CN103941166A - High-temperature gas breakdown characteristic detection device and method under VFTO condition - Google Patents

Abstract

The invention provides a high-temperature gas breakdown characteristic detection device and method under the VFTO condition. The device achieves detection of the gas breakdown process under the VFTO condition. The device comprises a gas sealing chamber, a heating unit, a discharging unit, a spectrometer, a thermodetector, a gas inflating, deflating and recycling unit, a voltage source, a VFTO generation unit, an ampere meter and a computer. The method detects the gas breakdown process from the microcosmic viewpoint, the spectrometer is used for measuring light intensity and wave length in the breakdown process, the temperature of particles in the breakdown process is obtained, and the viscosity coefficient, the conductivity and the diffusion coefficient of the particles are further obtained. According to particle collision characteristics under the VFTO condition, a collision item of a Boltzmann equation is corrected.

Description

High-temperature gas breakdown characteristics pick-up unit and method under a kind of VFTO

Technical field

The invention belongs to field of gas discharge, be specifically related to high-temperature gas breakdown characteristics pick-up unit and method under a kind of VFTO.

Background technology

Gas, liquid and solid dielectric breakdown characteristics under the normal conditions such as direct current, industrial frequency AC has carried out considerable research work, in recent years, the gas discharge rule of the dielectric insulation performance under extreme condition and multi-form and condition etc. has caused domestic and international extensive concern.At super extra-high voltage GIS (Gas Insulated Switchgear, fully closed combined electric unit), during isolator operation because the frequency of restriking is high, can produce VFTO (the Very Fast Transient Over-voltages of tens MHZ, fast transient overvoltage), the break performance of harm switch.Therefore, significant for the research of gas breakdown process under VFTO condition, however the current detection means for gas breakdown characteristic under VFTO condition is imperfection also.Under VFTO condition the state of gas breakdown process applying plasma often right and wrong from equilibrium state, should consider interparticle collision process, need to describe with Non-Boltzmann distrubution function, and the very high frequency due to VFTO, in breakdown process, under interparticle collision and power-frequency voltage, interparticle collision there are differences, and original Boltzmann collision model cannot be suitable for this extreme case.

Summary of the invention

The deficiency existing for prior art, the invention provides high-temperature gas breakdown characteristics pick-up unit and method under a kind of VFTO.

Technical scheme of the present invention:

A high-temperature gas breakdown characteristics pick-up unit under VFTO, comprising:

Gas confinement chamber, heating unit, discharge cell, spectrometer, temperature measurer, gas charge and discharge and recovery unit, voltage source, VFTO generation unit, reometer and computing machine;

Described gas confinement chamber, for the cylinder barrel shaped structure of sealing, adopts adiabatic transparent material, for filling gas;

Described heating unit comprises resistance wire and potsherd; Described resistance wire is arranged on gas confinement chamber intracavity bottom position; Described potsherd is laid on resistance wire surface;

Described discharge cell comprises anode electrode plate and cathode electrode plate; Described anode electrode plate and cathode electrode plate are arranged on respectively on the centre position of gas confinement chamber internal chamber wall, and anode electrode plate and cathode electrode plate staggered relatively;

The probe of described spectrometer is inserted in gas confinement chamber inner chamber and is placed between anode electrode plate and cathode electrode plate, and the output terminal of spectrometer connects an input end of computing machine;

Described temperature measurer is arranged on gas confinement chamber inner cavity top position;

Described gas charges and discharge with recovery unit and is communicated with gas confinement chamber inner chamber by tracheae;

Two output terminals of described voltage source are two terminals of contact resistance silk respectively;

Described VFTO generation unit comprises pulse trigger group, pulse producer group and VFTO combiner circuit; Described pulse trigger group comprises a plurality of pulse triggers; Described pulse producer group comprises a plurality of pulse producers; The input end of each pulse trigger in described pulse trigger group connects from the different output terminals of described computing machine respectively; The output terminal of each pulse trigger in described pulse trigger group is connected with the input end of each pulse producer in pulse producer group respectively; The output terminal of each pulse producer in described pulse producer group connects respectively each input end of VFTO combiner circuit, and the output terminal of VFTO combiner circuit is connected with the link of anode electrode plate and gas confinement chamber by reometer as the output terminal of VFTO generation unit; The zero potential end of described VFTO generation unit is connected with the link of cathode electrode plate and gas confinement chamber;

Described resistance wire is for heating the gas of gas confinement chamber; Between the metallic vapour that described potsherd produces while being used for Resistant heating and tested gas, isolate;

Anode electrode plate and the spacing between cathode electrode plate of described discharge cell are adjustable;

Described spectrometer is used for the intensity of spectrum and the wavelength of spectrum of measurement gas plasma generation and the wavelength of the intensity of the spectrum recording and spectrum is sent to computing machine;

Described voltage source is used to resistance wire power supply, makes resistance wire heating; Described temperature measurer is for measuring the temperature that is heated gas;

Described gas charges and discharge with recovery unit for the inflation of gas confinement chamber and vacuumizes processing;

The intensity of spectrum and the wavelength of spectrum that the gaseous plasma that described computing machine sends for receiving spectrum instrument produces also calculates various particle temperatures in plasma and the distribution of the various particles of gas breakdown process and calculate respectively the coefficient of diffusion of particle according to the distribution function of various particles in gas breakdown process, the conductivity of particle and the coefficient of viscosity of particle, and obtain VFTO for emulation, and the VFTO of acquisition is decomposed into the nanosecond pulse signal of a plurality of different cycles and sends to respectively each pulse trigger in the pulse trigger group of VFTO generation unit,

Each pulse trigger in described pulse trigger group is for the output frequency of each pulse producer of difference clamp-pulse generator group; Each pulse producer in described pulse producer group is for producing respectively the pulse signal of required frequency;

