Apparatus and method for generating large scale diffuse sheet plasma plumes

Abstract

The application provides a device and method for generating large-scale diffused sheet plasma plume, which comprises a copper tube electrode air channel, a cylindrical tube body with a slit parallel to the air channel axis on the side wall, the slit penetrating the tube wall; a dielectric plate, a ceramic rectangular plate body with an electrode attached to one end; a pulse power source, the positive pole of which is connected to the copper tube electrode air channel, the negative pole of which is connected to the electrode on the dielectric plate and the ground wire; and a gas storage tank connected to both ends of the copper tube electrode air channel through a gas supply pipeline for supplying argon or helium into the copper tube electrode air channel; the copper tube electrode air channel is fixed to one end of the dielectric plate, the slit on the side wall of the copper tube electrode air channel is obliquely opposite to the plate surface of the dielectric plate and points to the other opposite end of the dielectric plate. In the application, the cylindrical copper tube electrode air channel and the dielectric plate and the argon layer therebetween form a jet structure, which can generate large-scale diffused sheet plasma plume.

Description

Technical Field

[0001] This invention relates to an apparatus for generating plasma plumes, and more specifically to an apparatus and method for generating large-scale diffuse sheet-like plasma plumes. Background Technology

[0002] Atmospheric pressure plasma jets can generate plasma plumes in open environments, containing abundant reactive particles (such as OH radicals, O3, and excited-state N2), a large number of high-energy particles (such as electrons), and ultraviolet radiation. These reactive particles, high-energy particles, and ultraviolet radiation play important roles in many fields, such as surface modification, bio-sterilization, plasma pharmaceuticals, materials processing, and water treatment.

[0003] Plasma plumes are typically small in diameter, covering only a few square millimeters, which limits their application to large-scale materials. To achieve rapid processing of large-scale materials, the scale of the plasma plume needs to be increased. A simple approach is to combine multiple jets into a jet array, such as three parallel jets (see Applied Physics Letters, 2014, 105: 044102). However, because the jets are discrete, the large-scale plasma plumes generated by the jet array are often non-uniform. Another alternative is to use rectangular channels in the plasma jet, which produces a diffuse plasma plume, but at a relatively small scale. Therefore, developing large-scale uniform plasmas has become an important requirement in the field of materials processing. Summary of the Invention

[0004] One of the objectives of this invention is to provide an apparatus for generating large-scale diffuse sheet-like plasma plumes.

[0005] The second objective of this invention is to provide a method for generating large-scale diffuse sheet-like plasma plumes, in order to solve the problem of small-scale plasma plumes generated by existing technologies.

[0006] One of the objectives of this invention is achieved as follows: A device for generating large-scale diffuse sheet-like plasma plumes, comprising: The copper tube electrode airway is a cylindrical tube with a narrow slit on its side wall that is parallel to the axis of the airway and penetrates the tube wall. The dielectric plate is a rectangular plate made of ceramic, with an electrode attached to one end. A pulse power supply, its positive terminal connected to the copper tube electrode air passage, and its negative terminal connected to the electrode on the dielectric substrate and the ground wire; and The gas storage tank is connected to both ends of the copper tube electrode gas passage via a gas supply pipeline, and is used to introduce argon or helium into the copper tube electrode gas passage. The copper tube electrode gas channel is fixed to one end of the dielectric plate, and the slit on its side wall is obliquely opposite to the surface of the dielectric plate and points to the other opposite end of the dielectric plate.

[0007] Furthermore, the two sides of the copper tube electrode gas channel do not extend beyond the edge of the dielectric plate, so that the projection of the slit on the side wall falls entirely on the surface of the dielectric plate.

[0008] Furthermore, the angle between the line connecting the center of the cross-section of the copper tube electrode passage through the slit to the surface of the dielectric plate and the perpendicular line from the center of the cross-section of the copper tube electrode passage to the surface of the dielectric plate is 10°~15°.

[0009] Furthermore, an air valve, a pressure gauge, and a flow meter are installed on the air supply pipeline.

[0010] Furthermore, the thickness of the dielectric substrate is 1.5~2 mm.

[0011] The second objective of this invention is achieved as follows: A method for generating large-scale diffuse sheet-like plasma plumes includes the following steps: S1. To provide an apparatus for generating large-scale diffuse sheet-like plasma plumes as described in one of the objectives of this invention; S2. Turn on the pulse power supply switch to apply a pulse voltage to the copper tube electrode airway; S3. Open the gas valve to allow the working gas in the gas tank to enter the copper tube electrode gas passage through the gas supply line and be ejected from the slit of the copper tube electrode gas passage. S4. Adjust the output voltage of the pulse power supply to discharge along the airflow direction outside the slit of the copper tube electrode gas channel to form a large-scale diffuse sheet-like plasma plume.

[0012] Furthermore, in step d, the peak output voltage of the pulse power supply is adjusted to 2~5 kV.

[0013] This invention generates large-scale sheet-like plasma plumes in the open environment downstream of the gas channel by applying a pulsed voltage to the cylindrical copper tube electrode gas channel within a certain voltage range, and the plumes are essentially diffuse.

