquid outlet of the rubber hose 2-9 of the mechanism 2 fit together, and the first jet tube 4-1 integrates the jet electric ball valve 4-2 and the jet flowmeter 4-3; the upper liquid inlet of the second jet tube 4-4 is adhered to the lower liquid outlet of the first jet tube 4-1 on the support plate 4-5 through a waterproof sealant, and the lower liquid outlet of the second jet tube 4-4 is embedded in the jet hole of the bionic structure test plate 5; the function of the mainstream flowmeter 3-3 and the jet flowmeter 4-3 is to monitor the fluid supply flow in the system, and the size of the flow is controlled by the mainstream electric ball valve 3-2 and the jet electric ball valve 4-2, thereby realizing the function of adjusting the jet speed and the mainstream speed.

[0045] Combination Figure 5The bionic structure test board 5 is rectangular and includes three parts: a mobile device 5-1, a bionic two-phase jet test board 5-2, and a bionic groove test board 5-3. The mobile device 5-1 includes a bolt roller bearing 5-1-1, a guide rail 5-1-2, and a mounting plate 5-1-3. The bolt roller bearing 5-1-1 is fastened to a nut embedded in the top of the rectangular test pipe 6. The guide rail 5-1-2 is fixedly connected to the mounting plate 5-1-3 by screws. The mounting plate 5-1- 3 is spliced ​​to the bionic two-phase jet test plate 5-2 through a dovetail groove, and a magnetic fluid seal is formed between the mounting plate 5-1-3 and the supporting device of the rectangular test pipe 6; the bionic two-phase jet test plate 5-2 includes a plurality of connecting rods 5-2-1, a permanent magnet 5-2-2, an electromagnet 5-2-3, a sealing plate 5-2-4, and a first test plate 5-2-5, wherein the connecting rod 5-2-1 is provided with a permanent magnet 5-2-2, and the bottom of the permanent magnet 5-2-2 is connected to the circular rubber surface 5-2 -6 adhesion, the electromagnet 5-2-3 is pressed into the sealing plate 5-2-4 by interference fit, and every four connecting rods 5-2-1 are connected by a rotating shaft to form a jet hole, and each jet hole corresponds to a second group of flow control components 4, and the side edge of the first test plate 5-2-5 is spliced ​​to the bionic groove test plate 5-3 through a dovetail groove, and the sealing plate 5-2-4 and the first test plate 5-2-5 are stepped sealed; the bionic groove test plate 5-3 includes a plurality of bionic gill cleft rods 5-3-1, the first Second test plate 5-3-2, support plate 5-3-3, sealing rubber plate 5-3-4, the second test plate 5-3-2 and support plate 5-3-3 are respectively connected by hinges, the bionic gill rod 5-3-1 is fixedly connected to the second test plate 5-3-2 and support plate 5-3-3 by screws, the sealing rubber plate 5-3-4 is adhered to the edge of the support plate 5-3-3 by adhesive, and the side edge of the bionic groove test plate 5-3 is spliced ​​to the moving device 5-1 by a dovetail groove.

[0046] Combination Figure 6 to Figure 8In the two-phase jet test plate 5-2, every four connecting rods 5-2-1 form a jet hole, and each jet hole is embedded in a lower end liquid outlet of the second jet tube 4-4. The bionic two-phase jet test plate 5-2 is moved by the moving device 5-1, and the jet hole will change the size and direction of the diamond-shaped jet hole due to the change of the position of its four connecting rods 5-2-1; the power supply of the electromagnet 5-2-3 is turned on, and the magnetic pole and magnetic force of the electromagnet 5-2-3 can be changed by adjusting the current direction and size of the electromagnet 5-2-3, so as to attract or repel the permanent magnet 5-2-2, because the bottom of the permanent magnet 5-2-2 is adhered to the round rubber The surface 5-2-6 can realize the transformation of bionic pits and convex hulls and adjust the diameter and depth of the pits and convex hulls. The specific size of the pits and convex hulls is determined by the size of the permanent magnet 5-2-2; in the bionic groove test plate 5-3, the second test plates 5-3-2 in pairs form a bionic groove structure, and the arrangement of the bionic gill cleft rods 5-3-1 is the structure of shark gill clefts. The bionic groove test plate 5-3 is moved by the moving device 5-1, and the second test plates 5-3-2 in pairs can be contracted or stretched, thereby changing the width and depth of the bionic groove structure and the opening and closing of the bionic gill cleft structure. The specific size of the bionic groove structure is determined by the size of the second test plates 5-3-2.