Described VFTO combiner circuit carries out amplitude adjusting for the pulse signal that each pulse signal generator of pulse signals generator group produces respectively, and each pulse signal after amplitude is regulated carries out overlap-add procedure and phase adjusted is processed the required VFTO of rear output;

Adopt high-temperature gas breakdown characteristics pick-up unit under described VFTO to carry out the method that under VFTO, high-temperature gas breakdown characteristics detects, comprise the steps:

Step 1: regulate the spacing between anode electrode plate and cathode electrode plate, reach desirable value;

Step 2: gas charges and discharge with recovery unit gas confinement chamber is vacuumized to processing;

Step 3: gas charges and discharge with recovery unit to the gas that is filled with required pressure in gas confinement chamber;

Step 4: voltage source is powered to resistance wire;

Step 5: gas temperature in temperature measurer measurement gas sealing chamber;

Step 6: judge in gas confinement chamber, whether gas temperature reaches target temperature, is, performs step 7, no, turn and perform step 4;

Step 7: close voltage source, stop powering to resistance wire;

Step 8:VFTO generation unit is antianode battery lead plate and cathode electrode plate loading VFTO simultaneously;

Step 9: intensity and the wavelength of the spectrum that spectrometer measurement gaseous plasma produces is also sent to computing machine;

Step 10: whether change and judge whether gas punctures under VFTO according to reometer indicated value, if reometer indicated value changes, think that gas punctures under VFTO, turn and perform step 11, if reometer indicated value does not change, think that gas does not puncture under VFTO, turns and performs step 9;

Step 11: gas charges and discharge with recovery unit gas confinement chamber is vacuumized to processing;

Step 12: intensity and the wavemeter of the spectrum that computing machine produces according to the gaseous plasma receiving are calculated the various particle temperatures in plasma;

Step 13: computing machine calculates the distribution of various particles in gas breakdown process according to the various particle temperatures in gaseous plasma, obtains the distribution function of various particles in gas breakdown process;

In gas breakdown process, the distribution of various particles is obtained by Boltzmann equation (1),

$\frac{\∂f}{\∂t}+v\·\frac{\∂f}{\∂r}+\mathrm{eE}\·\frac{\∂f}{\∂p}={\▿}_p\·s---\left(1\right)$

Wherein, the particle current density that s is momentum space, individual/m ³; ▽ _pfor the total differential of s to momentum; P is the momentum of particle, and unit is kgm/s; S is s at the axial component of α _α, s _αby formula (2), obtained; α axle is X-axis, or α axle is Y-axis, or α axle is Z axis;

$s_{\mathrm{\α}}={\mathrm{\σ}}_t{u}^2\·|v-v^{\′}|\∫\∫\∫(f\frac{{\∂f}^{\′}}{{\∂p}_{\mathrm{\β}}^{\′}}-f^{\′}\frac{\∂f}{{\∂p}_{\mathrm{\β}}})\×({(v-v^{\′})}^2{\mathrm{\δ}}_{\mathrm{\α\β}}-(v_{\mathrm{\α}}-{v_{\mathrm{\α}}}^{\′})(v_{\mathrm{\β}}-{v_{\mathrm{\β}}}^{\′}))d^3{p}^{\′}---\left(2\right)$

Wherein, σ _tfor transport cross-section, by formula (3), obtained; U is reduced mass, m and m' are respectively the quality of the particle that particle that two momentum that collide are p and momentum are p', kg; V and v' are respectively the particle rapidity that particle rapidity that momentum is p and momentum are p', m/s; F is that momentum is the distribution function of the particle of p; F ' is the distribution function of the momentum particle that is p'; P ' _βfor momentum p' is at the axial component of β; β axle is X-axis, or β axle is Y-axis, or β axle is Z axis; p _βfor momentum p is at the axial component of β; δ _{α β}for unit tensor; v _αfor the momentum particle rapidity that is p is at the axial component of α, m/s; v _α' be momentum be p' the axial component of particle rapidity α, m/s; v _βfor the momentum particle rapidity that is p is at the axial component of β, m/s; v _β' be momentum be p' the axial component of particle rapidity β, m/s;

${\mathrm{\σ}}_t={\mathrm{\σ}}_e+{\mathrm{\σ}}_r=\frac{2\mathrm{\π}}{k^2}\underset{l=0}{\overset{\∞}{\mathrm{\Σ}}}(2l+1)(1-{\left|S_l\right|}^2)---\left(3\right)$

Wherein, σ _efor elastic scattering cross-section; σ _rfor inelastic scattering cross section; K is the wave number of incident particle, according to formula (4), determines; L is angular momentum, kgm ²/ s; S _lfor the random number that mould is less than 1, S _l=1 represents not exist completely this scattering, S _l=0 represents that the particle that angular momentum is l is absorbed completely;

Wherein, for Planck constant; E is the energy of scattering particle, joule; m ₁be in two impingment particles compared with the quality of lepton, unit is kg;

Step 14: computing machine calculates respectively the coefficient of viscosity of the coefficient of diffusion of particle, the conductivity of particle and particle according to the distribution function of various particles in gas breakdown process.

Beneficial effect: under VFTO of the present invention, high-temperature gas breakdown characteristics pick-up unit and method have following advantage compared with prior art:

1) with the research of breakdown process just to be measured to macroscopical parameters such as voltage breakdown different in the past, this device detects the breakdown process of gas from the angle of microcosmic, by the light intensity in spectrometer measurement breakdown process and wavelength, obtain the particle temperature in breakdown process, and be applied in the research method of the present invention's proposition, obtain coefficient of viscosity, conductivity, the coefficient of diffusion of particle.

2) according in GIS, can produce VFTO, the break performance of harm isolating switch.Almost there is no at present the research for gas breakdown process under this extreme condition of VFTO, and the present invention can realize the detection of gas breakdown process under VFTO condition.

