CN110376129B - Method and device for synchronously measuring combustion temperature field and soot concentration field - Google Patents

Method and device for synchronously measuring combustion temperature field and soot concentration field Download PDF

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CN110376129B
CN110376129B CN201910691877.2A CN201910691877A CN110376129B CN 110376129 B CN110376129 B CN 110376129B CN 201910691877 A CN201910691877 A CN 201910691877A CN 110376129 B CN110376129 B CN 110376129B
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王兆文
杜涛
石书国
郎兵
黄胜
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Huazhong University of Science and Technology
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Abstract

The invention belongs to the technical field of internal combustion engines, and particularly discloses a method and a device for synchronously measuring a combustion temperature field and a soot concentration field. The method comprises the following steps: separately extracting T2m‑1And T2m+1With non-parallel monochromatic light illuminationLight intensity and T of each pixel point in photo of to-be-detected spray combustion area for line spray combustion2mThe light intensity and RGB value of each pixel point in the photo of the to-be-detected spray combustion area which is not irradiated by the non-parallel monochromatic light at any moment and is subjected to spray combustion and the light intensity of each pixel point in the photo of the to-be-detected spray combustion area which is not subjected to spray combustion are transmitted by the non-parallel monochromatic light, so that the carbon smoke concentration field and the combustion temperature field in the spray combustion are obtained simultaneously. The device comprises a pulse light emitting module, a color CCD camera, a pulse generator and a computer. The invention can effectively solve the problem that the extinction method can not calculate the temperature field and the problem that the double-color method has large error in calculating the soot concentration field under high soot concentration.

Description

Method and device for synchronously measuring combustion temperature field and soot concentration field
Technical Field
The invention belongs to the technical field of internal combustion engines, and particularly relates to a method and a device for synchronously measuring a combustion temperature field and a soot concentration field.
Background
Internal combustion engines have unique advantages in terms of thermal efficiency, emission levels, power performance, reliability, etc., and have become indispensable prime movers in today's society. However, increasingly strict emission regulations put higher demands on energy conservation and emission reduction of the internal combustion engine, and although the emission can be reduced to a certain extent by purifying the external combustion engine, the problem can be solved fundamentally only by optimizing the combustion in the cylinder, so that the internal combustion engine is cleaner and more efficient.
With the development of laser diagnosis and high-speed imaging technology, the optical measurement is more and more widely applied to the measurement of a combustion temperature field and a soot concentration field, and powerful technical support is provided for the reasonable organization of combustion in a cylinder of an internal combustion engine. The two-color method and the extinction method are relatively simple in system, high in measurement accuracy and universal in application at present.
The two-color method can continuously and synchronously measure the combustion temperature field and the soot concentration field of the combustion flame with thin flame thickness or low soot concentration under the non-contact condition. The basic principle of the bicolor method is that a color image of a combustion process is obtained through shooting by a high-speed color CCD camera, an RGB value (red, green and blue basic color values) matrix is obtained from the color image, and according to a solid heat radiation theory and in combination with calibration data of a high-temperature black body furnace, the corresponding relation between the RGB value matrix and the combustion temperature can be found out, so that a combustion temperature field and a soot concentration field can be calculated in sequence. However, in the two-color measurement of the spray combustion of the internal combustion engine, the dense soot at the downstream of the measurement light path absorbs the soot radiation light at the upstream of the light path, so that the measurement error of the two-color measurement is large under the condition of high soot concentration, and therefore, the two-color measurement is not very suitable for the soot concentration field measurement of the spray combustion.
The extinction method can continuously measure the soot concentration field in the spray combustion experiment under the non-contact condition. The basic principle of the extinction method is that when a beam of light passes through the soot generation region, the incident light intensity gradually decreases after passing through the soot region due to absorption and scattering of the incident light by soot. In the process, the absorption effect of soot on incident light is far greater than the scattering effect. The relationship between the light intensity change and the soot concentration before and after the incident light passes through the soot area can be described by using the Beer-Lambert theory, so that the soot concentration is calculated by measuring the light intensity. Compared with the two-color method, the extinction method has smaller error in measuring the concentration of the soot under the condition of high soot concentration. At present, the extinction method cannot obtain temperature field distribution; meanwhile, measurement errors caused by neglecting the self-luminescence of soot exist; and generally uses laser as light source, the system is expensive.
