Plasma discharge apparatus generating a cross-induction vortex and method of use

Abstract

The application relates to a plasma discharge device generating cross-induction vortex and a use method, and belongs to the technical field of active flow control. The application utilizes the interaction between multiple vortex pairs to form a cross-vortex phenomenon, promotes the vortex continuously generated by pulse modulation to periodically have higher convection velocity and momentum flux on the basis of original characteristics, breaks the traditional surface dielectric barrier discharge single machine layout mode, solves the limitations of existing plasma-induced air flow in flow control, has better flow control performance, and has better service performance in flow separation, vortex breaking and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of active flow control, in particular to a plasma discharge device for generating cross-induced vortex and a use method thereof. BACKGROUND

[0002] When fluid flows on the surface or inside an object, it is easy to form unstable boundary layer, separation flow, shedding vortex and other phenomena due to factors such as pressure gradient and velocity gradient, which has certain negative impact in practical application. In order to change the flow characteristics, active flow control is one of the main methods. This method introduces additional airflow through certain energy consumption, which is coupled with the original flow to achieve improvement or suppression of the original flow structure.

[0003] Surface dielectric barrier discharge device is widely used in active flow control due to its simple structure, high robustness, easy control and low power, and the plasma induced airflow generated thereby can effectively control boundary layer instability, wing separation flow, blunt body shedding vortex and the like.

[0004] At present, the generation mode of surface dielectric barrier discharge includes continuous induced airflow with continuous excitation and pulse induced airflow with signal modulation. The continuous induced airflow generally has high speed and momentum flux, but the effective range and vortex flux are small. On the contrary, the pulse induced airflow has high effective range and vortex flux, but the speed and momentum flux are small. It can be seen that the actual performance of the surface dielectric barrier discharge device in the prior art in flow control is low, and the application range is narrow. At present, there is no device that generates plasma induced airflow with high speed, momentum flux, high effective range and high vortex flux at the same time. SUMMARY

[0005] In view of the above problems, the present application provides a discharge device for generating cross plasma induced vortex and a use method thereof, which utilizes the interaction between multiple vortex pairs to form a cross phenomenon between the vortexes, promotes the vortexes generated continuously with pulse modulation to periodically have higher convective speed and momentum flux on the basis of the original characteristics, breaks the traditional surface dielectric barrier discharge single machine layout mode, solves the limitations of the existing plasma induced airflow in flow control, has better flow control performance, and has better service performance in flow separation, vortex breaking and the like.

[0006] The present application provides a dielectric barrier discharge device for generating cross plasma induced vortex, comprising:

[0007] an insulating plate 1 and a discharge device one and a discharge device two placed at both ends of the insulating plate in a facing manner;

[0008] In one embodiment of the present application, the discharge device one comprises an exposed electrode one 2, an insulation medium one 4 and an encapsulated electrode one 3;

[0009] The discharge device two comprises an exposed electrode two, an insulation medium two and an encapsulated electrode two;

[0010] The encapsulated electrode one is arranged inside the insulation medium one near the side of the end of the insulation flat plate; the exposed electrode one is arranged outside the insulation medium one far from the side of the end of the insulation flat plate;

[0011] The encapsulated electrode two is arranged inside the insulation medium two near the side of the discharge end of the insulation flat plate; the exposed electrode two is arranged outside the insulation medium two far from the side of the discharge end of the insulation flat plate;

[0012] The encapsulated electrode one and the encapsulated electrode two are arranged concentrically outside the insulation flat plate; the end of the encapsulated electrode one 3 is aligned with the end of the insulation flat plate 1; the end of the encapsulated electrode two is aligned with the end of the insulation flat plate 1;

[0013] The exposed electrode one and the exposed electrode two are arranged concentrically outside the insulation medium one and the insulation medium two;

[0014] The length ratio of the encapsulated electrode one, the exposed electrode one, the insulation medium one and the insulation flat plate is 1:1:2:4;

[0015] Preferably, the relative dielectric constant of the insulation medium one 4 is 2-6;

[0016] Illustratively, the insulation flat plate 1 is acrylic organic glass; the exposed electrode one 2, the exposed electrode two, the encapsulated electrode one 3 and the encapsulated electrode two are all copper foils; the insulation medium one 4 and the insulation medium two are polyimide films.

