CN114019261A - Nanosecond pulse driven surface charge observation system for dielectric barrier discharge at any moment - Google Patents
Nanosecond pulse driven surface charge observation system for dielectric barrier discharge at any moment Download PDFInfo
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/24—Arrangements for measuring quantities of charge
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1218—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing using optical methods; using charged particle, e.g. electron, beams or X-rays
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Abstract
The invention discloses a nanosecond pulse driven surface charge observation system for dielectric barrier discharge at any moment, which comprises: a helium neon laser source, light beam amplifier, diaphragm, polarization beam splitter have set gradually at helium neon laser source's light path output, and wherein, the light beam of laser source is divided into two the tunnel through polarization beam splitter: one path enters a dielectric barrier discharge unit through an 1/8 wave plate, and the other path enters a camera framing unit through a convex lens and a small hole; three ICCD cameras are connected to the camera framing unit to realize surface charge observation at any discharge time; the three ICCD cameras are respectively connected with the digital oscilloscope, the nanosecond pulse power supply and the computer; a digital time delay generator is connected to the nanosecond pulse power supply, a high-voltage probe is connected to the digital oscilloscope, and the digital oscilloscope is connected with the near end of the dielectric barrier discharge unit; the output end of the high-voltage probe and the output end of the nanosecond pulse power supply are connected with the far end of the dielectric barrier discharge unit. The method is favorable for perfecting the action mechanism of the surface charge on the nanosecond pulse DBD.
Description
Technical Field
The invention belongs to the field of nanosecond pulse dielectric barrier discharge, relates to an observation system driven by nanosecond pulse voltage, and particularly relates to a nanosecond pulse driven surface charge observation system driven by dielectric barrier discharge at any moment.
Background
With the development of pulse power technology, scientific research finds that Dielectric Barrier Discharge (DBD) under pulse voltage has higher Discharge stability compared with traditional ac voltage driving, active particle density and energy conversion efficiency, and can generate large-volume low-temperature plasma under atmospheric pressure, and has great application prospects in the aspects of thin film deposition, surface modification, ozone generation, gas and water purification, and the like. Because nanosecond pulses have steep rising edges and short voltage action time, and discharge current is only generated at the rising edges and the falling edges in each pulse period, the research on a discharge mechanism and a mode under pulse discharge is more difficult.
In order to clarify the DBD discharge mechanism under nanosecond pulse driving, a large amount of research is carried out by domestic scholars, wherein the research method comprises the following steps: the method comprises the following steps of measuring discharge characteristics, shooting discharge images, simulating particles and the like, but nanosecond pulse gas discharge has some unconventional phenomena such as high breakdown voltage, high electron energy, multi-channel discharge and the like. At this time, the classical broth and streamer theory is no longer applicable, and many problems still remain to be solved, such as the discharge mechanism of the DBD under the nanosecond pulse, the relationship between the discharge characteristic and the control parameter, and the interaction between the charged particles generated by the discharge and the discharge.
The plasma generated by the nanosecond pulse DBD has a large amount of positive and negative charges and excited particles, and these charged particles will exist in and discharge air gaps and medium surfaces, so that the air gap electric field is changed, thereby affecting the discharge form. At present, experimental discharge in the nanosecond pulse DBD is mainly measured by discharge characteristics under a macroscopic condition and shot by a discharge image, but the observation of surface charges of a medium in a discharge air gap is only reported, namely the action mechanism of the surface charges on the nanosecond pulse DBD is not clear, and corresponding experimental exploration needs to be carried out.
Disclosure of Invention
In order to realize the observation of the surface charge of the air gap blocking medium in the nanosecond pulse DBD and clarify the action mechanism of the surface charge on the discharge, the invention aims to provide a nanosecond pulse driven surface charge observation system at any moment of the dielectric blocking discharge.