[0014] In this invention, a cylindrical copper tube electrode gas channel, a dielectric plate, and an argon gas layer therebetween form a jet structure. This invention utilizes lateral airflow and a dielectric barrier discharge structure to generate a large-scale, dispersed sheet-like plasma plume. This invention generates an essentially dispersed sheet-like plasma plume through a jet structure. The large-scale, dispersed sheet-like plasma plume generated by this invention solves the problem of uneven sample processing and even damage to fragile samples, making it suitable for applications such as material processing, sterilization and disinfection, aircraft stealth, and activated water purification.

[0015] The device for generating large-scale diffuse sheet-like plasma plumes is simple in structure, easy to operate, and inexpensive. The device is set up in an open atmospheric environment, eliminating the need for expensive vacuum devices and facilitating rapid processing of large-area fragile materials. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the device of the present invention.

[0017] Figure 2 This is a side view of the copper tube electrode gas channel and dielectric plate of the present invention.

[0018] Figure 3 This is a discharge diagram of a large-scale diffuse sheet-like plasma plume generated when the peak pulse voltage is 3 kV.

[0019] Figure 4 This is a discharge diagram of a diffuse sheet-like plasma plume generated when the pulse voltage peak value is 3 kV and the exposure time is 200 μs.

[0020] Figure 5 It shows the voltage waveform, current waveform, and plasma plume emission signal waveform when the peak pulse voltage is 3 kV.

[0021] The components include: 1. Gas storage tank; 2. Gas valve; 3. Gas supply pipeline; 4. Gas pressure gauge; 5. Flow meter; 6. Copper tube electrode gas passage; 7. Medium plate; 8. Electrode; 9. Pulse power supply. Detailed Implementation

[0022] The invention will now be described in further detail with reference to the accompanying drawings.

[0023] like Figure 1 and Figure 2 As shown, this invention provides a device for generating large-scale diffuse sheet-like plasma plumes, the structure of which includes a gas storage tank 1, a gas supply pipeline 3, a copper tube electrode gas channel 6, a dielectric plate 7, and a pulse power supply 9. The copper tube electrode gas channel 6 is a cylindrical tube with a slit on its side wall parallel to its axis, the slit penetrating the tube wall; the dielectric plate 7 is a rectangular plate made of ceramic, with an electrode attached to one side; the positive terminal of the pulse power supply 9 is connected to the copper tube electrode gas channel 6, and the negative terminal of the pulse power supply 9 is connected to the electrode on the dielectric plate 7 and the ground wire; the gas storage tank 1 is connected to both ends of the copper tube electrode gas channel 6 through the gas supply pipeline 3, for introducing argon or helium gas into the copper tube electrode gas channel 6.

[0024] The copper tube electrode airway 6 is fixed to one end of the dielectric plate 7. The slit on the side wall of the copper tube electrode airway 6 is obliquely opposite to the surface of the dielectric plate 7 and points to the other opposite end of the dielectric plate 7.

[0025] The dielectric plate 7 is placed horizontally, and an electrode 8 is placed below it. The dielectric plate 7 is grounded through the electrode 8. The angle between the line connecting the center of the cross-section of the copper tube electrode gas channel 6 through the slit to the surface of the dielectric plate 7 and the perpendicular line from the center of the cross-section of the copper tube electrode gas channel 6 to the surface of the dielectric plate 6 is 10°~15°. A gas valve 2, a pressure gauge 4, and a flow meter 5 are installed on the gas supply line 3. The gas in the gas storage tank 1 enters the copper tube electrode gas channel 6 through the gas supply line and is ejected at the slit of the copper tube electrode gas channel 6. By adjusting the pulse voltage amplitude output by the pulse power supply 9, a large-scale sheet-like plasma plume can be formed in the open environment outside the gas outlet. This plasma plume is essentially diffuse. That is, this invention utilizes the transverse airflow and the dielectric barrier discharge structure to generate a diffuse sheet-like plasma plume.

[0026] The gas pressure in this invention is standard atmospheric pressure, and the gas flow rate is 2 L / min.

[0027] The sides of the copper tube electrode air passage 6 do not extend beyond the edge of the dielectric plate 7, so that the projection of the slit on the side wall falls entirely on the surface of the dielectric plate 7. The thickness of the dielectric plate is 1.5~2 mm. The slit needs to avoid the connection between the copper tube electrode air passage 6 and the air supply line 3, and the length of the slit is less than or equal to the length of the copper tube electrode air passage 6. The copper tube electrode air passage 6 used in this invention is a copper tube with an outer diameter of 12 mm, an inner diameter of 5 mm, and a length of 80 mm. When the copper tube has the above dimensions, the minimum dimensions of the dielectric plate 7 are 60 mm long (length from left to right in the horizontal direction) and 50 mm wide (length from front to back in the horizontal direction). The dielectric plate 7 used in this invention is a ceramic dielectric plate with a length of 80 mm, a width of 50 mm, and a thickness of 1.8 mm. The electrode 8 covered below the dielectric plate 7 is a copper foil, and the dimensions of the electrode 8 are consistent with the dimensions of the dielectric plate 7, being 80 mm long, 50 mm wide, and 0.2 mm thick.