[0047] Combination Figure 1 , Figure 2 and Fig. 9The rectangular test pipe 6 includes a honeycomb 6-1, a damping net 6-2, a supporting device 6-3, a speed measuring device 6-4, and a reflux channel 6-5; the liquid inlet of the rectangular test pipe 6 is connected to the liquid outlet of the mainstream jet tube 3-1 of the first group of flow control mechanism 3, and the liquid inlet is installed with a honeycomb 6-1 and a damping net 6-2, the liquid outlet of the rectangular test pipe 6 is connected to the liquid inlet of the reflux channel 6-5, and the liquid outlet of the reflux channel 6-5 is connected to the water tank 1-4 of the mainstream supply mechanism 1, and the supporting device 6-3 is fixedly connected to both sides of the rectangular test pipe 6 by screws; the speed measuring device 6-4 includes a counter-beam photoelectric sensor 6-4-1 and a turntable device 6-4-2, the counter-beam photoelectric sensor 6-4-1 is fixedly connected to the turntable device 6-4-2 by screws, and the turntable device The device 6-4-2 is fixedly connected to the supporting device 6-3 and the bionic structure test board 5 by screws; the mainstream is pumped out from the mainstream jet tube 3-1, passes through the rectifying section equipped with the honeycomb 6-1 and the damping net 6-2, can play a rectifying role, improve the flow field quality, and is accelerated in the contraction section before being pumped into the rectangular test pipe 6. The mainstream passes through the bionic structure test board 5 for drag reduction tests under different working conditions, and finally realizes water circulation through the reflux channel 6-5; the turntable device 6-4-2 is evenly distributed with eight square protrusions. Due to the passage of the mainstream, the turntable device 6-4-2 is driven to rotate, so that the square protrusions periodically block the light of the transmitter, and the photoelectric sensor 6-4-1 outputs high and low level signals of a certain period. The better the drag reduction effect, the shorter the period. Therefore, the drag reduction effect of the bionic structure test board 5 can be evaluated according to the length of the period.

[0048] Installation process: Place the moving devices at both ends of the bionic structure test plate 5 in the supporting device 6-3 of the rectangular test pipe 6, the liquid inlet of the rectangular test pipe 6 is connected with the liquid outlet of the mainstream jet pipe 3-1 of the first group of flow control mechanism 3, and the liquid outlet is connected with the reflux channel 6-5; the mainstream flowmeter 3-3 and the jet flowmeter 4-3 are connected to the mainstream jet pipe 3-1 and the first jet pipe 4-1 through threaded connection, the mainstream electric ball valve 3-2 and the jet electric ball valve 4-2 are connected to the jet pipe 3-1 and the first jet pipe 4-1 through external threads, and the mortise and tenon of the upper end liquid inlet of the first jet pipe 3-1 is connected with the liquid outlet of the rubber hose 2-9 of the two-phase jet supply mechanism 2. The tenons fit together, the upper liquid inlet of the second jet tube 4-4 is adhered to the lower liquid outlet of the first jet tube 4-1 on the support plate 4-5 through waterproof sealant, and the lower liquid outlet of the second jet tube 4-4 is embedded in the jet hole of the bionic structure test plate 5; finally, the mainstream inverter 1-1, liquid jet inverter 2-1 and gas jet inverter 2-5, mainstream motor 1-2, liquid jet motor 2-2 and gas jet motor 2-6 are connected in sequence, the water suction pipes of the mainstream water pump 1-3 and the jet water pump 2-3 are placed in the water tank 1-4, the mainstream water pump 1-3, the jet water pump 2-3 and the jet air pump 2-5 are turned on to pump water and air.