In order to realize the task, the invention adopts the following technical solution:
a nanosecond pulse driven surface charge observation system for dielectric barrier discharge at any moment is characterized by comprising:
a helium neon laser source, light beam amplifier, diaphragm, polarization beam splitter have set gradually at helium neon laser source's light path output, and wherein, the light beam of laser source is divided into two the tunnel through polarization beam splitter: one path enters a dielectric barrier discharge unit through an 1/8 wave plate, and the other path enters a camera framing unit through a convex lens and a small hole; three ICCD cameras for imaging are connected to the camera framing unit to realize surface charge observation at any discharging time; the three ICCD cameras are respectively connected with the digital oscilloscope, the nanosecond pulse power supply and the computer; a digital time delay generator is connected to the nanosecond pulse power supply, a high-voltage probe is connected to the digital oscilloscope, and the digital oscilloscope is connected with the near end of the dielectric barrier discharge unit; the output end of the high-voltage probe and the output end of the nanosecond pulse power supply are connected with the far end of the dielectric barrier discharge unit.
According to the invention, the dielectric barrier discharge unit comprises a high-voltage end polytetrafluoroethylene insulating disc, a flat high-voltage electrode is arranged in the center of the high-voltage end polytetrafluoroethylene insulating disc, a discharge air gap is reserved below the flat high-voltage electrode, and a low-density polyethylene and bismuth silicate electrode are arranged below the discharge air gap; the two sides of the bismuth silicate electrode are respectively provided with a symmetrical insulating support, a symmetrical ground electrode and a measuring electrode are arranged below the insulating support, an insulating ring is arranged between the ground electrode and the measuring electrode, and 4 measuring resistors are bridged between the ground electrode and the measuring electrode and used for measuring dielectric barrier discharge current.
Further, the bismuth silicate electrode is composed of a reflecting film, bismuth silicate crystals, a BK7 glass substrate and an ITO thin film.
Preferably, the flat plate high-voltage electrode adopts a copper electrode with the diameter of 10 mm; the size of the bismuth silicate crystals is 20 × 0.16 mm.
Further preferably, the camera framing unit is composed of a relay lens, three polarization beam splitting prisms and three ICCD cameras, and mainly functions to divide the laser beam containing surface charge information of the small hole into three beams, and the three beams are respectively received and imaged by the three ICCD cameras to realize surface charge observation at any discharge time.
In the invention, the nanosecond pulse power supply is used for generating repeated nanosecond pulse voltage with the frequency of 0-100kHz, the amplitude of 0-10kV, the pulse width of 0-1ms and the rising and falling edges of 50-500 ns.
The wavelength of stable linear polarized light generated by the helium-neon laser is 632.8nm, and the diameter of a light spot is controlled by a beam amplifier and a diaphragm.
The digital delay generator selects the eight-channel digital delay pulse generator DG 645.
The 1/8 wave plate imparts a 45 degree phase retardation to polarized light to distinguish between positive and negative charge polarities by light intensity variations.
The nanosecond pulse driven dielectric barrier discharge surface charge observation system at any moment can observe the nanosecond pulse DBD air gap barrier dielectric surface charge distribution image at any moment in any period, has high measurement resolution, and is favorable for carrying out deep mechanistic research on the action mechanism of surface charge accumulation to discharge characteristics and discharge forms from the view of microscopic particle distribution.
Drawings
FIG. 1 is a structural diagram of a measurement system for the surface charge of a nanosecond pulsed DBD air gap blocking medium.
FIG. 2 is a schematic diagram of a dielectric barrier discharge cell structure.
Fig. 3 is a schematic view of the structure of a bismuth silicate electrode.
Fig. 4 is a schematic structural diagram of a framing unit of the camera.
FIG. 5 nanosecond pulsed DBD surface charge measurement trigger timing diagram.
Fig. 6 is a recording result of a digital oscilloscope in the experiment.
