CN109470662B - Device and method for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field - Google Patents
Device and method for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field Download PDFInfo
- Publication number
- CN109470662B CN109470662B CN201811068924.XA CN201811068924A CN109470662B CN 109470662 B CN109470662 B CN 109470662B CN 201811068924 A CN201811068924 A CN 201811068924A CN 109470662 B CN109470662 B CN 109470662B
- Authority
- CN
- China
- Prior art keywords
- kerosene
- fluorescence
- excitation
- excitation laser
- measurement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- 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
Abstract
The invention relates to a device and a method for eliminating kerosene interference in OH-PLIF measurement of a kerosene combustion field. Based on the characteristic that kerosene has broadband absorption, broadband emission, long fluorescence life and the like and is different from hydroxyl, the invention adopts different excitation lines, different measurement wave bands and different measurement delay modes to measure and obtain the single kerosene fluorescence distribution under the condition that the light path is basically unchanged, and subtracts the kerosene interference from the interfered OH measurement result to obtain an accurate OH distribution result. The invention greatly improves the detection accuracy of OH fluorescence intensity distribution in the kerosene combustion field.
Description
Technical Field
The invention relates to the field of combustion flow field parameter measurement, in particular to a device and a method for eliminating kerosene interference in measurement of OH-PLIF of a kerosene combustion field.
Background
Based on an OH-PLIF technology (wherein OH is hydroxyl, and PLIF is laser induced fluorescence), two-dimensional measurement of OH concentration and flow field temperature can be realized, and information of various aspects such as flame structure, combustion efficiency, reaction mechanism and the like can be obtained.
In practical engine use, aviation kerosene is a widely used fuel, and the broadband absorption spectrum completely covers the absorption band of OH in the 280-320nm waveband, as shown in FIG. 1; the emission spectrum of kerosene in this band completely covers the OH fluorescence emission band, as shown in FIG. 2; and the kerosene vapor had a longer fluorescence lifetime as shown in fig. 3. In addition, compared with OH, kerosene has higher fluorescence emission efficiency, so that in a kerosene combustion field, the fluorescence signal of residual kerosene causes great interference to OH-PLIF measurement, and in order to obtain more accurate OH fluorescence signals, the problem that the interference of the kerosene fluorescence signal needs to be eliminated at present is urgently solved when OH is measured in the kerosene combustion field.
Disclosure of Invention
The invention aims to provide a device and a method for eliminating kerosene interference in OH-PLIF measurement of a kerosene combustion field, which can obtain a kerosene interference distribution area and eliminate kerosene interference in OH fluorescent signals, and greatly improve the accuracy of OH measurement.
The design principle of the invention is as follows:
based on the characteristics that kerosene has broadband absorption, broadband emission, long fluorescence life and the like and is different from OH, the invention adopts the modes of different excitation lines, different measurement wave bands and different measurement delays to additionally measure and obtain the kerosene fluorescence intensity distribution, and obtains a more accurate OH distribution result by scaling the intensity proportion coefficient of kerosene fluorescence and pure kerosene fluorescence signals in OH and kerosene mixed fluorescence signals and deducting the kerosene interference from the interfered OH measurement result. The principle steps are as follows:
1. respectively obtaining OH and kerosene mixed fluorescence intensity distribution and single kerosene fluorescence intensity distribution;
2. calculating the correction coefficient of the fluorescence intensity of the single kerosene;
3. and deducting the kerosene fluorescence interference from the corresponding intensity correction coefficient in the OH and kerosene mixed fluorescence to obtain accurate OH fluorescence distribution.
Based on the introduction of the above principle, a specific technical scheme of the present invention is briefly described as follows:
1. OH, kerosene mixed fluorescence and single kerosene fluorescence near-simultaneous measurement process:
in order to reduce the influence of the change of the kerosene combustion field along with the time on the kerosene fluorescence correction process, the time interval between the OH and kerosene mixed fluorescence measurement and the pure kerosene fluorescence measurement needs to be as small as possible, generally needs to be better than 1000ns, and the two are optimal when being measured simultaneously. In the process, excitation light near 280nm is adopted to carry out fluorescence detection at 300-320 nm; the near-simultaneous measurement of kerosene (detection time interval about 1000ns) takes three ways according to the difference with OH fluorescence measurement in terms of excitation line, detection wavelength and fluorescence lifetime:
the first method is as follows: and adjusting an excitation line near the selected OH excitation wavelength to excite kerosene independently to obtain a kerosene fluorescence signal by utilizing the broadband absorption characteristic of kerosene compared with OH. The measurement system required in this way is specifically: the device comprises an excitation laser, a frequency domain filtering unit, an imaging detection unit, an auxiliary light path unit and a computer;
two excitation lasers L1 and L2 are provided, the laser pulse width of each excitation laser is 10ns, the wavelength range is 280-295nm, and the line width of the excitation light is 0.1cm-1The light emitting time intervals of the excitation laser L1 and the excitation laser L2 can be adjusted within 10-1000ns, and the specific experimental time interval is matched with the typical time scale of the object to be tested, so that the flow field is ensured not to be obviously changed within the time interval;
wherein the excitation laser L1 is positioned at an OH (1-0) band resonance excitation line, the wavelength in the air is 285.004nm, and OH and kerosene mixed fluorescence is excited by resonance; the excitation laser L2 is far away from an OH resonance excitation line and only excites to generate single kerosene fluorescence;
the frequency domain filtering unit adopts a 305-320nm band-pass filter for passing OH fluorescence interfered by kerosene fluorescence;
the imaging detection unit selects a double-frame double-exposure image enhancement camera or two image enhancement cameras, the sampling time of the cameras is respectively synchronous with an excitation laser L1 and an excitation laser L2, the exposure time is less than the light emitting time interval of two paths of laser, and a mixed fluorescence image C1 generated by L1 excitation and a kerosene fluorescence image C2 generated by L2 excitation are obtained through measurement.