[0028] The present invention also provides a method for generating large-scale diffuse sheet-like plasma plumes, comprising the following steps: S1. Settings Figure 1 The apparatus shown generates a large-scale diffuse sheet-like plasma plume, with its components connected.

[0029] S2. Turn on the switch of the pulse power supply 9 to apply a pulse voltage to the copper tube electrode airway 6.

[0030] The peak output voltage of pulse power supply 9 is adjusted to 0~10 kV. When the peak output voltage of pulse power supply 9 is 2-5 kV, the generated plasma plume is larger.

[0031] S3. Open the gas valve 2 to allow the working gas in the gas tank 1 to enter the copper tube electrode gas passage 6 through the gas supply line 3, and be ejected from the slit of the copper tube electrode gas passage 6, forming a transverse airflow outside the slit, so that the discharge propagates laterally along the direction of the airflow.

[0032] S4. Adjust the output voltage of the pulse power supply 9 to discharge along the airflow direction outside the slit of the copper tube electrode gas channel 6 to form a large-scale diffuse sheet-like plasma plume; gradually adjust the amplitude of the pulse voltage output by the pulse power supply 9 to make the diffuse sheet-like plasma plume reach its maximum length and brightness.

[0033] like Figure 3 As shown, when the peak output voltage of the pulse power supply 9 is adjusted to 3 kV, the diffuse sheet-like plasma plume generated downstream of the cylindrical copper electrode gas channel 6 has the largest size, the brightest brightness, and the best dispersion. Figure 3 The size of the sheet-like plasma plume reached 60 mm × 25 mm, indicating that a large sheet-like plasma plume was formed.

[0034] like Figure 4 The image shown is an image of a sheet-like plasma plume taken with a short exposure time (200 μs) when the peak output voltage of the pulse power supply 9 reaches 3 kV. The plasma plume appears diffuse.

[0035] like Figure 5 As shown, Figure 5 The top-middle figure shows the voltage waveform, the middle figure shows the current waveform, and the bottom figure shows the emission signal of the plasma plume. When the peak pulse voltage is 3 kV, a photomultiplier tube and an oscilloscope are connected. The oscilloscope is used to monitor and record the voltage, current, and emission signal of the diffuse sheet-like plasma plume applied to the electrodes of the cylindrical copper electrode channel 6. The large-scale diffuse sheet-like plasma plume discharges twice in each voltage cycle, corresponding to the rising and falling edges of the pulse power supply, respectively.

Claims

1. A device for generating large-scale diffuse sheet-like plasma plumes, characterized in that, include: The copper tube electrode airway is a cylindrical tube with a narrow slit on its side wall that is parallel to the axis of the airway and penetrates the tube wall. The dielectric plate is a rectangular plate made of ceramic, with an electrode attached to one end. A pulse power supply, its positive terminal connected to the copper tube electrode air passage, and its negative terminal connected to the electrode on the dielectric substrate and the ground wire; and The gas storage tank is connected to both ends of the copper tube electrode gas passage via a gas supply pipeline, and is used to introduce argon or helium into the copper tube electrode gas passage. The copper tube electrode gas channel is fixed to one end of the dielectric plate, and the slit on its side wall is obliquely opposite to the surface of the dielectric plate and points to the other opposite end of the dielectric plate.

2. The apparatus for generating large-scale diffuse sheet-like plasma plumes according to claim 1, characterized in that, The copper tube electrode gas passages do not extend beyond the edge of the dielectric plate on both sides, so that the projection of the slits on the sidewalls falls entirely on the surface of the dielectric plate.

3. The apparatus for generating large-scale diffuse sheet-like plasma plumes according to claim 1, characterized in that, The angle between the line connecting the center of the cross-section of the copper tube electrode passage through the slit to the surface of the dielectric plate and the perpendicular line from the center of the cross-section of the copper tube electrode passage to the surface of the dielectric plate is 10°~15°.

4. The apparatus for generating large-scale diffuse sheet-like plasma plumes according to claim 1, characterized in that, An air valve, a pressure gauge, and a flow meter are installed on the air supply pipeline.

5. The apparatus for generating large-scale diffuse sheet-like plasma plumes according to claim 1, characterized in that, The thickness of the dielectric substrate is 1.5~2 mm.

6. A method for generating large-scale diffuse sheet-like plasma plumes, characterized in that, Includes the following steps: S1. The apparatus for generating large-scale diffuse sheet-like plasma plumes as described in any one of claims 1-5; S2. Turn on the pulse power supply switch to apply a pulse voltage to the copper tube electrode airway; S3. Open the gas valve to allow the working gas in the gas tank to enter the copper tube electrode gas passage through the gas supply line and be ejected from the slit of the copper tube electrode gas passage. S4. Adjust the output voltage of the pulse power supply to discharge along the airflow direction outside the slit of the copper tube electrode gas channel to form a large-scale diffuse sheet-like plasma plume.

7. The method for generating large-scale diffuse sheet-like plasma plumes according to claim 6, characterized in that, In step d, the peak output voltage of the pulse power supply is adjusted to 2-5 kV.

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