3) in gas breakdown process, between particle, there is complicated collision, the distribution of particle need to be described with Non-Boltzmann distrubution, very high frequency due to VFTO, different under the collision of particle and power frequency condition in its breakdown process, so collision term correction that need to be to Boltzmann when particle density distributes solve breakdown process under VFTO condition in.The present invention, according to the feature of particle encounter under VFTO, revises the collision term of Boltzmann equation.

Accompanying drawing explanation

Fig. 1 is the annexation schematic diagram of high-temperature gas breakdown characteristics pick-up unit under the VFTO of one embodiment of the present invention;

Fig. 2 is the structural representation of the gas confinement chamber ring flange used of one embodiment of the present invention;

Fig. 3 is that the gas of one embodiment of the present invention charges and discharge the annexation schematic diagram with recovery unit: (a) be the structural representation of vacuumized part; (b) be the structural representation of injection section;

Fig. 4 is the circuit theory diagrams of the VFTO generation unit of one embodiment of the present invention;

Fig. 5 is the process flow diagram of high-temperature gas breakdown characteristics detection method under the VFTO of one embodiment of the present invention.

Embodiment

Below in conjunction with accompanying drawing, one embodiment of the present invention are elaborated.

High-temperature gas breakdown characteristics pick-up unit under the VFTO of present embodiment, as shown in Figure 1, comprising: gas confinement chamber 7, heating unit, discharge cell, spectrometer 5, temperature measurer 3, gas charges and discharge and recovery unit 1, voltage source 12, VFTO generation unit 11, reometer 16 and computing machine 15;

The cylinder barrel shaped structure that described gas confinement chamber 7 is sealing, for filling gas, adopts adiabatic glass material to make, and wall thickness is about 20mm, and the barrel-shaped intracavity diameter of gas confinement chamber 7 cylinder is about 170mm, is highly about 400mm; Gas confinement chamber 7 tip positions are connected with upper flange plate 6, and gas confinement chamber 7 bottom positions are connected with lower flange 10; Upper flange plate 6 is identical with the structure of lower flange 10, as shown in Figure 2, at upper flange plate 6, apart from 85mm place, its center of circle with at lower flange 10, apart from 85mm place, its center of circle, open respectively the circle groove that a width is 20mm, in two circle grooves, place respectively rubber gasket 17.Upper flange plate 6 is all connected in the way to insert gas confinement chamber and by bolt 18, carries out surrounding and fix with lower flange 10.For hot test, rubber seal 17 adopts FFKM, has very strong high-temperature stability.

Described heating unit comprises resistance wire 13 and potsherd 9; Described resistance wire 13 heats for the gas to gas confinement chamber, for increasing heating surface area and gas being heated evenly, resistance wire is twisted into thigh, and tiling is arranged on the surface location of gas confinement chamber intracavity bottom lower flange 10; The material of resistance wire 13 is ferrum-chromium-aluminum OCr27Al7MO2, and maximum temperature that can heated air is 1400 ℃; The stupalith on resistance wire 13 surfaces is alumina ceramic plate, and model is TO-247.The metallic vapour producing while avoiding resistance wire 13 heating produces and disturbs breakdown process plasma measurement, tiled on the resistance wire 13 surfaces potsherd 9 of one deck high thermal conductivity coefficient, isolates between the metallic vapour producing when to resistance wire 13 heating and tested gas; Because ceramic ductility is poor, for ease of installing, the diameter of potsherd 9 is than the little 4mm of the internal diameter of gas confinement chamber 7, and with respect to gas confinement chamber 7 internal diameters, 4mm is very little amount, and resistance wire is arranged in below potsherd, therefore measurement that can plasma exerts an influence.

Described discharge cell comprises anode electrode plate 14 and cathode electrode plate 8; Described anode electrode plate 14 and cathode electrode plate 8 are arranged on respectively on the centre position of gas confinement chamber 7 internal chamber walls, and anode electrode plate 14 and cathode electrode plate 8 staggered relatively, and the spacing between anode electrode plate 14 and cathode electrode plate 8 is adjustable; Anode electrode plate 14 and cathode electrode plate 8 are disc plate electrode, and material is copper, and diameter is 20mm,

The probe 4 of described spectrometer 5 is inserted in gas confinement chamber 7 inner chambers and is placed between anode electrode plate 14 and cathode electrode plate 8, be positioned at the position apart from anode electrode plate 14 tops and cathode electrode plate 8 top 5mm, and probe 4 parts that are placed in gas confinement chamber 7 inner chambers arrange convex lens, can increase the measurement range of probe 4.Spectral intensity and spectral wavelength when the emission spectrum by spectrometer 5 measurement gas plasma generation acquires gas breakdown under VFTO, utilize light intensity ratio method to obtain the temperature of each particle in gaseous plasma.What the spectrometer 5 in present embodiment adopted is AvaSpec-ULS2048-x-USB2 double-channel spectrometer, can record wavelength coverage is 200-1100nm, and A/D conversion adopts 16 1MHZ, and the minimum response time is 0.1ms, detector adopts CCD linear array, and pixel is 2*3648.

Described temperature measurer 3 is arranged on gas confinement chamber 7 inner cavity top positions, for measuring the temperature that is heated gas; What the temperature measurer 3 in present embodiment adopted is fixed infrared temperature detector, and model is SCIT-2MK2A, and temperature-measuring range is 600 ℃-2000 ℃, and aiming mode is that optics is visual; It is bolted on upper flange plate 6.Because infrared thermometer 3 can only be surveyed any temperature, may cause measurement result to have very large error, the present invention adopts multiangular measurement, with bolt, infrared thermometer is fixed on bearing, can measure the temperature of multiple directions, every 15 degree, measure once, and measured value is averaged to the gas temperature in cavity.