The auxiliary light path unit is used for adjusting the excitation laser light path, and comprises a light beam direction adjusting unit, a light beam shaping unit, a laser beam shaping unit and a laser beam shaping unit, wherein the light beam direction adjusting unit and the light beam shaping unit are used for realizing uniform sheet light excitation and acquiring the energy of excitation laser; the reflector, the beam combiner, the beam splitter and the beam shaping device are all arranged in sequence along the light path of the excitation laser; a part of the light beam split by the beam splitter is received by the energy meter.
And the computer calculates the accurate OH fluorescence intensity distribution through the acquired single kerosene fluorescence intensity distribution and OH and kerosene mixed fluorescence intensity distribution.
The second method comprises the following steps: the fluorescence emission band of kerosene wider than OH is utilized, and the kerosene fluorescence measurement is carried out at the wave band of 340-360nm by utilizing the frequency-domain filtering unit. The measurement system required in this manner is substantially the same as in the first manner, except that:
the laser has a pulse width of 10ns, a wavelength range of 280-295nm, and a line width of 0.1cm-1(ii) a The excitation laser is positioned on an OH (1-0) band resonance excitation line, the wavelength in the air is 285.004nm, and OH and kerosene mixed fluorescence is excited by resonance;
the number of the frequency domain filtering units is two, one is a 305-320nm band-pass filter F1 used for selectively transmitting the hydroxyl fluorescence interfered by the kerosene fluorescence; the other is a 335-;
the imaging detection unit is two image enhancement cameras or one image enhancement camera with a light splitting double-imaging system, two measurement images C1 and C2 can be measured and obtained, the detection time of the imaging detection unit is synchronous relative to excitation laser, and the measurement gate width can be 10-200 ns.
The third method comprises the following steps: kerosene fluorescence measurements were made using kerosene which had a longer lifetime than OH, and a longer time interval (about 100ns) after excitation by the excitation light.
The excitation laser is one, the laser pulse width is 10ns, the wavelength can be tuned in the range of 280-295nm, and the line width of the excitation light is less than 0.1cm-1(ii) a In the measurement process, the output wavelength of the excitation laser is in an OH resonance excitation line, the wavelength in the air is 285.004nm, and OH and kerosene mixed fluorescence is excited by resonance;
the frequency domain filtering unit is a 305-320nm band-pass filter which is used for selectively transmitting OH fluorescence interfered by kerosene fluorescence;
the imaging detection unit comprises two image enhancement cameras, the sampling gate width is set within the range of 20-100ns, the sampling time delay of the two image enhancement cameras relative to the excitation laser is within 15-200ns, the sampling time delay of the two image enhancement cameras is larger than the sampling gate width of the two image enhancement cameras, and OH and kerosene mixed fluorescence images C1 and kerosene fluorescence images C2 are obtained through measurement respectively.
2. Intensity proportionality coefficient calibration process:
because single-camera multi-frame rapid exposure measurement or dual-camera measurement is required in the near-simultaneous measurement of mixed fluorescence and kerosene fluorescence, the fluorescence intensity response of the detection system in the two measurement processes needs to be calibrated in order to avoid the difference of the intensity response to fluorescence in the multi-exposure and dual-camera measurement processes. In the invention, the intensity proportion coefficient is obtained by adjusting the excitation line to singly excite the kerosene fluorescence near the OH excitation wavelength in the combustion field to be measured, simultaneously measuring the kerosene fluorescence signal in the mixed fluorescence measurement system and the kerosene fluorescence measurement system, and calibrating the intensity response of the two measurement systems. It is noted that when using dual camera measurements, it is often necessary to perform image matching corrections before the intensity scaling factor is calculated due to differences in the measured view angles.
3. The process of deducting the kerosene fluorescence proportion in the mixed fluorescence comprises the following steps:
in the process, firstly, imaging correction is carried out on the measurement images in the two measurement processes (mainly aiming at dual-camera measurement), and then, in the OH and kerosene mixed fluorescence measurement result, kerosene fluorescence measurement results and intensity proportionality coefficients are combined to correspondingly deduct kerosene fluorescence interference of each space point. The more accurate OH fluorescence distribution can be directly obtained by deducting the region with less kerosene interference; the region with a large proportion of kerosene fluorescence in the mixed fluorescence (for example, 80%) can be identified, and the strong interference region can be eliminated in the final OH fluorescence distribution.
The invention has the beneficial effects that:
1. based on the characteristic that kerosene has broadband absorption, broadband emission, long fluorescence life and the like and is different from OH, the invention obtains the interference intensity information of residual kerosene on OH fluorescence by obtaining single kerosene fluorescence in the OH measurement of the kerosene combustion field, and provides reference basis for feasibility and implementation mode of OH fluorescence measurement.
2. According to the invention, the kerosene fluorescence is additionally measured and correspondingly deducted in the measurement of the OH fluorescence in the kerosene combustion field, so that the interference of the kerosene fluorescence on the measurement of the OH fluorescence is eliminated or reduced, and the accuracy of the measurement of the OH fluorescence intensity is greatly improved.