Fig. 7 shows the result of the ICCD camera in the experiment. Wherein (a) is the image taken by the ICCD camera 1, (b) is the image taken by the ICCD camera 2, (c) is the image taken by the ICCD camera 3, and (d) is the surface charge measurement scale.
The symbols in fig. 1 represent: 1. He-Ne laser source, 2, beam amplifier, 3, diaphragm, 4, Polarization Beam Splitter (PBS), 5, 1/8 wave plate, 6, Dielectric Barrier Discharge (DBD) unit, 7, convex lens, 8, aperture, 9, camera framing unit, 10, ICCD camera, 11, digital oscilloscope, 12, high voltage probe, 13, digital time delay generator (model DG645), 14, nanosecond pulse power supply.
The symbols in fig. 2 represent: 601. insulating support, 602, ground electrode, 603, measuring electrode, 604, measuring resistance, 605, insulating ring, 606, bismuth silicate electrode, 607, high-voltage end polytetrafluoroethylene insulating disc, 608, discharge air gap, 609, high-voltage electrode, 610, low-density polyethylene (LDPE).
The symbols in fig. 3 represent: 60601. a reflecting film 60602, bismuth silicate crystal (BSO), 60603, BK7 glass substrate, 60604 and ITO film.
The symbols in fig. 4 represent: 901. a relay lens 902, a polarization beam splitter prism 10, an ICCD camera 903 and a splitter.
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Detailed Description
First, briefly describing the observation principle of the surface charge of the discharge, bismuth silicate crystal (BSO) is an electro-optic effect crystal, i.e. when an external electric field is applied to the crystal, the refractive index of the crystal will change linearly with the change of the electric field, also called Pockels effect, so that the effect can be used to perform real-time measurement of the dynamic distribution of the surface charge of the medium during the discharge process. When charges are accumulated on the surface of the bismuth silicate crystal (BSO), an electric field on the bismuth silicate crystal (BSO) is changed, a delay phase appears when light passes through the bismuth silicate crystal (BSO), a certain linear relation exists between the electric field intensity caused by the surface charges at any position on the surface of the bismuth silicate crystal (BSO) and the surface charge density, and the distribution of the surface charges of the medium can be obtained by measuring the distribution of the delay phase of the light and processing and operation of a computer.
Referring to fig. 1, this embodiment provides a nanosecond pulse driven system for observing surface charges at any time of dielectric barrier discharge, including:
a helium neon laser source 1, the light path output end at helium neon laser source 1 sets gradually beam amplifier 2, diaphragm 3, polarization beam splitter 4, and wherein, the light beam of laser source 1 divides into two the tunnel through polarization beam splitter 4: one path enters a dielectric barrier discharge unit 6 through an 1/8 wave plate 5, and the other path enters a camera framing unit 9 through a convex lens 7 and a small hole 8; three ICCD cameras 10 for imaging are connected to the camera framing unit 9 to realize surface charge observation at any discharging time; the three ICCD cameras 10 are respectively connected with the digital oscilloscope 11, the nanosecond pulse power supply 14 and the computer 15; a nanosecond pulse power supply 14 is connected with a digital delay generator 13, a digital oscilloscope 11 is connected with a high-voltage probe 12, and the digital oscilloscope 11 is connected with the near end (low-voltage end) of the dielectric barrier discharge unit 6; the output end of the high-voltage probe 12 and the output end of the nanosecond pulse power supply 14 are connected with the far end (high-voltage end) of the dielectric barrier discharge unit 6.
Referring to fig. 2, in this embodiment, the dielectric barrier discharge unit 6 includes a high-voltage end teflon insulating disc 607, a flat high-voltage electrode 609 is disposed in the center of the high-voltage end teflon insulating disc 607, a discharge air gap 608 is left below the flat high-voltage electrode 609, and a low-density polyethylene 610 and a bismuth silicate electrode 606 are disposed below the discharge air gap 608; symmetrical insulating supports 601 are respectively arranged on two sides of a bismuth silicate electrode 606, a symmetrical ground electrode 602 and a measuring electrode 603 are arranged below the insulating supports 601, an insulating ring 605 is arranged between the ground electrode 602 and the measuring electrode 603, and 4 measuring resistors 604 with the resistance value of 200 omega are bridged between the ground electrode 602 and the measuring electrode 603; for measuring the dielectric barrier discharge current.