Described gas charges and discharge with recovery unit 1 and is communicated with gas confinement chamber 7 inner chambers by tracheae 2, for the processing that vacuumizes of the recovery of the charging and discharging of gas, gas and gas confinement chamber; For prevent inflation and while vacuumizing gas spill, in present embodiment, gas charges and discharge with recovery unit 1 and is communicated with gas confinement chamber inner chamber by pick out a threaded stainless steel tracheae 2 on upper flange plate 6, while being used for testing, the gas of certain air pressure is filled with in gas confinement chamber; After experiment finishes, the gas in gas confinement chamber is vacuumized to prevent that harmful gas from polluting.

For prevent inflation and while vacuumizing gas spill, in present embodiment, gas charges and discharge with recovery unit 1 and is connected with gas confinement chamber 7 by tracheae 2, there is screw thread on tracheae 2 surfaces, it is closely connected with the stainless-steel tube that gas confinement chamber 7 upper flange plates 6 pick out; During experiment, the gas of certain air pressure is filled with in gas confinement chamber 7, after experiment finishes, the gas in gas confinement chamber 7 is vacuumized to prevent that harmful gas from polluting; Gas charges and discharge with recovery unit 1 and comprises vacuum extractor and aerating device; Vacuumized part comprises gas recycling can 25, vacuum meter 19, vacuum pump 24, rain glass 22, valve 20, valve 21 and valve 23, as shown in Fig. 3 (a), when gas confinement chamber 7 vacuumizes, valve 20, valve 21, valve 23 are opened, gas is extracted out by vacuum pump 24, and maximum vacuum is 10Pa; Injection section comprises gas-holder 29, filtrator 28, compressor 27, rain glass 26 and valve 30, as shown in Fig. 3 (b), during gas confinement chamber 7 inflation, the gas of gas-holder 26 is filled with in gas confinement chamber 7 by filtrator 28 and compressor 27, and highest pressure is 3.8Mpa;

Two output terminals of described voltage source 12 are two terminals of contact resistance silks 13 respectively, are used to resistance wire 13 power supplies, make resistance wire 13 heatings, make gas very fast higher temperature that reaches before electric discharge not; What the voltage source 12 in present embodiment adopted is GQ-AD type 3000W rearrangeable switch power supply, maximum voltage 1500V, maximum current 2000A.

Described VFTO generation unit, as shown in Figure 4, comprises pulse trigger group 31, pulse producer group 32 and VFTO combiner circuit 33; It is the pulse trigger of 501003CDB (CD3) that n in present embodiment in pulse trigger group 31 pulse trigger all adopts model, and it is the pulse producer of the complete solid state pulse power source of SPG200 that the pulse producer of the n in pulse producer group 32 all adopts model;

Described pulse trigger group 31 comprises n pulse trigger, for the output frequency of clamp-pulse generator group 32; Described pulse producer group 32 comprises n pulse producer, for generation of the pulse signal of certain frequency; The input end of each pulse trigger in described pulse trigger group 31 connects from the different output terminals of computing machine 15 respectively; The output terminal of each pulse trigger in described pulse trigger group 31 is connected with the input end of each pulse producer in pulse producer group 32 respectively; The output terminal of each pulse producer in described pulse producer group 32 connects respectively each input end of VFTO combiner circuit 33, and the output terminal of VFTO combiner circuit 33 is connected with the link of gas confinement chamber 7 with anode electrode plate 14 by reometer 16 as the output terminal of VFTO generation unit 11; The zero potential end of described VFTO generation unit 11 is connected with the link of gas confinement chamber 7 with cathode electrode plate 8;

Between each input end of described VFTO combiner circuit 33 and the negative input end of first order operational amplifier 34, be in series with respectively resistance R 1, resistance R 2, resistance R n, as shown in Figure 4, between the negative input end of first order operational amplifier 34 and its output terminal, be parallel with resistance R n+1, the positive input terminal of first order operational amplifier 34 is by resistance R n+2 ground connection, the output terminal of first order operational amplifier 34 connects the negative input end of second level operational amplifier 35 by resistance R n+3, between the negative input end of second level operational amplifier 35 and its output terminal, be parallel with resistance R n+4, the positive input terminal of second level operational amplifier 35 is by resistance R n+5 ground connection.

The VFTO that present embodiment Computer 15 simulation calculation produce while going out isolator operation in certain GIS, and this VFTO is decomposed into the nanosecond pulse signal of n different amplitudes, different frequency, computing machine 15 is set in the frequency values of each pulse signal decompositing respectively in each pulse trigger in pulse trigger group 31, each pulse trigger in pulse trigger group 31 produces respectively pulse signal according to each pulse producer in the pulse signal frequency value trigger generator group 32 setting respectively, each pulse producer in pulse producer group 32 is sent to pulse signal respectively each input end of VFTO combiner circuit 33, resistance R 1 in VFTO combiner circuit 33, R2, each pulse signal amplitude that Rn decomposites according to computing machine 15 regulates the amplitude of each pulse signal receiving respectively, through resistance R 1, R2, n pulse signal after Rn regulates obtains required VFTO at VFTO combiner circuit 33 output terminal out ends after 34 stacks of first order operational amplifier and second level operational amplifier 35 control phases, the VFTO that goes out with computing machine 15 simulation calculation is identical or be close.

The frequency of the nanosecond pulse signal that each pulse producer in pulse producer group 32 produces be respectively respectively f1, f2 ..., fn, its voltage is respectively u ₁, u ₂..., u _n, after 34 stacks of first order operational amplifier, obtain u _n+1,

$u_{n+1}=-\frac{R_{n+1}}{R_1}{u}_1-\frac{R_{n+1}}{R_2}{u}_2-...-\frac{R_{n+1}}{R_n}{u}_n---\left(5\right)$

U _n+1after second level operational amplifier 35 control phases, obtain u _n+2, i.e. VFTO

$u_{n+2}=-\frac{R_{n+4}}{R_{n+3}}{u}_{n+1}=\mathrm{VFTO}---\left(6\right)$

Wherein, R _n+3, R _n+4for resistance, unit is Ω, and R _n+4=R _n+3;

The intensity of spectrum and the wavelength of spectrum that the gaseous plasma that described computing machine 15 sends for receiving spectrum instrument 5 produces also calculates various particle temperatures in gaseous plasma and the distribution of the various particles of gas breakdown process and calculate respectively the coefficient of diffusion of particle according to the distribution function of various particles in gas breakdown process, the conductivity of particle and the coefficient of viscosity of particle, and the VFTO producing during for simulation calculation GIS isolator operation, and the VFTO of acquisition is decomposed into a plurality of identical amplitudes, the nanosecond pulse signal of different cycles also sends to respectively each pulse trigger in the pulse trigger group 31 of VFTO generation unit.

