JP2024041461A - Combustion-diagnosing apparatus, combustion-diagnosing system, and program of combustion-diagnosing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diagnose a combustion state of a flame with a simple configuration.

SOLUTION: A combustion-diagnosing apparatus 3 diagnoses a combustion state of a flame based on an image of the flame captured by a visible light camera 2 and includes: a signal extraction part 33 for extracting signals in one or more specific wavelength bands from the flame portion of the image; and a combustion-diagnosing part 34 for diagnosing the combustion state based on signals in the specific wavelength bands.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a technique for diagnosing the combustion state of a flame, and particularly to a technique for diagnosing the combustion state of a flame based on an image of the flame captured by a visible light camera.

When incomplete combustion occurs in various types of combustion equipment, such as thermal power plants and household stoves, combustion efficiency decreases. In addition, when incomplete combustion occurs, harmful components such as carbon monoxide are also emitted, so combustion diagnosis (monitoring) of combustion equipment is essential.

Therefore, a method has been proposed for diagnosing the combustion state based on the intensity of light emission of a specific wavelength (self-luminescence or spontaneous luminescence) observed from a flame. FIG. 10 is a graph showing an example of flame emission spectrum intensity. Common flame self-luminescence includes OH radical self-luminescence having a peak at 306 nm, CH radical self-luminescence having a peak at 430 nm, and C2 radical self-luminescence having a peak at 516 nm. By measuring the intensity of these self-luminous emissions, the combustion state of the flame can be diagnosed.

Patent Document 1 discloses that the state of the flame is detected by separating flame light using a spectrometer and measuring the intensity of OH radical self-luminescence. Further, Patent Document 2 also discloses that the state of the flame is detected by dividing flame light into spectra using a spectrometer and measuring the intensity of CH radical self-luminescence or C2 radical self-luminescence.

International Publication No. 2005/045379 International Publication No. 2008/059976

However, since the techniques described in Patent Documents 1 and 2 require a spectroscope, an inexpensive imaging device such as a visible light camera cannot be used.

On the other hand, in order to measure CH radical self-luminescence and C2 radical self-luminescence using a visible light camera, the lens of the visible light camera is equipped with a special filter that passes light in a band including 430 nm, and a special filter that passes light in a band including 516 nm. It is possible to image the flame by attaching a special filter that allows it to pass through. However, such a special filter is expensive, and it is necessary to replace the special filter attached to the lens, so that CH radical self-emission and C2 radical self-emission cannot be measured at the same time.

The present invention has been made to solve the above problems, and an object of the present invention is to diagnose the combustion state of a flame with a simple configuration.

In order to solve the above problems, the present invention includes the following aspects.
Item 1.
A combustion diagnosis device that diagnoses the combustion state of the flame based on an image of the flame captured by a visible light camera,
a signal extraction unit that extracts signals in one or more specific wavelength bands from the flame portion of the image;
a combustion diagnosis section that diagnoses the combustion state based on the signal in the specific wavelength band;
A combustion diagnostic device equipped with.
Item 2.
The signal extraction section includes:
a G signal extraction unit that extracts the G signal;
a B signal extraction unit that extracts the B signal;
Equipped with
The combustion diagnosis section includes:
2. The combustion diagnosis device according to item 1, further comprising an equivalence ratio diagnosis section that diagnoses the equivalence ratio of fuel in the flame as the combustion state based on the G signal and the B signal.
Item 3.
The equivalence ratio diagnosis section is
3. The combustion diagnosis device according to item 2, wherein each intensity of CH radical self-emission and C2 radical self-emission in the flame is calculated from the G signal and the B signal, and the equivalence ratio is diagnosed based on the intensities.
Item 4.
The signal extraction section includes:
comprising an R signal extraction section that extracts the R signal,
The combustion diagnosis section includes:
2. The combustion diagnosis device according to item 1, further comprising a combustion temperature diagnosis section that diagnoses the combustion temperature of the flame based on the R signal.
Item 5.
The signal extraction section includes:
comprising an R signal extraction section that extracts the R signal,
The combustion diagnosis section includes:
3. The combustion diagnosis device according to item 2, which calculates the intensity of OH radical self-luminescence in the flame based on the R signal and the equivalence ratio.
Item 6.
The combustion diagnosis section includes:
6. The combustion diagnosis device according to item 5, further comprising a combustion rate diagnosis section that diagnoses the combustion rate of the flame based on the intensity of the OH radical self-luminescence.
Section 7.
a visible light camera that captures images of the flame;
a combustion diagnosis device that diagnoses the combustion state of the flame based on an image of the flame captured by the visible light camera;
A combustion diagnosis system comprising:
A combustion diagnosis system, wherein the combustion diagnosis device is the combustion diagnosis device according to any one of items 1 to 6.
Section 8.
A combustion diagnosis program that causes a computer to operate as the combustion diagnosis device according to any one of items 1 to 6.