Therefore, there is a need in the art to provide a measuring method and device that can achieve synchronous measurement of the spray combustion temperature field and the soot concentration field of the internal combustion engine, and that has higher precision and lower cost.
Disclosure of Invention
Aiming at the defects or the improvement requirements in the prior art, the invention provides a method and a device for synchronously measuring a combustion temperature field and a soot concentration field, wherein the respective advantages of a bicolor method and an extinction method can be correspondingly combined by researching and designing the process conditions of the bicolor method and the extinction method so as to synchronously and accurately measure the combustion temperature field and the soot concentration field in a spray combustion experiment; in addition, the invention also carries out corresponding design and research on the time period when the non-parallel monochromatic light irradiates the spray combustion area to be detected and the shooting time period of the color CCD camera, so that the picture of the non-parallel monochromatic light which is acquired in a very short time and penetrates through the spray combustion area to be detected and the picture of the non-parallel monochromatic light which does not penetrate through the spray combustion area to be detected are effectively compared, then, the carbon smoke concentration field is calculated by adopting an extinction method, the temperature field is calculated by adopting a two-color method, the combustion temperature field and the carbon smoke concentration field in the spray combustion experiment can be synchronously and accurately measured, and the problems that the temperature field cannot be calculated by adopting the extinction method and the error of the carbon smoke concentration field is large when the two-color method is used for calculating the.
In order to achieve the above object, according to one aspect of the present invention, a method for synchronously measuring a combustion temperature field and a soot concentration field is provided, comprising the steps of:
s1 photograph A of non-parallel monochromatic light passing through non-spray burning area to be tested by color CCD camera0；
S2, irradiating a to-be-tested spray combustion area subjected to spray combustion by using non-parallel monochromatic light with a pulse frequency of X, and simultaneously continuously photographing the to-be-tested spray combustion area by using a color CCD camera with a photographing frequency of Y, wherein Y is N times of X, and N is an integer not less than 2;
s3 obtaining T2mPhotograph B of a test spray burning area where spray burning is to be performed with non-parallel monochromatic light irradiation at that time2mAnd T2m-1Time and T2m+1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m-1And photograph C2m+1；
S4 obtaining photo A0Photograph B2mPhotograph C2m-1And photograph C2m+1Obtaining the light intensity of each pixel point to obtain a photo C2m-1And photograph C2m+1The RGB value of each pixel point in the image;
s5 is based on photo A0Photograph B2mPhotograph C2m-1And photograph C2m+1The light intensity of each pixel point is used for establishing a KL factor of the soot concentration of each pixel point, so that a soot concentration field of spray combustion is established;
s6 calibration photograph C2m-1Or photograph C2m+1The brightness temperature corresponding to the RGB value of each pixel point in the picture, and a picture C is established according to the brightness temperature2m-1Or photograph C2m+1And establishing a temperature field of spray combustion according to the temperature model of each pixel point.
As a further preferable example, in step S5, the KL factor model of soot concentration at each pixel point is:
Figure BDA0002148096040000031
or
Figure BDA0002148096040000032
Or
Figure BDA0002148096040000033
Wherein the KL value is a KL factor representing the soot concentration, I0,iIs a photograph A0Light intensity of the middle pixel I, I2m-1,iIs a photograph C2m-1Light intensity of the middle pixel I, I2m+1,iIs a photograph C2m+1Light intensity of the middle pixel I, I2m,iIs a photograph B2mThe light intensity of the middle pixel point i.
Preferably, in step S5 and step S5, the KL factors of the pixels are in one-to-one correspondence with the positions of the pixels, so as to construct a soot concentration field for spray combustion.