3. The invention provides three measurement systems and methods, so that the mode of deducting the kerosene fluorescence interference in OH and kerosene mixed fluorescence is more flexible, and the method can adapt to various conditions and scenes.
Drawings
FIG. 1 is a graph of data of OH and kerosene vapor absorption spectra in the 250-400nm wavelength band.
FIG. 2 shows fluorescence emission spectra of OH excited by 282nm laser and kerosene vapor.
FIG. 3 is a time relaxation curve of 282nm wave band laser excitation kerosene steam and OH fluorescence intensity.
FIG. 4 is a schematic view of a measuring device according to the present invention.
FIG. 5 is a schematic diagram of the OH measurement process of a kerosene combustion field.
FIG. 6 is a schematic diagram of the selection of OH, kerosene steam fluorescence measurement excitation lines.
FIG. 7 is a schematic diagram of the parameters of the frequency-domain filter unit for OH and kerosene vapor fluorescence measurement.
FIG. 8 is a schematic diagram of positions of measurement signals in a fluorescence intensity relaxation curve under different time delay conditions in OH and kerosene vapor fluorescence measurement.
The reference numbers are as follows:
the device comprises a 1-excitation laser, a 2-reflector, a 3-beam combiner, a 4-beam splitter, a 5-beam shaping device, a 6-kerosene combustion field, a 7-energy meter, an 8-frequency-domain filtering unit, a 9-imaging detection unit and a 10-computer.
Detailed Description
In order to introduce the technical solutions and technical effects of the present invention more accurately, the present invention is further described below.
The basic architecture of the measuring device required by the method in the invention comprises an excitation laser 1, a frequency domain filtering unit 8, an imaging detection unit 9, an auxiliary light path unit and a computer 10.
The excitation laser 1 is used for exciting OH and kerosene mixed fluorescence and single kerosene fluorescence in the kerosene combustion field 6; at least one excitation laser, two of which are shown in fig. 4, excitation laser L1 and excitation laser L2;
the frequency domain filtering unit 8 is used for selecting a detection fluorescence waveband and inhibiting stray light of excitation light; the frequency-domain filtering unit comprises at least one band-pass filter, two sets of which appear in fig. 4, F1 passing OH, kerosene mixed fluorescence and F2 passing kerosene fluorescence only;
the imaging detection unit 9 is used for performing imaging measurement on the fluorescence signal; the imaging detection unit is at least one, and can select a double-frame double-exposure image enhancement camera or two image enhancement cameras or an image enhancement camera with a light splitting double-imaging system or two ICCDs;
the auxiliary light path unit can realize the adjustment and control of the light path, including the direction adjustment of the light beam and the shaping of the light beam to realize the uniform sheet-shaped optical excitation, and the typical optical sheet width is more than 20mm and the thickness is less than 0.5 mm; the specific structure of the device comprises a reflector 2, a beam combiner 3, a beam splitter 4, an energy meter 7 and a beam shaping device 5; the reflector 2, the beam combiner 3, the beam splitter 4 and the beam shaping device 5 are all arranged in sequence along the optical path of the excitation laser; a part of the beam split by the beam splitter 4 is received by the energy meter 7.
The reflecting mirror 2 is used for adjusting the reflection of the excitation laser by 45 degrees so as to realize collinear (surface) propagation of two paths of laser, the beam combining mirror 3 realizes light sheet coincidence in a measuring area, the beam splitting mirror 4 is used for providing a small amount of reflected excitation laser so as to conveniently implement real-time monitoring of laser energy, and the energy meter 7 realizes measurement of excitation laser energy
The computer 10 calculates an accurate OH fluorescence intensity distribution from the acquired individual kerosene fluorescence intensity distribution, OH, kerosene mixture fluorescence intensity distribution, and the intensity correction coefficient.
The principle method steps are shown in fig. 5:
【1】 The excitation laser is adjusted by the auxiliary light path unit to excite OH and residual kerosene steam in a kerosene combustion field to generate OH and kerosene mixed fluorescence and single kerosene fluorescence, and the OH and kerosene mixed fluorescence and the single kerosene fluorescence pass through the frequency domain filtering unit and then are respectively obtained in the imaging detection unit to obtain the intensity distribution of the OH and kerosene mixed fluorescence and the single kerosene fluorescence;
【2】 Through a calibration experiment, the detection efficiency of the fluorescence intensity of the two detection systems relative to the excitation energy is calculated, and the correction coefficient of the fluorescence intensity of the single kerosene is obtained and is used for correcting the difference of the two detection systems in the aspects of detection parameters, camera response and the like;
【3】 And deducting the interference of the single kerosene fluorescence from the corresponding single kerosene fluorescence intensity correction coefficient in the OH and kerosene mixed fluorescence to obtain accurate OH fluorescence intensity distribution.