Referring to fig. 3, in this embodiment, the bismuth silicate electrode 606 is composed of a reflective film 60601, a bismuth silicate crystal 60602, a BK7 glass substrate 60603, and an ITO thin film 60604.
The flat high-voltage electrode 609 adopts a copper electrode with the diameter of 10 mm; the bismuth silicate crystals 60602 have a size of 20 × 0.16 mm.
Referring to fig. 4, in this embodiment, the camera framing unit 9 is composed of a relay lens 901, three polarization beam splitting prisms 902, and three ICCD cameras 10, and mainly functions to divide the laser beam containing surface charge information of the pinhole 8 into three beams, and the three beams are respectively received and imaged by the three ICCD cameras 10 to realize surface charge observation at any discharge time. The ICCD camera 10 has pixels of 1024 multiplied by 1024, a single pixel size of mum, the shortest exposure time of 2ns and the light sensing range of 200-900 nm.
In this embodiment, the nanosecond pulse power supply 14 is used for generating a repeated nanosecond pulse voltage with a frequency of 0-100kHz, an amplitude of 0-10kV, a pulse width of 0-1ms, and a rising-falling edge of 50 ns-500 ns. The nanosecond pulse power supply 14 can be triggered by an internal or external signal to generate a high-voltage pulse, and can synchronously generate a low-voltage square wave pulse signal after being triggered by the external signal for triggering other devices. And the designed trigger time sequence is utilized to accurately trigger the dielectric barrier discharge unit 6, and the measurement of the preset time sequence is completed, so that the surface charge can be observed at any discharge time.
The wavelength of stable linear polarized light generated by the helium-neon laser 1 is 632.8nm, and the diameter of a light spot is controlled by a beam amplifier 2 and a diaphragm 3.
The digital delay generator 13 selects the eight-channel digital delay pulse generator DG 645.
The 1/8 wave plate 5 performs 45-degree phase retardation on polarized light to distinguish the positive and negative charge polarities by light intensity variation.
In the nanosecond pulse driven dielectric barrier discharge surface charge observation system at any time, the he-ne laser 1, the beam amplifier 2, the diaphragm 3, the Polarization Beam Splitter (PBS)4, the 1/8 wave plate 5, the convex lens 7, the small hole 8 and other related optical elements form an optical measurement unit, and the optical measurement unit plays roles in generation of incident light, adjustment of spot diameter, polarization beam splitting, phase adjustment, recording of reflected light intensity and the like.
The helium-neon laser 1 can generate stable linear polarized light with the wavelength of 632.8nm, the diameter of a laser beam emitted by the helium-neon laser 1 is only 1mm, the diameter of the laser beam is amplified by a beam amplifier 2, and the beam amplifier 2 is assembled with the helium-neon laser 1.
To achieve the adjustment of the diameter of the light spot, a diaphragm 3 is placed after the beam amplifier 2. Before the experimental measurement is started, the diameter of the light spot is adjusted through the diaphragm 3, the light spot is ensured to cover the whole area of the dielectric barrier discharge unit 6, and the measurement of the surface charge of the dielectric in the whole area of the dielectric barrier discharge unit 6 is realized.
The Polarizing Beam Splitter (PBS)4 functions to separate two components perpendicular to each other in incident light, allows p-polarized light to pass therethrough, and reflects s-polarized light. When the laser light emitted from the beam amplifier 2 passes through a Polarization Beam Splitter (PBS)4, only p-polarized light passes therethrough. 1/8 wave plate 5 imparts a 45 degree phase retardation to polarized light to distinguish between positive and negative charge polarities by light intensity variations. The p-polarized light becomes incident light for surface charge density distribution measurement after passing through 1/8 wave plate 5.