Under the VFTO of employing present embodiment, high-temperature gas breakdown characteristics pick-up unit carries out the method that under VFTO, high-temperature gas breakdown characteristics detects, and comprises the steps:

Step 1: regulate the spacing between anode electrode plate 14 and cathode electrode plate 8 to arrive 5mm;

Step 2: gas charges and discharge with 1 pair of gas confinement chamber 7 of recovery unit and vacuumizes processing;

Step 3: gas charges and discharge with recovery unit 1 to the SF6 gas that is filled with 0.1MPa in gas confinement chamber 7;

Step 4: voltage source 12, to resistance wire 13 power supplies, makes its heating;

Step 5: infrared thermometer 3, from the temperature of a plurality of measurement of angle gas confinement chamber 7 interior SF6, is averaged the gas temperature in sealing chamber 7 using measured value;

Step 6: judge whether gas temperature reaches 1000 ° of target temperatures, is, performs step 7, no, turn and perform step 4;

Step 7: close voltage source 12, stop to resistance wire 13 power supplies;

Step 8:VFTO generation unit 11 is antianode battery lead plate 14 and cathode electrode plate 8 loading VFTO simultaneously;

Step 9: spectrometer 5 is measured spectral intensity and the wavelength of plasma in SF6 gas and is sent to computing machine 15;

Step 10: whether change to judge whether SF6 gas punctures under VFTO according to reometer 16 indicated values, if reometer 16 indicated values change, think gas breakdown, if reometer 16 indicated values do not change, think that gas does not puncture;

Step 11: gas charge and discharge with 1 pair of gas confinement chamber 7 of recovery unit in remaining SF6 gas vacuumize processing;

Step 12: spectral intensity and wavemeter that computing machine produces according to the SF6 gaseous plasma receiving are calculated the various particle temperatures in plasma;

Step 13: computing machine 15 calculates the distribution of various particles in gas breakdown process according to the various particle temperatures in gaseous plasma, obtains the distribution function of various particles in gas breakdown process;

In gas breakdown process under VFTO, particle momentum change in collision process is very little, the described process of collision integral can be processed as the diffusion in momentum space, and collision term can be write as:

$c\left(f\right)=-{\▿}_p\·s=-\frac{{\∂s}_{\mathrm{\α}}}{{\∂p}_{\mathrm{\α}}}---\left(7\right)$

Wherein, the particle current density that s is momentum space, individual/m ³, represent the population in unit volume unit in momentum space; ▽ _pfor the total differential of s to momentum; s _αfor s is at the axial component of α, α axle is X-axis, or α axle is Y-axis, or α axle is Z axis; P is the momentum of particle, and unit is kgm/s; p _αfor momentum p is at the axial component of α; The particle that is p for a momentum and momentum are that p' is at d ³the Collision Number that between particle in p', time per unit occurs is

W (p+q/2, p '-q/2; Q) f (p) f ' (p ') d ³qd ³wherein, q is momentum transfer to p ' (8); P ' is the momentum of particle, and unit is kgm/s; W is w function, and w function is expressed by colliding the momentum p of two particle and momentum p' and momentum transfer q;

According to detailed balancing condition, function w initiating particle and the eventually exchange of last particle are symmetrical

w(p+q/2,p′-q/2；q)＝w(p+q/2,p′-q/2；-q) (9)

Consider that momentum space point P is perpendicular to the unit area of α axle, according to definition, particle current density s _αit is the population from left to right surpassing through this area from right to left through this Area Ratio the unit interval.If the α component that particle is accepted momentum in collision equals q _α, the result of this collision is that through the particle of this area, before collision, their this component value is positioned at from p for from left to right _α-q _αto P _α, therefore, the population through this area is from left to right

$\mathrm{\Σ}\underset{q_{\mathrm{\α}}>0}{\∫}{d}^{3}q\∫d^3{p}^{\′}\underset{p_{\mathrm{\α}}-q_{\mathrm{\α}}}{\overset{p_{\mathrm{\α}}}{\∫}}w(p+q/2,p^{\′}-q/2;q)f\left(p\right)f^{\′}\left(p^{\′}\right){\mathrm{dp}}_{\mathrm{\α}}---\left(10\right)$

Wherein, f is that momentum is the distribution function of the particle of p; F ' is the distribution function of the momentum particle that is p';

Population through this area is from left to right

$\mathrm{\Σ}\underset{q_{\mathrm{\α}}>0}{\∫}{d}^{3}q\∫d^3{p}^{\′}\underset{p_{\mathrm{\α}}-q_{\mathrm{\α}}}{\overset{p_{\mathrm{\α}}}{\∫}}w(p+q/2,p^{\′}-q/2;-q)f(p+q)f^{\′}(p^{\′}-q){\mathrm{dp}}_{\mathrm{\α}}---\left(11\right)$

From formula (8), the w in two integrations is identical, therefore the difference of these integrations contains poor by long-pending expression formula

f(p)f′(p′)-f(p+q)f′(p′-q)

Due to momentum transfer, q is very little, and power series that can be to above-mentioned poor generate q, finally obtain