The apparatus and method of the present invention are described in more detail below with reference to three examples:
example 1:
the excitation laser L1 and the excitation laser L2 are adopted, the pulse width of the laser is selected but not limited to 10ns, the wavelength is in the range of 280-295nm, and the line width of the excitation light is better than 0.1cm-1In order to improve the excitation resolution, the excitation laser L1 is positioned at an OH (1-0) band resonance excitation line, the OH ground state rotation energy level is excited in resonance, and simultaneously, the kerosene steam in a combustion field is excited to generate kerosene fluorescence, the wavelength of the excitation line in the embodiment is selected from but not limited to P1(7), and the wavelength of the excitation line in the air is 285.004 nm; the excitation wavelength of the excitation laser L2 is close to that of the excitation laser L1, but far away from the OH resonance excitation line, which is only capable of exciting kerosene fluorescence, and is selected from but not limited to 284.97nm in this example, and the positions of the two excitation lines are shown in FIG. 6. The two excitation lasers have time delay and are adjustable in time delay interval, the minimum value which is larger than the service life of kerosene excitation fluorescence is selected within the parameter range of a detection system, the influence of flame state change at the interval of double-amplitude measurement on the measurement is reduced while the mutual interference of the double-amplitude measurement is reduced, the kerosene vapor fluorescence intensity time relaxation curve and the detection system parameters are comprehensively referred to in the embodiment of the invention in figure 3, and the excitation time delay of the two excitation lasers is selected to be 500 ns;
the frequency domain filtering unit adopts a band-pass filter for receiving 305-320nm to filter stray light of the excitation laser and selectively transmits the hydroxyl fluorescence (1-1) and (0-0) wave bands and part of the kerosene fluorescence wave band;
the imaging detection unit selects a double-frame double-exposure image enhancement camera, and the detection system can obtain two measurement images C1 and C2 at a minimum time interval of 500ns, and the measurement gate width is shorter than 200ns, in this case 20 ns.
The specific measurement method of example 1, comprising the steps of:
step 1: excitation of only kerosene vapor with the excitation laser L2 to produce fluorescence, C1 synchronized with L2, gate width 20NS, kerosene fluorescence intensity NS 'normalized with respect to excitation light intensity obtained in the image C1 by the frequency domain filter unit'1K(x,y)；
Step 2: excitation of only kerosene vapor with the excitation laser L2 to produce fluorescence, C2 synchronized with L2, gate width 20NS, kerosene fluorescence intensity NS 'normalized with respect to excitation light intensity obtained in the image C2 by the frequency domain filter unit'2K(x,y)；
And step 3: calculating to obtain the system strength correction coefficient
kL(x,y)＝NS'1K(x,y)/NS'2K(x,y)；
And 4, step 4: under the same combustion parameter setting condition as the step 1-3, an excitation laser L1 is used for exciting OH and kerosene steam, a double-frame double-exposure image enhancement camera is synchronous with the excitation laser, the door width is 20ns, and a mixed fluorescence signal S is obtained1M(x, y); the kerosene steam is excited by using an excitation laser L2, a double-frame double-exposure image enhancement camera is synchronous with an excitation laser L2, the door width is 20ns, and a kerosene fluorescence signal S is obtained2K(x, y), measuring the energy of the two excitation lights in real time in the measuring process;
and 5: normalizing the fluorescent signals with respect to the respective excitation energies to obtain NS1M(x,y)、NS2K(x,y)；
Step 6: eliminating kerosene fluorescence interference in the mixed fluorescence signal, the OH fluorescence signal is distributed as follows: NS (server)OH(x,y)＝NS1M(x,y)-kL(x,y)·NS2K(x,y)。
Example 2
This embodiment requires only one excitation laser L1, selected but not limited to a 10ns pulse width pulsed laserThe width of the excitation line is better than 0.1cm-1In order to obtain a stronger OH fluorescence signal, the wavelength is in an OH (1-0) band resonance excitation line in the range of 280-295nm, and the OH of the combustion field and kerosene steam are simultaneously excited to generate an OH and kerosene fluorescence mixed signal, in this case, but not limited to, the P1(7) excitation line is selected as the measurement wavelength, the wavelength in the air is 285.004nm, but not limited to, the wavelength in the air is 284.97nm as the calibration wavelength.
The frequency domain filter unit comprises two frequency domain filter units, one is a 305-320nm band-pass filter F1, and the frequency domain filter unit is used for passing the hydroxyl fluorescence interfered by the kerosene fluorescence; the other is a 335-; the transmission range of the frequency domain filtering unit is shown in fig. 7;
the imaging detection unit is two image enhancement cameras or one image enhancement camera with a light splitting double-imaging system capable of realizing the same function, two measurement images C1 and C2 can be measured and obtained, the detection time of the imaging detection unit is synchronous relative to the excitation laser, and the measurement gate width can be 10-200 ns.
