Hypersonic velocity boundary layer interference regulation and control method based on flow direction V-shaped sliding arc array

Abstract

The invention provides a flow direction V-shaped sliding arc array-based plasma exciter, which is characterized in that a bottom plate adopts an integrated step structure, and a plurality of groups of V-shaped electrode cavities are sequentially arranged in an upper-layer bottom plate along the flow direction and are used for placing copper electrodes and tungsten needle electrodes which penetrate through the upper-layer bottom plate and are electrically connected with a high-voltage-resistant silica gel lead penetrating through a lower-layer bottom plate. The invention further provides a power supply circuit of the plasma exciter based on the flow direction V-shaped sliding arc array. The power supply circuit comprises a direct-current power supply, a high-voltage pulse power supply, a first electronic switch Q1, a second electronic switch Q2, a first resistor R1, a second resistor R2, a first high-voltage silicon stack D1, a second high-voltage silicon stack D2 and an array formed by connecting a plurality of V-shaped sliding arc plasma exciters in series. In addition, the invention provides a hypersonic boundary layer interference regulation and control method based on the flow direction V-shaped sliding arc array. In hypersonic flow control, the method can effectively regulate and control shock wave / boundary layer interference, inhibit flow separation and optimize aerodynamic performance, and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the field of active flow control, and in particular to a plasma excitation device based on a flow-direction V-shaped sliding arc array. Background Art

[0002] In the field of aviation, for the problem of boundary layer interference control at hypersonic speeds, a pulsed surface arc plasma actuator is mostly used for flow control. As an active flow control device, this actuator has the advantages of fast response speed and high excitation intensity. It can inject a large amount of thermal energy into the flow field through arc heating in a short time, change the original shock wave structure or promote the momentum mixing inside the boundary layer through the thermal blockage effect, and thus achieve the purpose of suppressing flow separation. In recent years, many experimental research results have shown that pulsed surface arc plasma has good control ability over the shock wave position and shock wave / boundary layer interference in hypersonic flow. For example, by controlling the position and intensity of pulsed surface arc excitation, the flow separation phenomenon can be effectively improved, the aerodynamic performance can be adjusted to optimize the aerodynamic characteristics of the aircraft, and it has broad application prospects. However, when the actuator with multiple sets of electrodes arranged in the traditional method works in a low-pressure environment, not only the dielectric breakdown voltage threshold is high, but also problems such as insufficient excitation range, creeping discharge between groups, and low service life are prone to occur, and the expected excitation effect cannot be well generated.

[0003] In summary, designing a simple and efficient actuator structure to achieve pulsed surface arc plasma excitation is still an urgent problem to be studied and solved. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a plasma actuator based on a flow-direction V-shaped sliding arc array, specifically as follows:

[0005] The bottom plate adopts an integrated stepped structure. The whole bottom plate is a rectangular block, and a stepped structure with upper and lower layers is formed by cutting part of the material. Among them, the upper bottom plate 1 is large in size, and the lower bottom plate 5 is small in size. The centers of their projections on the horizontal plane coincide. The four sides of the lower bottom plate 5 are parallel to the four sides of the upper bottom plate 1 and maintain a certain distance. The upper bottom plate 1 is used to fix the electrodes and assemble with the experimental model, and the lower bottom plate 5 is used to fix the silica gel wires and assemble with the experimental model;

[0006] In the upper-layer bottom plate 1, an electrode cavity 2 in the shape of an "A-shaped keyway" is provided for placing a first electrode 7 that matches its shape and size; one end of the first electrode 7 is a semi-circular arc with a diameter equal to the width of the cavity, and the other end is cut off a semi-circular arc of the same diameter for mating with a second electrode 6 of the same diameter and being embedded into the cavity together; the electrode cavities 2 are arranged in pairs in a "V-shaped" form, with the upstream being the narrow-spacing end and the downstream being the wide-spacing end, and the size from the narrow spacing to the wide spacing is selected according to the model and experimental environment; concentric stepped holes are vertically drilled downward from the downstream end of each cavity through the upper-layer bottom plate 1 and the lower-layer bottom plate 5. Among them, a small cylindrical hole 3 is drilled through the part of the upper-layer bottom plate 1, with a diameter equal to the width of the electrode cavity, for installing the second electrode 6, and a large cylindrical hole 4 is drilled through the part of the lower-layer bottom plate 5, with a diameter larger than that of the small cylindrical hole 3, and the specific size should be the same as the diameter of the selected wire 8 for installing the wire 8. The small cylindrical hole 3 and the large cylindrical hole 4 have a coincident axis; finally, the second electrode 6 is electrically connected to the wire 8.

[0007] In the upper-layer bottom plate 1, multiple groups of V-shaped electrode cavities are arranged in sequence along the flow direction, and the symmetry axes of their projections on the horizontal plane are on a straight line, and this straight line coincides with the long-side symmetry axis of the upper-layer bottom plate 1. The first electrodes 7 are respectively installed in each V-shaped electrode cavity; the height of the small cylindrical hole 3 is the same as the thickness of the upper-layer bottom plate 1, and the height of the large cylindrical hole 5 is the same as the thickness of the lower-layer bottom plate; the lower end of the second electrode 6 is embedded in the wire 8, and the two are inserted upward from the bottom of the lower-layer bottom plate 5 into the stepped hole. Among them, the second electrode 6 is inserted into the above-mentioned small cylindrical hole 3, and the wire 8 is inserted and stuck in the large cylindrical hole 4. The upper surface of the second electrode 6 is flush with the surface of the first electrode 7; any one end wire of the first group of exciters along the flow direction is selected as the positive terminal, and the other end is the negative terminal. The positive terminal is connected to the high-voltage output terminal of the circuit, and the positive terminal directions of the remaining groups are the same as those of the first group; in a "Z-shaped" connection method, the negative terminal of the first group is connected to the positive terminal of the second group of exciters, the negative terminal of the second group is connected to the positive terminal of the third group of exciters, and so on. The negative terminal of the last group is connected to the wiring terminal of the circuit to realize the series power-on of multiple groups of exciters.