[0017] Preferably, the discharge device one and the discharge device two are surface dielectric barrier discharge device one and surface dielectric barrier discharge device two respectively;

[0018] Another object of the present application is to provide a method for using the plasma discharge device for generating cross plasma induced eddy current, comprising:

[0019] Driving the dielectric barrier discharge device with a voltage; the voltage is high-frequency high-amplitude alternating voltage;

[0020] Setting a modulation frequency and an excitation voltage source;

[0021] The excitation voltage source is connected with the signal generator, and outputs a periodic excitation voltage based on the preset modulation frequency. The discharge device one and the discharge device two periodically generate discharges based on the periodic excitation voltage. During the discharging process, the discharge device one and the discharge device two periodically generate multiple groups of vortex pairs rotating in opposite directions based on the multiple groups of vortex pairs rotating in opposite directions, and multiple groups of spanning plasma vortex structures are formed based on the multiple groups of vortex pairs rotating in opposite directions.

[0022] Preferably, the signal generator is a square wave signal generator, a sine wave signal generator or a triangular wave signal generator.

[0023] In the present application, after the excitation voltage source is connected with the signal generator, a periodic excitation voltage is outputted based on the preset modulation frequency. The air around the discharge device one and the discharge device two is ionized to generate ion one and ion two based on the periodic excitation voltage. The ion one and the ion two move under the action of the electric field and respectively transfer momentum to adjacent molecule one and molecule two to form induced velocity one and induced velocity two which are emitted from the discharge device one and the discharge device two along the horizontal direction. The molecule one and the molecule two continuously move backward along the horizontal direction according to the induced velocity one and the induced velocity two, respectively, to promote the surrounding molecules of the molecule one and the molecule two to move to the middle to maintain the continuity of the air medium, and then form upward and downward opposite rotating movements to obtain counterclockwise rotating vortexes and clockwise rotating vortexes. Corresponding vortex pairs rotating in opposite directions are formed based on the counterclockwise rotating vortexes and the clockwise rotating vortexes. Multiple groups of vortex pairs rotating in opposite directions are periodically generated by the dielectric barrier discharge device, and multiple groups of spanning plasma vortex structures are formed based on the multiple groups of vortex pairs rotating in opposite directions.

[0024] Preferably, the amplitude of the excitation voltage can ionize the air to form discharges without breaking the insulating medium; and the excitation frequency of the excitation voltage is above kHz.

[0025] Preferably, during the discharging process, multiple groups of vortex pairs rotating in opposite directions are generated, wherein each two groups of vortex pairs rotating in opposite directions form a period, that is, multiple groups of vortex pairs rotating in opposite directions are periodically generated during the discharging process; and two groups of vortex pairs rotating in opposite directions generated in each period form a spanning plasma vortex structure.

[0026] It can be understood that the spanning plasma vortex structure, that is, the two groups of vortex pairs rotating in opposite directions, span each other.

[0027] Exemplarily, the spanning plasma vortex structure includes vortex pair one 51 and vortex pair two 52; and the vortex pair one 51 and the vortex pair two 52 are adjacent vortex pairs.

[0028] Further, the adjacent vortex pair one 51 and vortex pair two 52 generate vortex interaction, the induced velocity of the vortex pair one 51 reduces the distance between the counterclockwise vortex P2 and the clockwise vortex N2 in the vortex pair two 52, and enhances the convection velocity of the counterclockwise vortex P2 and the clockwise vortex N2 in the vortex pair two 52; on the contrary, the induced velocity of the vortex pair two 52 increases the distance between the counterclockwise vortex P1 and the clockwise vortex N1 in the vortex pair one 51, and reduces the convection velocity of the counterclockwise vortex P1 and the clockwise vortex N1 in the vortex pair one 51, thereby forming the convection velocity difference between the vortex pair one and the vortex pair two, and making the vortex pair two 52 catch up with and cross the vortex pair one 51 based on the convection velocity difference.