According to the present invention, the combustion state of a flame can be diagnosed with a simple configuration.

1 is a block diagram showing the configuration of a combustion diagnosis system according to an embodiment of the present invention. It is a graph which shows an example of the photoelectric conversion characteristic with respect to the wavelength of R pixel, G pixel, and B pixel. (a) is a graph showing a spectrum of black body radiation according to Planck's radiation law, and (b) is a graph in which a part of the spectrum of black body radiation is expanded. 3 is a graph showing the relationship between the integral value of radiant energy (Int-E) and temperature. (a) is a graph showing the relationship between the intensity of C2 radical self-luminescence and the intensity of the G signal, and (b) is a graph showing the sum of 0.274 times the intensity of C2 radical self-luminescence and the intensity of CH radical self-luminescence. It is a graph showing the relationship between the intensity of the B signal and the intensity of the B signal. For fuels with different hydrogen mixing ratios (α), the predicted value (horizontal axis) based on the G signal and B signal and the measured value (vertical axis) of the ratio of the respective intensities of CH radical self-luminescence and C2 radical self-luminescence. It is a graph showing a relationship. 13 is a graph showing the relationship between the intensity of the R signal and the actual measured value of the integral of the radiant energy of the flame. (a) is a graph showing the relationship between the equivalence ratio (horizontal axis) and the intensity of the R signal (vertical axis), and (b) is a graph showing the relationship between the equivalence ratio (horizontal axis) and the intensity of OH radical self-luminescence (the vertical axis). ) is a graph showing the relationship between (a) is a graph showing the relationship between the intensity of the R signal (horizontal axis) and the intensity of OH radical self-luminescence (vertical axis), and (b) is a graph showing the relationship between the intensity of the R signal (horizontal axis) and the intensity of OH radical self-luminescence (vertical axis). It is a graph classifying into a mixture with an equivalence ratio of less than 1 (lean group) and a mixture with an equivalence ratio of 1 or more (rich group). It is a graph showing an example of the emission spectrum intensity of flame.

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below, and various changes can be made without departing from the spirit thereof.

(overall structure)
FIG. 1 is a block diagram showing the configuration of a combustion diagnosis system 1 according to an embodiment of the present invention. The combustion diagnosis system 1 includes a visible light camera 2 and a combustion diagnosis device 3.

The visible light camera 2 is a camera manufactured primarily for the purpose of capturing images of visible light. Therefore, the visible light camera 2 does not include cameras that aim to capture light other than visible light, such as infrared cameras and ultraviolet cameras. It may have a function of detecting an infrared light component with a long wavelength or an ultraviolet light component with a slightly shorter wavelength than visible light. Examples of the visible light camera 2 include a commercially available digital camera and a camera installed in a smartphone, and may also be a video camera capable of capturing moving images.

(visible light camera)
In this embodiment, the visible light camera 2 includes an R pixel, a G pixel, and a B pixel in its light receiving section, and generates an image by converting incident light into an R signal, a G signal, and a B signal. The image may be either a still image or a moving image. FIG. 2 is a graph showing an example of photoelectric conversion characteristics with respect to wavelength of an R pixel, a G pixel, and a B pixel. The photoelectric conversion characteristics vary to some extent depending on the model of the visible light camera 2. Note that although the visible light camera 2 uses the RGB method, other methods such as the CMYK method, the RYYB method, and the RGBY method may be used.

In the combustion diagnosis system 1, fuel to be diagnosed is combusted to form a flame, and the visible light camera 2 is installed so that the flame faces the lens of the visible light camera 2. Although the fuel is not particularly limited, in this embodiment, it includes city gas, propane gas, hydrogen gas, and the like. The photographing environment is preferably a dark place, but may be an environment where there is background light whose brightness does not change over time.

(Combustion diagnosis device)
The combustion diagnosis device 3 is a device that diagnoses the combustion state of a flame based on an image of the flame captured by the visible light camera 2. The combustion diagnosis device 3 can be configured with a general-purpose computer, and its hardware configuration includes a processor such as a CPU or GPU (not shown), a main storage device such as a DRAM or SRAM (not shown), and an HDD or SSD. It is equipped with an auxiliary storage device 30 such as. The auxiliary storage device 30 stores various programs for operating the combustion diagnosis device 3, such as a combustion diagnosis program P.

The combustion diagnosis device 3 includes an image acquisition section 31, a background light removal section 32, a signal extraction section 33, and a combustion diagnosis section 34 as functional blocks. These functional blocks can be realized in software by the processor of the combustion diagnosis device 3. In this case, each of the above sections can be realized by the processor reading out the combustion diagnosis program P stored in the auxiliary storage device 30 into the main storage device and executing it. The combustion diagnosis program P may be downloaded to the combustion diagnosis device 3 via a communication network such as the Internet, or may be downloaded via a computer-readable non-temporary recording medium such as a CD-ROM on which the combustion diagnosis program P is recorded. It may also be installed in the combustion diagnosis device 3.

The image acquisition unit 31 acquires data of the flame image transferred from the visible light camera 2. The image from the visible light camera 2 may be transferred to the combustion diagnosis device 3 by wire or wirelessly, or may be transferred to the combustion diagnosis device 3 via a recording medium.

The background light removal unit 32 removes background light from the flame image acquired by the image acquisition unit 31. The auxiliary storage device 30 stores in advance a background image captured by the visible light camera 2 in an environment where there is no flame, and the background light removal unit 32 extracts the background image from the brightness of each pixel of the flame image. By subtracting the brightness of each pixel, an image reflecting the brightness of only the flame is generated. Note that when the flame is imaged in a dark place, the processing by the background light removal unit 32 may be omitted.

The signal extraction unit 33 extracts signals in one or more specific wavelength bands from the flame portion of the image. In this embodiment, the signals in the specific wavelength band are three signals, an R signal, a G signal, and a B signal, and the signal extraction unit 33 includes an R signal extraction unit 331 that extracts the R signal, and an R signal extraction unit 331 that extracts the G signal. A G signal extraction section 332 that extracts an R signal, and an R signal extraction section 333 that extracts an R signal are provided. Note that the function of the signal extraction section 33 can also be realized using commercially available software such as XnConvert.

The combustion diagnosis section 34 diagnoses the combustion state of the flame based on the signals (R signal, G signal, and B signal) in specific wavelength bands extracted by the signal extraction section 33. In this embodiment, the combustion diagnosis section 34 includes a combustion temperature diagnosis section 341 that diagnoses the combustion temperature of the flame, a combustion speed diagnosis section 342 that diagnoses the combustion speed of the flame, and an equivalence ratio that diagnoses the equivalence ratio of the fuel of the flame. The diagnostic unit 343 is also provided with a diagnostic unit 343.

(Diagnosis of equivalence ratio)
First, the equivalence ratio diagnosis section 343 will be explained. The equivalence ratio diagnosis section 343 diagnoses the equivalence ratio of the fuel of the flame (mixture ratio of fuel and air) based on the G signal and the B signal. More specifically, the equivalence ratio diagnosis section 343 calculates the respective intensities of CH radical self-emission and C2 radical self-emission in the flame from the G signal and the B signal, and diagnoses the equivalence ratio based on the intensities. The respective intensities of CH radical self-luminescence and C2 radical self-luminescence are calculated as follows.

Since CH radical self-emission has a peak at 430 nm, the luminance component of CH radical self-emission is mainly recorded in the B signal, but depending on the model of visible light camera 2, the luminance component of CH radical self-emission is recorded in the G signal. may be recorded. Similarly, since C2 radical self-emission has a peak at 516 nm, the luminance component of C2 radical self-emission is mainly recorded in the G signal, but depending on the model of visible light camera 2, C2 radical self-emission is recorded in the B signal. luminance components may be recorded.

Therefore, by setting the conversion efficiencies of CH radical self-luminescence (430 nm) and C2 radical self-luminescence (516 nm) recorded as G signals as a(G430) and a(G516), respectively, the following equation (1) can be obtained. .

I _G = a (G430) * I _CH + a (G516) * I _C2 ... (1)

Here, _IG is the intensity of the G signal, _ICH is the intensity of the signal component due to CH radical self-emission, and _IC2 is the intensity of the signal component due to C2 radical self-emission.

Furthermore, if the conversion efficiency of CH radical self-luminescence (430 nm) and C2 radical self-luminescence (516 nm) recorded as the B signal is set as a(B430) and a(B516), respectively, the following equation (2) can be obtained. .

I _B =a(B430)*I _CH +a(B516)*I _C2 ...(2)

Here, _IB is the intensity of the B signal. By solving equations (1) and (2) simultaneously, the following equations (3) and (4) are obtained.

I _C2 = I _G /{a(G516)-a(G430) [a(B516)/a(B430)]-I _B /{a(B430)[a(G516)/a(G430)]-a( B516)} ...(3)
I _CH =I _G /{a(G430)-a(G516)[a(B430)/a(B516)]-I _B /{a(B516)[a(G430)/a(G516)]-a( B430)} ...(4)

The value of a(B516)/a(B430) on the right side of equation (3) is determined by the filter that transmits only light with a wavelength of 430 nm and the filter that transmits only light with a wavelength of 516 nm when imaging a flame with visible light camera 2. It can be determined by attaching filters alternately to take images and taking the ratio of the B signal with a wavelength of 430 nm and the B signal with a wavelength of 516 nm. Similarly, the value of a(G430)/a(G516) on the right side of equation (4) is determined by the difference between the filter that transmits only light with a wavelength of 430 nm and the light with a wavelength of 516 nm when imaging a flame with visible light camera 2. It can be determined by taking images by alternately attaching filters that transmit only the 430 nm wavelength and the 516 nm wavelength G signal. Therefore, by performing multiple regression analysis, which is a two-variable least squares method, the coefficients a ₁ , b ₁ , a ₂ , and b ₂ of the following equations (5) and (6) can be determined.

I _C2 =a ₁ *I _G -b ₁ *I _B ...(5)
I _CH =a ₂ *I _G -b ₂ *I _B ...(6)

In this way, each intensity of CH radical self-luminescence and C2 radical self-luminescence can be calculated. Since the ratio between the intensity of CH radical self-luminescence and the intensity of C2 radical self-luminescence changes depending on the equivalence ratio of the fuel, the equivalence ratio diagnostic unit 343 calculates the ratio based on the intensities of CH radical self-luminescence and C2 radical self-luminescence The equivalence ratio can be predicted using

(Diagnosis of combustion temperature)
The combustion temperature diagnosis section 341 diagnoses the combustion temperature of the flame based on the R signal. The present inventor discovered that the combustion temperature of a flame can be predicted based on the R signal as described below.

As shown in FIG. 2, the R signal records a radiation intensity of approximately 560 nm to 690 nm.
FIG. 3(a) is a graph showing a spectrum of blackbody radiation according to Planck's law of radiation, and FIG. 3(b) is a graph showing a part of the spectrum of blackbody radiation enlarged. Here, in FIG. 3(b), when the radiant energy (E) of each spectrum in the band from 560 nm to 690 nm is integrated, as shown in FIG. 4, the integral value of the radiant energy (Int-E) and The relationship with temperature is required.

From FIG. 4, it can be seen that the integral value of radiant energy in the band of 560 nm to 690 nm can be approximated to a quadratic function of temperature. Since the intensity of the R signal is approximately proportional to the integral value of radiant energy in the band of 560 nm to 690 nm, it can be seen that there is a high correlation between the R signal and temperature. Based on this correlation, the combustion temperature diagnostic unit 341 can predict the combustion temperature of the flame based on the R signal.

(Diagnosis of combustion rate)
The combustion rate diagnosis unit 342 calculates the intensity of OH radical self-luminescence in the flame based on the R signal and the equivalence ratio, and diagnoses the combustion rate of the flame based on the intensity of the OH radical spontaneous emission. Since the OH radical self-luminescence is ultraviolet light (306 nm), it cannot be detected by the visible light camera 2. However, as shown in Example 3 to be described later, the present inventor has determined that there is a difference between the R signal and the intensity of the OH radical self-luminescence. It was found that there is a correlation between Based on this correlation, the intensity of OH radical self-luminescence in the flame can be calculated based on the R signal and the equivalence ratio predicted by the equivalence ratio diagnosis section 343. Furthermore, since the intensity of OH radical self-luminescence has a correlation with the burning speed of the flame, the combustion rate diagnosis unit 342 can predict the burning speed of the flame based on the intensity of OH radical self-luminescence.

(Brief Summary)
As described above, in this embodiment, the combustion diagnosis device 3 determines the combustion state of the flame (the equivalence ratio of the fuel in the flame, the combustion temperature of the flame, the combustion temperature of the flame, combustion rate) can be diagnosed. That is, this embodiment does not require a spectroscope or a camera that can detect light other than visible light, so the combustion state of the flame can be diagnosed with a simple configuration.

In addition, in a configuration in which a special filter is attached to the lens of a visible light camera to measure CH radical self-emission and C2 radical self-emission, it is necessary to replace the special filter attached to the lens. cannot be measured at the same time. In contrast, in this embodiment, the intensities of CH radical self-emission and C2 radical self-emission in the flame are calculated from the G signal and B signal extracted from one image. Self-luminescence can be measured at the same time.

(Additional notes)
The present invention is not limited to the above-described embodiments, and various changes can be made within the scope of the claims, and forms obtained by appropriately combining the technical means disclosed in the embodiments may also be incorporated into the present invention. Included in technical scope.

In the above embodiment, the equivalence ratio of the air-fuel mixture, the combustion temperature of the flame, and the combustion speed of the flame are diagnosed as the combustion state of the flame, but only a part of these may be diagnosed. . For example, when only the equivalence ratio of the air-fuel mixture is to be diagnosed, the signal extraction unit 33 may extract only the G signal and the B signal as signals in a specific wavelength band. Furthermore, when only the combustion temperature of the flame is to be diagnosed, the signal extraction unit 33 may extract only the R signal as a signal in a specific wavelength band.

In the above embodiment, the intensities of CH radical self-luminescence, C2 radical self-luminescence, and OH radical self-luminescence are used as indicators for diagnosing the combustion state, but the present invention is not limited to these, and for example, CN The intensity of radical self-luminescence or CH3 radical self-luminescence may be used.

In Example 1, it was verified whether the present invention can diagnose the fuel equivalence ratio with high accuracy. Specifically, based on the G signal and the B signal, the ratio of the intensities of CH radical self-luminescence and C2 radical self-luminescence used for equivalence ratio diagnosis is calculated, and this is compared with the actual measurement value to perform diagnosis. Accuracy was verified.

The flame was imaged using a digital single-lens reflex camera (EOS 40D) manufactured by Canon Inc. as the visible light camera 2. A mixture of methane and hydrogen was used as fuel. Using a general-purpose computer as the combustion diagnosis device 3, the ratio of the intensity of CH radical self-luminescence and C2 radical self-luminescence was calculated based on the G signal and the B signal.

As a result of verifying the performance of the visible light camera 2 used in this example, the conversion efficiency a(G430) of 430 nm recorded as a G signal is 0 (a(G430)/a(G516) in equation (4)) It was confirmed that the value of a(B516)/a(B430) in equation (3) was 0.274. Therefore, the following equations (7) and (8) were obtained from equations (5) and (6).

I _C2 = I _G /a (G516) ... (7)
I _CH =I _B /a(B430)-0.274*I _C2 ...(8)

FIG. 5A is a graph showing the relationship between the intensity of C2 radical self-luminescence and the intensity of the G signal. The straight line in the graph is derived from equation (7). Further, the marks plotted in the graph indicate the relationship between the intensity of C2 radical self-luminescence and the intensity of the G signal in flames imaged while changing the mixture ratio (α) of hydrogen in the fuel. From the positional relationship between the straight line and each plotted mark, it can be seen that the relationship between the intensity of C2 radical self-luminescence and the intensity of the G signal generally satisfies equation (7), regardless of the hydrogen mixing ratio. That is, it was confirmed that there is a high correlation between the intensity of C2 radical self-luminescence and the intensity of the G signal.

FIG. 5(b) is a graph showing the relationship between the sum of 0.274 times the intensity of C2 radical self-luminescence and the intensity of CH radical self-luminescence, and the intensity of the B signal. The straight line in the graph is derived from equation (8). In addition, the marks plotted in the graph are the sum of 0.274 times the intensity of C2 radical self-luminescence and the intensity of CH radical self-luminescence in flames imaged while changing the hydrogen mixture ratio (α) of the fuel, The relationship with the intensity of the B signal is shown. From the positional relationship between the straight line and each plotted mark, the relationship between the sum of 0.274 times the intensity of C2 radical self-luminescence and the intensity of CH radical self-luminescence and the intensity of the B signal, regardless of the hydrogen mixing ratio. It can be seen that approximately satisfies equation (8). That is, it was confirmed that there is a high correlation between the sum of 0.274 times the intensity of C2 radical self-luminescence and the intensity of CH radical self-luminescence, and the intensity of the B signal.

Figure 6 shows the predicted values (horizontal axis) and actual measured values (vertical axis) of the ratio of the respective intensities of CH radical self-luminescence and C2 radical self-luminescence for fuels with different hydrogen mixing ratios (α). It is a graph showing the relationship with the axis). The actual measured values of the intensities of CH radical self-emission and C2 radical self-emission were obtained using a high-sensitivity ICCD camera (C9164 manufactured by Hamamatsu Photonics Co., Ltd.) that can measure up to ultraviolet light, and a filter that only transmits CH or C2 self-emission was attached. Measurements were made by photographing the flame. Since the plotted mark is located near the straight line indicating that the measured value and the predicted value are equal, the ratio of the respective intensities of CH radical self-luminescence and C2 radical self-luminescence can be determined with high precision using the G signal and B signal. It turns out that it can be predicted.

As a result, it was found that the fuel equivalence ratio can be diagnosed with high accuracy according to the present invention.

In Example 2, it was verified whether the present invention can diagnose the combustion temperature of a flame with high accuracy. Specifically, the diagnostic accuracy was verified by calculating the integral value of the radiant energy used for diagnosing the combustion temperature based on the R signal and comparing it with the actually measured value.

The visible light camera 2 and fuel used in this example were the same as in Example 1 above. The R signal was extracted from images of flames of fuels with different hydrogen mixing ratios (α), and the intensity of the R signal was obtained. In addition, the integral value of the flame radiant energy was determined by numerically integrating Planck's radiation equation shown below.

FIG. 7 is a graph showing the relationship between the intensity of the R signal and the actually measured value of the integral of the flame radiant energy. Since the plotted mark is located near the straight line that indicates the theoretical relationship between the R signal intensity and the integral value of radiant energy, there is a high correlation between the integral value of radiant energy and the R signal intensity. I found out something.

As a result, it was found that the combustion temperature of a flame can be diagnosed with high accuracy according to the present invention.

In Example 3, it was verified whether the intensity of OH radical self-luminescence could be predicted with high accuracy from the R signal, G signal, and B signal.

The visible light camera 2 and fuel used in this example were the same as in Examples 1 and 2 above. The R signal was extracted from images of flames of fuels with different hydrogen mixing ratios (α) and equivalence ratios, and the intensity of the R signal was obtained. In addition, the intensity of OH radical self-luminescence of the flame was measured by photographing the flame by attaching a filter that allows only OH self-luminescence to pass through an ICCD camera capable of measuring ultraviolet light.

FIG. 8(a) is a graph showing the relationship between the equivalence ratio (horizontal axis) and the intensity of the R signal (vertical axis), and FIG. 8(b) is a graph showing the relationship between the equivalence ratio (horizontal axis) and the OH radical self-luminescence. It is a graph showing the relationship with intensity (vertical axis). Comparing these two graphs, their shapes are very similar. Therefore, the present inventor investigated the correlation between the intensity of the R signal and the intensity of OH radical self-luminescence.

FIG. 9A is a graph showing the relationship between the intensity of the R signal (horizontal axis) and the intensity of OH radical self-luminescence (vertical axis). From this graph, a certain degree of correlation between the intensity of the R signal and the intensity of OH radical self-luminescence can be read.

FIG. 9(b) is a graph in which each fuel is classified into an air-fuel mixture with an equivalence ratio of less than 1 (lean group) and an air-fuel mixture with an equivalence ratio of 1 or more (rich group) in the graph shown in FIG. 9(a). be. From FIG. 9(b), it was found that the intensity of the R signal and the intensity of OH radical self-luminescence had a strong correlation between them by dividing them into only the lean group and the rich group. From the above, it was found that the OH self-emission intensity can be predicted with high accuracy from the R signal.

As described above, the equivalence ratio can be predicted from the ratio of the intensities of the CH radical self-luminescence and the C2 radical self-luminescence calculated from the G signal and the B signal. It was also found that the intensity of OH radical self-luminescence can be predicted with high accuracy from the R signal.

Note that the reason why there is a high correlation between the intensity of the R signal and the intensity of OH radical self-luminescence is considered as follows.

It is known that the reaction formula of OH ^* , which is the source of the intensity of OH radical self-luminescence, is as follows.

CH+O ₂ =CO+OH ^* ...(9)

When OH ^* transitions to the ground state, light (self-luminescence) is observed due to the following reaction.

OH ^* =OH+hν...(10)

It is known that in the reaction of formula (9), the influence of O ₂ is greater than that of CH. In the high temperature field, O ₂ was dissociated into oxygen atoms O, and the wavelengths of self-luminescence of O atoms were 557.7 nm and 630 nm. Since these two wavelength bands are included in the wavelength band of the R signal, it is considered that the self-emission intensity of OH and the intensity of the R signal have a high correlation.

1 Combustion diagnosis system 2 Visible light camera 3 Combustion diagnosis device 30 Auxiliary storage device 31 Image acquisition unit 32 Background light removal unit 33 Signal extraction unit 331 R signal extraction unit 332 G signal extraction unit 333 R signal extraction unit 34 Combustion diagnosis unit 341 Combustion Temperature diagnosis section 342 Burning rate diagnosis section 343 Equivalence ratio diagnosis section

Claims (8)

A combustion diagnosis device that diagnoses the combustion state of the flame based on an image of the flame captured by a visible light camera,
a signal extraction unit that extracts signals in one or more specific wavelength bands from the flame portion of the image;
a combustion diagnosis section that diagnoses the combustion state based on the signal in the specific wavelength band;
A combustion diagnostic device equipped with. The signal extraction section includes:
a G signal extraction unit that extracts the G signal;
a B signal extraction unit that extracts the B signal;
Equipped with
The combustion diagnosis section includes:
The combustion diagnosis device according to claim 1, further comprising an equivalence ratio diagnosis section that diagnoses the equivalence ratio of fuel in the flame as the combustion state based on the G signal and the B signal. The equivalence ratio diagnosis section is
3. The combustion diagnosis device according to claim 2, wherein each intensity of CH radical self-emission and C2 radical self-emission in the flame is calculated from the G signal and the B signal, and the equivalence ratio is diagnosed based on the intensities. The signal extraction section includes:
comprising an R signal extraction section that extracts the R signal,
The combustion diagnosis section includes:
The combustion diagnostic device according to claim 1, further comprising a combustion temperature diagnostic section that diagnoses the combustion temperature of the flame based on the R signal. The signal extraction section includes:
comprising an R signal extraction section that extracts the R signal,
The combustion diagnosis section includes:
The combustion diagnostic device according to claim 2, wherein the intensity of OH radical self-luminescence in the flame is calculated based on the R signal and the equivalence ratio. The combustion diagnosis section includes:
The combustion diagnosis device according to claim 5, further comprising a combustion rate diagnosis section that diagnoses the combustion rate of the flame based on the intensity of the OH radical self-luminescence. a visible light camera that captures images of the flame;
a combustion diagnosis device that diagnoses the combustion state of the flame based on an image of the flame captured by the visible light camera;
A combustion diagnosis system comprising:
A combustion diagnosis system, wherein the combustion diagnosis device is the combustion diagnosis device according to any one of claims 1 to 6. A combustion diagnosis program that causes a computer to operate as the combustion diagnosis apparatus according to any one of claims 1 to 6.