More preferably, in step S6, the RGB values include red light signal intensity, green light signal intensity, and blue light signal intensity constituting each pixel point; calibrating the brightness temperature corresponding to each value in the RGB value matrix by adopting a high-temperature black body furnace;
the temperature model is as follows:
Figure BDA0002148096040000041
or
Figure BDA0002148096040000042
Wherein λ is1、λ2The wavelength is corresponding to any two color lights of red light, green light and blue light; c2Is a known constant; t isa1Is λ1Brightness temperature, T, of the corresponding color lighta2Is λ2Brightness temperature, T, of the corresponding color light2m-1,iIs a photograph C2m-1Temperature, T, of the middle pixel point i2m+1,iIs a photograph C2m+1The temperature of the middle pixel point i.
More preferably, in step S6, the picture C is taken2m-1Or photograph C2m+1The temperature of each pixel point in the fuel gas is in one-to-one correspondence with the position of each pixel point, so that a temperature field of spray combustion is constructed.
More preferably, Y is 2 times X.
According to another aspect of the present invention, there is provided a combustion temperature field and soot concentration field synchronous measuring device, comprising a pulse light emitting module, a color CCD camera and a pulse generator, wherein,
the pulse light emission module and the color CCD camera are respectively arranged at two opposite ends of the spray combustion area to be detected, the pulse light emission module is used for emitting non-parallel monochromatic light, and the color CCD camera is used for shooting a picture of the spray combustion area to be detected according to the requirement;
the pulse generator is provided with two output ends, one output end is connected with the pulse light emitting module, the other output end is connected with the color CCD camera, and the signal of the color CCD cameraThe signal output end is connected with a computer, when the color CCD camera works, the pulse generator controls the pulse light emitting module to emit non-parallel monochromatic light, and simultaneously the pulse generator controls the color CCD camera to shoot T2mPhotograph B of burning spray area to be measured irradiated by non-parallel monochromatic light at any moment2m、T2m-1Time and T2m+1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m-1And photograph C2m+1And combine the pictures B2mPhotograph C2m-1And photograph C2m+1Transmitting to computer, computer checking picture B2mPhotograph C2m-1And photograph C2m+1Processing to obtain a photograph B2mLight intensity of each pixel point in the picture C2m-1And photograph C2m+1And processing the light intensity of each pixel point to construct a soot concentration field and a temperature field of spray combustion.
Further preferably, the pulsed light emitting module and the color CCD camera are arranged on the same axis.
As further preferred, the pulse light emission module includes pulse LED light source, scattering lens group and fresnel lens, wherein, LED light source and scattering lens group connect the setting, and scattering lens group and fresnel lens interval set up, fresnel lens sets up in the one side that is close to the spray combustion area that awaits measuring, pulse LED light source, scattering lens group and fresnel lens's center pin collineation.
Preferably, the pulsed light emitting module further comprises a heat sink disposed on the pulsed LED light source; the non-parallel monochromatic light scattered by the Fresnel lens completely covers the spray combustion area to be measured.
Generally, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:
1. according to the method, corresponding design and research are carried out on the time period when the non-parallel monochromatic light irradiates the spray combustion area to be detected and the shooting time period of the color CCD camera, so that a picture obtained in a very short time when the non-parallel monochromatic light penetrates through the spray combustion area to be detected and a picture when no non-parallel monochromatic light penetrates through the spray combustion area to be detected are effectively compared, meanwhile, the carbon smoke concentration field is calculated by adopting an extinction method principle, the temperature field is calculated by adopting a two-color method principle, the combustion temperature field and the carbon smoke concentration field at different spray combustion moments (namely all moments in the spray combustion process) in the spray combustion experiment can be synchronously and accurately measured, and the problems that the temperature field cannot be calculated by adopting the extinction method and the error is large when the carbon smoke concentration field is calculated by the two-color method under the condition of high carbon smoke.
2. The traditional extinction method brings system errors because of neglecting the existence of self-luminescence in combustion, and the invention calculates the carbon smoke concentration field by utilizing the difference of two continuous frames of pictures. Compared with the traditional extinction method, the method directly eliminates the system error caused by self-luminescence in combustion, and further improves the measurement precision of the carbon smoke concentration field.
3. The invention utilizes the characteristics of high power, low cost and high stroboflash of the pulse LED light source to replace an expensive and complicated laser light source commonly used by an extinction method, thereby simplifying the system and reducing the cost.
4. The invention can synchronously and accurately measure the combustion temperature field and the soot concentration field in the experiment, and the experiment efficiency is greatly improved.