The specific measurement method of embodiment 2, comprising the steps of:
step 1: selecting an excitation laser L1 to excite kerosene steam with a calibration wavelength of 284.97nm to generate OH and kerosene fluorescence mixed signals, and respectively obtaining individual kerosene fluorescence intensity S 'in images C1 and C2 of the imaging detection unit through band-pass filters F1 and F2'1K(x,y)、S'2K(x,y)；
Step 2: performing space imaging correction on the two time synchronous images, eliminating the difference caused by different measurement angles, and obtaining the corrected fluorescence intensity CS 'of the single kerosene'1K(x,y)、CS'2K(x,y)；
And step 3: calculating to obtain different wavelength correction coefficients kW(x,y)＝CS'1K(x,y)/CS'2K(x,y)；
And 4, step 4: under the same combustion parameter setting conditions as those in the step 1-3, an excitation line P1(7) is selected, and the mixed fluorescence intensity S of OH and kerosene is obtained through a band-pass filter F11M(x, y) obtaining the kerosene fluorescence intensity S through a bandpass filter F22K(x,y)；
And 5: for two frames at the same timeThe step images are subjected to spatial imaging correction to eliminate the difference caused by different measurement angles, and the corrected OH and kerosene mixed fluorescence intensity CS is obtained1M(x,y)、CS2K(x,y)；
Step 6: eliminating kerosene fluorescence interference in the mixed fluorescence signal, and distributing the OH fluorescence signal into CSOH(x,y)＝CS1M(x,y)-kW(x,y)·CS2K(x,y)。
Example 3
In this case, only one excitation laser L1 is required, the pulse width of the excitation laser is selected but not limited to 10ns, and the line width is better than 0.1cm-1The wavelength is in a 280-295nm range OH (1-0) band resonance excitation line, and a combustion field OH and kerosene steam are simultaneously excited to generate an OH and kerosene fluorescence mixed signal, wherein the measurement wavelength is selected but not limited to a P1(7) excitation line, the wavelength in air is 285.004nm, and the calibration wavelength is selected but not limited to the wavelength in air is 284.97 nm;
the frequency-domain filtering unit is selected but not limited to 305-320nm band-pass filter for filtering stray light of the excitation laser, selectively transmitting the hydroxyl fluorescence (1-1) and (0-0) wave band and part of the kerosene fluorescence wave band,
in the embodiment, two ICCDs are selected as imaging detection units, the sampling gate width is less than 100ns, 20ns is selected in the embodiment, the delay of the relative excitation light is set within 15-200ns by the C1 and C2 delay of the two cameras, and the delay difference of the two is greater than the sampling gate width so as to avoid the two to contain a common signal, T is respectively selected in the embodiment1＝20、T2The fluorescence signal S was measured and obtained separately 60ns1And S2The positions of the measured signal intensities at different time delays in the time relaxation curves are shown in fig. 8.
The specific measurement method of embodiment 3, comprising the steps of:
step 1: selecting an excitation laser L1 to excite kerosene steam with a calibration wavelength of 284.97nm to generate OH and kerosene fluorescence mixed signals, passing through a 305-320nm band-pass filter, and obtaining the fluorescence intensity S 'of the separate kerosene by the two ICCDs at the time delays T1 and T2 respectively'1K(x,y)、S'2K(x,y)；
Step 2: spatial imaging correction elimination of angle measurement for two time-synchronous imagesAnd obtaining the fluorescence intensity of two corrected independent kerosene according to the difference caused by different degrees: CS'1K(x,y)、CS'2K(x,y)；
And step 3: calculating to obtain the correction coefficients k of the kerosene intensities with different delaysT(x,y)＝CS'1K(x,y)/CS'2K(x,y)；
And 4, step 4: selecting a P1(7) excitation line under the same combustion parameter setting conditions as the steps 1-3, and obtaining the mixed fluorescence intensity S of OH and kerosene at the time delay T11M(x, y) the kerosene fluorescence intensity S was obtained at the time delay T22K(x,y)；
And 5: the two time synchronous images are subjected to space imaging correction to eliminate the difference caused by different measurement angles, and the corrected OH and kerosene mixed fluorescence intensity CS is obtained1M(x,y)、CS2K(x,y)；
Step 6: eliminating kerosene fluorescence interference in the mixed fluorescence signal, and distributing the OH fluorescence signal into CSOH(x,y)＝CS1M(x,y)-kT(x,y)·CS2K(x,y)。
Claims (5)
1. A device for eliminating kerosene interference in OH-PLIF measurement of a kerosene combustion field is characterized in that: the device comprises an excitation laser, a frequency domain filtering unit, an imaging detection unit, an auxiliary light path unit and a computer;
the excitation laser is used for exciting OH and kerosene in a kerosene combustion field to obtain fluorescence signals, wherein the fluorescence signals comprise two types: the excitation laser excites OH and kerosene on an OH resonance excitation line to obtain a mixed fluorescence signal or can only excite kerosene to generate single kerosene fluorescence on a non-OH resonance excitation line;
the frequency domain filtering unit is used for selectively transmitting OH fluorescence interfered by kerosene fluorescence and single kerosene fluorescence and filtering stray light signals of other wave bands;
the imaging detection unit is used for carrying out imaging measurement on the two fluorescence signals to obtain the distribution condition of the fluorescence intensity of the single kerosene and the distribution condition of the fluorescence intensity of the OH and kerosene mixture;
the auxiliary light path unit is used for adjusting the excitation laser emitted by the excitation laser, and comprises the steps of adjusting the direction of a light beam, shaping the light beam to realize uniform sheet-shaped optical excitation and acquiring the energy of the excitation laser;
the computer calculates the accurate OH fluorescence intensity distribution through the acquired single kerosene fluorescence intensity distribution, OH and kerosene mixed fluorescence intensity distribution and the intensity correction coefficient;
the excitation laser is one, the laser pulse width is 10ns, the wavelength can be tuned in the range of 280-295nm, and the line width of the excitation light is less than 0.1cm-1(ii) a In the measurement process, the output wavelength of the excitation laser is in an OH resonance excitation line, the wavelength in the air is 285.004nm, and OH and kerosene mixed fluorescence is excited by resonance;
the frequency domain filtering unit is a 305-320nm band-pass filter which is used for selectively transmitting OH fluorescence interfered by kerosene fluorescence;
the imaging detection unit comprises two image enhancement cameras, the sampling gate width is set within the range of 20-100ns, the sampling time delay of the two image enhancement cameras relative to the excitation laser is respectively 15-100ns and 100-200ns, the sampling time interval of the two image enhancement cameras is larger than that of the two image enhancement cameras, and OH and kerosene mixed fluorescence images C1 and kerosene fluorescence images C2 are obtained through measurement respectively.