[0049] The working principle of the whole test device is: the speed of the mainstream motor 1-2 is adjusted by the mainstream frequency converter 1-1, and the mainstream motor 1-2 drives the mainstream water pump 1-3 to pump out the water in the water tank 1-4 through the mainstream jet tube 3-1, and then passes through the rectifying section equipped with the honeycomb 6-1 and the damping net 6-2, which can play a rectifying role and improve the flow field quality. After being accelerated in the contraction section, it is pumped into the rectangular test pipe 6, and then the water is circulated through the reflux channel 6-5. The speeds of the liquid jet motor 2-2 and the gas jet motor 2-6 are adjusted by the liquid jet frequency converter 2-1 and the gas jet frequency converter 2-5 respectively, and the liquid jet motor 2-2 drives the jet water pump 1-3 to pump the water in the water tank 1-4 into the liquid jet inner cavity 2-4 through the water outlet pipe, and the gas jet motor 2-6 drives the jet air pump 2-7 to introduce the compressed air into the gas jet inner cavity 2-8 through the air guide pipe. The function of the mainstream flowmeter 3-3 and the jet flowmeter 4-3 is to monitor the fluid supply flow in the system. The flow rate is controlled by the mainstream electric ball valve 3-2 and the jet electric ball valve 4-2, so as to realize the function of adjusting the mainstream speed and the two-phase jet speed. By moving the moving device 5-1 at both ends of the bionic structure test board 5, the size, direction and groove shape of the bionic jet hole can be changed; by controlling the DC motor 2-10-2 to rotate 180 degrees forward and reverse, the two-phase jet conversion can be realized; by adjusting the current direction and size of the electromagnet 5-2-3, the shape of the bionic pit convex hull can be changed.

[0050] The method for evaluating the drag reduction effect of a bionic structure test plate of the present invention comprises the following steps: 1) starting the jet water pump 1-3, the jet air pump 2-7 of the two-phase jet supply mechanism 2 and the mainstream water pump 1-3 of the mainstream supply mechanism 1, closing the jet electric ball valve 4-2 of the second group of flow control mechanisms 4, closing the power supply of the electromagnet 5-2-3, and extending the bionic two-phase jet test plate 5-2 and the bionic groove test plate 5-3 to the initial position through the moving device 5-1, and opening the mainstream electric ball valve 3-2 of the first group of flow control mechanisms 3. At this time, the jet velocity is 0 m / s, and there are no bionic pits, convex hulls and groove structures. The three opposing photoelectric sensors 6-4-1 measure the situation where the bionic two-phase jet test plate 5-2 and the bionic groove test plate 5-3 are not used. The high and low level periods measured by the opposing photoelectric sensors 6-4-1 are recorded, and the period differences T1 and T2 are obtained by subtracting them. ② By adjusting the mainstream electric ball valve 3-2 of the first group of flow control mechanism 3, keep it equal to the mainstream speed of the first step, then open the jet electric ball valve 4-2 of the second group of flow control mechanism 4, turn on the power of the electromagnet 5-2-3, move the bionic two-phase jet test plate 5-2 and the bionic groove test plate 5-3 through the moving device 5-1, and record the period differences t1 and t2 between the three opposing photoelectric sensors 6-4-1 under the current working condition, and can record the t a and t b ③ When the bionic groove test plate 5-3 is extended to the initial position, the drag reduction effect of the mobile bionic two-phase jet test plate 5-2 is expressed by the drag reduction rate DR1: DR1 = 100% × (T1-t1) T1; when the jet electric ball valve 4-2 of the second group of flow control mechanism 4 is closed, the power supply of the electromagnet 5-2-3 is turned off, and the bionic two-phase jet test plate 5-2 is extended to the initial position, the drag reduction effect of the bionic groove test plate 5-3 is expressed by the drag reduction rate DR2: DR2 = 100% × (T2-t2) / T2; the drag reduction effect of the coupled bionic two-phase jet test plate 5-2 and the groove test plate 5-3 is expressed by the drag reduction rate DR3: DR3 = 100% × [(T1+T2)-(t1+t2)] / (T1+T2), the drag reduction rate DR i The larger the value, the better the drag reduction effect. The drag reduction rate DR under different working conditions can be compared. i The optimal drag reduction is obtained. When adjusting the current size and direction of the electromagnet 5-2-3, controlling the DC motor 2-10-2 to rotate 180° forward and reverse, and moving the bionic two-phase jet test plate 5-2 and the bionic groove test plate 5-3, repeating the above steps, the drag reduction effect under different working conditions can be measured, and the working condition with the optimal drag reduction effect can be obtained. This experimental device can also change the jet speed and the mainstream speed by adjusting the mainstream electric ball valve 3-2 and the jet electric ball valve 4-2 of the first group of flow control mechanisms 3 and the second group of flow control mechanisms 4, so as to simulate the drag reduction at different jet speeds and mainstream speeds.