[0029] Further, according to the Biot-Savart law, the adjacent vortex pair generates vortex interaction, the vortex pair one 51 is a front vortex, and the vortex pair two 52 is a rear vortex; the induced velocity of the front vortex reduces the vortex distance h2 between the counterclockwise vortex P2 and the clockwise vortex N2 in the rear vortex, and enhances the vortex convection velocity of the rear vortex; on the contrary, the induced velocity of the rear vortex increases the vortex distance h1 between the counterclockwise vortex P1 and the clockwise vortex N1 in the front vortex, and reduces the vortex convection velocity of the front vortex; the convection velocity difference between the vortex pairs makes the rear vortex gradually approach the front vortex, until the rear vortex exceeds the front vortex, and completes the crossing behavior, and the spatial positions of the front vortex and the rear vortex are exchanged, thereby preparing for the next crossing behavior. Figure 2 ;

[0030] For example, the vortex pair two 52 includes the counterclockwise vortex P2 and the clockwise vortex N2.

[0031] The vortex pair one 51 includes the counterclockwise vortex P1 and the clockwise vortex N1.

[0032] The ratio of the convection velocity of the counterclockwise vortex P2 and the clockwise vortex N2 in the vortex pair two 52 to the convection velocity of the counterclockwise vortex P1 and the clockwise vortex N1 in the vortex pair one 51 is greater than 1, thereby forming the convection velocity difference between the vortex pairs.

[0033] In an embodiment of the present application, the crossing plasma vortex structure includes the vortex pair one and the vortex pair two; the circulation in the vortex pair one and the vortex pair two reaches a maximum value at the same increasing rate, and then the circulation attenuates.

[0034] Further, the circulation attenuation rate of the vortex pair one is less than the circulation attenuation rate of the vortex pair two.

[0035] The ratio of the circulation attenuation rate of the vortex pair two to the circulation attenuation rate of the vortex pair one is greater than 1, thereby forming the convection velocity difference between the vortex pairs.

[0036] Further, the expression of the circulation of the vortex pair one and the vortex pair two in the cross plasma vortex structure is as follows:

[0037] Gamma * = Gamma0 / x0U0

[0038] Wherein, Gamma * is the dimensionless start vortex circulation of the cross plasma vortex structure, U0 is the initial convection velocity between the vortex pair one and the vortex pair two, x0 is the initial convection distance between the vortex pair one and the vortex pair two, and Gamma0 is the initial circulation intensity of the vortex pair one or the vortex pair two.

[0039] Further, the present application further comprises the dimensionless time of forming the cross plasma vortex structure, and the expression is as follows:

[0040] T * =tU0 2 / v

[0041] Wherein, T * is the dimensionless time of forming the cross plasma vortex structure, t is the discharge time, U0 is the initial convection velocity between the vortex pair one and the vortex pair two, and v is the kinematic viscosity of air.

[0042] The cross plasma vortex structure in the present application realizes the periodic cross motion, and the vortex pair one (the front vortex pair) in the cross plasma vortex structure has an increasing trend of the vortex distance due to the vortex induction velocity of the vortex pair two (the rear vortex pair), and the convection velocity of the corresponding vortex pair one decreases; while the vortex pair two has a smaller vortex distance due to the induced air flow of the vortex pair one, and has a convection velocity greater than that of the vortex pair one. Correspondingly, the velocity difference between the two vortex pairs makes the rear vortex pair constantly chase and approach the front vortex pair, and the chasing, crossing and overtaking behavior is completed within a certain time.

[0043] The crossing behavior between the double vortex pairs in the cross plasma vortex structure in the present application is accompanied by strong turbulent kinetic energy and Reynolds stress, effectively enhances the momentum and vorticity exchange between the vortex pairs, and correspondingly generates strong momentum and vorticity flux, which can enhance the flow control performance of the plasma induced air flow.