5. The device correspondingly designs and researches the pulse light emitting module, the color CCD camera, the pulse generator and the computer, so that a picture obtained in a short time after non-parallel monochromatic light penetrates through a combustion spray area to be measured and a picture without the non-parallel monochromatic light penetrating through the combustion spray area to be measured are effectively compared, and meanwhile, the computer processes the picture shot by the color CCD camera and the light intensity of the corresponding picture to obtain the KL factor of the carbon smoke concentration and the temperature field of the carbon smoke.
Drawings
FIG. 1 is a schematic structural diagram of a synchronous measurement device for a combustion temperature field and a soot concentration field according to the present invention;
FIG. 2 is a timing diagram of the trigger signal from the pulse generator of FIG. 1.
The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:
the method comprises the following steps of 1-a heat dissipation device, 2-a pulse LED light source, 3-a scattering lens group, 4-a Fresnel lens, 5-a combustion spray area to be measured, 6-a color CCD camera and 7-a pulse generator.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention discloses a method for synchronously measuring a combustion temperature field and a soot concentration field, which comprises the following steps of:
step one, taking a picture A of non-parallel monochromatic light after the non-parallel monochromatic light penetrates through a combustion spray area to be measured by adopting a color CCD camera0At this time, the combustion spray area to be measured is not subjected to spray combustion. At the same time, photograph A is extracted0Light intensity (I) of each pixel point0，1，…，I0，i) The light intensity here will be used as a contrast, and at the same time, the frequency of the stroboscopic light shot by the color CCD camera is not limited.
Step two, in the process of carrying out spray combustion in the spray combustion area to be tested, at T2mAt the moment, non-parallel monochromatic light with the pulse frequency of X is adopted to irradiate a spray combustion area to be measured, and a color CCD camera with the pulse frequency of Y is adopted to shoot T2mPhotograph B of moment non-parallel monochromatic light after penetrating through combustion spray area to be measured2mAnd obtaining B2mLight intensity (I) of each pixel point2m，1，…，I2m，i) The light intensity is the sum of the residual light intensity of the non-parallel monochromatic light after penetrating through the combustion spray area to be detected and the soot glow light intensity of the combustion spray area to be detected; at T2m-1At the moment, a picture C of a to-be-sprayed combustion area to be tested for spraying combustion without non-parallel monochromatic light irradiation is taken by a color CCD camera2m-1And taking the picture C2m-1Light intensity (I) of each pixel point2m-1，1，…，I2m-1，i) And RGB value, the light intensity is soot glowing light intensity of the combustion spray area to be measured; at T2m+1At the moment, a picture C of a to-be-sprayed combustion area to be tested for spraying combustion without non-parallel monochromatic light irradiation is taken by a color CCD camera2m+1And taking the picture C2m+1Light intensity (I) of each pixel point2m+1，1，…，I2m+1，i) And RGB value, the light intensity is soot glowing light intensity of the combustion spray area to be measured; wherein i is an integer of not less than 0.
In this step, the stroboscopic frequency of the image captured by the color CCD camera is at least 2 times or more of the irradiation frequency of the non-parallel monochromatic light, i.e., Y is N times of X, and N is an integer not less than 2, and as a preferred embodiment of the present invention, the stroboscopic frequency of the image captured by the color CCD camera is 2 times of the irradiation frequency of the non-parallel monochromatic light, i.e., Y is 2 times of X.
Step three, acquiring a photo A0Photograph B2mPhotograph C2m-1And photograph C2m+1Obtaining the light intensity of each pixel point to obtain a photo C2m-1And photograph C2m+1And the RGB value of each pixel point.
Step four, according to the picture A0Photograph B2mAnd photograph C2m-1And photograph C2m+1And the light intensity of each pixel point establishes a KL factor of the soot concentration of each pixel point, and the KL factor of each pixel point corresponds to the position of each pixel point one by one, so that a soot concentration field of spray combustion is established.