After the incident light enters the bismuth silicate electrode 606 of the dielectric barrier discharge unit 6, a part of laser is reflected back at the interface of the BSO unit 606 and the low density polyethylene 610, and the part of reflected light is still linearly polarized light; the other part of the laser transmission medium generates diffuse reflection on the surface of the flat high-voltage electrode 609 (copper electrode), and the reflected light is natural light. When the surface of the medium has no surface charge, the Pockels effect can not occur when the laser passes through the bismuth silicate electrode 606. The part reflected by the interface is still p-polarized light and is not recorded by the ICCD camera 10 after passing through the Polarizing Beam Splitter (PBS)4, while the laser light reflected by the surface of the flat plate high voltage electrode 609 (copper electrode) is split by the Polarizing Beam Splitter (PBS)4 and is recorded by the ICCD camera 10 as initial light intensity. When surface charges are deposited on the surface of the medium, laser light reflected by the interface can also contain s-polarized light carrying surface charge information besides p-polarized light due to the action of the Pockels effect. At this time, after being split by the Polarization Beam Splitter (PBS)4, the light intensity recorded by the ICCD camera 10 may include s-polarized light generated by the Pockels effect in addition to the s-component of the natural light reflected by the surface of the copper electrode. When the light intensity is processed for charge calculation, the difference between the measured light intensity and the initial light intensity is made, and the s component of the natural light reflected by the surface of the flat high-voltage electrode 609 (copper electrode) is removed to obtain s-polarized light only generated by the Pockels effect, so that the two-dimensional distribution of the surface charge density is accurately calculated.
In the experiment, laser light was reflected at the interface between the BK7 glass substrate 60603 and the bismuth silicate crystal 60602, and disturbance reflection light was generated, and therefore, a plurality of light spots were observed in the reflection light generated by the PBS. In the experiment, the light spots containing surface charge information are converged through the convex lens 7, and then separated out through the small hole 8, so that the light spots enter the camera framing unit 9, and further useful light spots used for calculating charge distribution can be obtained.
The camera framing unit 9 divides the light spot passing through the pinhole 8 into three same light spot signals through the relay lens 901 and the polarization beam splitter prism 902, the three ICCD cameras 10 record light intensity change signals in the whole experiment process through the three polarization beam splitter prisms 902, so as to obtain a distribution image of surface charges, and the distribution image is respectively connected with the digital oscilloscope 11, the nanosecond pulse power supply 14 and the computer 15 through the line divider 903. The digital oscilloscope 11 and the high voltage probe 12 are used for recording a pulse voltage signal and a discharge current signal in the discharge process and a shutter signal output when the ICCD camera 10 shoots, so as to judge the shooting time of the three ICCD cameras 10.
In the experiment, the dielectric barrier discharge unit 6 is fastened and fixed inside the housing cavity by two fixing parts. The flat high-voltage electrode 609 is connected with an external high-voltage guide rod through a thread, and high voltage generated by the nanosecond pulse power supply 14 and the high-voltage probe 12 is introduced into the dielectric barrier discharge unit 6 from the external high-voltage guide rod. The flat high-voltage electrode 609 is embedded in a high-voltage end polytetrafluoroethylene insulating disc 607 by adopting an extrusion processing technology, and the surface of the whole flat high-voltage electrode 609 is polished to prevent the edge discharge effect at the edge of the electrode. The bottom of the high voltage insulating teflon disc 607 is provided with a recess whose depth is the height of the discharge air gap 608. The machining accuracy of the groove depth ensures the accuracy of the surface charge measurement and the height of the discharge air gap 608. The air gap height of the DBD discharge device can be changed by using high voltage insulating disks of different air gap heights. The high-voltage end insulating disc 607 is tightly combined with the insulating support 601, the insulating ring 605 and the ground electrode 602 through screws, the measuring electrode 603 is an annular electrode, and the bismuth silicate electrode 606 is embedded in the middle of the insulating support 601. The flat plate high voltage electrode 609 used in the experiment was a copper electrode with a diameter of 10 mm. In order to eliminate the influence of residual impurities on the surface of the electrode on the discharge characteristic, the copper electrode can be used after aging through multiple times of gas discharge before formal experiments.