[0044] Compared with the prior art, the present application has at least the following beneficial effects:

[0045] (1) The present application can periodically generate the cross continuous reverse vortex pair by symmetrically placing two discharge devices and adopting the selected excitation mode, and the cross continuous reverse vortex pair has high speed, effective range, momentum flux and vorticity flux at the same time, and can realize better flow control effect;

[0046] (2) The cross-type vortex velocity and frequency generated by the present application are controlled by the excitation voltage and the modulation signal respectively, and the cross-type vortex phenomenon with larger velocity and higher frequency can be generated;

[0047] (3) The device of the present application is composed of electrodes with micron-level thickness, insulating medium and insulating plates with millimeter-level thickness, without any large power loading system, and has simple overall structure and convenient modulation, and can be arranged on an object without changing the shape of the object, so that active flow control is realized. BRIEF DESCRIPTION OF DRAWINGS

[0048] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated herein and constitute a part of the detailed description. The drawings illustrate embodiments of the present application and, together with the detailed description, serve to explain the principles of the present application.

[0049] Figure 1 The figure is a schematic diagram of the cross-type plasma-induced vortex generation device in the embodiment of the present application;

[0050] Figure 2 The figure is a process diagram of the cross-type plasma-induced vortex formation in the embodiment of the present application;

[0051] Figure 3 The figure is a schematic diagram of the key parameter values of the cross-type plasma-induced vortex formation in the embodiment of the present application;

[0052] Figure 4 The figure is a schematic diagram of the motion characteristics of the cross-type plasma-induced vortex in the embodiment of the present application;

[0053] Figure 5 The figure is a schematic diagram of the cross-type plasma-induced vortex circulation variation in the embodiment of the present application;

[0054] Figure 6 The figure is a comparison diagram of the cross-type plasma-induced vortex characteristics in the embodiment of the present application.

[0055] Reference signs:

[0056] 1 insulating plate, 2 exposed electrode, 3 encapsulated electrode, 4 insulating medium, 51 vortex pair 1, 52 vortex pair 2 DETAILED DESCRIPTION

[0057] In order to enable the above-mentioned objects, features and advantages of the present application to be more clearly understood, the present application will be further described below with reference to the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. In addition, the present application can also be implemented in other ways different from those described herein, and therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0058] One specific embodiment of the present application is as follows: Figures 1-6In order to illustrate the effectiveness of the method of the present application, the above technical solutions of the present application are described in detail below through a specific embodiment, and the specific implementation steps are as follows:

[0059] The present application provides a kind of medium resistance discharge equipment of cross type plasma induced vortex, comprising:

[0060] Insulating plate 1 and discharge device one and discharge device two are placed in the way of facing each other at both ends of insulating plate;

[0061] In one embodiment of the present application, the discharge device one includes exposed electrode one 2, insulating medium one 4 and encapsulated electrode one 3;

[0062] The discharge device two includes exposed electrode two, insulating medium two and encapsulated electrode two;

[0063] The encapsulated electrode one is arranged inside the insulating medium one close to one side of the end of the insulating plate;The exposed electrode one is arranged outside the insulating medium one away from one side of the end of the insulating plate;

[0064] The encapsulated electrode two is arranged inside the insulating medium two close to one side of the discharge end of the insulating plate;The exposed electrode two is arranged outside the insulating medium two away from one side of the discharge end of the insulating plate;

[0065] The encapsulated electrode one and the encapsulated electrode two are arranged concentrically outside the insulating plate;The end of the encapsulated electrode one 3 is aligned with the end of the insulating plate 1;The end of the encapsulated electrode two is aligned with the end of the insulating plate 1;

[0066] The exposed electrode one and the exposed electrode two are arranged concentrically outside the insulating medium one and the insulating medium two;

[0067] The length ratio of the encapsulated electrode one, the exposed electrode one, the insulating medium one and the insulating plate is 1:1:2:4;

[0068] Preferably, the relative dielectric constant of the insulating medium one 4 is 2-6;

[0069] Illustratively, the insulating plate 1 is acrylic organic glass;The exposed electrode one 2, the exposed electrode two, the encapsulated electrode one 3 and the encapsulated electrode two are all copper foil;The insulating medium one 4 and the insulating medium two are polyimide film.