[0051] 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 coupling drag reduction test device with a variable bionic structure, characterized in that: The device comprises a mainstream supply mechanism (1), a two-phase jet supply mechanism (2), a first group of flow control mechanisms (3), a second group of flow control mechanisms (4), a bionic structure test plate (5) and a rectangular test pipe (6); The liquid outlet of the mainstream supply mechanism (1) is connected to the liquid inlet of the first group of flow control mechanisms (3), and the liquid outlet of the first group of flow control mechanisms (3) is connected to the liquid inlet of the rectangular test pipe (6); the liquid outlet of the two-phase jet supply mechanism (2) is connected to the liquid inlet of the second group of flow control mechanisms (4), and the liquid outlet of the second group of flow control mechanisms (4) is embedded in the bionic structure test plate (5); the bionic structure test plate (5) is fixed on the top of the rectangular test pipe (6); The bionic structure test plate (5) comprises a bionic two-phase jet test plate (5-2), a bionic groove test plate (5-3), and two moving devices (5-1); one end of the bionic two-phase jet test plate (5-2) is connected to one end of the bionic groove test plate (5-3), and the other end of the bionic two-phase jet test plate (5-2) and the other end of the bionic groove test plate (5-3) are respectively connected to a moving device (5-1); through the movement of the moving device (5-1), the jet holes on the bionic two-phase jet test plate (5-2) and the grooves on the bionic groove test plate (5-3) are deformed, thereby achieving coupled drag reduction; The mainstream supply mechanism (1) comprises a mainstream frequency converter (1-1), a mainstream motor (1-2), a mainstream water pump (1-3), and a water tank (1-4); the power output end of the mainstream frequency converter (1-1) is connected to the power input end of the mainstream motor (1-2); the power output end of the mainstream motor (1-2) is connected to the power input end of the mainstream water pump (1-3); the liquid inlet of the mainstream water pump (1-3) is connected to the water tank (1-4) through a water inlet pipe; the liquid outlet of the mainstream water pump (1-3) is connected to the liquid inlet of the first group of flow control mechanisms (3) through a water outlet pipe; the rotation speed of the mainstream motor (1-2) is adjusted by the mainstream frequency converter (1-1); the mainstream motor (1-2) drives the mainstream water pump (1-3) to pump water out of the water tank (1-4) and enter the first group of flow control mechanisms (3); The two-phase jet supply mechanism (2) comprises a liquid jet supply mechanism, a gas jet supply mechanism, a two-phase jet conversion device (2-10) and a jet box (2-11); the liquid jet supply mechanism comprises a liquid jet frequency converter (2-1), a liquid jet motor (2-2) and a jet water pump (2-3); the gas jet supply mechanism comprises a gas jet frequency converter (2-5), a gas jet motor (2-6) and a jet air pump (2-7); and the jet box (2-11) comprises a liquid jet inner cavity (2-4), a gas jet inner cavity (2-8) and a conversion device placement cavity that are isolated from each other; The power output end of the liquid jet frequency converter (2-1) is connected to the power input end of the liquid jet motor (2-2), the power output end of the liquid jet motor (2-2) is connected to the power input end of the mainstream water pump (1-3), the liquid inlet of the jet water pump (2-3) is connected to the water tank (1-4) through an inlet pipe, and the liquid outlet of the jet water pump (2-3) is sealed and connected to the liquid jet inner cavity (2-4) through an outlet pipe; The power output end of the gas jet frequency converter (2-5) is connected to the power input end of the gas jet motor (2-6), the power output end of the gas jet motor (2-6) is connected to the power input end of the jet air pump (2-7), and the air outlet of the jet air pump (2-7) is sealed and connected to the gas jet inner cavity (2-8) through an air guide pipe; The two-phase jet conversion device (2-10) is installed in the conversion device placement cavity; The two-phase jet conversion device (2-10) is composed of multiple groups, each group comprising a bolt (2-10-1), a DC motor (2-10-2), a DC power supply (2-10-3), a shift switch (2-10-4), a driving gear (2-10-5), a driven gear (2-10-6), and two hoses (2-9). The two-phase jet conversion device (2-10) is rotatably connected to the jet box (2-11) via the bolt (2-10-1), and the DC motor (2-10-2) is connected to the DC power supply (2-10-3) and the shift switch via an electric wire. The switch (2-10-4) is connected to the output shaft of the DC motor (2-10-2) by the driving gear (2-10-5), and the driven gear (2-10-6) is connected to the bolt (2-10-1); two hoses (2-9) are arranged on the driven gear (2-10-6), and one end of one of the hoses (2-9) is connected to the liquid jet cavity (2-4), and the other end is connected to the second group of flow control mechanisms (4); one end of the other hose (2-9) is connected to the gas jet cavity (2-8), and the other end is connected to the second group of flow control mechanisms (4); The DC motor (2-10-2) is powered by a DC power supply (2-10-3), the shift switch (2-10-4) controls the forward and reverse rotation of the DC motor (2-10-2), the output shaft of the DC motor (2-10-2) drives the driving gear (2-10-5), the driving gear (2-10-5) drives the driven gear (2-10-6), so that the rubber hose (2-9) of the gas jet and the liquid jet rotates 180 degrees, realizing the two-phase jet conversion and simulating different working conditions; The first group of flow control mechanisms (3) comprises a mainstream jet tube (3-1), a mainstream electric ball valve (3-2) and a mainstream flow meter (3-3); the mainstream jet tube (3-1) integrates the mainstream electric ball valve (3-2) and the mainstream flow meter (3-3); the liquid inlet of the mainstream jet tube (3-1) is connected to the liquid outlet of the mainstream water pump (1-3) of the mainstream supply mechanism (1); and the liquid outlet of the mainstream jet tube (3-1) is connected to the liquid inlet of the rectangular test pipe (6); The second group of flow control mechanisms (4) is a plurality of groups, each group comprising a first jet tube (4-1), a jet electric ball valve (4-2), a jet flow meter (4-3) and a second jet tube (4-4); the tongue and groove of the upper liquid inlet of the first jet tube (4-1) and the liquid outlet of the rubber hose (2-9) of the two-phase jet supply mechanism (2) are mutually matched, and the first jet tube (4-1) integrates the jet electric ball valve (4-2) and the jet flow meter (4-3); the upper liquid inlet of the second jet tube (4-4) is bonded to the lower liquid outlet of the first jet tube (4-1), and the lower liquid outlet of the second jet tube (4-4) is embedded in the jet hole of the bionic structure test plate (5).

2. The coupling drag reduction test device of the variable bionic structure according to claim 1 is characterized in that: The moving device (5-1) in the bionic structure test plate (5) comprises a bolt roller bearing (5-1-1), a guide rail (5-1-2), and a mounting plate (5-1-3); the bolt roller bearing (5-1-1) is fastened to the top of the rectangular test pipe (6); the guide rail (5-1-2) is fixedly connected to the mounting plate (5-1-3); and the mounting plate (5-1-3) is spliced ​​to the bionic two-phase jet test plate (5-2); The bionic two-phase jet test plate (5-2) comprises a plurality of connecting rods (5-2-1), permanent magnets (5-2-2), electromagnets (5-2-3), a sealing plate (5-2-4), a first test plate (5-2-5) and a circular rubber surface layer (5-2-6); the connecting rods (5-2-1) are provided with permanent magnets (5-2-2) at the bottom thereof and are bonded to the circular rubber surface layer (5-2-6); the electromagnets (5-2-3) are interference-pressed into the sealing plate (5-2-4); every four connecting rods (5-2-1) are connected via a rotating shaft to form a jet hole; each jet hole corresponds to a second group of flow control mechanisms (4); the side edge of the test plate (5-2-5) is spliced ​​to the bionic groove test plate (5-3) via a dovetail groove; a step seal is formed between the sealing plate (5-2-4) and the test plate (5-2-5); The bionic groove test plate (5-3) comprises a plurality of bionic gill cleft rods (5-3-1), a second test plate (5-3-2), a support plate (5-3-3), and a sealing rubber plate (5-3-4); the second test plate (5-3-2) and the support plate (5-3-3) are respectively connected via hinges; the bionic gill cleft rods (5-3-1) are fixedly connected to the second test plate (5-3-2) and the support plate (5-3-3); the sealing rubber plate (5-3-4) is adhered to the edge of the support plate (5-3-3) via an adhesive; and the side edge of the bionic groove test plate (5-3) is spliced ​​to another moving device (5-1) via a dovetail groove; In the bionic two-phase jet test plate (5-2), every four connecting rods (5-2-1) form a jet hole, and each jet hole is embedded in a lower end liquid outlet of the second jet tube (4-4). The bionic two-phase jet test plate (5-2) is moved by the moving device (5-1), and the jet hole changes in size and direction due to the change in the position of its four connecting rods (5-2-1); the power supply of the electromagnet (5-2-3) is turned on, and the magnetic pole and magnetic force of the electromagnet (5-2-3) are changed by adjusting the current direction and size of the electromagnet (5-2-3), so as to attract or repel the permanent magnet (5-2-2). Because the bottom of the permanent magnet (5-2-2) is adhered to the circular rubber surface layer (5-2-6), the bionic concave and convex hulls are changed and the diameter and depth of the concave and convex hulls are adjusted; In the bionic groove test plate (5-3), pairs of second test plates (5-3-2) form a bionic groove structure, and the arrangement of the bionic gill slit rods (5-3-1) is the structure of shark gill slits. The bionic groove test plate (5-3) is moved by the moving device (5-1), and pairs of second test plates (5-3-2) are contracted or extended, thereby changing the width and depth of the bionic groove structure and the opening and closing of the bionic gill slit structure.

3. The coupling drag reduction test device of the variable bionic structure according to claim 1 is characterized in that: The rectangular test pipe (6) comprises a honeycomb (6-1), a damping net (6-2), a supporting device (6-3), a reflux channel (6-5) and a plurality of velocity measuring devices (6-4); the liquid inlet of the rectangular test pipe (6) is connected to the liquid outlet of the mainstream jet pipe (3-1) of the first group of flow control mechanisms (3), the liquid inlet is equipped with a honeycomb (6-1) and a damping net (6-2), the liquid outlet of the rectangular test pipe (6) is connected to the liquid inlet of the reflux channel (6-5), and the liquid outlet of the reflux channel (6-5) is connected to the mainstream jet pipe (3-1). The water tank (1-4) of the supply mechanism (1) is connected, and the support device (6-3) is fixedly connected to both sides of the rectangular test pipe (6); the speed measuring device (6-4) is respectively installed on one of the support devices (6-3), the bionic structure test plate (5), and the other support device (6-3) along the water flow direction; the speed measuring device (6-4) comprises a through-beam photoelectric sensor (6-4-1) and a turntable device (6-4-2), and the through-beam photoelectric sensor (6-4-1) is fixedly connected to the turntable device (6-4-2).

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