In this embodiment, the ITO film 60604 on the bottom surface of the BK7 glass substrate 60603, the height of the discharge air gap 608 between the bottom surface of the high voltage electrode 609 and the ground electrode 602 and the measurement electrode 603, and the low density polyethylene 610 together constitute the dielectric barrier discharge unit 6. In order to ensure that the measuring light source can smoothly pass through the lower electrode and pass through the bismuth silicate electrode, the measuring electrode 603 and the ground electrode 602 are both designed into copper rings with through holes in the middle. The ITO film 60604 is in direct contact with the measuring electrode 603. The upper surface of the copper ring of the measuring electrode 603 and the ITO film 60604 together serve as the lower electrode of the dielectric barrier discharge unit 6.
Since media surface charge measurement based on the Pockels effect calculates the surface charge density distribution mainly by recording the light intensity of reflected light with the ICCD camera 10, the setting of the exposure time of the ICCD camera 10 directly affects the time resolution of the entire measurement system. In order to meet the requirement of nanosecond-level exposure time and the requirement of surface charge distribution measurement at any moment, a high-speed camera framing unit 9 is built by three ICCD cameras 10, and the camera framing unit 9 is composed of a relay lens 901, three polarization beam splitting prisms 902 and three ICCD cameras 10. The relay lens 901 is a core component, and is mainly used for adjusting a focal plane of light spot imaging to be just located on a photosensitive chip of the ICCD camera 10. The polarizing beam splitter 902 functions to split the laser light containing surface charge information from the aperture 8 into three beams, which are received and imaged by three ICCD cameras 10. By controlling the trigger time of the ICCD camera 10, the density distribution of the surface charges of the medium in the nanosecond pulse DBD discharge process can be measured in real time, and the change rule of the surface residual charges can be further researched.
The ICCD camera 10 in the camera framing unit 9 is fixed to the spectroscopic box by a special port, ensuring that the position of the ICCD camera 10 is fixed and does not shake during the measurement. The triggering time delay and the gate width of the ICCD camera 10 can be manually set on the computer 15 by using software, the gate width is at least 2ns, and the gate width set by the software is the time resolution of the whole observation system. In order to ensure the accuracy and stability of the optical measurements, the entire camera framing unit 9 is placed on a mechanical support table, which is placed on an optically stable platform. The mechanical support table has four support components that can be used to adjust the height and levelness of the ICCD camera 10. In the experiment, in order to make the whole reflected light spot be completely received by the ICCD camera 10, the inclination angle of the camera framing unit 9 in the space is adjusted by adjusting the four supporting components, so as to ensure the integrity of the light spot recorded by the ICCD camera 10.
The nanosecond pulse DBD surface charge measurement trigger timing diagram is shown in fig. 5. When surface charge distribution in nanosecond pulse DBD discharge is researched, firstly, an eight-channel digital delay pulse generator DG645 is used for generating a low-voltage pulse signal to trigger the nanosecond pulse power supply 14, and when the pulse voltage generates repeated pulse voltage, the low-voltage pulse signal is generated and used for triggering other related experimental equipment. The number of pulses generated by the nanosecond pulse power supply 14 can be artificially set, and when a surface charge image under the nth pulse voltage needs to be shot (n is 100 in fig. 5), the frequency and the pulse of the preset nanosecond pulse can indicate that the initial discharge time of the 100 th pulse is t after the nanosecond pulse power supply 14 is triggered0I.e. t0As the trigger signal time delay of the ICCD camera 10, the shutter delay time and the shutter opening time t of the three ICCD cameras 10 are set by the software in the computern(the ICCD camera 10 records the actual time that the light intensity has elapsed), it is possible to achieve a shot at any time at the 100 th pulse voltage. In addition, after the ICCD camera 10 is exposed and shot, a square wave voltage pulse signal is also generated at the same time, the signal starting time is the exposure starting time of the ICCD camera 10, the pulse of the signal is the opening time of a camera shutter, and the nanosecond pulse voltage signal, the DBD discharge current signal and the exposure signal of the ICCD camera 10 are collected and displayed by the digital oscilloscope 11 at the same time, so that experimenters can determine the shooting time of the ICCD camera 10 conveniently, and the effect of experimental observation results is guaranteedAnd (4) sex.