[0070] Preferably, the discharge device one and the discharge device two are surface dielectric barrier discharge device one and surface dielectric barrier discharge device two respectively;

[0071] Another object of the present application is to provide a use method of a plasma discharge device generating cross type plasma induced vortex, comprising:

[0072] The dielectric barrier discharge device is driven by using a voltage; the voltage is a high-frequency and high-amplitude alternating voltage;

[0073] A preset modulation frequency and an excitation voltage source are provided;

[0074] The excitation voltage source is connected with a signal generator, and based on the preset modulation frequency, a periodic excitation voltage is outputted, and based on the periodic excitation voltage, the discharge device one and the discharge device two periodically generate discharges, and during the discharges, the discharge device one and the discharge device two periodically generate multiple groups of reverse rotating vortex pairs, and based on the multiple groups of reverse rotating vortex pairs, multiple groups of spanning plasma vortex structures are formed;

[0075] Preferably, the signal generator is a square wave signal generator, a sine wave signal generator or a triangular wave signal generator.

[0076] In the present application, after the excitation voltage source is connected with the signal generator, based on the preset modulation frequency, a periodic excitation voltage is outputted, and based on the periodic excitation voltage, the air around the discharge device one and the discharge device two is ionized to generate ion one and ion two, and the ion one and the ion two move under the action of the electric field and respectively transmit momentum to adjacent molecule one and molecule two to form induced velocity one and induced velocity two which are emitted from the discharge device one and the discharge device two along the horizontal direction, and the molecule one and the molecule two continuously move backward along the horizontal direction according to the induced velocity one and the induced velocity two to respectively promote the surrounding molecules of the molecule one and the molecule two to move to the middle to maintain the continuity of the air medium, and then form upward and downward opposite rotating movements to obtain counterclockwise rotating vortexes and clockwise rotating vortexes, and based on the counterclockwise rotating vortexes and the clockwise rotating vortexes, corresponding reverse rotating vortex pairs are formed; the dielectric barrier discharge device periodically generates multiple groups of reverse rotating vortex pairs, and based on the multiple groups of reverse rotating vortex pairs, multiple groups of spanning plasma vortex structures are formed.

[0077] Preferably, the amplitude of the excitation voltage can ionize the air to form discharges without breaking the insulating medium; and the excitation frequency of the excitation voltage is above kHz.

[0078] Preferably, during the discharges, multiple groups of reverse rotating vortex pairs are generated, wherein, every two groups of reverse rotating vortex pairs form a period, that is, multiple groups of reverse rotating vortex pairs are periodically generated during the discharges; and the two groups of reverse rotating vortex pairs generated in each period form a spanning plasma vortex structure.

[0079] It can be understood that the spanning plasma vortex structure is that two groups of reverse rotating vortex pairs span each other.

[0080] Exemplarily, the crosswise plasma vortex structure comprises: vortex pair one 51 and vortex pair two 52; the vortex pair one 51 and the vortex pair two 52 are adjacent vortex pairs;

[0081] Further, the adjacent vortex pair one 51 and the vortex pair two 52 generate vortex interaction, the induced velocity of the vortex pair one 51 reduces the distance between the counterclockwise rotating vortex P2 and the clockwise rotating vortex N2 in the vortex pair two 52, and enhances the convection velocity of the counterclockwise rotating vortex P2 and the clockwise rotating vortex N2 in the vortex pair two 52; on the contrary, the induced velocity of the vortex pair two 52 increases the distance between the counterclockwise rotating vortex P1 and the clockwise rotating vortex N1 in the vortex pair one 51, and reduces the convection velocity of the counterclockwise rotating vortex P1 and the clockwise rotating vortex N1 in the vortex pair one 51, thereby forming a convection velocity difference between the vortex pair one and the vortex pair two, and enabling the vortex pair two 52 to catch up with and cross the vortex pair one 51 based on the convection velocity difference.