Wherein the KL factor model of soot concentration at each pixel point is:
Figure BDA0002148096040000081
or
Figure BDA0002148096040000082
Or
Figure BDA0002148096040000083
Wherein the KL value is a KL factor representing soot concentration; i is0Is a photograph A0Light intensity of the middle pixel I, I2m,iIs a photograph B2mLight intensity of the middle pixel I, I2m-1,iIs T2m-1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation2m-1Light intensity of the middle pixel I, I2m+1,iIs T2m+1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m+1The light intensity of the middle pixel point i.
Step five, calibrating the photo C2m-1Or a photograph C2m+1The brightness temperature corresponding to the RGB value of each pixel point in the picture, and a picture C is established according to the brightness temperature2m-1Or a photograph C2m+1And establishing a temperature field of spray combustion according to the temperature model of each pixel point. Specifically, the RGB values of the pixels include red light signal intensity, green light signal intensity, and blue light signal intensity, two optional colors are selected from red light, green light, and blue light, a high temperature black body furnace is used to calibrate a luminance temperature curve corresponding to each value in the RGB value matrix, and a relationship between monochromatic light intensity and luminance temperature at different wavelengths is given on the curve, so as to obtain the photograph C2m-1Or photograph C2m+1The brightness temperature corresponding to the RGB value of each pixel point in the picture, and a picture C is established according to the brightness temperature2m-1Or a photograph C2m+1And establishing a temperature field of spray combustion according to the temperature model of each pixel point.
The temperature model is:
Figure BDA0002148096040000091
or
Figure BDA0002148096040000092
Wherein λ is1、λ2The wavelength is corresponding to any two color lights of red light, green light and blue light; c2Is a known constant; t isa1Is λ1Brightness temperature, T, of the corresponding color lighta2Is λ2Brightness temperature, T, of the corresponding color light2m-1,iIs a photograph C2m-1Temperature, T, of the middle pixel point i2m+1,iIs a photograph C2m+1The temperature of the middle pixel point i.
As shown in fig. 1 and fig. 2, the device for synchronously measuring a combustion temperature field and a soot concentration field of the present invention includes a pulse light emitting module, a color CCD camera 6, a pulse generator 7 and a computer. Pulse light emission module includes heat abstractor 1, pulse LED light source 2, scattering lens group 3 and fresnel lens 4, and pulse LED light source 2 directly shines or shines the burning spray region 5 that awaits measuring through the optics window, LED light source 2 and scattering lens group 3 connect the setting, and scattering lens group 3 and fresnel lens 4 interval set up, fresnel lens 4 sets up in the one side that is close to the spraying combustion region that awaits measuring, the center pin collineation of pulse LED light source 2, scattering lens group 3 and fresnel lens 4. The heat dissipation device 1 is arranged on the pulse LED light source 2 and used for dissipating heat of the pulse LED light source 2.
The pulse LED light source 2 can emit monochromatic visible light, the pulse frequency and the pulse width are controlled by the pulse generator 7, the pulse width is 1 microsecond at the lowest, and the pulse frequency exceeds 2 ten thousand Hz. The diameter of the Fresnel lens 4 is larger than the maximum length of the combustion spray area 5 to be measured, and the Fresnel lens has the function of diffusing and homogenizing incident light, so that the emergent non-parallel light covers the whole area to be measured and the brightness distribution is uniform.
The exposure time and the shooting frequency of the color CCD camera 6 are controlled by the pulse generator 7, the exposure time is 1 microsecond at the shortest, the highest shooting frequency is more than 4 ten thousand frames per second, and the resolution is 1024 x 1024 at the highest. And meanwhile, the signal output end of the color CCD camera 6 is connected with a computer and is used for transmitting the pictures shot by the computer to the computer. When the pulse light emitting module works, the pulse generator controls the pulse light emitting module to emit non-parallel monochromatic lightAnd simultaneously the pulse generator controls the color CCD camera to shoot T2mPhotograph B of burning spray area to be measured irradiated by non-parallel monochromatic light at any moment2m、T2m-1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m-1And T2m-1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m+1And combine the pictures B2mPhotograph C2m-1And photograph C2m+1Transmitting to computer, computer checking picture B2mPhotograph C2m-1And photograph C2m+1Processing to obtain a photograph B2mLight intensity of each pixel point in the picture C2m-1And photograph C2m+1And processing the light intensity of each pixel point to construct a soot concentration field and a temperature field of spray combustion.