$s_{\mathrm{\α}}=\mathrm{\Σ}\underset{q_{\mathrm{\α}}>0}{\∫}{d}^{3}q\∫d^3{p}^{\′}\underset{p_{\mathrm{\α}}-q_{\mathrm{\α}}}{\overset{p_{\mathrm{\α}}}{\∫}}w(p,p^{\′};q)[f\left(p\right)\frac{\∂f^{\′}\left(p^{\′}\right)}{{\∂p}_{\mathrm{\β}}^{\′}}-f^{\′}\left(p^{\′}\right)\frac{\∂f\left(p\right)}{{\∂p}_{\mathrm{\β}}}]q_{\mathrm{\β}}{q}_{\mathrm{\α}}{d}^3{p}^{\′}---\left(12\right)$

Wherein, p ' _βfor momentum p' is at the axial component of β; β axle is X-axis, or β axle is Y-axis, or β axle is Z axis; p _βfor momentum p is at the axial component of β;

Introduce collision cross-section and replace function w

wd ³q＝|v-v′|dσ (13)

Therefore every class particle has following form at the momentum flow density of momentum space

$s_{\mathrm{\α}}=\mathrm{\Σ}\∫[f\left(p\right)\frac{\∂f^{\′}\left(p^{\′}\right)}{{\∂p}_{\mathrm{\β}}^{\′}}-f^{\′}\left(p^{\′}\right)\frac{\∂f\left(p\right)}{{\∂p}_{\mathrm{\β}}}]B_{\mathrm{\α\β}}{d}^3{p}^{\′}---\left(14\right)$

$B_{\mathrm{\α\β}}=\frac{1}{2}\∫q_{\mathrm{\α}}{q}_{\mathrm{\β}}|v-v^{\′}|\mathrm{d\σ}---\left(15\right)$

Wherein, B _{α β}for the amount of particle encounter, it is a tensor; q _αfor the axial momentum transfer of α; q _βfor the axial momentum transfer of β; V and v' are respectively the particle rapidity that particle rapidity that momentum is p and momentum are p', m/s; For low-angle skew, B _{α β}(v _β-v _β')=0, therefore

$B_{\mathrm{\α\β}}=\frac{1}{2}B[{\mathrm{\δ}}_{\mathrm{\α\β}}-\frac{(v_{\mathrm{\α}}-v_{\mathrm{\α}}^{\′})(v_{\mathrm{\β}}-v_{\mathrm{\β}}^{\′})}{{(v-v^{\′})}^2}]---\left(16\right)$

B＝B _αα＝u ²|v-v′| ³σ _t

Wherein, B _{α α}for B _{α β}scalar form;

In gas breakdown process, the distribution of various particles is obtained by Boltzmann equation (1),

$\frac{\∂f}{\∂t}+v\·\frac{\∂f}{\∂r}+\mathrm{eE}\·\frac{\∂f}{\∂p}={\▿}_p\·s---\left(1\right)$

Wherein, the particle current density that s is momentum space, individual/m ³; ▽ _pfor the total differential of s to momentum; P is the momentum of particle, and unit is kgm/s; S is s at the axial component of α _α, s _αby formula (2), obtained; α axle is X-axis, or α axle is Y-axis, or α axle is Z axis;

$s_{\mathrm{\α}}={\mathrm{\σ}}_t{u}^2\·|v-v^{\′}|\∫\∫\∫(f\frac{{\∂f}^{\′}}{{\∂p}_{\mathrm{\β}}^{\′}}-f^{\′}\frac{\∂f}{{\∂p}_{\mathrm{\β}}})\×({(v-v^{\′})}^2{\mathrm{\δ}}_{\mathrm{\α\β}}-(v_{\mathrm{\α}}-{v_{\mathrm{\α}}}^{\′})(v_{\mathrm{\β}}-{v_{\mathrm{\β}}}^{\′}))d^3{p}^{\′}---\left(2\right)$

Wherein, σ _tfor transport cross-section, by formula (3), obtained; U is reduced mass, m and m' are respectively the quality of the particle that particle that two momentum that collide are p and momentum are p', kg; V and v' are respectively the particle rapidity that particle rapidity that momentum is p and momentum are p', m/s; F is that momentum is the distribution function of the particle of p; F ' is the distribution function of the momentum particle that is p'; P ' _βfor momentum p' is at the axial component of β; β axle is X-axis, or β axle is Y-axis, or β axle is Z axis; p _βfor momentum p is at the axial component of β; δ _{α β}for unit tensor; v _αfor the momentum particle rapidity that is p is at the axial component of α, m/s; v _α' be momentum be p' the axial component of particle rapidity α, m/s; v _βfor the momentum particle rapidity that is p is at the axial component of β, m/s; v _β' be momentum be p' the axial component of particle rapidity β, m/s;

${\mathrm{\σ}}_t={\mathrm{\σ}}_e+{\mathrm{\σ}}_r=\frac{2\mathrm{\π}}{k^2}\underset{l=0}{\overset{\∞}{\mathrm{\Σ}}}(2l+1)(1-{\left|S_l\right|}^2)---\left(3\right)$

Wherein, σ _efor elastic scattering cross-section; σ _rfor inelastic scattering cross section; K is the wave number of incident particle, according to formula (4), determines; L is angular momentum, kgm ²/ s; S _lfor the random number that mould is less than 1, S _l=1 represents not exist completely this scattering, S _l=0 represents that the particle that angular momentum is l is absorbed completely;

Wherein, for Planck constant; E is the energy of scattering particle, joule; m ₁be in two impingment particles compared with the quality of lepton, unit is kg;

The concrete operations mode that solves formula (1) Boltzmann equation is: zoning is divided into macroscopic view little (can replace with a bit), the fritter of microcosmic large (comprising abundant particle), plasma in each fritter is balance, can represent with same distribution function, between fritter and fritter, be linear unbalanced, establish

F=f ⁰(1+h) (17) wherein, f ⁰for local ANALOGY OF BOLTZMANN DISTRIBUTION; H is change;