[0082] Further, according to the Biot-Savart law, the adjacent two vortex pairs generate vortex interaction, the vortex pair one 51 is a front vortex, and the vortex pair two 52 is a rear vortex; the induced velocity of the front vortex reduces the vortex distance h2 between the counterclockwise rotating vortex P2 and the clockwise rotating vortex N2 in the rear vortex, and enhances the vortex convection velocity of the rear vortex; on the contrary, the induced velocity of the rear vortex increases the vortex distance h1 between the counterclockwise rotating vortex P1 and the clockwise rotating vortex N1 in the front vortex, and reduces the vortex convection velocity of the front vortex; the convection velocity difference between the vortex pairs enables the rear vortex to gradually approach the front vortex, until the rear vortex exceeds the front vortex, and completes the cross behavior; the spatial positions of the front vortex and the rear vortex are exchanged, and are prepared for the next cross behavior; as shown in the following figure: Figure 2 ;

[0083] Exemplarily, the vortex pair two 52 comprises the counterclockwise rotating vortex P2 and the clockwise rotating vortex N2;

[0084] The vortex pair one 51 comprises the counterclockwise rotating vortex P1 and the clockwise rotating vortex N1;

[0085] The ratio of the convection velocity of the counterclockwise rotating vortex P2 and the clockwise rotating vortex N2 in the vortex pair two 52 to the convection velocity of the counterclockwise rotating vortex P1 and the clockwise rotating vortex N1 in the vortex pair one 51 is greater than 1, thereby forming a convection velocity difference between the vortex pairs.

[0086] In one embodiment of the present application, the crosswise plasma vortex structure comprises the vortex pair one and the vortex pair two; the circulation in the vortex pair one and the vortex pair two reaches a maximum value at a same increasing rate, and then the circulation attenuates.

[0087] Further, the circulation attenuation rate of the vortex pair one is less than the circulation attenuation rate of the vortex pair two;

[0088] The ratio of the circulation decay rate of the vortex pair two to the circulation decay rate of the vortex pair one is greater than 1, forming a convection velocity difference between the vortex pairs.

[0089] Further, the expression of the circulation in the vortex pair one and the vortex pair two in the cross-type plasma vortex structure is:

[0090] Gamma * = Gamma0 / x0 U0

[0091] Wherein, Gamma * is the dimensionless start vortex circulation of the cross-type plasma vortex structure, U0 is the initial convection velocity between the vortex pair one and the vortex pair two, x0 is the initial convection distance between the vortex pair one and the vortex pair two, and Gamma0 is the initial circulation intensity of the vortex pair one or the vortex pair two.

[0092] Further, the present application also includes the dimensionless time for forming the cross-type plasma vortex structure, and the expression is:

[0093] T * = t U0 2 / v

[0094] Wherein, T * is the dimensionless time for forming the cross-type plasma vortex structure, t is the discharge time, U0 is the initial convection velocity between the vortex pair one and the vortex pair two, and v is the kinematic viscosity of air.

[0095] The cross-type plasma vortex structure in the present application realizes the periodic cross movement, and the vortex pair one (the front vortex pair) in the cross-type plasma vortex structure has an increasing trend of the vortex distance due to the vortex induction velocity of the vortex pair two (the rear vortex pair), and the convection velocity of the vortex pair one decreases; while the vortex pair two has a smaller vortex distance due to the induced air flow of the vortex pair one, and has a convection velocity greater than that of the vortex pair one. Correspondingly, the velocity difference between the two vortex pairs makes the rear vortex pair constantly chase and approach the front vortex pair, and the chasing, crossing and overtaking behavior is completed within a certain time.

[0096] The crossing behavior between the two vortex pairs in the cross-type plasma vortex structure in the present application is accompanied by strong turbulent kinetic energy and Reynolds stress, effectively enhancing the momentum and vorticity exchange between the vortex pairs, and correspondingly generating strong momentum and vorticity flux, which can enhance the flow control performance of the plasma-induced air flow.

[0097] Embodiment one

[0098] A dielectric barrier discharge device for generating transgressive plasma-induced eddy currents consists of an insulating plate 1, an exposed electrode 2, an encapsulated electrode 3, and an insulating medium 4. Specifically, the insulating plate 1 is an acrylic plexiglass with a thickness of 3 mm, the exposed electrode 2 and the encapsulated electrode 3 are both copper foils with a thickness of 0.05 mm and a width of 100 mm, and the insulating medium 4 is a polyimide film with a thickness of 0.15 mm and a width of 200 mm.