Fig. 6 shows the recording result of the digital oscilloscope in the experiment, in which two ICCD cameras 10 respectively discharge with the pulse rising edge and the pulse falling edge and then shoot.
In the figure, the ICCD exposure 1, the ICCD exposure 2, and the ICCD exposure 3 respectively refer to exposure by the first ICCD camera 10, exposure by the second ICCD camera 10, and exposure by the third ICCD camera 10; the positions of the first ICCD camera 10, the second ICCD camera 10 and the third ICCD camera 10 are from top to bottom in fig. 1 and 4.
Fig. 7 shows the result of the ICCD camera 10 in the experiment, in which (a) the image is taken by the first ICCD camera 10, (b) the image is taken by the second ICCD camera 10, and (c) the image is taken by the third ICCD camera 10. (d) The figure is a surface charge measurement scale. The distribution of the surface charge can be clearly seen from the figure.
In summary, the nanosecond-pulse-driven system for observing surface charges of dielectric barrier discharge at any time can perform discharge characteristic measurement and dynamic observation of surface charges of barrier dielectric at any time under the repetition frequency nanosecond pulse, and the observation result is clear and effective. The experimental result of the system can be used for analyzing and researching the action mechanism of the surface charge of the medium in the nanosecond pulse DBD on the discharge characteristic and the memory effect of the surface charge in a microscopic angle, and the system is favorable for perfecting the action mechanism of the surface charge on the nanosecond pulse DBD.
Claims (10)
1. A nanosecond pulse driven surface charge observation system for dielectric barrier discharge at any moment is characterized by comprising:
a helium neon laser source (1), the light path output end at helium neon laser source (1) sets gradually beam amplifier (2), diaphragm (3), polarization beam splitter (4), and wherein, the light beam of laser source (1) is divided into two the tunnel through polarization beam splitter (4): one path enters a dielectric barrier discharge unit (6) through an 1/8 wave plate (5), and the other path enters a camera framing unit (9) through a convex lens (7) and a small hole (8); three ICCD cameras (10) for imaging are connected to the camera framing unit (9) to realize surface charge observation at any discharge time; the three ICCD cameras (10) are respectively connected with the digital oscilloscope (11), the nanosecond pulse power supply (14) and the computer (15); a nanosecond pulse power supply (14) is connected with a digital delay generator (13), a digital oscilloscope (11) is connected with a high-voltage probe (12), and the digital oscilloscope (11) is connected with the near end of the dielectric barrier discharge unit (6); the output end of the high-voltage probe (12) and the output end of the nanosecond pulse power supply (14) are connected with the far end of the dielectric barrier discharge unit (6).
2. The nanosecond pulse driven dielectric barrier discharge surface charge observation system at any moment according to claim 1, wherein the dielectric barrier discharge unit (6) comprises a high-voltage end polytetrafluoroethylene insulating disc (607), a flat high-voltage electrode (609) is arranged in the center of the high-voltage end polytetrafluoroethylene insulating disc (607), a discharge air gap (608) is reserved below the flat high-voltage electrode (609), and a low-density polyethylene (610) and a bismuth silicate electrode (606) are arranged below the discharge air gap (608); symmetrical insulating supports (601) are respectively arranged on two sides of a bismuth silicate electrode (606), a symmetrical ground electrode (602) and a measuring electrode (603) are arranged below the insulating supports (601), an insulating ring (605) is arranged between the ground electrode (602) and the measuring electrode (603), and 4 measuring resistors (604) are bridged between the ground electrode (602) and the measuring electrode (603) and used for measuring dielectric barrier discharge current.