[0008] In an embodiment of the present invention, the size range of the upper-layer bottom plate 1 is as follows: the length is 60 - 80 mm, the width is 30 - 50 mm, and the height is 4 - 8 mm; the size range of the lower-layer bottom plate 5 is as follows: the length is 55 - 75 mm, the width is 25 - 45 mm, and the height is 4 - 8 mm.

[0009] In a specific embodiment of the present invention, the bottom plate is made of alumina ceramic material; the entire bottom plate is a rectangular block with rounded corners. The size range of the upper-layer bottom plate 1 is as follows: the length is 70 mm, the width is 40 mm, and the height is 5 mm; the size range of the lower-layer bottom plate 5 is as follows: the length is 64 mm, the width is 34 mm, and the height is 5 mm.

[0010] The second electrode 6 is a tungsten needle electrode;

[0011] The first electrode 7 is a copper electrode;

[0012] The wire 8 is a high-voltage-resistant silicone wire.

[0013] In another embodiment of the present invention, the length of the electrode cavity 2 is 10 - 15 mm, the width is 1 - 2 mm, and the height is 2 - 3 mm.

[0014] In another specific embodiment of the present invention, the length of the electrode cavity 2 is 12 mm, the width is 1.2 mm, and the height is 3 mm; the distance from the narrow spacing to the wide spacing of the electrode cavity 2 linearly increases from 3 mm to 10 mm.

[0015] In yet another specific embodiment of the present invention,

[0016] Three groups of V-shaped electrode cavities are arranged in sequence along the flow direction in the upper floor 1;

[0017] The diameter of the small cylindrical hole 3 is 1.2 mm and the height is 2 mm. The diameter of the large cylindrical hole 5 is 3 mm and the height is the same as the thickness of the lower floor; the lower end of the second electrode 6 is embedded in the wire 8 by about 2 - 3 mm;

[0018] The connection between the wire 8 and the bottom of the lower floor 5 is further fixed and sealed with insulating strong glue to prevent detachment.

[0019] There is also provided a working process of a plasma actuator based on a flow-direction V-shaped sliding arc array, which is based on the above-mentioned plasma actuator based on a flow-direction V-shaped sliding arc array. This process is divided into three stages: an energy deposition stage, an arc initiation stage, and an arc sliding stage, which are specifically as follows:

[0020] (1) Energy deposition stage: A high-frequency pulsed voltage of 10 kV - 30 kV and a DC voltage of 500 V - 1000 V are applied between the two electrodes of the actuator. The electric field rapidly increases, and the air between the electrodes gradually begins to be ionized, generating free electrons and ions; during this process, the frequency of the high-voltage pulsed power supply is 0.1 kHz - 30 kHz, which determines the change rate of the electric field and affects the initiation and discharge intensity of the arc;

[0021] (2) Arc initiation stage: Due to the geometric structure design of the V-shaped electrodes, the downstream gap is large and the upstream gap is small. The breakdown requirement is lower for the upstream than for the downstream. Therefore, the air between the upstream electrodes is first broken down to form a discharge arc;

[0022] (3) Arc sliding stage: After the arc startup stage, the arc that is first formed upstream on the surface of the V-shaped first electrode 7 starts to slide downstream. In the arc sliding region, the arc effectively converts electrical energy into heat energy, deposits it in the gas, and forms a high-temperature plasma; the arc excitation formed by each group of excitation sources slides from the upstream with a narrow pitch to the downstream with a wide pitch along the flow direction. Therefore, the flow direction excitation range is greatly increased, and it has a good flow control effect.

[0023] In addition, a power supply circuit for a plasma actuator based on a flow-direction V-shaped sliding arc array is provided. Based on the above-mentioned plasma actuator based on a flow-direction V-shaped sliding arc array, the power supply circuit includes a DC power supply, a high-voltage pulse power supply, first and second electronic switches Q1 and Q2, first and second resistors R1 and R2, first and second high-voltage silicon stacks D1 and D2, and an array formed by connecting a number of V-shaped sliding arc plasma actuators in series;

[0024] The high-voltage pulse power supply, the first high-voltage silicon stack D1, and the arrays of a plurality of V-shaped sliding arc plasma actuators are connected in series, and the negative terminal of the high-voltage pulse power supply is grounded to form a high-voltage breakdown circuit;

[0025] The first electronic switch Q1 and the first resistor R1 are connected in series to form a first switch branch; the second electronic switch Q2 and the second resistor R2 are connected in series to form a second switch branch; the two switch branches are connected in parallel to form a switch circuit; the DC power supply, the switch circuit, and the capacitor C1 form a series circuit, and the negative terminal of the DC power supply is grounded to form a DC power supply circuit; the DC power supply circuit, the second high-voltage silicon stack D2, and the high-voltage breakdown circuit form a series circuit, where the positive terminal of the second high-voltage silicon stack D2 is connected to the negative terminal of the switch branch, and the negative terminal is connected to the positive terminal of the first high-voltage silicon stack D1.