[0099] The device is excited by sinusoidal alternating current with a peak-to-peak voltage of 18kV and a frequency of 7kHz. Its pulse modulation signal is a square wave with a 50% duty cycle and a modulation frequency range from 8Hz to 160Hz.

[0100] Driven by an excitation voltage, the device continuously generates opposing rotating eddy current pairs. At modulation frequencies such as 40Hz and 60Hz, the eddy current pairs form a straddling plasma vortex structure every two pulse cycles. Under the mutual influence of vortex-induced velocities, the front eddy current pair (eddy current pair one) moves linearly along the flow direction, accompanied by an increase in the vortex distance between the counterclockwise rotating vortex P1 and the clockwise rotating vortex N1. The rear eddy current pair also moves linearly along the flow direction, but the vortex distance between the counterclockwise rotating vortex P2 and the clockwise rotating vortex N2 decreases, creating a convective velocity difference between the eddy current pairs. This causes the rear eddy current pair to gradually catch up with the front eddy current pair, such as... Figure 2 As shown; the rear vortex pair completes the crossing behavior between the front vortex pair, and then the spatial positions of the front and rear vortex pairs interchange, preparing for the next crossing behavior, completing the chasing-crossing-overtaking behavior within two pulse cycles; as... Figure 4 ;

[0101] The convection velocity of vortex pair two is 1.7 times that of vortex pair one.

[0102] When the peak-to-peak excitation voltage is 18 kV and the frequency is 7 kHz, the pulse modulation frequency corresponding to the straddle plasma vortex structure is between 8 Hz and 160 Hz; the time T of the straddle plasma vortex structure generation... * Between (100, 240); circulation parameter Γ * Between (6, 9); excessively large Γ * Excessive T, which promotes the fusion of vortex pairs, * This leads to the independent development of vortex pairs due to weak interactions.

[0103] The periodic circulation changes of the transgressive plasma vortex structure, such as Figure 5 As shown, the two vortex pairs exhibit the same growth trend after their formation, that is, they reach the maximum vortex intensity at the same growth rate within the same time period. However, the subsequent vortex decay is significantly different due to the crossing behavior. Specifically, the circulation decay rate of the rear vortex pair is 1.5 times that of the front vortex pair.

[0104] The characteristic comparison among continuous, spanning and pulsed plasma vortex structures is shown in Figure 6 Specifically, the spanning plasma vortex structure has strong velocity amplitude, effective range, momentum flux and vorticity flux, and can effectively improve the service performance of plasma-induced airflow in flow control.

[0105] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application.

Claims

1. A plasma discharge device for generating a cross plasma-induced vortex, characterized in that, The device comprises an insulating plate (1) and discharge devices I and II placed at both ends of the insulating plate in a face-to-face manner; The discharge device I comprises an exposed electrode I (2), an insulating medium I (4) and an encapsulated electrode I (3); The discharge device II comprises an exposed electrode II, an insulating medium II and an encapsulated electrode II; The encapsulated electrodes I and II are arranged concentrically on the outside of the insulating plate, and the exposed electrodes I and II are arranged concentrically on the outside of the insulating medium I and II; The ends of the encapsulated electrodes I and II are aligned with the ends of the insulating plate (1); The discharge devices I and II periodically generate discharges, and during the discharges, the discharge devices I and II generate multiple groups of counter-rotating vortex pairs, and based on the multiple groups of counter-rotating vortex pairs, multiple groups of cross-type plasma vortex structures are formed; The cross-type plasma vortex structure comprises vortex pair I (51) and vortex pair II (52), and the vortex pair I (51) and the vortex pair II (52) are adjacent vortex pairs; The adjacent vortex pair I (51) and the vortex pair II (52) generate vortex interaction, the induced velocity of the vortex pair I (51) reduces the distance between the counterclockwise vortex P2 and the clockwise vortex N2 in the vortex pair II (52), and enhances the convection velocity of the counterclockwise vortex P2 and the clockwise vortex N2 in the vortex pair II (52), and vice versa, the induced velocity of the vortex pair II (52) increases the distance between the counterclockwise vortex P1 and the clockwise vortex N1 in the vortex pair I (51), and reduces the convection velocity of the counterclockwise vortex P1 and the clockwise vortex N1 in the vortex pair I (51), forming a convection velocity difference between the vortex pair I and the vortex pair II, and based on the convection velocity difference, the vortex pair II (52) chases and crosses the vortex pair I (51).