Specifically, as shown in fig. 2, the pulsed LED light source 2 is controlled and triggered by the pulse generator 7 to generate high-frequency pulsed monochromatic visible light, the monochromatic visible light passes through the scattering lens group 3, the fresnel lens 4 generates uniform non-parallel monochromatic light, the non-parallel monochromatic light passes through the spray burning area 5 to be detected, the shooting frequency of the color CCD camera 6 is 2 times of the stroboscopic frequency of the pulsed LED light source 2, so that the former (i.e. 2m-1 moment) of the two continuous photographs is the sum of the residual light intensity after the LED light source passes through the spray burning area 5 to be detected and the soot and glow light intensity in the spray burning area 5 to be detected, and the latter (i.e. 2m moment) is the soot and glow light intensity in the spray burning area 5 to be detected only. Subtracting the light intensity of the latter picture (namely the 2m moment) from the light intensity of the former picture (namely the 2m-1 moment) to obtain the residual light intensity of the LED light source after the LED light source penetrates through the combustion spray area 5 to be measured, and obtaining a KL factor representing the soot concentration according to the Beer-Lambert theory, namely the KL factor representing the soot concentration
(I2m-1-I2m)/I0＝exp(-KL)
In the formula: i is2m-1The light intensity received for the previous picture; i is2mThe light intensity received for the latter photograph; i is0Is the original background light intensity of the LED received by the camera before the start of the spray.
Further, the sum of the residual light intensity after the LED light source passes through the 2 to-be-detected combustion spray area 5 to be absorbed by the LED light source at the moment of 2m-2 and the light intensity of the soot incandescent light in the to-be-detected combustion spray area 5 can be obtained, and a KL factor representing the soot concentration, namely the KL factor representing the soot concentration can be obtained according to the Beer-Lambert theory
(I2m-1-I2m-2)/I0＝exp(-KL)
Or the KL factor representing the soot concentration can be obtained according to the Beer-Lambert theory, namely
Figure BDA0002148096040000111
Utilize in the burning spray region 5 that awaits measuring soot incandescent light color photograph (2 m moment promptly), can decompose and obtain RGB value matrix (red, green, blue three wavelength signal intensity), combine thermal radiation theory and high temperature black body stove calibration result can calculate and obtain the temperature field distribution, promptly:
Figure BDA0002148096040000112
in the formula, λ1、λ2The wavelength is corresponding to any two color lights of red light, green light and blue light; c2Is a known constant; t isa1Is λ1Brightness temperature, T, of the corresponding color lighta2Is λ2And the brightness and temperature of the corresponding colored light are given by a calibration curve of the high-temperature black body furnace.
In order to ensure the measurement accuracy, it is necessary to ensure that the time interval between the two pictures is sufficiently small, i.e. the frequency of the LED pulse light source 2 and the color CCD camera 6 is sufficiently high. Meanwhile, the high enough frequency can more accurately reflect the transient characteristics of a combustion temperature field and a soot concentration field in the spray combustion process.
The invention combines the advantages of a double-color method and an extinction method, utilizes a designed high-frequency light source and a designed high-frequency photograph, calculates the soot concentration field by using the extinction method principle, calculates the temperature field by using the double-color method principle, and can synchronously and accurately measure the combustion temperature field and the soot concentration field in the spray combustion experiment. The method solves the problems that the extinction method cannot calculate the temperature field and the two-color method has large error in calculating the soot concentration field under high soot concentration, has the characteristics of high power, low cost and high stroboflash, replaces an expensive and complicated laser light source commonly used by the extinction method, can simplify the system and reduce the cost.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (9)

1. A method for synchronously measuring a combustion temperature field and a soot concentration field is characterized by comprising the following steps:
s1 photograph A of non-parallel monochromatic light passing through non-spray burning area to be tested by color CCD camera0；
S2, irradiating a spray combustion area to be tested for spray combustion by using non-parallel monochromatic light with a pulse frequency of X, and continuously photographing the spray combustion area to be tested by using a color CCD camera with a photographing frequency of Y, wherein Y is N times of X, and N is an integer not less than 2;
s3 obtaining T2mPhotograph B of a test spray burning area where spray burning is to be performed with non-parallel monochromatic light irradiation at that time2mAnd T2m-1Time and T2m+1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m-1And photograph C2m+1；
S4 obtaining photo A0Photograph B2mPhotograph C2m-1And photograph C2m+1Obtaining the light intensity of each pixel point to obtain a photo C2m-1And photograph C2m+1The RGB value of each pixel point in the image;
s5 is based on photo A0Photograph B2mPhotograph C2m-1And photograph C2m+1The light intensity of each pixel point establishes the KL factor of the soot concentration of each pixel point, so as to construct the spray combustionA soot concentration field;
s6 calibration photograph C2m-1Or photograph C2m+1The brightness temperature corresponding to the RGB value of each pixel point in the picture, and a picture C is established according to the brightness temperature2m-1Or photograph C2m+1And establishing a temperature field of spray combustion according to the temperature model of each pixel point.
2. The method according to claim 1, wherein in step S5, the KL factor model of soot concentration at each pixel point is:
Figure FDA0002759104880000011
or
Figure FDA0002759104880000012
Or
Figure FDA0002759104880000021
Wherein the KL value is a KL factor representing the soot concentration, I0,iIs a photograph A0Light intensity of the middle pixel I, I2m-1,iIs a photograph C2m-1Light intensity of the middle pixel I, I2m+1,iIs a photograph C2m+1Light intensity of the middle pixel I, I2m,iIs a photograph B2mThe light intensity of the middle pixel point i.
3. The method according to claim 1, wherein in step S5, the soot concentration field of the spray combustion is constructed by one-to-one correspondence of the KL factors of the respective pixel points and the positions of the respective pixel points.
4. The method according to claim 1, wherein in step S6, the step of processing the picture C is performed by combining the picture C with the picture C2m-1Or photograph C2m+1The temperature of each pixel point in the fuel gas is in one-to-one correspondence with the position of each pixel point, so that a temperature field of spray combustion is constructed.
5. The method of claim 1, wherein Y is 2 times X.
6. An apparatus for implementing the method of any one of claims 1 to 5, comprising a pulsed light emission module, a color CCD camera and a pulse generator, wherein,
the pulse light emission module and the color CCD camera are respectively arranged at two opposite ends of the spray combustion area to be detected, the pulse light emission module is used for emitting non-parallel monochromatic light, and the color CCD camera is used for shooting a picture of the spray combustion area to be detected according to the requirement;
the pulse generator is provided with two output ends, one output end is connected with the pulse light emission module, the other output end is connected with the color CCD camera, the signal output end of the color CCD camera is connected with a computer, during work, the pulse generator controls the pulse light emission module to emit non-parallel monochromatic light, and simultaneously the pulse generator controls the color CCD camera to shoot T-shaped images2mPhotograph B of burning spray area to be measured irradiated by non-parallel monochromatic light at any moment2m、T2m-1Time and T2m+1Photograph C of spray combustion area to be tested for spray combustion without non-parallel monochromatic light irradiation at any moment2m-1And photograph C2m+1And combine the pictures B2mPhotograph C2m-1And photograph C2m+1Transmitting to computer, computer checking picture B2mPhotograph C2m-1And photograph C2m+1Processing to obtain a photograph B2mLight intensity of each pixel point in the picture C2m-1And photograph C2m+1And processing the light intensity of each pixel point to construct a soot concentration field and a temperature field of spray combustion.
7. The apparatus of claim 6, wherein the pulsed light emission module and the color CCD camera are arranged on the same axis.
8. The device according to claim 6, wherein the pulsed light emitting module comprises a pulsed LED light source, a scattering lens group and a Fresnel lens, wherein the LED light source and the scattering lens group are connected, the scattering lens group and the Fresnel lens are arranged at intervals, the Fresnel lens is arranged at one side close to a spray combustion area to be measured, and central axes of the pulsed LED light source, the scattering lens group and the Fresnel lens are collinear.
9. The device of claim 8, wherein the pulsed light emitting module further comprises a heat sink disposed on the pulsed LED light source; the non-parallel monochromatic light scattered by the Fresnel lens completely covers the spray combustion area to be measured.
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