[0026] In addition, a power supply method for a power supply circuit of a plasma actuator based on a flow-direction V-shaped sliding arc array is provided. Based on the above-mentioned power supply circuit of a plasma actuator based on a flow-direction V-shaped sliding arc array, the method is as follows:

[0027] The high-voltage pulse power supply outputs a high-voltage pulse and applies it across the high-voltage silicon stack D1 and the plasma actuator array. When the pulse amplitude exceeds the sum of the breakdown voltages corresponding to the air gaps of all V-shaped sliding arc actuators, discharge breakdown is achieved to form an arc;

[0028] The DC power supply injects energy into the arc channel between the electrodes of multiple V-shaped sliding arc plasma actuator arrays through two resistors R1, R2, and two high-voltage silicon stacks D1, D2, generating a strong discharge current. During this process, the diameter of the discharge arc rapidly increases, the temperature rises, and the energy enhances. In addition, the two resistors R1 and R2 in the DC power supply circuit are connected in parallel and are respectively controlled by the corresponding two electronic switches Q1, Q2 to determine whether to be connected to the circuit, facilitating the comparison of the excitation effects of the actuators under different excitation energies. The capacitor C1 is connected in parallel across the second high-voltage silicon stack D2 and both ends of the V-shaped sliding arc plasma actuator array, used to quickly release the stored energy after the high-voltage pulse breakdown, establish a DC continuous current channel to ensure stable power supply, and at the same time, it can also absorb voltage spikes and suppress load fluctuations, reduce the power consumption of the DC circuit, and protect electronic components.

[0029] Finally, a method for regulating the hypersonic boundary layer interference based on the flow direction of the V-shaped sliding arc array is provided. Based on the above-mentioned plasma actuator based on the flow direction of the V-shaped sliding arc array and the power supply circuit of the above-mentioned plasma actuator based on the flow direction of the V-shaped sliding arc array, when three groups of excitation sources are arranged along the flow direction, during the arc discharge process, the first group of excitation sources generates high-temperature plasma. Part of the plasma will interact with the airflow in the boundary layer and participate in the boundary layer regulation. The regulation mechanism is that the high-energy ions in the plasma collide frequently with the gas molecules in the boundary layer, transferring energy and momentum, causing the original airflow velocity distribution in the boundary layer to change, inducing the generation of new velocity components, and at the same time changing the viscosity and temperature distribution of the gas, affecting the thickness and stability of the boundary layer. Another part will flow towards the regions where the second group and the third group of excitation sources are located under the action of the high-speed airflow. Due to the conductivity of the plasma itself, it will affect the electric field distribution, especially the synergistic effect of the high-temperature plasma and the hot airflow, making the electric field intensity on the surfaces of the second group and the third group of electrodes increase significantly. This effect directly leads to a decrease in the breakdown voltage requirements for the second group and the third group of excitation sources during operation, making it easier to generate arc discharge and generate high-temperature plasma. The high-temperature plasma generated by the second group of excitation sources, part of it participates in regulating the boundary layer, and the other part flows towards the region of the third group of excitation sources driven by the high-speed airflow. Its conductivity will further enhance the electric field intensity in the region of the third group of excitation sources, further reducing the breakdown voltage requirements for the third group of excitation sources. After being affected by the high-temperature plasma from the first group and the second group, the breakdown requirements for the third group of excitation sources are relatively lower, and it is easier to generate high-temperature plasma. This part of the plasma mainly interacts fully with the boundary layer in the subsequent region, transferring a large amount of energy and momentum to the airflow in the boundary layer, further strengthening the boundary layer regulation effect. Since the third group is the last group, the plasma generated by it will eventually gradually diffuse, mix, and dissipate during the process of regulating the boundary layer, completing the regulation process of the entire actuator on the high-speed boundary layer flow field.

[0030] The present invention provides a plasma actuator based on a flow-direction V-shaped sliding arc array and an implementation method, which solves the disadvantages of traditional array actuators, such as small flow-direction excitation range, easy creepage, and high breakdown requirements in low-voltage environments. In particular, the sliding of the V-shaped arc effectively slows down the ablation concentration phenomenon on the electrode surface, thereby reducing the damage of the high-temperature arc to the actuator and improving the service life of the actuator, which is of great significance for promoting the engineering application of active flow control.

[0031] The advantages of the present invention are as follows:

[0032] (1) Large excitation range. Different from the multi-path parallel intermittent and discontinuous arrangement method commonly used in traditional arc array actuators, under the premise of maintaining the same discharge coverage area, the present invention utilizes the characteristic of the continuous sliding of the arc along the V-shaped electrode surface to realize the flow-direction extension of the discharge trajectory and form a large-range continuous high-energy excitation region.

[0033] (2) Low breakdown voltage. The present invention follows the series form of "anode - cathode - anode - cathode..." of traditional arc array actuators in circuit connection, and the high-voltage pulse power supply needs to break down each path of electrodes simultaneously. Different from the traditional method, the V-shaped array structure adopted by the present invention has a relay effect. Part of the high-temperature plasma generated by the upstream electrode discharge moves to the downstream electrode region with the airflow, and the ions are coupled with the electric field between the downstream electrodes, enabling the subsequent electrodes to form a discharge channel at a lower voltage, thereby reducing the breakdown voltage of the series array electrodes. In particular, under the condition of the same flow-direction excitation range, the number of excitation paths of the present invention is less than that of the traditional structure. The combination of this structural characteristic and the above-mentioned plasma relay effect forms a double effect of reducing the breakdown voltage requirement.

[0034] (3) Arc erosion resistance and long service life. In traditional arc array actuators, due to the concentrated continuous discharge of the arc, serious ablation will occur in local areas, affecting performance and shortening the service life. Through the unique arc sliding effect of the present invention, the arc force of each path is evenly distributed on the electrode surface, effectively avoiding the ablation concentration phenomenon, reducing the local overheating and the damage speed of the material, thereby improving the service life. In addition, due to the continuous sliding of the arc, the surface material of the electrode can be "self-repaired" periodically, enabling it to maintain excellent stability and reliability in high-temperature and low-voltage environments. Brief Description of the Drawings

[0035] Figure 1 A top view showing the structure of the plasma actuator of the present invention;

[0036] Figure 2 A bottom view showing the structure of the plasma actuator of the present invention;

[0037] Figure 3 A front view showing the structure of the plasma actuator of the present invention;

[0038] Figure 4 Shows the three-dimensional modeling diagram of the plasma actuator of the present invention in the working state;

[0039] Figure 5 Shows the top view of the plasma actuator of the present invention in the working state;

[0040] Figure 6 Shows the schematic diagram of the power supply circuit of the plasma actuator of the present invention in the working state;

[0041] Figure 7 Shows the schematic structural diagram of the plasma actuator of the present invention applied to the compression corner model;

[0042] Figure 8 Shows the working mechanism diagram of the plasma actuator of the present invention applied to the compression corner model. Detailed implementation manners

[0043] The present invention will be described in detail below with reference to the accompanying drawings.

[0044] Figures 1 - 3 Shows the schematic structural diagram of the plasma actuator of the present invention. The bottom plate adopts an integral stepped structure and is made of alumina ceramic material. The whole bottom plate is a rectangular block with rounded corners, and a stepped structure with upper and lower layers is formed by cutting part of the material. Among them, the upper bottom plate 1 is larger in size, and the lower bottom plate 5 is smaller in size. The projection centers of the two on the horizontal plane coincide. The four sides of the lower bottom plate 5 are parallel to the four sides of the upper bottom plate 1 and maintain a certain distance. The size range of the upper bottom plate 1 is as follows: the length is 60 - 80 mm (preferably 70 mm), the width is 30 - 50 mm (preferably 40 mm), and the height is 4 - 8 mm (preferably 5 mm), which is used to fix the electrodes and assemble with the experimental model. The size range of the lower bottom plate 5 is as follows: the length is 55 - 75 mm (preferably 64 mm), the width is 25 - 45 mm (preferably 34 mm), and the height is 4 - 8 mm (preferably 5 mm), which is used to fix the silica gel wires and assemble with the above experimental model.

[0045] To achieve the sliding of the arc with the airflow, an electrode cavity 2 in the shape of an "A-shaped keyway" is provided in the upper bottom plate 1. The length of the cavity is 10 - 15 mm (preferably 12 mm), the width is 1 - 2 mm (preferably 1.2 mm), and the height is 2 - 3 mm (preferably 3 mm), which is used to place a copper electrode 7 that matches its shape and size. It should be noted that one end of the copper electrode 7 is a semi-circular arc with a diameter equal to the width of the cavity, and the other end is cut off a semi-circular arc of the same diameter for cooperation with a tungsten needle electrode 6 of the same diameter, and they are embedded into the cavity together. The above-mentioned electrode cavities 2 are arranged in pairs in a "V-shaped" form, with the narrow-spacing end upstream and the wide-spacing end downstream. The size from the narrow spacing to the wide spacing is reasonably selected according to the model and experimental environment, and preferably, the spacing linearly increases from 3 mm to 10 mm. Concentric stepped holes are vertically drilled downward from the downstream end (wide-spacing end) of each cavity through the upper bottom plate 1 and the lower bottom plate 5. Among them, a small cylindrical hole 3 with a diameter equal to the width of the electrode cavity is drilled through the part of the upper bottom plate 1 for installing the tungsten needle electrode 6, and a large cylindrical hole 4 with a diameter larger than that of the small cylindrical hole 3 is drilled through the part of the lower bottom plate 5. The specific size should be the same as the diameter of the selected high-voltage-resistant silicone wire 8 for installing the high-voltage-resistant silicone wire 8. The small cylindrical hole 3 and the large cylindrical hole 4 have coincident axes. Finally, the tungsten needle electrode 6 is electrically connected to the high-voltage-resistant silicone wire 8.

[0046] In an example of the present invention, three groups of V-shaped electrode cavities are arranged in sequence along the flow direction in the upper base plate 1, and the symmetry axes of their projections on the horizontal plane are on a straight line, which coincides with the long-side symmetry axis of the upper base plate 1. The copper electrodes 7 are respectively installed in each V-shaped electrode cavity. In a specific embodiment of the present invention, the diameter of the above-mentioned small cylindrical hole 3 is 1.2 mm, the height is 2 mm, and the height is the same as the thickness of the upper base plate 1; the diameter of the large cylindrical hole 5 is 3 mm, and the height is the same as the thickness of the lower base plate. The lower end of the tungsten needle electrode 6 is embedded in the high-voltage-resistant silicone wire 8 by about 2-3 mm, and the two are integrally inserted into the stepped hole from the bottom of the lower base plate 5. Among them, the tungsten needle electrode 6 is inserted into the above-mentioned small cylindrical hole 3, and the high-voltage-resistant silicone wire 8 is inserted into and stuck in the large cylindrical hole 4. The upper surface of the tungsten needle electrode 6 is flush with the surface of the copper electrode 7. The connection between the high-voltage-resistant silicone wire 8 and the bottom of the lower base plate 5 is further fixed and sealed with insulating strong glue to prevent falling off. Select any one end wire of the first group of exciters along the flow direction as the positive terminal, and the other end is the negative terminal. The positive terminal is connected to the high-voltage output terminal of the circuit, and the positive terminal directions of the remaining groups are the same as those of the first group. According to the "Z"-shaped connection method, connect the negative terminal of the first group to the positive terminal of the second group of exciters, connect the negative terminal of the second group to the positive terminal of the third group of exciters, and finally connect the negative terminal of the third group to the wiring terminal of the circuit, then the series power-on of the three groups of exciters can be realized. It should be particularly noted that if the high-voltage output terminal and the grounding terminal in the above connection method are exchanged, the series power-on effect of the three groups of exciters can also be achieved, and this series connection method is well known to those skilled in the art.

[0047] Figures 4 - 5 The working process of the plasma exciter of the present invention is shown, which is mainly divided into three stages: the energy deposition stage, the arc starting stage, and the arc sliding stage:

[0048] (1) Energy deposition stage: A high-frequency pulse voltage of 10 kV - 30 kV and a DC voltage of 500 V - 1000 V are applied between the two electrodes of the exciter. The electric field rapidly increases, and the air between the electrodes gradually begins to be ionized, generating free electrons and ions. During this process, the frequency of the high-voltage pulse power supply is 0.1 kHz - 30 kHz, which determines the change rate of the electric field and affects the arc starting and discharge intensity.

[0049] (2) Arc starting stage: Due to the geometric structure design of the V-shaped electrode, the downstream gap is large, the upstream gap is small, and the breakdown requirement is lower than that of the downstream. Therefore, the air between the upstream electrodes is first broken down to form a discharge arc.

[0050] (3) Arc sliding stage: After the arc startup stage, the arc that forms first on the upstream of the surface of the V-shaped copper electrode 7 starts to slide downstream. In the arc sliding region, the arc effectively converts electrical energy into heat energy, which is deposited in the gas to form a high-temperature plasma. The arc excitation formed by each group of excitation sources slides from the upstream with a narrow pitch to the downstream with a wide pitch along the flow direction. Therefore, the flow direction excitation range is greatly increased, and it has a good flow control effect in the research on hypersonic shock / boundary layer interference and can greatly reduce the cost investment. In the application example of the present invention, three groups of excitation sources are arranged along the flow direction. During the arc discharge process, the first group of excitation sources generates a high-temperature plasma. Part of the plasma will interact with the airflow in the boundary layer and participate in the boundary layer regulation. The regulation mechanism is that the high-energy ions in the plasma collide frequently with the gas molecules in the boundary layer, transferring energy and momentum, which changes the original airflow velocity distribution in the boundary layer, induces the generation of new velocity components, and at the same time changes the viscosity and temperature distribution of the gas, affecting the thickness and stability of the boundary layer. Another part will flow to the regions where the second group and the third group of excitation sources are located under the action of the high-speed airflow. Because the plasma itself has conductivity, it will affect the electric field distribution, especially the synergistic effect of the high-temperature plasma and the hot airflow, which significantly increases the electric field intensity on the surfaces of the second group and the third group of electrodes. This effect directly reduces the breakdown voltage requirement for the second group and the third group of excitation sources during operation, making it easier to generate arc discharge and generate high-temperature plasma; for the high-temperature plasma generated by the second group of excitation sources, part of it participates in the boundary layer regulation as described above, and the other part flows to the region of the third group of excitation sources driven by the high-speed airflow, and its conductivity will further enhance the electric field intensity in the region of the third group of excitation sources, further reducing the breakdown voltage requirement for the third group of excitation sources. After being affected by the high-temperature plasma from the first group and the second group, the third group of excitation sources has a relatively lower breakdown requirement and is more likely to generate high-temperature plasma. This part of the plasma mainly acts fully with the boundary layer in the subsequent region, transferring a large amount of energy and momentum to the airflow in the boundary layer, further strengthening the boundary layer regulation effect. Since the third group is the last group, the plasma generated by it will gradually diffuse, mix and dissipate during the process of regulating the boundary layer, completing the regulation process of the entire actuator on the high-speed boundary layer flow field.

[0051] Therefore, compared with the traditional pulsed arc plasma actuator, the flow direction excitation region of the V-shaped sliding arc array plasma actuator of the present invention is significantly improved, and the breakdown requirement is reduced, and it has a stronger flow control ability in occasions such as hypersonic shock / boundary layer interference and shock control that require a higher excitation frequency and a large excitation range.

[0052] Figure 6The power supply circuit of the plasma actuator of the present invention is shown. This circuit mainly includes a DC power supply (voltage in the kilovolt range), a high-voltage pulse power supply (pulse voltage 10 kV - 30 kV), first and second electronic switches Q1, Q2 (MOSFETs are recommended), first and second resistors R1, R2 (resistance value in the hundreds of ohms range), first and second high-voltage silicon stacks D1 and D2, and an array formed by connecting several V-shaped sliding arc plasma actuators in series.

[0053] In the circuit, the high-voltage pulse power supply, the first high-voltage silicon stack D1, and the array of multiple V-shaped sliding arc plasma actuators are connected in series. The negative terminal of the high-voltage pulse power supply is grounded to form a high-voltage breakdown loop. The high-voltage pulse power supply outputs a high-voltage pulse (parameters such as frequency and pulse width can be set according to specific experimental conditions. In this example, the recommended frequency range is 0.1 kHz - 30 kHz, and the pulse width is 500 ns - 1000 ns), which is applied across the first high-voltage silicon stack D1 and the plasma actuator array. When the pulse amplitude exceeds the sum of the breakdown voltages corresponding to the air gaps of all V-shaped sliding arc actuators, discharge breakdown occurs, forming an arc.

[0054] The first electronic switch Q1 and the first resistor R1 (resistance value in the order of 100 Ω) are connected in series to form a first switch branch; the second electronic switch Q2 and the second resistor R2 (resistance value in the order of 100 Ω) are connected in series to form a second switch branch. The two switch branches are connected in parallel to form a switch circuit. The DC power supply (recommended voltage value 500 V - 1000 V), the switch circuit, and the capacitor C1 (recommended capacitance 0.1 μF - 0.5 μF) form a series circuit, with the negative terminal of the DC power supply grounded to form a DC power supply loop. The DC power supply loop, the second high-voltage silicon stack D2, and the high-voltage breakdown loop form a series circuit, where the positive terminal of the second high-voltage silicon stack D2 is connected to the negative terminal of the switch branch, and the negative terminal is connected to the positive terminal of the first high-voltage silicon stack D1.

[0055] The DC power supply injects energy into the arc channel between the electrodes of the array of multiple V-shaped sliding arc plasma actuators through the two resistors R1, R2, and the two high-voltage silicon stacks D1, D2, generating a strong discharge current. During this process, the diameter of the discharge arc increases rapidly, the temperature rises, and the energy increases. In addition, the two resistors R1 and R2 in the DC power supply loop are connected in parallel and are respectively controlled by the corresponding two electronic switches Q1, Q2 to determine whether to be connected to the circuit, which is convenient for comparing the excitation effects of the actuator under different excitation energies. The capacitor C1 is connected in parallel across the second high-voltage silicon stack D2 and the V-shaped sliding arc plasma actuator array, mainly used to quickly release the stored energy after the high-voltage pulse breakdown, establish a DC continuous current channel to ensure stable power supply, and at the same time, it can also absorb voltage spikes and suppress load fluctuations, reduce the power consumption of the DC circuit, and protect electronic components.

[0056] Figure 7Shows the structural schematic diagram of the plasma actuator of the present invention in a compression corner flat plate model. The model consists of an array of V-shaped sliding arc plasma actuators 9, a compression corner flat plate 10, a tail strut 11, and auxiliary components such as bolts. The range of the leading edge wedge angle of the compression corner flat plate 10 is 15° to 25° (preferably 20°), and the slope of the tail compression corner ranges from 30° to 45°, which is specifically determined according to the wind speed and experimental environment. The array of V-shaped sliding arc plasma actuators 9 is placed in the hollow cavity in front of the compression corner. The shape and size of the cavity are the same as those of the actuator ceramic block. The range of the distance from the center of the cavity to the corner is 55 mm to 75 mm, and the specific value needs to be determined in combination with the experimental conditions. The upper surface of the actuator is flush with the upper surface of the flat plate. The orientation of the V-shaped electrodes of the actuator: the V-shaped opening faces the compression corner, that is, the direction from the narrow end to the wide end of the V-shaped electrode is the same as the air flow direction. The flat plate model equipped with the actuator is connected by bolts and cooperates with the tail strut 11. The tail strut 11 is used to fix the model on the wind tunnel test bench to ensure the normal conduct of the experiment. In this application, the array of V-shaped sliding arc plasma actuators of the present invention can adjust the number and spacing of the actuators as needed to optimize the excitation effect. The unique electrode shape and layout can greatly improve the plasma generation efficiency and effect, improve the air flow characteristics at the compression corner, and enhance the experimental performance of the model.

[0057] Figure 8 Shows the schematic diagram of the working mechanism of the plasma actuator of the present invention applied to a compression corner flat plate model. The plasma actuator interacts with the turbulent boundary layer through the periodic disturbance generated by high-frequency pulsed discharge, significantly reducing the turbulent pulsation energy and suppressing the growth of the separation bubble. At the same time, the local high-speed hot air flow caused by the discharge arc can adjust the direction of the compression wave, making the air flow pressure distribution more uniform, reducing the separation area, and significantly improving the air flow attachment characteristics in the corner area. In summary, the above schematic diagram provides an intuitive visual reference for studying the application of the invented actuator in the compression corner model.

[0058] When the actuator works, the high-energy arc continuously slides along the surface of the V-shaped electrode from the narrow-spacing end to the wide-spacing end, forming a large-range continuous high-energy excitation region, significantly enhancing the flow direction excitation range; by arranging three groups of V-shaped electrode cavity arrays along the flow direction, the requirement for the breakdown voltage can be reduced by using the relay effect; at the same time, the sliding effect of the arc slows down the ablation concentration phenomenon on the electrode surface, which helps to improve the service life and stability of the actuator; in the high-speed flow control of the present invention, it can effectively regulate the shock wave / boundary layer interference, suppress the flow separation, and optimize the aerodynamic performance, having a wide range of application prospects.

Claims

1. A plasma actuator based on a flow V-shaped sliding arc array, characterized in that: The details are as follows: The bottom plate adopts an integrated step structure, the entire bottom plate is a rectangular block, and a step structure with upper and lower layers is formed by cutting part of the material; wherein the upper bottom plate (1) is large in size, and the lower bottom plate (5) is small in size, and the projection centers of the two on the horizontal plane coincide, and the four sides of the lower bottom plate (5) are parallel to the four sides of the upper bottom plate (1) and maintain a certain distance; the upper bottom plate (1) is used to fix the electrode and is assembled with the experimental model, and the lower bottom plate (5) is used to fix the silicone wire and is assembled with the experimental model; An electrode cavity (2) shaped like an "A-type keyway" is provided in the upper bottom plate (1) for accommodating a first electrode (7) of a shape and size matching the cavity; one end of the first electrode (7) is a semicircular arc with a diameter the same as the width of the cavity, and the other end is cut off from a semicircular arc of the same diameter, so as to cooperate with a second electrode (6) of the same diameter and be embedded in the cavity together; the electrode cavities (2) are arranged in pairs in a "V-shape", with the upstream end being a narrow spacing end and the downstream end being a wide spacing end, and the size from the narrow spacing to the wide spacing is selected according to the model and the experimental environment; a plurality of electrodes (6) are provided vertically from the downstream end of each cavity. A concentric stepped hole is formed by penetrating the upper bottom plate (1) and the lower bottom plate (5) downwardly, wherein a small cylindrical hole (3) is formed in the portion penetrating the upper bottom plate (1), the diameter of which is the same as the width of the electrode cavity and is used to install the second electrode (6); a large cylindrical hole (4) is formed in the portion penetrating the lower bottom plate (5), the diameter of which is larger than the diameter of the small cylindrical hole (3) and the specific size of which is the same as the diameter of the selected wire (8) and is used to install the wire (8); the small cylindrical hole (3) and the large cylindrical hole (4) have overlapping axes; and finally the second electrode (6) is electrically connected to the wire (8); A plurality of groups of V-shaped electrode cavities are arranged in sequence along the flow direction in the upper bottom plate (1), and the symmetry axes projected on the horizontal plane are on a straight line, which coincides with the long side symmetry axis of the upper bottom plate (1). The first electrode (7) is installed in each V-shaped electrode cavity; the height of the small cylindrical hole (3) is consistent with the thickness of the upper bottom plate (1), and the height of the large cylindrical hole (4) is consistent with the thickness of the lower bottom plate; the lower end of the second electrode (6) is embedded in the wire (8), and the two are inserted into the step hole from the bottom of the lower bottom plate (5) upward as a whole, wherein the second electrode (6) is inserted into the small cylindrical hole (3), and the wire (8 ) is inserted and stuck in the large cylindrical hole (4), and the upper surface of the second electrode (6) is flush with the surface of the first electrode (7); any end of the wire along the flow to the first group of exciters is selected as the positive terminal, and the other end is the negative terminal, the positive terminal is connected to the high-voltage output end of the circuit, and the direction of the positive terminals of the remaining groups is the same as that of the first group; in a "Z"-shaped connection method, the negative terminal of the first group is connected to the positive terminal of the second group of exciters, the negative terminal of the second group is connected to the positive terminal of the third group of exciters, and so on, the negative terminal of the last group is connected to the wiring terminal of the circuit, so as to realize the series power-on of multiple groups of exciters.

2. The plasma actuator based on the flow V-shaped sliding arc array according to claim 1, characterized in that: The size range of the upper bottom plate (1) is as follows: length 60-80 mm, width 30-50 mm, height 4-8 mm; the size range of the lower bottom plate (5) is as follows: length 55-75 mm, width 25-45 mm, height 4-8 mm.

3. The plasma actuator based on the flow V-shaped sliding arc array according to claim 2, characterized in that: The bottom plate is made of alumina ceramic material; the entire bottom plate is a rectangular block with rounded corners, and the size range of the upper bottom plate (1) is as follows: length 70mm, width 40mm, height 5mm; the size range of the lower bottom plate (5) is as follows: length 64mm, width 34mm, height 5mm; The second electrode (6) is a tungsten needle electrode; The first electrode (7) is a copper electrode; The conductor (8) is a high-voltage resistant silicone conductor.

4. The plasma actuator based on the flow V-shaped sliding arc array according to claim 1, characterized in that: The electrode cavity (2) has a length of 10-15 mm, a width of 1-2 mm, and a height of 2-3 mm.

5. The plasma actuator based on the flow V-shaped sliding arc array according to claim 1, characterized in that: The length of the electrode cavity (2) is 12 mm, the width is 1.2 mm, and the height is 3 mm; the spacing from the narrow spacing to the wide spacing of the electrode cavity (2) increases linearly from 3 mm to 10 mm.

6. The plasma actuator based on the flow V-shaped sliding arc array according to claim 1, characterized in that: Three groups of V-shaped electrode cavities are arranged in sequence along the flow direction in the upper bottom plate (1); The diameter of the small cylindrical hole (3) is 1.2 mm and the height is 2 mm. The diameter of the large cylindrical hole 5 is 3 mm and the height is consistent with the thickness of the lower bottom plate. The lower end of the second electrode (6) is embedded in the wire (8) by about 2-3 mm. The joint between the wire (8) and the bottom of the lower bottom plate (5) is further fixed and sealed with insulating strong glue to prevent it from falling off.

7. The working process of the plasma actuator based on the flow V-shaped sliding arc array, which is based on the plasma actuator based on the flow V-shaped sliding arc array according to any one of claims 1 to 6, characterized in that: The process is divided into three stages: energy deposition stage, arc starting stage, and arc sliding stage, as follows: (1) Energy deposition stage: A high-frequency pulse voltage of 10-30 kV and a DC voltage of 500-1000 V are applied between the two electrodes of the exciter. The electric field is rapidly enhanced, and the air between the electrodes gradually begins to be ionized, generating free electrons and ions. During this process, the frequency of the high-voltage pulse power supply is 0.1 kHz-30 kHz, which determines the rate of change of the electric field and affects the start-up and discharge intensity of the arc. (2) Arc starting stage: Due to the geometric structure design of the V-shaped electrode, the downstream gap is large and the upstream gap is small, and the breakdown requirement is lower than that of the downstream. Therefore, the air between the upstream electrodes is broken down first, forming a discharge arc; (3) Arc sliding stage: After the arc starting stage, the arc first formed on the surface of the V-shaped first electrode (7) begins to slide downstream. In the arc sliding area, the arc effectively converts electrical energy into thermal energy, which is deposited in the gas to form a high-temperature plasma. The arc excitation formed by each group of excitation sources slides along the flow direction from the upstream with a narrow spacing to the downstream with a wide spacing. Therefore, the flow direction excitation range is greatly increased, and a good flow control effect is achieved.

8. A power supply circuit for a plasma actuator based on a flow-direction V-shaped sliding arc array, which is based on the plasma actuator based on a flow-direction V-shaped sliding arc array as claimed in any one of claims 1 to 6, characterized in that: The power supply circuit comprises a DC power supply, a high-voltage pulse power supply, a first and a second electronic switch Q1, Q2, a first and a second resistor R1, R2, a first and a second high-voltage silicon stack D1 and D2, and an array formed by a plurality of V-shaped sliding arc plasma actuators connected in series; A high-voltage pulse power supply, a first high-voltage silicon stack D1, and a plurality of V-shaped sliding arc plasma exciter arrays are connected in series, and the negative end of the high-voltage pulse power supply is grounded to form a high-voltage breakdown circuit; The first electronic switch Q1 and the first resistor R1 are connected in series to form a first switch branch; the second electronic switch Q2 and the second resistor R2 are connected in series to form a second switch branch; the two switch branches are connected in parallel to form a switch circuit; the DC power supply, the switch circuit, and the capacitor C1 form a series loop, and the negative end of the DC power supply is grounded to form a DC power supply loop; the DC power supply loop, the second high-voltage silicon stack D2, and the high-voltage breakdown loop form a series loop, wherein the positive end of the second high-voltage silicon stack D2 is connected to the negative end of the switch branch, and the negative end is connected to the positive end of the first high-voltage silicon stack D1.

9. A power supply method for a power supply circuit of a plasma actuator based on a flow to V-shaped sliding arc array, which is based on the power supply circuit of a plasma actuator based on a flow to V-shaped sliding arc array as claimed in claim 8, characterized in that: The method is as follows: The high-voltage pulse power supply outputs a high-voltage pulse applied to the high-voltage silicon stack D1 and the plasma actuator array. When the pulse amplitude exceeds the sum of the breakdown voltages corresponding to the air gaps of all V-shaped sliding arc actuators, discharge breakdown is achieved to form an arc. The DC power supply injects energy into the arc channel between the electrodes of the multiple V-shaped sliding arc plasma exciter arrays through two resistors R1 and R2 and two high-voltage silicon stacks D1 and D2, generating a strong discharge current. In this process, the discharge arc diameter increases rapidly, the temperature rises, and the energy is enhanced. In addition, the two resistors R1 and R2 in the DC energy supply circuit are connected in parallel, and whether to connect to the circuit is controlled by the corresponding two electronic switches Q1 and Q2, respectively, so as to facilitate the comparison of the excitation effect of the exciter under different excitation energies. The capacitor C1 is connected in parallel to the second high-voltage silicon stack D2 and the V-shaped sliding arc plasma exciter array, and is used to quickly release the stored energy after the high-voltage pulse breaks down, establish a DC freewheeling channel to ensure stable energy supply, and at the same time reduce the power consumption of the DC circuit and protect electronic components by absorbing voltage spikes and smoothing load fluctuations.

10. A method for controlling hypersonic boundary layer interference based on a flow V-shaped sliding arc array, which is based on the plasma actuator based on a flow V-shaped sliding arc array according to any one of claims 1 to 6, and the power supply circuit of the plasma actuator based on a flow V-shaped sliding arc array according to claim 8, characterized in that: When three groups of excitation sources are arranged along the flow direction, during the arc discharge process, the first group of excitation sources generates high-temperature plasma, and a part of the plasma will interact with the airflow in the boundary layer and participate in the boundary layer regulation. The regulation mechanism is that the high-energy ions in the plasma frequently collide with the gas molecules in the boundary layer, transferring energy and momentum, causing the original airflow velocity distribution in the boundary layer to change, inducing the generation of new velocity components, and changing the viscosity and temperature distribution of the gas at the same time, affecting the thickness and stability of the boundary layer. The other part will flow to the area where the second and third groups of excitation sources are located under the support of high-speed airflow. Because the plasma itself is conductive, it will affect the electric field distribution, especially the synergistic effect of high-temperature plasma and hot airflow, which significantly increases the electric field intensity on the surface of the second and third groups of electrodes; this effect directly leads to a reduction in the breakdown voltage requirements required for the second and third groups of excitation sources when they are working, making it easier to generate arc discharge and high-temperature plasma; A part of the high-temperature plasma generated by the second group of excitation sources participates in regulating the boundary layer, and the other part flows to the third group of excitation sources under the drive of the high-speed airflow. Its conductivity will further enhance the electric field strength in the third group of excitation sources, so that the breakdown voltage requirement of the third group of excitation sources is further reduced; after being affected by the high-temperature plasma from the first and second groups, the third group of excitation sources has a relatively lower breakdown requirement and is easier to generate high-temperature plasma. This part of the plasma mainly interacts fully with the boundary layer in the subsequent area, transfers a large amount of energy and momentum to the airflow in the boundary layer, and further enhances the boundary layer regulation effect. Since the third group is the last group, the plasma it generates will eventually diffuse, mix and dissipate gradually in the process of regulating the boundary layer, completing the entire process of the exciter regulating the high-speed boundary layer flow field.

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