2. The plasma discharge device for generating cross-type plasma-induced vortex flow according to claim 1, wherein the encapsulated electrode I is arranged inside the insulating medium I close to one side of the end of the insulating plate, the exposed electrode I is arranged outside the insulating medium I away from one side of the end of the insulating plate, the encapsulated electrode II is arranged inside the insulating medium II close to one side of the discharge end of the insulating plate, and the exposed electrode II is arranged outside the insulating medium II away from one side of the discharge end of the insulating plate.

3. The plasma discharge device for generating cross-type plasma-induced vortex flow according to claim 1, wherein the length ratio of the encapsulated electrode I, the exposed electrode I, the insulating medium I and the insulating plate is 1:1:2:

4.

4. The plasma discharge device for generating cross-type plasma-induced vortex flow according to claim 1, wherein the insulating plate (1) is made of acrylic organic glass, the exposed electrode I (2), the exposed electrode II, the encapsulated electrode I (3) and the encapsulated electrode II are all made of copper foil, and the insulating medium I and the insulating medium II (4) are made of polyimide film. The device comprises: a voltage is used to drive the dielectric barrier discharge device. ​ 5. A method of using a plasma discharge device for generating a cross plasma induced vortex, using the plasma discharge device according to any one of claims 1 to 4, characterized in that, ​ ​ A preset modulation frequency and an excitation voltage source; The excitation voltage source is connected with a signal generator, and outputs a periodic excitation voltage based on the preset modulation frequency; discharge device one and discharge device two periodically generate discharges based on the periodic excitation voltage; during the discharging process, discharge device one and discharge device two generate multiple groups of counter-rotating eddy current pairs, and multiple groups of spanning plasma vortex structures are formed based on the multiple groups of counter-rotating eddy current pairs.

6. The method of using a plasma discharge apparatus of claim 5, wherein, The voltage is a high-frequency and high-amplitude alternating voltage; the signal generator is a square wave signal generator, a sine wave signal generator or a triangular wave signal generator.

7. The method of using a plasma discharge apparatus of claim 5, wherein, During the discharging process, discharge device one and discharge device two generate multiple groups of counter-rotating eddy current pairs, wherein each two groups of counter-rotating eddy current pairs form a cycle; and the two groups of counter-rotating eddy current pairs generated in each cycle form a spanning plasma vortex structure.

8. The method of using a plasma discharge apparatus of claim 5, wherein, The spanning plasma vortex structure includes eddy current pair one (51) and eddy current pair two (52); the circulation in the eddy current pair one (51) and the eddy current pair two (52) reaches a maximum value at the same increasing rate, and then the circulation decays.

9. The method of claim 8, wherein, The eddy current pair two (52) includes an anticlockwise rotating vortex P2 and a clockwise rotating vortex N2; The eddy current pair one (51) includes an anticlockwise rotating vortex P1 and a clockwise rotating vortex N1; The ratio of the convection velocity of the anticlockwise rotating vortex P2 and the clockwise rotating vortex N2 in the eddy current pair two (52) to the convection velocity of the anticlockwise rotating vortex P1 and the clockwise rotating vortex N1 in the eddy current pair one (51) is greater than 1, forming a difference in the convection velocity between the eddy current pairs.

10. The method of claim 8, wherein, The expression of the circulation in the eddy current pair one and the eddy current pair two in the spanning plasma vortex structure is: ​ * = ​ 0 / x 0 U 0 wherein, ​ * is the dimensionless start-up vortex ring momentum of the cross plasma vortex structure, U 0 is the initial convective velocity between vortex pair one and vortex pair two, x 0 is the initial convective distance between vortex pair one and vortex pair two, ​ 0 is the initial circulation strength of vortex one or vortex pair two.

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