2. The device for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field according to claim 1, characterized in that: the auxiliary light path unit comprises a reflector, a beam combiner, a beam splitter, an energy meter and a light beam shaping device;
the reflecting mirror, the beam combining mirror, the beam splitting mirror and the beam shaping device are all arranged in sequence along the light path of the excitation laser;
a part of the light beam split by the beam splitter is received and detected by the energy meter.
3. A method for eliminating kerosene interference in OH-PLIF measurement of a kerosene combustion field is characterized in that a device for eliminating kerosene interference in OH-PLIF measurement of the kerosene combustion field comprises an excitation laser, a frequency domain filtering unit, an imaging detection unit, an auxiliary light path unit and a computer;
the excitation laser is used for exciting OH and kerosene in a kerosene combustion field to obtain fluorescence signals, wherein the fluorescence signals comprise two types: the excitation laser excites OH and kerosene on an OH resonance excitation line to obtain a mixed fluorescence signal or can only excite kerosene to generate single kerosene fluorescence on a non-OH resonance excitation line;
the frequency domain filtering unit is used for selectively transmitting OH fluorescence interfered by kerosene fluorescence and single kerosene fluorescence and filtering stray light signals of other wave bands;
the imaging detection unit is used for carrying out imaging measurement on the two fluorescence signals to obtain the distribution condition of the fluorescence intensity of the single kerosene and the distribution condition of the fluorescence intensity of the OH and kerosene mixture;
the auxiliary light path unit is used for adjusting the excitation laser emitted by the excitation laser, and comprises the steps of adjusting the direction of a light beam, shaping the light beam to realize uniform sheet-shaped optical excitation and acquiring the energy of the excitation laser;
the computer calculates the accurate OH fluorescence intensity distribution through the acquired single kerosene fluorescence intensity distribution, OH and kerosene mixed fluorescence intensity distribution and the intensity correction coefficient;
the number of the excitation lasers is two, namely an excitation laser L1 and an excitation laser L2, the laser pulse widths of the two excitation lasers are both 10ns, and the line width of excitation light is less than 0.1cm-1The wavelength can be tuned in the range of 280-295nm, and the light emitting time interval of the excitation laser L1 and the excitation laser L2 can be adjusted in the range of 10-1000 ns;
wherein the excitation laser L1 is positioned on an OH resonance excitation line, the wavelength in the air is 285.004nm, and OH and kerosene mixed fluorescence is excited by resonance; the excitation laser L2 is far away from an OH resonance excitation line, the wavelength of 284.97nm is selected, and only single kerosene fluorescence is generated by excitation;
the frequency domain filtering unit adopts a 305-320nm band-pass filter for filtering experimental stray light by penetrating OH fluorescence interfered by kerosene fluorescence;
the imaging detection unit selects a double-frame double-exposure image enhancement camera or two image enhancement cameras, the sampling time is respectively synchronous with an excitation laser L1 and an excitation laser L2, the exposure time is less than the laser light-emitting time interval, and a mixed fluorescence image C1 generated by excitation of the excitation laser L1 and a kerosene fluorescence image C2 generated by excitation of the excitation laser L2 are obtained through measurement;
the specific steps for obtaining the accurate OH fluorescence intensity are as follows:
【1】 An excitation laser L1 is used for synchronizing with the sampling time of the 1 st frame of the imaging detection unit, the gate width is 20ns, and an OH and kerosene mixed fluorescent signal S is obtained1M(x, y); the excitation laser L2 is used for synchronizing with the 2 nd frame sampling time of the imaging detection unit, the gate width is 20ns, and the single kerosene fluorescence signal S is obtained2K(x, y), measuring the laser energy of the two excitation lasers in real time in the measuring process;
【2】 Under the same detection parameter setting conditions as the step [ 1 ], the excitation laser L1 is adjusted to the same wavelength as the excitation laser L2, kerosene is excited together, and the space distribution S 'of the fluorescence intensity of the kerosene is obtained through measurement'1K(x, y) and S'2K(x, y) monitoring and recording the laser energy of the two excitation lasers in real time;
【3】 S 'is excited by excitation laser L1 and excitation laser L2'1K(x,y)、S'2K(x,y)、S1M(x, y) and S2K(x, y) normalization to obtain NS'1K(x,y)、NS'2K(x,y)、NS1M(x, y) and NS2K(x, y) calculating to obtain an intensity correction coefficient Nk for each spatial positionL(x,y)＝NS'1K(x,y)/NS'2K(x,y)；
【4】 Eliminating kerosene fluorescence interference in the normalized mixed fluorescence signal according to the intensity correction coefficient proportion, and then the OH intensity distribution is as follows: NS (server)OH(x,y)＝NS1M(x,y)-NkL(x,y)·NS2K(x,y)。
4. A method for eliminating kerosene interference in OH-PLIF measurement of a kerosene combustion field is characterized in that a device for eliminating kerosene interference in OH-PLIF measurement of the kerosene combustion field comprises an excitation laser, a frequency domain filtering unit, an imaging detection unit, an auxiliary light path unit and a computer;