3. The nanosecond pulsed driven dielectric barrier discharge surface charge observation system at any moment according to claim 1, wherein the bismuth silicate electrode (606) is composed of a reflective film (60601), bismuth silicate crystals (60602), BK7 glass substrate (60603) and ITO thin film (60604).
4. The nanosecond pulse driven dielectric barrier discharge surface charge observation system at any moment according to claim 2, wherein the flat plate high voltage electrode (609) is a copper electrode with a diameter of 10 mm; the bismuth silicate crystals (60602) have a size of 20 × 0.16 mm.
5. The nanosecond pulse driven dielectric barrier discharge surface charge observation system at any moment according to claim 1, wherein the camera framing unit (9) is composed of a relay lens (901), three polarization beam splitting prisms (902) and three ICCD cameras (10), and is mainly used for dividing laser containing surface charge information of the pinhole (8) into three beams which are respectively received and imaged by the three ICCD cameras (10) so as to realize surface charge observation at any moment of discharge.
6. The nanosecond pulsed driven dielectric barrier discharge surface charge observation system at any moment according to claim 1, wherein said nanosecond pulsed power supply (14) is adapted to generate repetitive nanosecond pulsed voltages with a frequency of 0-100kHz, an amplitude of 0-10kV, a pulse width of 0-1ms, and a rising and falling edge of 50-500 ns.
7. The nanosecond pulse driven surface charge observing system for dielectric barrier discharge at any time according to claim 1, wherein said he-ne laser (1) is used to generate stable linearly polarized light with a wavelength of 632.8nm, and the spot diameter is controlled by the beam amplifier (2) and the diaphragm (3).
8. The nanosecond pulse driven dielectric barrier discharge surface charge observation system at any instant according to claim 1, wherein said digital delay generator (13) is selected as eight-channel digital delay pulse generator DG 645.
9. The nanosecond pulsed driven surface charge observation system of any time of dielectric barrier discharge, as set forth in claim 2, wherein the 4 measuring resistors (604) have a resistance of 200 Ω.
10. The nanosecond pulsed driven dielectric barrier discharge surface charge observation system at any time according to claim 1, wherein said 1/8 wave plate (5) performs a 45 degree phase retardation on polarized light to distinguish between positive and negative charge polarities by light intensity variation.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111230625.3A CN114019261A (en) | 2021-10-22 | 2021-10-22 | Nanosecond pulse driven surface charge observation system for dielectric barrier discharge at any moment |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107991544A (en) * | 2017-12-25 | 2018-05-04 | 西安交通大学 | Surface charge DYNAMIC DISTRIBUTION measuring system and method in a kind of dielectric barrier discharge |
| CN111273135A (en) * | 2020-02-07 | 2020-06-12 | 西安交通大学 | System and method for measuring dielectric barrier discharge characteristics under airflow regulation |
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2021
- 2021-10-22 CN CN202111230625.3A patent/CN114019261A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107991544A (en) * | 2017-12-25 | 2018-05-04 | 西安交通大学 | Surface charge DYNAMIC DISTRIBUTION measuring system and method in a kind of dielectric barrier discharge |
| CN111273135A (en) * | 2020-02-07 | 2020-06-12 | 西安交通大学 | System and method for measuring dielectric barrier discharge characteristics under airflow regulation |
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| Title |
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| 邵涛等: "空气中纳秒脉冲均匀介质阻挡放电研究", 《高电压技术》 * |
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Application publication date: 20220208 |