Bringing formula (17) into formula (1) obtains

$[\frac{\∂}{\∂t}+v\·\frac{\∂}{\∂r}+\mathrm{eE}\·\frac{\∂}{\∂p}](f^0+f^{0}h)=f^0{\▿}_p\·s\·h---\left(18\right)$

For the very little situation of momentum change

$f^0=n\left(r\right){\left[2\mathrm{\π}{k}_{B}t(r,t)\right]}^{-\frac{3}{2}}\exp [-\frac{m{|v-u\left(r\right)|}^2}{{2\mathrm{mk}}_{B}T(r,t)}]---\left(19\right)$

Wherein, u (r)=<v>, is the average velocity of local particle, and unit is m/s; k _bfor Planck's constant; T (r, t) is local temperature, and unit is K, and it is relevant with time t with particle locus r, and its value can obtain by the pick-up unit in the present invention; By solving equation (18), obtain the distribution function of each particle.

Step 14: computing machine calculates respectively the coefficient of viscosity of the coefficient of diffusion of particle, the conductivity of particle and particle according to the distribution function of various particles in gas breakdown process.

Diffusion coefficient D, conductivityσ and coefficient of viscosity η are obtained by formula (20), formula (21) and formula (22)

$D=-\frac{1}{n}{\&Integral;\&Integral;\&Integral;d}^3{\mathrm{vfv}}_x\frac{1}{{\&dtri;}_p\&CenterDot;s}{v}_x---\left(20\right)$

$\mathrm{\&sigma;}=-\frac{e^2}{{2m}_2{k}_{B}T(r,t)}{\&Integral;\&Integral;\&Integral;d}^3{\mathrm{vfv}}_x\frac{1}{{\&dtri;}_p\&CenterDot;s}{v}_x---\left(21\right)$

$\mathrm{\&eta;}=-\frac{m_2}{k_{B}T(r,t)}{\&Integral;\&Integral;\&Integral;d}^3{\mathrm{vfv}}_x{v}_y\frac{1}{{\&dtri;}_p\&CenterDot;s^T}{v}_x{v}_y---\left(22\right)$

Wherein, n is population density, individual/m ³; v _xfor the speed component of particle in X-direction, m/s; v _yfor the speed component of particle in Y direction, m/s; E is electronics carried charge, coulomb; m ₂for the quality of all kinds of particles, Kg.

In the SF6 gas that step 13 is obtained, each distribution of particles is brought formula (20), formula (21) and formula (22) into and is obtained diffusion coefficient D, conductivityσ and coefficient of viscosity η.

Claims (10)

1. a high-temperature gas breakdown characteristics pick-up unit under VFTO, is characterized in that: comprising:

Gas confinement chamber, heating unit, discharge cell, spectrometer, temperature measurer, gas charge and discharge and recovery unit, voltage source, VFTO generation unit, reometer and computing machine;

Described gas confinement chamber, for the cylinder barrel shaped structure of sealing, adopts adiabatic transparent material, for filling gas;

Described heating unit comprises resistance wire and potsherd; Described resistance wire is arranged on gas confinement chamber intracavity bottom position; Described potsherd is laid on resistance wire surface;

Described discharge cell comprises anode electrode plate and cathode electrode plate; Described anode electrode plate and cathode electrode plate are arranged on respectively on the centre position of gas confinement chamber internal chamber wall, and anode electrode plate and cathode electrode plate staggered relatively;

The probe of described spectrometer is inserted in gas confinement chamber inner chamber and is placed between anode electrode plate and cathode electrode plate, and the output terminal of spectrometer connects an input end of computing machine;

Described temperature measurer is arranged on gas confinement chamber inner cavity top position;

Described gas charges and discharge with recovery unit and is communicated with gas confinement chamber inner chamber by tracheae;

Two output terminals of described voltage source are two terminals of contact resistance silk respectively;

Described VFTO generation unit comprises pulse trigger group, pulse producer group and VFTO combiner circuit; Described pulse trigger group comprises a plurality of pulse triggers; Described pulse producer group comprises a plurality of pulse producers; The input end of each pulse trigger in described pulse trigger group connects from the different output terminals of described computing machine respectively; The output terminal of each pulse trigger in described pulse trigger group is connected with the input end of each pulse producer in pulse producer group respectively; The output terminal of each pulse producer in described pulse producer group connects respectively each input end of VFTO combiner circuit, and the output terminal of VFTO combiner circuit is connected with the link of anode electrode plate and gas confinement chamber by reometer as the output terminal of VFTO generation unit; The zero potential end of described VFTO generation unit is connected with the link of cathode electrode plate and gas confinement chamber.

2. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that: described resistance wire is for heating the gas of gas confinement chamber; Between the metallic vapour that described potsherd produces while being used for Resistant heating and tested gas, isolate.

3. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that: anode electrode plate and the spacing between cathode electrode plate of described discharge cell are adjustable.

4. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that: described spectrometer is used for the intensity of spectrum and the wavelength of spectrum of measurement gas plasma generation and the wavelength of the intensity of the spectrum recording and spectrum is sent to computing machine.

5. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that: described voltage source is used to resistance wire power supply, makes resistance wire heating; Described temperature measurer is for measuring the temperature that is heated gas.

6. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that: described gas charges and discharge with recovery unit for the inflation of gas confinement chamber and vacuumizes processing.

7. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that:

The intensity of spectrum and the wavelength of spectrum that the gaseous plasma that described computing machine sends for receiving spectrum instrument produces also calculates various particle temperatures in plasma and the distribution of the various particles of gas breakdown process and calculate respectively the coefficient of diffusion of particle according to the distribution function of various particles in gas breakdown process, the conductivity of particle and the coefficient of viscosity of particle, and obtain VFTO for emulation, and the VFTO of acquisition is decomposed into the nanosecond pulse signal of a plurality of different cycles and sends to respectively each pulse trigger in the pulse trigger group of VFTO generation unit.

8. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that:

Each pulse trigger in described pulse trigger group is for the output frequency of each pulse producer of difference clamp-pulse generator group; Each pulse producer in described pulse producer group is for producing respectively the pulse signal of required frequency.

9. high-temperature gas breakdown characteristics pick-up unit under VFTO according to claim 1, is characterized in that:

Described VFTO combiner circuit is for the pulse of each pulse signal generator generation of pulse signals generator group respectively

Signal carries out amplitude adjusting, and each pulse signal after amplitude is regulated carries out overlap-add procedure and phase adjusted is processed the required VFTO of rear output.

10. adopt high-temperature gas breakdown characteristics pick-up unit under VFTO claimed in claim 1 to carry out the method that under VFTO, high-temperature gas breakdown characteristics detects, it is characterized in that: comprise the steps:

Step 1: regulate the spacing between anode electrode plate and cathode electrode plate, reach desirable value;

Step 2: gas charges and discharge with recovery unit gas confinement chamber is vacuumized to processing;

Step 3: gas charges and discharge with recovery unit to the gas that is filled with required pressure in gas confinement chamber;

Step 4: voltage source is powered to resistance wire;

Step 5: gas temperature in temperature measurer measurement gas sealing chamber;

Step 6: judge in gas confinement chamber, whether gas temperature reaches target temperature, is, performs step 7, no, turn and perform step 4;

Step 7: close voltage source, stop powering to resistance wire;

Step 8:VFTO generation unit is antianode battery lead plate and cathode electrode plate loading VFTO simultaneously;

Step 9: intensity and the wavelength of the spectrum that spectrometer measurement gaseous plasma produces is also sent to computing machine;

Step 10: whether change and judge whether gas punctures under VFTO according to reometer indicated value, if reometer indicated value changes, think that gas punctures under VFTO, turn and perform step 11, if reometer indicated value does not change, think that gas does not puncture under VFTO, turns and performs step 9;

Step 11: gas charges and discharge with recovery unit gas confinement chamber is vacuumized to processing;

Step 12: intensity and the wavemeter of the spectrum that computing machine produces according to the gaseous plasma receiving are calculated the various particle temperatures in plasma;

Step 13: computing machine calculates the distribution of various particles in gas breakdown process according to the various particle temperatures in gaseous plasma, obtains the distribution function of various particles in gas breakdown process;

In gas breakdown process, the distribution of various particles is obtained by Boltzmann equation (1),

$\frac{\&PartialD;f}{\&PartialD;t}+v\&CenterDot;\frac{\&PartialD;f}{\&PartialD;r}+\mathrm{eE}\&CenterDot;\frac{\&PartialD;f}{\&PartialD;p}={\&dtri;}_p\&CenterDot;s---\left(1\right)$

Wherein, the particle current density that s is momentum space, individual/m ³; ▽ _pfor the total differential of s to momentum; P is the momentum of particle, and unit is kgm/s; S is s at the axial component of α _α, s _αby formula (2), obtained; α axle is X-axis, or α axle is Y-axis, or α axle is Z axis;

$s_{\mathrm{\&alpha;}}={\mathrm{\&sigma;}}_t{u}^2\&CenterDot;|v-v^{\&prime;}|\&Integral;\&Integral;\&Integral;(f\frac{{\&PartialD;f}^{\&prime;}}{{\&PartialD;p}_{\mathrm{\&beta;}}^{\&prime;}}-f^{\&prime;}\frac{\&PartialD;f}{{\&PartialD;p}_{\mathrm{\&beta;}}})\&times;({(v-v^{\&prime;})}^2{\mathrm{\&delta;}}_{\mathrm{\&alpha;\&beta;}}-(v_{\mathrm{\&alpha;}}-{v_{\mathrm{\&alpha;}}}^{\&prime;})(v_{\mathrm{\&beta;}}-{v_{\mathrm{\&beta;}}}^{\&prime;}))d^3{p}^{\&prime;}---\left(2\right)$

Wherein, σ t is transport cross-section, by formula (3), is obtained; U is reduced mass, m and m' are respectively the quality of the particle that particle that two momentum that collide are p and momentum are p', kg; V and v' are respectively the particle rapidity that particle rapidity that momentum is p and momentum are p', m/s; F is that momentum is the distribution function of the particle of p; F ' is the distribution function of the momentum particle that is p'; P ' _βfor momentum p' is at the axial component of β; β axle is X-axis, or β axle is Y-axis, or β axle is Z axis; p _βfor momentum p is at the axial component of β; δ _{α β}for unit tensor; v _αfor the momentum particle rapidity that is p is at the axial component of α, m/s; v _α' be momentum be p' the axial component of particle rapidity α, m/s; v _βfor the momentum particle rapidity that is p is at the axial component of β, m/s; v _β' be momentum be p' the axial component of particle rapidity β, m/s;

${\mathrm{\&sigma;}}_t={\mathrm{\&sigma;}}_e+{\mathrm{\&sigma;}}_r=\frac{2\mathrm{\&pi;}}{k^2}\underset{l=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}(2l+1)(1-{\left|S_l\right|}^2)---\left(3\right)$ Wherein, σ _efor elastic scattering cross-section; σ _rfor inelastic scattering cross section; K is the wave number of incident particle, according to formula (4), determines; L is angular momentum, kgm ²/ s; S _lfor the random number that mould is less than 1, S _l=1 represents not exist completely this scattering, S _l=0 represents that the particle that angular momentum is l is absorbed completely;

wherein, for Planck constant; E is the energy of scattering particle, joule; m ₁be in two impingment particles compared with the quality of lepton, unit is kg;

Step 14: computing machine calculates respectively the coefficient of viscosity of the coefficient of diffusion of particle, the conductivity of particle and particle according to the distribution function of various particles in gas breakdown process.