CN106018878A - Plasma velocity measurement method and system - Google Patents
Plasma velocity measurement method and system Download PDFInfo
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- CN106018878A CN106018878A CN201610303629.2A CN201610303629A CN106018878A CN 106018878 A CN106018878 A CN 106018878A CN 201610303629 A CN201610303629 A CN 201610303629A CN 106018878 A CN106018878 A CN 106018878A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/26—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6402—Atomic fluorescence; Laser induced fluorescence
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
- G01N2201/06113—Coherent sources; lasers
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Abstract
The invention discloses a plasma velocity measurement method and system. The method comprises the following steps: calibrating a frequency stating point of a macroscopic velocity of a flow field plasma to be measured; obtaining a curve of fluorescence signal intensity changing along with a laser frequency by performing measurement on the flow field plasma to be measured based on laser induced flourescense; and according to a measurement result, obtaining a Doppler broadening effect component through separation, and obtaining actual velocity distribution of the flow field plasma to be measured through conversion by taking the frequency starting point as a reference. According to the invention, plasma velocity measurement is carried out based on the laser induced flourescense, an ion motion velocity is measured through measuring a Doppler effect excited when ions are stimulated in a flow field to be measured, the noncontact type measurement technology is brand new, disturbance to the flow field to be measured does not exist, influences of electromagnetic interference widely existing in an electric thruster are eliminated, and the apparatus and system have the advantages of high precision, high interference immunity and wide applicability, thereby being widely promoted and applied.
Description
Technical field
The present invention relates to electric propulsion Plasma Diagnostics field, especially, relate to a kind of plasma speed measuring method and
System.
Background technology
In space craft jet-propulsion technical field, accelerate ion with electrostatic force or accelerate the electricity of plasma with Lorentz force
Thruster occupies increasingly consequence, and its technology development space is the biggest.The working medium that electric thruster is sprayed be low temperature etc. from
Daughter, has the most higher macroscopic velocity of 15000m/s-40000m/s, and pressure is relatively low simultaneously, is typically only several Pa to hundreds of
The pressure of Pa.For features such as evaluation thrust vectoring, working medium utilization ratio and plume contaminations, need accurately to measure jet macroscopic velocity
Spatial distribution.
So far above-mentioned low temperature plasma macroscopic velocity distribution is measured or one needs to continue perfect technology.The most existing
Method mainly include two kinds: (1) Mach probe method.This is a kind of contact measurement method, and probe itself can produce by stream field
Interference；On the other hand, the certainty of measurement of Mach probe is affected by magnetic fields, and under conditions of magnetic field is relatively strong, measurement result exists bigger
Error, and the impact in magnetic field may often be such that and can not ignore in electric thruster.(2) NPLS method.Nanometer is introduced in flow field
Grain is as trace particle, and by following the trail of the information such as the speed in Particles Moving measuring and calculating background flow field, this method only reflects neutral gas
Velocity field.Owing to electric thruster accelerates charged particle by body force, and himself gas density is low, neutral trace particle
Motion and charged particle have the biggest difference.Therefore, need that development is a kind of novel is applicable to electric thruster low pressure plasma jet badly
Macroscopic velocity become more meticulous measure method and system.
Summary of the invention
The invention provides a kind of plasma measurement method and system, cause solving the contact type measurement of existing Mach probe
Flow field disturbance and certainty of measurement is limited by magnetic field, NPLS method introduce nanoparticle cannot be applied directly to electric thruster flow field
Plasma speed measure technical problem.
The technical solution used in the present invention is as follows:
According to an aspect of the present invention, it is provided that a kind of plasma speed measuring method, the method includes:
The frequency Fixed Initial Point of flow field to be measured plasma macroscopic velocity is demarcated, using the stationary plasma source of gas of the same race as reference
Source, measures the laser-induced fluorescence (LIF) signal of reference source, and the laser frequency selecting fluorescence signal intensity highest point is frequency Fixed Initial Point；
Treat flow measurement field plasma to obtain fluorescence signal intensity and change song based on laser-induced fluorescence measurement, measurement with laser frequency
Line；
According to measurement result isolated dopplerbroadening effect component, on the basis of frequency Fixed Initial Point, carry out replacement obtain treating flow measurement
The actual speed distribution of field plasma.
Further, treat flow measurement field plasma to include based on laser-induced fluorescence measurement:
Using laser instrument as fluorescence excitation light source, exciting light enters through light path system to be made with particle on the internal tested point in flow field
With the most outwards radiofluorescence；
Fluorescence signal is through phase sensitive detection to extract and treated device collection from background noise, and processor scans laser with preset frequency
The output frequency of device, obtains fluorescence signal intensity with laser frequency change curve.
Further, according to measurement result isolated dopplerbroadening effect component, replace on the basis of frequency Fixed Initial Point
The actual speed distribution obtaining flow field to be measured plasma includes:
Fluorescence signal intensity is obtained measured spectra line style with laser frequency change curve by integrated normalized；
Measured spectra line style is carried out Doppler effect isolated dopplerbroadening effect component；
With frequency Fixed Initial Point, dopplerbroadening effect component is carried out Doppler-shift and obtain the speed-probability density of target area particle
Relation.
According to a further aspect in the invention, it is provided that a kind of plasma speed measures system, and this system includes:
Caliberating device, for demarcating the frequency Fixed Initial Point of flow field to be measured plasma macroscopic velocity, with gas of the same race static wait from
The laser-induced fluorescence (LIF) signal of reference source, as reference source, is measured in daughter source, selects the laser frequency of fluorescence signal intensity highest point
For frequency Fixed Initial Point；
Measurement apparatus, is used for treating flow measurement field plasma based on laser-induced fluorescence measurement, measure obtain fluorescence signal intensity with
Laser frequency change curve；
After-treatment device, for according to measurement result isolated dopplerbroadening effect component, enters on the basis of frequency Fixed Initial Point
Row replacement obtains the actual speed distribution of flow field to be measured plasma.
Further, measurement apparatus includes: as the laser instrument of fluorescence excitation light source, and the outfan of laser instrument connects light path system,
Exciting light enters through light path system and has an effect with particle and outside radiofluorescence on the internal tested point in flow field；
Measurement apparatus also includes: for fluorescence signal is coupled into the optical fiber collimator of optical fiber, optical fiber collimator connects light through optical fiber
Fine monochromator, photomultiplier tube and lock-in amplifier, the outfan of lock-in amplifier is connected to the processor of data acquisition, place
The fluorescence signal intensity that reason device scanning laser frequency and record lock-in amplifier detect through phase sensitive detection with obtain fluorescence signal intensity with
Laser frequency change curve.
Further, light path system includes the beam splitter being located at laser exit, and the part light that exciting light reflects through beam splitter enters
Band meter is to monitor laser frequency, and band meter connects processor；Exciting light through beam splitter transmission the most chopped device of part light,
Polygonal mirror, condenser lens enter and are allowed to excited absorption outside radiofluorescence inside flow field to be measured to have an effect with particle.
Further, laser instrument is tunable laser.
Further, the focal length of condenser lens is not less than 2m, and the focal beam spot diameter of line focus lens outgoing is less than 1mm.
Further, caliberating device uses and can have an X-rayed hollow cathode lamp as reference source.
Further, after-treatment device includes:
First processing module, for obtaining measured spectra with laser frequency change curve by integrated normalized to fluorescence signal intensity
Line style；
Second processing module, for carrying out Doppler effect isolated dopplerbroadening effect component to measured spectra line style；
3rd processing module, obtains target area for dopplerbroadening effect component being carried out Doppler-shift with frequency Fixed Initial Point
The speed of particle-probability density relation.
The method have the advantages that
Plasma speed measuring method of the present invention and system, carry out plasma speed measurement based on laser-induced fluorescence (LIF), pass through
Measure Doppler effect that flow field to be measured intermediate ion is excited to excite to measure ion motion speed, be a kind of brand-new contactless survey
, there is not the disturbance treating flow measurement field, and will not be affected by the electric and magnetic interference being widely present in electric thruster in amount technology,
There is the advantage that precision height, strong interference immunity, the suitability are wide, can wide popularization and application.
In addition to objects, features and advantages described above, the present invention also has other objects, features and advantages.Below
With reference to the accompanying drawings, the present invention is further detailed explanation.
Accompanying drawing explanation
The accompanying drawing of the part constituting the application is used for providing a further understanding of the present invention, the illustrative examples of the present invention and
Its explanation is used for explaining the present invention, is not intended that inappropriate limitation of the present invention.In the accompanying drawings:
Fig. 1 is the schematic flow sheet of preferred embodiment of the present invention plasma speed measuring method；
Fig. 2 is laser-induced fluorescence (LIF) energy level transition schematic diagram in the preferred embodiment of the present invention；
Fig. 3 is the principle schematic of the multiple effect superposition of measured spectra line style in the preferred embodiment of the present invention；
Fig. 4 is the principle schematic of post processing in the preferred embodiment of the present invention；
Fig. 5 is the structural representation that preferred embodiment of the present invention plasma speed measures system；
Fig. 6 is the structural representation of measurement apparatus in preferred embodiment of the present invention plasma speed measurement system.
Description of reference numerals:
100, caliberating device；
200, measurement apparatus；
300, after-treatment device；310, the first processing module；320, the second processing module；330, the 3rd processing module；
201, laser instrument；202, beam splitter；203, band meter；204, chopper；205, the first reflecting mirror；
206, the second reflecting mirror；207, the 3rd reflecting mirror；208, condenser lens；209, the first protecting window；
210, Second Protection Window mouth；211, optical fiber collimator；212, optical fiber monochromator；
213, photomultiplier tube；214, lock-in amplifier；215, processor；216, optical fiber；217, laser beam；
400, flow field to be measured；401, tested point.
Detailed description of the invention
It should be noted that in the case of not conflicting, the embodiment in the application and the feature in embodiment can be mutually combined.
Describe the present invention below with reference to the accompanying drawings and in conjunction with the embodiments in detail.
According to an aspect of the present invention, it is provided that a kind of plasma speed measuring method, the present embodiment is based on laser-induced fluorescence (LIF)
Electric thruster plasma jet macroscopic velocity is measured by (Laser induced fluorescence, LIF) method, utilizes
After the interaction of laser and intended particle makes its excited absorption, spontaneous radiation goes out fluorescence, comes by measuring the dopplerbroadening of fluorescence
The VELOCITY DISTRIBUTION of particle is calculated.With reference to Fig. 1, the present embodiment method includes:
Step S101, the frequency Fixed Initial Point of flow field to be measured plasma macroscopic velocity is demarcated, with the stationary plasma of gas of the same race
The laser-induced fluorescence (LIF) signal of reference source, as reference source, is measured in source, and the laser frequency selecting fluorescence signal intensity highest point is frequency
Rate Fixed Initial Point；
Owing to the plasma speed of the present embodiment measuring and calculating is macroscopic velocity and the superposition of microcosmic heat movement speed, macroscopic view speed to be obtained
The absolute value of degree, it should be determined that the frequency Fixed Initial Point of macroscopic velocity, the present embodiment realizes by the following method: with gas of the same race
The laser-induced fluorescence (LIF) line style of reference source, as reference source, is measured in stationary plasma source.Due to reference source plasma macroscopic view speed
Degree is zero, and the laser frequency that can select now fluorescence signal intensity highest point is frequency Fixed Initial Point.The meaning of frequency Fixed Initial Point exists
In having demarcated the laser frequency absolute position that macroscopic velocity is 0, the Doppler effect of particle is worth in heat centered by frequency Fixed Initial Point
Mechanics statistics line style distribution.
Step S103, treats flow measurement field plasma and obtains fluorescence signal intensity with laser based on laser-induced fluorescence measurement, measurement
Frequency variation curve；
Under the technical program, should formulate for different particles to be measured and each suitably excite strategy.Fig. 2 shows that laser lures
Lead particle energy levels transition schematic diagram in fluorescence forming process.With reference to Fig. 2, it is in the particle effect absorbing light by laser of energy level 1
Sub-energy generation excited absorption effect is excited to high level (i.e. energy level 2), is then transitted to downwards separately by spontaneous radiation effect
One low-lying level (i.e. energy level 3), unnecessary energy with the form of fluorescence to external radiation.Wherein hv1For incident photon energy, corresponding
Optical maser wavelength is λ1；hv2For fluorescence photon energy, corresponding wavelength of fluorescence is λ2.In order to make fluorescence have higher intensity profit
In detection, it is necessary to assure energy level 1 has higher population density.Preferably, energy level 1 is chosen to be the metastable state of particle.
In the present embodiment, it is preferable that treat flow measurement field plasma and include based on laser-induced fluorescence measurement:
Using laser instrument as fluorescence excitation light source, exciting light enters through light path system to be made with particle on the internal tested point in flow field
With the most outwards radiofluorescence；In the present embodiment, using tunable dye laser as excitation source, incident laser is through light path system
System conducts and focuses on the tested point of flow field, has an effect with intended particle and is allowed to excited absorption outside radiofluorescence；
Fluorescence signal is through phase sensitive detection to extract and treated device collection from background noise, and processor scans laser with preset frequency
The output frequency of device, obtains fluorescence signal intensity with laser frequency change curve.Specifically, fluorescence is collected through signals collecting light path
And be converted to the signal of telecommunication by photodetector, and then through phase sensitive detection to extract from background noise, can with preset frequency scanning
The output frequency of tunable dye laser instrument, obtains laser frequency and fluorescence signal intensity corresponding relation by above two steps.
Step S105, according to measurement result isolated dopplerbroadening effect component, replaces on the basis of frequency Fixed Initial Point
Obtain the actual speed distribution of flow field to be measured plasma.
Wherein, measurement result be fluorescence signal intensity with laser frequency change curve, after integrated normalized, obtain measured spectra
Line style.Measured spectra line style is the Overlay of multiple effect, with reference to Fig. 3, satisfies including hyperfine structure, natural broadening, energy
With effect and Doppler effect.Wherein, hyperfine structure is the fundamental line formed by nuclear spin and isotopic spliting
Type, natural broadening and energy saturation effect belong to homogeneously broadening effect, and Doppler effect is the frequency that particle all to tested point is relevant
Move and frequency exhibition effect.In the calculation, the lorentzian curve of natural broadening is modified, by two by the saturation by calculating laser
Person is unified to be processed for equivalent HOMOGENEOUS BROADENING.
The present embodiment, according to measurement result isolated dopplerbroadening effect component, carries out replacing on the basis of frequency Fixed Initial Point
Actual speed to flow field to be measured plasma is distributed and includes:
Fluorescence signal intensity is obtained measured spectra line style with laser frequency change curve by integrated normalized；
Measured spectra line style is carried out Doppler effect isolated dopplerbroadening effect component；
With frequency Fixed Initial Point, dopplerbroadening effect component is carried out Doppler-shift and obtain the speed-probability density of target area particle
Relation.
In the present embodiment, the purpose that measurement result carries out post processing is in the middle of measured spectra line style to isolate dopplerbroadening
Effect component, then the speed-probability density information of target area particle is obtained by Doppler's replacement.Preferably, in the present embodiment
The deconvolution filtering algorithm using Gaussian filter carries out the separation of Doppler effect.The filtering parameter band of Gaussian filter is extended the deadline
The result bigger parameter of impact, too high band tolerance are made noise separation thorough by one, and the too low band tolerance can make line style send out
Raw distortion, therefore the filtering parameter band of Gaussian filter is extended the deadline and should be determined according to actual signal to noise ratio.
In the present embodiment, the band tolerance determining Gaussian filter with the following method is adopted: divide by treating the repetitive measurement of flow measurement field
Analyse its signal to noise ratio snr value, as the foundation adding noise in later step.Calculate actual laser power in plasma to be measured
Saturation, convert into and simulate HOMOGENEOUS BROADENING effect into lorentzian curve, by obtaining cold plasma with hyperfine structure as convolution
Body line style.On the one hand, the Doppler effect of cold plasma line style Yu matching is carried out convolution, add suitable white noise obtain with
The above simulation line style of the signal to noise ratio such as measured signal, carries out Fourier transformation to simulation line style and obtains I (ω)；On the other hand, to cold
Plasma line style obtains C (ω) as Fourier transformation, and the two enters Gauss Deconvolution Filters program, divides with initial strip tolerance Ω
Separate out Doppler effect.The theoretical Doppler effect obtained with matching before by the Doppler effect of isolated compares through row, if
The requirement of signal to noise ratio and the distortion factor is unsatisfactory for, and adjusts the value iteration again of band tolerance；If meeting requirement, the value of output bandwidth limit.
In Fig. 4, fft is Fourier transformation, and c (v) is cold plasma line style, and C (ω) is the domain space conversion of cold plasma line style
Value, I (ω) such as is at the domain space transformed value of signal to noise ratio simulation line style.
According to a further aspect in the invention, also providing for a kind of plasma speed and measure system, with reference to Fig. 5, the present embodiment measures system
System includes:
Caliberating device 100, for demarcating the frequency Fixed Initial Point of flow field to be measured plasma macroscopic velocity, with the static state etc. of gas of the same race
Plasma source, as reference source, measures the laser-induced fluorescence (LIF) signal of reference source, selects the laser frequency of fluorescence signal intensity highest point
Rate is frequency Fixed Initial Point；
Measurement apparatus 200, is used for treating flow measurement field plasma and obtains fluorescence signal intensity based on laser-induced fluorescence measurement, measurement
With laser frequency change curve；
After-treatment device 300, for according to measurement result isolated dopplerbroadening effect component, on the basis of frequency Fixed Initial Point
Carrying out replaces obtain flow field to be measured plasma actual speed distribution.
In the present embodiment, owing to the plasma speed of measuring and calculating comprises macroscopic velocity and the superposition of microcosmic heat movement speed, obtain
The absolute value of macroscopic velocity, it should be determined that the frequency Fixed Initial Point of macroscopic velocity, the present embodiment caliberating device 100 is with gas of the same race
The laser-induced fluorescence (LIF) line style of reference source, as reference source, is measured in stationary plasma source.Due to reference source plasma macroscopic view speed
Degree is zero, and the laser frequency that can select now fluorescence signal intensity highest point is frequency Fixed Initial Point.The meaning of frequency Fixed Initial Point exists
In having demarcated the laser frequency absolute position that speed is 0, the Doppler effect of particle value centered by frequency Fixed Initial Point is distributed.
Preferably, use the hollow cathode lamp had an X-rayed of filling gas to be measured of the same race as reference source.And the light that caliberating device 100 uses
Road keeps consistent as far as possible with the optical path of measurement apparatus 200, reduces the error brought by steric effect.
With reference to Fig. 6, the present embodiment measurement apparatus 200 includes: as the laser instrument 201 of fluorescence excitation light source, laser instrument 201
Outfan connects light path system, and the laser beam 217 of fluorescence excitation light source output enters within flow field 400 to be measured through light path system
Have an effect outside radiofluorescence on tested point 401 and with particle；Measurement apparatus 200 also includes: for being coupled by fluorescence signal
Entering the optical fiber collimator 211 of optical fiber, optical fiber collimator 211 connects optical fiber monochromator 212, photomultiplier tube 213 through optical fiber 216
And lock-in amplifier 214, the outfan of lock-in amplifier 214 is connected to the processor 215 of data acquisition, and processor 215 is swept
Retouch laser frequency and fluorescence signal intensity that record lock-in amplifier 214 detect through phase sensitive detection is to obtain fluorescence signal intensity with sharp
Light frequency change curve.Preferably, Transmission Fibers 216 uses line footpath for being not less than 200 microns of wide footpath multimode fibres.
Alternatively, with reference to Fig. 6, the present embodiment light path system includes the beam splitter 202 being located at laser instrument 201 outlet, fluorescence excitation
The some light that light source reflects through beam splitter 202 enters band meter 203 to monitor laser frequency, and band meter 203 connects processor
215, in order to processor 215 gathers laser frequency；Fluorescence excitation light source through the some light of beam splitter 202 transmission successively through cutting
Ripple device the 204, first reflecting mirror the 205, second reflecting mirror the 206, the 3rd reflecting mirror 207, condenser lens 208 enter flow field to be measured
400 is internal.
Preferably, the present embodiment laser instrument 201 uses narrow line width regulatable dye laser, it is desirable to excited absorption wave band go out light
Power is not less than 500mW, and power output pulsation amplitude is not higher than 3%, slowly scans laser frequency (recommending 30MHz/s), sweeps
Ensureing during retouching that wavelength stability is 0.1pm, the energy that laser beam reflects about 5% through beam splitter 202 enters band meter 203
Carrying out the monitoring of laser frequency, the chopper 204 that its complementary energy is rotated by certain frequency (about 1KHz) is modulated, then
Entering vacuum system through polygonal mirror group, condenser lens 208 focus on the tested point 401 within plasma, light is believed
Number it is coupled into optical fiber 216 by optical fiber collimator 211 and enters, after grating beam splitting from the entrance slit of optical fiber monochromator 212
With the slit width outgoing of about 10 μm, it is converted into current signal subsequently into after photomultiplier tube (PMT) 213, utilizes phase-locked
Amplifier 214 carries out phase sensitive detection to the chopping frequency of this signal Yu chopper 204, thus is believed by the week fluorescent of induced with laser
Number extracting from high background noise, last communication with PC is acquired tracer signal intensity.
Preferably, the fluorescence signal in order to make measurement obtain has higher intensity, needs to improve the laser energy density of tested point,
The present embodiment utilizes convergent lens 208 to be focused laser so that the focal beam spot diameter of laser is less than 1mm.Due to length
Focus lens spatially has higher stability to the focal path of laser, the focal distance f of condenser lens > 2m.Need in the measurements
Installing protecting window between condenser lens 208 and optical fiber collimator 211 additional prevents high-energy particle bombardment from corroding.With reference to Fig. 6, this reality
Execute example and the first protecting window 209 is set in the outlet of condenser lens 208, the second protection is set in the porch of optical fiber collimator 211
Window 210.
The present embodiment after-treatment device 300 includes:
First processing module 310, for obtaining measured light with laser frequency change curve by integrated normalized to fluorescence signal intensity
Spectral line type；
Second processing module 320, for carrying out Doppler effect isolated dopplerbroadening effect component to measured spectra line style；
3rd processing module 330, obtains target area for dopplerbroadening effect component being carried out Doppler-shift with frequency Fixed Initial Point
The speed of territory particle-probability density relation.
The concrete processing procedure of the present embodiment after-treatment device 300 refer to said method embodiment, here, repeat no more.
From above description it is known that the present embodiment carries out plasma speed measurement based on laser-induced fluorescence (LIF), by measuring
The Doppler effect that flow field to be measured intermediate ion is excited to excite, to measure ion motion speed, is a kind of brand-new non-contact measurement skill
, there is not the disturbance treating flow measurement field, and will not be affected by the electric and magnetic interference being widely present in electric thruster, precision in art
Height and strong interference immunity.And in technical solution of the present invention, laser is by within the minimum hot spot within focal length lens focus to 1mm
Having an effect with particle to be measured, finally measuring the particle rapidity obtained is the speed in light spot focus region, i.e. spatial resolution is excellent
In 1mm.For in theory, if reasonable selection laser-induced fluorescence (LIF) excite strategy, this programme can measure Arbitrary Particles
Speed, and there is no selectivity for intended particle is the most charged, it is possible to achieve strange land measurement, fiber-optic transfer, optical laboratory divide
Analysis, has the strongest practical expansion.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for those skilled in the art
For, the present invention can have various modifications and variations.All within the spirit and principles in the present invention, any amendment of being made, etc.
With replacement, improvement etc., should be included within the scope of the present invention.
Claims (10)
1. a plasma speed measuring method, it is characterised in that including:
The frequency Fixed Initial Point of flow field to be measured plasma macroscopic velocity is demarcated, using the stationary plasma source of gas of the same race as
Reference source, measures the laser-induced fluorescence (LIF) signal of described reference source, and the laser frequency of selection fluorescence signal intensity highest point is
Described frequency Fixed Initial Point；
Treat flow measurement field plasma based on laser-induced fluorescence measurement, measure and obtain fluorescence signal intensity and become with laser frequency
Change curve；
According to measurement result isolated dopplerbroadening effect component, carry out replacing on the basis of described frequency Fixed Initial Point
Actual speed to flow field to be measured plasma is distributed.
Plasma speed measuring method the most according to claim 1, it is characterised in that described in treat flow measurement field plasma
Include based on laser-induced fluorescence measurement:
Using laser instrument as fluorescence excitation light source, exciting light enters through light path system and sends out with particle on the internal tested point in flow field
Raw effect outwards radiofluorescence；
Fluorescence signal is through phase sensitive detection to extract and treated device collection from background noise, and described processor is with preset frequency
Scan the output frequency of described laser instrument, obtain fluorescence signal intensity with laser frequency change curve.
Plasma speed measuring method the most according to claim 1, it is characterised in that
Described according to measurement result isolated dopplerbroadening effect component, on the basis of described frequency Fixed Initial Point, carry out generation
The actual speed distribution getting flow field to be measured plasma in return includes:
Fluorescence signal intensity is obtained measured spectra line style with laser frequency change curve by integrated normalized；
Described measured spectra line style is carried out Doppler effect isolated dopplerbroadening effect component；
With described frequency Fixed Initial Point, described dopplerbroadening effect component is carried out Doppler-shift and obtain target area particle
Speed-probability density relation.
4. a plasma speed measures system, it is characterised in that including:
Caliberating device (100), for demarcating the frequency Fixed Initial Point of flow field to be measured plasma macroscopic velocity, with gas of the same race
Stationary plasma source as reference source, measure the laser-induced fluorescence (LIF) signal of described reference source, select fluorescence signal strong
The laser frequency of degree highest point is described frequency Fixed Initial Point；
Measurement apparatus (200), is used for treating flow measurement field plasma and obtains fluorescence based on laser-induced fluorescence measurement, measurement
Signal intensity is with laser frequency change curve；
After-treatment device (300), for according to measurement result isolated dopplerbroadening effect component, with described frequency
Carrying out on the basis of Fixed Initial Point replaces obtain flow field to be measured plasma actual speed distribution.
Plasma speed the most according to claim 4 measures system, it is characterised in that
Described measurement apparatus (200) including: as the laser instrument (201) of fluorescence excitation light source, described laser instrument (201)
Outfan connect light path system, exciting light through light path system enter have an effect with particle on the internal tested point in flow field and to
External radiation fluorescence；
Described measurement apparatus (200) also includes: for fluorescence signal is coupled into the optical fiber collimator (211) of optical fiber, institute
State optical fiber collimator (211) and connect optical fiber monochromator (212), photomultiplier tube (213) and phase-locked through optical fiber (216)
Amplifier (214), the outfan of described lock-in amplifier (214) is connected to the processor (215) of data acquisition, institute
State processor (215) scanning laser frequency and record the fluorescence letter that described lock-in amplifier (214) detects through phase sensitive detection
Number intensity is to obtain fluorescence signal intensity with laser frequency change curve.
Plasma speed the most according to claim 5 measures system, it is characterised in that
Described light path system includes being located at the beam splitter (202) that described laser instrument (201) exports, and described exciting light is through described
Part light entrance band meter (203) that beam splitter (202) reflects is to monitor laser frequency, and described band meter (203) is even
Connect described processor (215)；Described exciting light through described beam splitter (202) transmission the most chopped device of part light (204),
Polygonal mirror, condenser lens (208) enter internal being allowed to have an effect with particle in flow field to be measured (400) and are excited to inhale
Receive and outside radiofluorescence.
Plasma speed the most according to claim 5 measures system, it is characterised in that
Described laser instrument (201) is tunable laser.
Plasma speed the most according to claim 6 measures system, it is characterised in that
The focal length of described condenser lens (208) is not less than 2m, straight through the focal beam spot of described condenser lens (208) outgoing
Footpath is less than 1mm.
Plasma speed the most according to claim 4 measures system, it is characterised in that
Described caliberating device (100) uses can have an X-rayed hollow cathode lamp as reference source.
Plasma speed the most according to claim 4 measures system, it is characterised in that
Described after-treatment device (300) including:
First processing module (310), for obtaining by integrated normalized with laser frequency change curve fluorescence signal intensity
To measured spectra line style；
Second processing module (320), for carrying out Doppler effect isolated Doppler's exhibition to described measured spectra line style
Broad effect component；
How general 3rd processing module (330), for carrying out with described frequency Fixed Initial Point to described dopplerbroadening effect component
Strangle conversion and obtain the speed-probability density relation of target area particle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610303629.2A CN106018878B (en) | 2016-05-10 | 2016-05-10 | Plasma velocity measurement method and system |
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| CN106526228A (en) * | 2016-11-02 | 2017-03-22 | 中国人民解放军国防科学技术大学 | Self-calibrating method and system for laser-induced-fluorescence-based speed measurement |
| CN106771344A (en) * | 2016-12-20 | 2017-05-31 | 中国科学院力学研究所 | The single beam laser multidimensional velocity measuring system and method in high speed low density gas flow field |
| CN106954330A (en) * | 2017-03-07 | 2017-07-14 | 河北大学 | The apparatus and method for measuring plasma filament swing circle |
| CN107167629A (en) * | 2017-05-25 | 2017-09-15 | 兰州空间技术物理研究所 | A kind of ion thruster plume region particle rapidity distribution measurement system |
| CN108601188A (en) * | 2018-07-25 | 2018-09-28 | 北京航空航天大学 | Novel Mach probe |
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| CN112666137A (en) * | 2020-12-02 | 2021-04-16 | 中国科学院合肥物质科学研究院 | LIF measurement fluorescence signal narrow-band filtering system and method based on FP interferometer |
| CN117042273A (en) * | 2023-07-18 | 2023-11-10 | 中国人民解放军国防科技大学 | Two-dimensional plasma velocity measurement system and method based on super-resolution spectrometer |
| CN117222090A (en) * | 2023-07-18 | 2023-12-12 | 中国人民解放军国防科技大学 | Planar plasma velocity measurement system and method capable of adjusting high spatial resolution |
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| CN106526228A (en) * | 2016-11-02 | 2017-03-22 | 中国人民解放军国防科学技术大学 | Self-calibrating method and system for laser-induced-fluorescence-based speed measurement |
| CN106771344A (en) * | 2016-12-20 | 2017-05-31 | 中国科学院力学研究所 | The single beam laser multidimensional velocity measuring system and method in high speed low density gas flow field |
| CN106771344B (en) * | 2016-12-20 | 2019-06-28 | 中国科学院力学研究所 | The single beam laser multidimensional velocity measuring system and method in high speed low density gas flow field |
| CN106954330A (en) * | 2017-03-07 | 2017-07-14 | 河北大学 | The apparatus and method for measuring plasma filament swing circle |
| CN106954330B (en) * | 2017-03-07 | 2020-03-31 | 河北大学 | Device and method for measuring plasma filament rotation period |
| CN107167629A (en) * | 2017-05-25 | 2017-09-15 | 兰州空间技术物理研究所 | A kind of ion thruster plume region particle rapidity distribution measurement system |
| CN108601188A (en) * | 2018-07-25 | 2018-09-28 | 北京航空航天大学 | Novel Mach probe |
| CN111596092A (en) * | 2020-05-18 | 2020-08-28 | 天津大学 | Laser-induced phosphorescence particle-based imaging speed measurement device and method |
| CN112666137A (en) * | 2020-12-02 | 2021-04-16 | 中国科学院合肥物质科学研究院 | LIF measurement fluorescence signal narrow-band filtering system and method based on FP interferometer |
| CN117042273A (en) * | 2023-07-18 | 2023-11-10 | 中国人民解放军国防科技大学 | Two-dimensional plasma velocity measurement system and method based on super-resolution spectrometer |
| CN117222090A (en) * | 2023-07-18 | 2023-12-12 | 中国人民解放军国防科技大学 | Planar plasma velocity measurement system and method capable of adjusting high spatial resolution |
| CN117042273B (en) * | 2023-07-18 | 2024-04-16 | 中国人民解放军国防科技大学 | Two-dimensional plasma velocity measurement system and method based on super-resolution spectrometer |
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