An electromagnetic activation device applied to turbulent boundary layer active control experiment

Abstract

The application discloses an electromagnetic activation device applied to a turbulent boundary layer active control experiment, comprising an upper cover plate, an upper cover support, an adjusting screw rod, an adjusting nut, a wire outlet pipe, a connector, a reinforced support strip, an insertion plate, an activation plate base and a PCB electrode plate, wherein the upper cover plate, the upper cover support, the adjusting screw rod, the adjusting nut, the wire outlet pipe, the connector and the reinforced support strip are outer structural members, and the insertion plate, the activation plate base and the PCB electrode plate are three experimental main members; a voltage is applied to the PCB plate, an exposed electrode plate of the PCB plate can form an electric field in water, interacts with a magnetic field generated by magnetic poles installed in the activation plate base, forms an extended Lorentz force, and thus controls a flow field. The experimental device has good structural stability and adjustability, effectively solves the problems of poor waterproofing, exposed magnetic poles, uneven electrode sheet arrangement and easy falling-off of similar experimental devices.

Description

Technical Field

[0001] This invention relates to electromagnetic activation devices, and more specifically to an electromagnetic activation device for active control experiments of turbulent boundary layers. Background Technology

[0002] When underwater vehicles such as UUVs and torpedoes move, they are affected by a viscous fluid boundary layer. The drag generated by this boundary layer is a crucial factor affecting their speed. Viscous fluid flowing over blunt surfaces can also cause flow separation, leading to vibration and noise, and in severe cases, instability. To mitigate these issues, boundary layer control measures are implemented to alter its structure, thereby improving not only the vehicle's speed and propulsion efficiency but also its stability. After years of development, flow control has made significant progress in drag reduction and range extension.

[0003] Since the 1980s, the control of coherent boundary layer structures in turbulent flow has been a cutting-edge research topic. Based on whether energy input is required, flow control methods can be broadly categorized into passive and active control. In recent years, active control of turbulence has become a hot topic in turbulence control technology research. Electromagnetic force, as an important active control method, has advantages such as fast response speed, good control effect, and high flexibility. However, in current research, the applied electromagnetic force varies with time, resulting in the inability to form stable flow field characteristic structures. To study the intrinsic relationship and related mechanisms between these characteristic structures and drag reduction, research on spanwise electromagnetic force control that varies only with space, especially related experimental research, is urgently needed. However, related experimental research equipment often suffers from drawbacks such as rudimentary design, inadequate packaging, and poor adjustability. Summary of the Invention

[0004] The purpose of this invention is to provide an electromagnetic activation device for active control experiments of turbulent boundary layers, which effectively solves the problems of inadequate waterproofing, exposed magnetic poles, uneven electrode arrangement, and even easy detachment in existing experimental devices, thereby forming a stable flow field.

[0005] The technical solution to achieve the purpose of this invention is as follows: an electromagnetic activation device for active control experiments of turbulent boundary layers, comprising an upper cover plate and an insertion plate. The upper cover plate is connected to the two sides of the insertion plate by reinforcing support strips. The insertion plate includes a front edge, a flat plate area, and a rear edge. The flat plate area has a groove, and an activation plate base adapted to the groove is placed inside the groove. The activation plate base is provided with multiple magnetic pole mounting slots for mounting magnetic poles. A PCB electrode plate identical to the activation plate base is mounted on the activation plate base. The flat plate area of ​​the insertion plate has a through hole, and the activation plate base has an outlet hole identical to the through hole. An outlet tube runs through the upper cover plate and is connected to the through hole via a connector. The power supply wire of the PCB electrode plate is led out through the outlet hole. The sides of the front and rear edges of the insertion plate are arc-shaped to prevent flow separation. By applying voltage to the PCB electrode plate, its exposed electrodes form an electric field in the water, which interacts with the magnetic field generated by the magnetic poles installed in the activation plate base to form a Lorentz force in the extension direction.

[0006] Furthermore, the side curve of the leading edge of the insertion plate is as follows:

[0007] n=2

[0008] Where AR is the leading edge ellipsoid ratio, i.e. α represents the length of the major axis of the ellipse. It represents the length of the minor axis of the ellipse.

[0009] Furthermore, the side edge of the rear edge of the insertion plate is a standard elliptical arc.