the excitation laser is used for exciting OH and kerosene in a kerosene combustion field to obtain fluorescence signals, wherein the fluorescence signals comprise two types: the excitation laser excites OH and kerosene on an OH resonance excitation line to obtain a mixed fluorescence signal or can only excite kerosene to generate single kerosene fluorescence on a non-OH resonance excitation line;
the frequency domain filtering unit is used for selectively transmitting OH fluorescence interfered by kerosene fluorescence and single kerosene fluorescence and filtering stray light signals of other wave bands;
the imaging detection unit is used for carrying out imaging measurement on the two fluorescence signals to obtain the distribution condition of the fluorescence intensity of the single kerosene and the distribution condition of the fluorescence intensity of the OH and kerosene mixture;
the auxiliary light path unit is used for adjusting the excitation laser emitted by the excitation laser, and comprises the steps of adjusting the direction of a light beam, shaping the light beam to realize uniform sheet-shaped optical excitation and acquiring the energy of the excitation laser;
the computer calculates the accurate OH fluorescence intensity distribution through the acquired single kerosene fluorescence intensity distribution, OH and kerosene mixed fluorescence intensity distribution and the intensity correction coefficient;
the excitation laser is one, the laser pulse width is 10ns, the wavelength can be tuned in the range of 280-295nm, and the line width of the excitation light is less than 0.1cm-1(ii) a In the measurement process, the output wavelength of the excitation laser is in an OH resonance excitation line, the wavelength in the air is 285.004nm, and OH and kerosene mixed fluorescence is excited by resonance;
the number of the frequency domain filtering units is two, one is a 305-320nm band-pass filter F1 used for selectively transmitting the hydroxyl fluorescence interfered by the kerosene fluorescence; the other is a 335-;
the imaging detection unit is two image enhancement cameras or one image enhancement camera with a light splitting double-imaging system, the detection time of the imaging detection unit is synchronous relative to the excitation laser, the measurement gate width can be 10-200ns, and an OH and kerosene mixed fluorescence image C1 and a kerosene fluorescence image C2 can be obtained through measurement at the same time;
the specific steps for obtaining the accurate OH fluorescence intensity are as follows:
【1】 The excitation laser selects OH resonance excitation line to excite kerosene combustion field, and OH and kerosene mixed fluorescence intensity S is obtained through a band-pass filter F11M(x, y) obtaining kerosene alone by means of a bandpass filter F2Fluorescence intensity S2K(x,y)；
【2】 Under the same detection parameter setting conditions as the step [ 1 ], a non-OH resonance excitation wavelength of 284.97nm is selected, only kerosene fluorescence is excited to generate, and the kerosene fluorescence intensity S 'is obtained through a band-pass filter F1'1K(x, y), kerosene fluorescence intensity S 'was obtained through bandpass filter F2'2K(x,y)；
【3】 Will S1M(x, y) and S2K(x,y)、S'1K(x, y) and S'2K(x, y) image matching correction was performed to eliminate the difference due to the difference in measurement angle, and corrected fluorescence intensity CS 'was obtained'1K(x,y)、CS'2K(x,y)、CS1M(x, y) and CS2K(x, y), and calculating to obtain the coal oil fluorescence intensity correction coefficient Ck under different detection wavelengthsW(x,y)＝CS'1K(x,y)/CS'2K(x,y)；
【4】 Eliminating kerosene fluorescence interference in the mixed fluorescence signal, and distributing the OH fluorescence signal into CSOH(x,y)＝CS1M(x,y)-CkW(x,y)·CS2K(x,y)。
5. A method for eliminating kerosene interference in measurement of OH-PLIF of kerosene combustion field, characterized in that, the device for eliminating kerosene interference in measurement of OH-PLIF of kerosene combustion field according to claim 1 is adopted, and the following steps are adopted to obtain accurate OH fluorescence intensity:
【1】 The excitation laser selects OH resonance excitation line to excite kerosene combustion field, and OH and kerosene mixed fluorescence intensity S is obtained at time delay T11M(x, y) obtaining the fluorescence intensity S of the kerosene alone at a delay T22K(x,y)；
【2】 Under the same detection parameter setting conditions as the step [ 1 ], selecting a non-OH resonance excitation wavelength of 284.97nm, only exciting to generate kerosene fluorescence, and respectively obtaining two independent kerosene fluorescence intensities by a band-pass filter F1 during time delay T1 and T2: s'1K(x,y)、S'2K(x,y)；
【3】 Will S1M(x, y) and S2K(x,y)、S'1K(x, y) and S'2K(x, y) respectively carrying out image matching correction to eliminate the image matching correction caused by different measurement anglesDifference, CS 'is obtained'1K(x,y)、CS'2K(x,y)、CS1M(x, y) and CS2K(x, y), calculating to obtain the space distribution Ck of the correction coefficients of the kerosene fluorescence intensities with different delaysT(x,y)＝CS'1K(x,y)/CS'2K(x,y)；
【4】 Eliminating kerosene fluorescence interference in the mixed fluorescence signal, and distributing the OH fluorescence signal into CSOH(x,y)＝CS1M(x,y)-CkT(x,y)·CS2K(x,y)。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811068924.XA CN109470662B (en) | 2018-09-13 | 2018-09-13 | Device and method for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811068924.XA CN109470662B (en) | 2018-09-13 | 2018-09-13 | Device and method for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109470662A CN109470662A (en) | 2019-03-15 |