[0010] Furthermore, an upper cover bracket is installed on the upper cover plate, and an adjusting screw is installed on each upper cover bracket. One end of the adjusting screw passes through the upper cover bracket and the upper cover plate in sequence and extends to the top of the platen area of ​​the insertion plate. The adjusting screw is connected to both sides of the upper cover bracket and the side of the upper cover plate near the upper cover bracket through adjusting nuts to adjust the horizontal posture of the insertion plate.

[0011] Furthermore, the upper cover support is in the shape of an inverted U-shape and is made of plexiglass.

[0012] Furthermore, there are two upper cover brackets, and two adjusting screws are installed on each upper cover bracket. The two upper cover brackets are symmetrically distributed, and the four adjusting screws are respectively positioned at the four corners of the insertion plate flat area. The connection between the adjusting screws and the upper cover plate is sealed with sealing gaskets and waterproof adhesive.

[0013] Furthermore, the outlet tube is made of 304 stainless steel, the connector is connected to the outlet tube by welding, and it is fixed to the insertion plate by screws and waterproofed by applying glue.

[0014] Furthermore, the insertion plate is made of black POM and is machined as a single CNC unit. The groove in the flat area of ​​the insertion plate is a rectangular groove, and the wire hole is located at the center of one end of the rectangular groove. The reinforcing support strip is made of aluminum with an anodized outer surface and is fixed to the insertion plate by screws.

[0015] Furthermore, the activation board base is made of transparent acrylic, which is connected and fixed to the insertion plate by screws. The activation board base has grooves on both sides that are adapted to the PCB electrode board, and the PCB electrode board is installed on the activation board base through the grooves.

[0016] Furthermore, the upper surface of the PCB electrode board has regularly arranged electrodes, and the back end has reserved solder joints. The magnetic pole mounting grooves are evenly distributed and staggered with the electrode positions on the upper surface of the PCB electrode board.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The present invention designs an upper cover plate, an upper cover bracket, an adjusting screw, an adjusting nut, an outlet tube, a connector and a reinforcing support bar as a fixing device and a leveling device that are matched with the experimental insertion plate, thus ensuring the adjustability of the device posture;

[0019] (2) This invention creatively proposes an electromagnetic force generation device that combines the activation board base and the PCB electrode plate packaging, avoiding problems such as waterproofing, exposed magnetic poles, uneven electrode arrangement, and even easy detachment that have occurred in similar experimental devices in the past.

[0020] (3) By installing the electromagnetic force generating device in the insertion plate, the present invention ensures the stability of the flow above the plate, thereby ensuring the reliability of the experiment. Attached Figure Description

[0021] Figure 1 This is a perspective view of the overall assembly of the electromagnetic activation device.

[0022] Figure 2 This is a cross-sectional view of the reinforcing ribs of the electromagnetic activation device assembly.

[0023] Figure 3 This is a center sectional view of the electromagnetic activation device assembly.

[0024] Figure 4 This is a perspective view of the PCB electrode board.

[0025] Figure 5 This is an oblique view of the insert plate.

[0026] Figure 6 This is the top view of the insert panel.

[0027] Figure 7 To activate the angled view of the plate base.

[0028] Figure 8 To activate the top view of the base of the board.

[0029] Figure 9 To enhance the oblique view of the support strip.

[0030] Figure 10 This is a simulation diagram of the electromagnetic force arrangement generated by the present invention. Detailed Implementation

[0031] The structure and embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0032] This invention addresses the above-mentioned problems by proposing an electromagnetic activation device for active control experiments of turbulent boundary layers. Its main structure includes an upper cover plate 1, an upper cover support 2, an adjusting screw 3, an adjusting nut 4, an outlet pipe 5, a connector 6, a reinforcing support bar 7, an insertion plate 8, an activation plate base 9, and a PCB electrode plate 10. The upper cover plate 1, upper cover support 2, adjusting screw 3, adjusting nut 4, outlet pipe 5, connector 6, and reinforcing support bar 7 are external structural components. The upper cover plate 1 and reinforcing support bar 7 are fixing devices. The upper cover support 2, adjusting screw 3, and adjusting nut 4 are leveling devices, fabricated to fit the experimental water tunnel, and adjusted according to actual conditions.

[0033] according to Figure 1 The upper cover plate 1 is made to fit the experimental water hole, and the specific design will be adjusted according to the actual situation.

[0034] like Figure 1 , Figure 2 The upper cover bracket 2 is made of plexiglass and is used to fix the adjusting screws 3. There are two screws, one at the front end and one at the rear end of the upper cover plate. The overall shape resembles a handle and can withstand sufficient tension and pressure, while enhancing the structural stability of the cover plate. There are four adjusting screws 3 in total, two at the front and two at the back, passing through the upper cover plate 1. One end is directly opposite the four corners of the insertion plate flat area 12 and is fixed by the reinforcing support strip 7, thereby pulling the hanging insertion plate 8. The other end passes through the upper cover bracket 2. Each adjusting screw 3 has three adjusting nuts 4. One of them is close to the outside of the upper cover plate 1 and is the adjusting nut. The other two are located on the upper and lower sides of the handle of the upper cover bracket 2, which are used to withstand the tension of the weight below and provide structural stability. This adjustment structure connects to the four corners of the insertion plate 8, and the adjusting nuts on it can effectively adjust its level. After the four adjusting screws 3 are leveled, the positions where they pass through the upper cover plate 1 are sealed with sealing washers and waterproof glue.

[0035] like Figure 2 , Figure 3The lead-out tube 5 is made of 304 stainless steel. One end of it is located outside the upper cover plate 1, and the other end is connected to the pre-reserved wire hole 15 of the insertion plate via connector 6. Connector 6 is also made of 304 stainless steel and is connected to the lead-out tube 5 by welding. It is fixed to the insertion plate 8 by screws and waterproofed by applying adhesive. Its main function is to lead out the wires for connecting the power supply that are soldered to the back of the PCB electrode board 10.

[0036] like Figure 1 , Figure 2 , Figure 9 The reinforcing support strip 7 is primarily made of 6061 aluminum with an anodized outer surface. This material is a heat-treatable alloy with good formability, weldability, and machinability. It also possesses moderate strength and maintains good workability after annealing. It exhibits excellent machinability, weldability, electroplating properties, good corrosion resistance, high toughness, no deformation after processing, dense and defect-free material, ease of polishing, easy application of coloring films, and excellent oxidation effects. The main functions of the reinforcing support strip 7 are: 1. To connect the upper cover plate and the insert plate 8, and to fix it to the insert plate 8 with screws to prevent bending deformation during hoisting.

[0037] like Figure 1 , Figure 2 , Figure 5 , Figure 6 The insert plate 8 is made of black POM (acetal alloy). POM is a high-melting-point, highly crystalline thermoplastic engineering plastic with a working temperature range of -60°C to 100°C. Due to its high surface strength and smoothness, POM has excellent sliding properties and wear resistance. POM exhibits virtually no tensile stress and possesses high heat and chemical stability. The insert plate 8 is machined as a single CNC unit, and its external structure includes: a front edge 11, a flat plate area 12, a rear edge 13, a rectangular groove 14, and a wire hole 15. The side arc of the front edge 11 of the insert plate satisfies the equation of an elliptic curve.

[0038] n=2

[0039] Where AR is the leading edge ellipsoid ratio, i.e. α represents the length of the major axis of the ellipse. The length of the minor axis of the ellipse is indicated by the parameter, which is selected based on the test section parameters of the experimental water tunnel. The arc of the rear edge 13 of the insertion plate is a standard elliptical arc, designed to ensure that the flow does not separate. The rectangular groove 14 is located in the center of the flat plate area 12 of the insertion plate, and its size can fit tightly with the base 9 of the activation plate. A wire hole 15 is opened at the center of the end of the rectangular groove 14 for leading out the wires connecting the PCB electrode board 10 to the power supply.

[0040] like Figure 7 , Figure 8 The activation plate base 9 is made of transparent acrylic, with a magnetic pole mounting groove 17 machined in the middle and a wire outlet hole 18 machined at the rear end. It is connected and fixed to the insertion plate 8 by screws.

[0041] like Figure 4 The PCB electrode board 10 is specially designed and manufactured for generating an electric field. The upper surface has electrodes arranged in a regular pattern, and the back end has reserved solder joints. It is installed in the reserved slot of the activation board base 9.

[0042] After assembly, it can be used for water tunnel turbulent boundary layer experiments. Its mechanism involves applying voltage to the PCB board, causing its exposed electrodes to generate an electric field in the water. This electric field interacts with the magnetic field generated by the magnetic poles mounted in the activation plate base, forming a Lorentz force (i.e., electromagnetic force) that extends in the direction of the flow field, thus controlling the flow. The resulting electromagnetic force is arranged as follows: Figure 10 As shown, the electrodes are arranged sinusoidally along the flow direction and decrease exponentially in the normal direction. The experimental device has good structural stability and adjustability, effectively solving problems such as inadequate waterproofing, exposed magnetic poles, uneven electrode arrangement, and even easy detachment that have occurred in similar experimental devices in the past.

Claims

1. An electromagnetic activation device for active control experiments of turbulent boundary layers, characterized in that, The device includes a top cover plate (1) and an insertion plate (8). The top cover plate (1) is connected to the two sides of the insertion plate (8) by reinforcing support strips (7). The insertion plate (8) includes a front edge (11), a flat plate area (12), and a rear edge (13). The flat plate area (12) has a groove, and an activation plate base (9) adapted to the groove is placed inside the groove. The activation plate base (9) is provided with multiple magnetic pole mounting slots (17) for installing magnetic poles. A PCB electrode board (10) identical to the activation plate base (9) is installed on the activation plate base (9). The flat plate area (12) of the insertion plate is provided with a wire hole (15). The activation board base (9) is provided with a wire outlet hole (18) that is consistent with the wire hole (15). The upper cover plate (1) is provided with a wire outlet tube (5). The wire outlet tube (5) is connected to the wire hole (15) through the connector (6). The wires connecting the power supply of the PCB electrode board (10) are led out through the wire outlet hole (18). The sides of the front edge (11) and rear edge (13) of the insertion board are arc-shaped to prevent the flow from separating. By applying voltage to the PCB electrode board (10), its exposed electrodes form an electric field in the water, which interacts with the magnetic field generated by the magnetic poles installed in the activation board base (9) to form a Lorentz force in the extension direction. The side curve of the leading edge (11) of the insertion plate is: ， n=2 Where AR is the leading edge ellipsoid ratio, i.e. α represents the length of the major axis of the ellipse. Indicates the length of the minor axis of the ellipse; The upper cover plate (1) is equipped with an upper cover bracket (2), and each upper cover bracket (2) is equipped with an adjusting screw (3). One end of the adjusting screw (3) passes through the upper cover bracket (2) and the upper cover plate (1) in sequence and extends to the upper part of the plate plate area (12) of the insertion plate. The adjusting screw (3) is connected to both sides of the upper cover bracket (2) and the side of the upper cover plate (1) near the upper cover bracket (2) by adjusting nuts to adjust the horizontal posture of the insertion plate (8). There are two upper cover brackets (2), and two adjusting screws (3) are installed on each upper cover bracket (2). The two upper cover brackets (2) are symmetrically distributed, and the four adjusting screws (3) are respectively facing the four corners of the insertion plate flat area (12). The connection between the adjusting screws (3) and the upper cover plate (1) is sealed by sealing gaskets and waterproof glue. The outlet tube (5) is made of 304 stainless steel. The connector (6) is connected to the outlet tube (5) by welding and fixed to the insertion plate (8) by screws and waterproofed by applying glue. The activation board base (9) has grooves on both sides that are adapted to the PCB electrode board (10), and the PCB electrode board (10) is installed on the activation board base (9) through the grooves. The upper surface of the PCB electrode board (10) has electrodes arranged in a regular pattern, and the back end has a solder joint reserved. The magnetic pole mounting groove (17) is evenly distributed and intersects with the electrode positions on the upper surface of the PCB electrode board (10).

2. The electromagnetic activation device for active control experiments of turbulent boundary layers according to claim 1, characterized in that, The side of the rear edge (13) of the insertion plate is a standard elliptical arc.

3. The electromagnetic activation device for active control experiments of turbulent boundary layers according to claim 1, characterized in that, The upper cover bracket (2) is in the shape of an inverted U-shape and is made of plexiglass.

4. The electromagnetic activation device for active control experiments of turbulent boundary layers according to claim 1, characterized in that, The insertion plate (8) is made of black POM and is machined as a whole by CNC. The groove of the plate area (12) of the insertion plate is a rectangular groove (14). The wire hole (15) is located at the center of one end of the rectangular groove (14). The reinforcing support strip (7) is made of aluminum with an anodized outer surface and is fixed to the insertion plate (8) by screws.

5. The electromagnetic activation device for active control experiments of turbulent boundary layers according to claim 1, characterized in that, The activation plate base (9) is made of transparent acrylic and is connected and fixed to the insertion plate (8) by screws.

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