| CN109470662B true CN109470662B (en) | 2021-06-08 |
Family
ID=65664630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811068924.XA Active CN109470662B (en) | 2018-09-13 | 2018-09-13 | Device and method for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109470662B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2758869C1 (en) * | 2020-09-30 | 2021-11-02 | Федеральное государственное бюджетное учреждение науки Институт теплофизики им. С.С. Кутателадзе Сибирского отделения Российской академии наук | Method for measuring the temperature field in reacting gas flows based on planar laser-induced fluorescence of a hydroxyl radical |
| CN113720825B (en) * | 2021-11-04 | 2022-02-08 | 四川丹诺迪科技有限公司 | Optical instant detector and detection method and application |
| CN117030669A (en) * | 2023-08-08 | 2023-11-10 | 哈尔滨工业大学(深圳)(哈尔滨工业大学深圳科技创新研究院) | Gas concentration detection method, gas concentration detection device, computer equipment and storage medium |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103941038A (en) * | 2014-04-25 | 2014-07-23 | 西北核技术研究所 | Flow field flow velocity measuring device and method capable of eliminating vibration interference |
| CN104897632A (en) * | 2015-06-01 | 2015-09-09 | 哈尔滨工业大学 | Method for measuring three-dimensional spatial distribution of OH group concentration in transient combustion field based on scanning planar laser induced fluorescence imaging system |
| CN105300952A (en) * | 2015-12-02 | 2016-02-03 | 南京先进激光技术研究院 | Atmosphere OH free radical measurement system and method |
| CN106404410A (en) * | 2016-12-02 | 2017-02-15 | 江苏大学 | Apparatus capable of simultaneously measuring diesel spray structure and combustion characteristic and method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9702300B2 (en) * | 2014-02-12 | 2017-07-11 | King Fahd University Of Petroleum And Minerals | Applications of oxy-fuel combustion technology into gas turbine combustors and ion transport membrane reactors |
-
2018
- 2018-09-13 CN CN201811068924.XA patent/CN109470662B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103941038A (en) * | 2014-04-25 | 2014-07-23 | 西北核技术研究所 | Flow field flow velocity measuring device and method capable of eliminating vibration interference |
| CN104897632A (en) * | 2015-06-01 | 2015-09-09 | 哈尔滨工业大学 | Method for measuring three-dimensional spatial distribution of OH group concentration in transient combustion field based on scanning planar laser induced fluorescence imaging system |
| CN105300952A (en) * | 2015-12-02 | 2016-02-03 | 南京先进激光技术研究院 | Atmosphere OH free radical measurement system and method |
| CN106404410A (en) * | 2016-12-02 | 2017-02-15 | 江苏大学 | Apparatus capable of simultaneously measuring diesel spray structure and combustion characteristic and method thereof |
Non-Patent Citations (4)
| Title |
|---|
| Investigation of flameholding mechanisms in a kerosene-fueled scramjet combustor;Yu-hang Wang,et al.;<Acta Astronautica>;20170908;第140卷;402-408 * |
| Simultaneous measurements of equivalence ratio and flame structure in multipoint injectors using PLIF;Orain Mikael，et al.;<Comptes Rendus Mecanique>;20090721;第337卷(第6-7期);373-384 * |
| Yu-hang Wang,et al..Investigation of flameholding mechanisms in a kerosene-fueled scramjet combustor.<Acta Astronautica>.2017,第140卷402-408. * |
| 超音速燃烧室氢氧基平面激光诱导荧光测量;杨仕润 等;《激光技术》;20040228;第28卷(第1期);20-22,32 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109470662A (en) | 2019-03-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109470662B (en) | Device and method for eliminating kerosene interference in OH-PLIF measurement of kerosene combustion field | |
| CN102353447B (en) | Spectrum scaling apparatus used for spectrum imager | |
| JP2020517096A5 (en) | ||
| US5777733A (en) | Spectrometer with wavelength calibration | |
| CN106537104B (en) | Device and method for light beam characterization | |
| US10794766B2 (en) | Method and device for raman spectroscopy | |
| CN102288391A (en) | Spectral target generator for measuring optical transfer function | |
| US20190145892A1 (en) | Far-Infrared Imaging Device and Far-Infrared Imaging Method | |
| CN106546333B (en) | High dynamic range infrared imaging spectrometer | |
| JP2010217100A (en) | Exhaust gas analyzer | |
| RU2010109456A (en) | METHOD CALIBRATION METHOD | |
| EP1544641A1 (en) | Dose distribution reading method for glass dosimeter | |
| TWI798614B (en) | Combined ocd and photoreflectance apparatus, system and method | |
| US20210215537A1 (en) | Composite multispectral raman spectroscopy method and device | |
| CN113295387B (en) | Optical parameter testing system and method for multiband strip-shaped optical filter | |
| CN109799077A (en) | The linear variable filter detection device of imaging spectrometer | |
| JP2020529617A (en) | A system that acquires point values for composing images using terahertz waves | |
| KR101438748B1 (en) | Optical coherence tomography device and tomography method thereof | |
| CN110865396B (en) | Frequency sweep calibration device and method for high spectral resolution laser radar | |
| RU2540451C1 (en) | Laser location system | |
| JP7194437B2 (en) | Interference signal strength acquisition method and interference signal strength acquisition device | |
| KR101337087B1 (en) | Doppler lidar apparatus and method for operating doppler lidar apparatus | |
| KR20130007447A (en) | Temperature measuring apparatus, substrate processing apparatus and temperature measuring method | |
| Kirkwood et al. | Calibration of initial measurements from the full aperture backscatter system on the National Ignition Facility | |
| JPS6053834A (en) | Laser raman microprobe |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |