A method for simultaneously detecting two-dimensional flame and water wall temperature distribution of a power plant boiler

Abstract

The application provides a method for simultaneously detecting two-dimensional flame and water wall temperature distribution of a power station boiler, which obtains visible light image and infrared image of the flame by using an image detection method, obtains radiation intensity information of the flame in two spectral bands of visible light and infrared, reconstructs the flame temperature distribution by using the visible light band radiation information, reconstructs the water wall temperature distribution by using the infrared band information, decouples the flame radiation and the water wall radiation, and realizes simultaneous detection of the flame temperature and the water wall temperature distribution. The image detection method of the application can intuitively and quickly monitor the heating surface wall temperature change rate and wall temperature deviation, prevent boiler tube explosion and leakage, and significantly improve the safety and economy of the boiler operation.

Description

Technical Field

[0001] This invention belongs to the field of combustion detection technology, specifically a method for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler. Background Technology

[0002] During deep peak-shaving operation of boilers, the rate of change and deviation of the heating surface wall temperature easily exceed the limit, significantly increasing the probability of tube rupture and leakage. Therefore, monitoring the heating surface wall temperature is a necessary means to prevent overheating and ensure the safe and stable operation of the unit. However, due to constraints from local resources and coal prices, many coal-fired power plants have begun to blend a large proportion of economical coal types that are prone to slagging. Severe slagging and fouling of the boiler heating surface seriously affects the safety of combustion and hydrodynamics in the furnace, posing new demands and challenges for wall temperature detection technology.

[0003] Current methods for detecting water-cooled wall temperature primarily involve using thermocouples at selected points to measure the temperature on the back-fire side of the furnace tubes. However, due to limitations in the placement of these measurement points, accurate wall temperature distribution is difficult to obtain. Methods using mathematical models to indirectly calculate wall temperature distribution have been widely adopted; however, the accuracy of these calculations needs further improvement due to the variability and uncertainty of the input variables. While acoustic methods can achieve online detection of wall temperature distribution, the noise generated by high-speed flue gas significantly increases measurement errors. Furthermore, the high flame temperature and large amount of dust in power plant boilers make it difficult for traditional thermocouple temperature measurement methods to obtain accurate flame temperatures. Additionally, thermocouples are point measurements and cannot provide a comprehensive temperature field distribution.

[0004] Radiation thermometry is a non-contact detection method with significant technical advantages and widespread applications in high-temperature measurement scenarios. Its principle is to reconstruct the source term distribution within the furnace by capturing radiation intensity information at the furnace boundary. The challenge in monitoring boiler heating surface wall temperature using radiation principles lies in the fact that the heating surface is covered by a pulverized coal flame, which is a complex mixed medium of absorption, emission, and scattering. The discontinuous absorption and emission of triatomic gases such as water and carbon dioxide, the continuous emission, scattering, and absorption of particles such as ash and carbon black, and the continuous emission and reflection from the wall surface all interact and interfere with each other. Obtaining the true wall temperature requires solving scientific problems such as flame spectral characteristic identification, solving for the combined flame spectral parameters and wall spectral emissivity, and filtering out flame self-emission radiation. Furthermore, in power plant boilers, the water-cooled walls are covered by flames, and the flame temperature is much higher than the water-cooled wall temperature. The radiation energy information of the water-cooled wall is completely obscured by the flame radiation energy, making it difficult to simultaneously reconstruct the flame temperature and water-cooled wall temperature using radiation energy information from a single band. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler. The method acquires visible light and infrared images of the flame through image detection, obtains boundary radiation intensity information of the flame in the visible light and infrared spectral bands, and decouples and solves the flame radiation and wall radiation received by the detector by combining the inverse radiation problem solution method, thereby achieving simultaneous online detection of the flame temperature and wall temperature distribution.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler, the specific steps of which are as follows:

[0007] S1 simultaneously acquires visible light and infrared images at a certain height section inside the furnace of the power plant boiler;

[0008] S2 obtains the monochromatic radiation intensity matrix of all pixels in the middle row of the visible light image at the corresponding wavelength. λ1 ;

[0009] Obtain the monochromatic radiation intensity matrix I of all pixels G values ​​in the middle row of a visible light image at the corresponding wavelength. λ2 ;

[0010] Obtain the monochromatic radiation intensity matrix I of the temperature of all pixels in the middle row of the infrared image at the corresponding wavelength. λ3 ;

[0011] S3 utilizes the monochromatic radiation intensity matrix I λ1 The initial flame temperature distribution matrix T is obtained by matrix reconstruction and inverse solution of the flame radiation intensity calculation model. j Using the monochromatic radiation intensity matrix I λ2 The matrix reconstruction and inverse solution of the flame radiation intensity calculation model yielded the medium region absorption coefficient matrix K. λ Cross-iteration, based on the determined medium region absorption coefficient matrix K λ Obtain the true flame temperature distribution matrix T g ;

[0012] S4 substitutes the actual flame temperature distribution data and the absorption coefficient of the medium region into the flame radiation intensity calculation model to obtain the flame monochromatic radiation intensity data at infrared wavelengths; from the monochromatic radiation intensity matrix I... λ3 The monochromatic radiation intensity of the flame under infrared wavelength is removed from the data to obtain the monochromatic radiation intensity of the water-cooled wall. The monochromatic radiation intensity of the water-cooled wall is used to perform matrix reconstruction and inverse solution of the flame radiation intensity calculation model to obtain the water-cooled wall temperature distribution matrix.

[0013] Furthermore, in S1, an image detector is arranged at a certain height section inside the furnace of the power plant boiler. The image detector includes a visible light detector and an infrared detector.

[0014] Furthermore, in S2, a fitting relationship is established between the R and G values ​​of each pixel in the visible light image and the monochromatic radiation intensity at the corresponding wavelength. This fitting relationship is then used to obtain the monochromatic radiation intensity matrix I corresponding to the R and G values ​​of all pixels in the middle row of the visible light image. λ1 and I λ2 .

[0015] Furthermore, in S2, a fitting relationship is established between the temperature signal of each pixel in the infrared image and the monochromatic radiation intensity at the corresponding wavelength. Based on the fitting relationship, the monochromatic radiation intensity matrix I corresponding to the temperature values ​​of all pixels in the middle row of the infrared image is obtained. λ3 .

[0016] Furthermore, in S3, the two-dimensional cross-section of the furnace is divided into m grids to obtain spatial elements; the wall is divided into n grids to obtain wall elements; the detector is divided into P imaging elements. The radiation intensity received by the i-th imaging element from a certain line-of-sight direction is ignored, resulting in the following flame radiation intensity calculation model:

[0017]

[0018] Among them, I λ (i) represents the radiation intensity received by the i-th imaging unit, R d,gIλ (ji) represents the proportion of monochromatic radiation energy emitted by the j-th wall element and space element that is received by the i-th imaging element per unit area and unit angle, k λ m is the absorption coefficient of the medium region. -1 T g Represents the temperature of a space cell, ΔV g , represent the volume of the spatial unit, and C1 and C2 are Planck constants.

[0019] Furthermore, in S3,

[0020] (1) Using the monochromatic radiation intensity matrix I λ1 Matrix reconstruction was performed on the flame radiation intensity calculation model to obtain:

[0021]

[0022]

[0023]

[0024] in, This is a monochromatic radiation temperature imaging matrix; For temperature T j Blackbody radiation energy matrix at wavelength λ1, W·m -3 σ is the Boltzmann constant, k λ m is the absorption coefficient of the medium region. -1 Let the optical parameters that are uniformly distributed across the entire field be used as the absorption coefficient k of the medium region. λ The initial value for iteration;

[0025] Solving equation (4-1) inversely yields the initial flame temperature T for each pixel. j The initial flame temperature matrix T is constructed. j :

[0026]

[0027]

[0028] In the formula, D is an identity matrix with diagonal elements of 1;

[0029] (2) Using the monochromatic radiation intensity matrix I λ2 Matrix reconstruction was performed on the flame radiation intensity calculation model to obtain:

[0030]

[0031]

[0032]

[0033] The initial flame temperature T of each pixel j By introducing formula (4-4) and solving it inversely, the absorption coefficient matrix of the medium region is obtained.

[0034]

[0035] in, This is called the medium region absorption coefficient imaging matrix; σ is the absorption coefficient matrix of the medium region, where σ is the Boltzmann constant;

[0036] (3) Perform cross-iteration of steps (1) and (2) until the reconstructed values ​​of the medium region absorption coefficients of each grid no longer change, thus constructing a determined medium region absorption coefficient matrix. Based on the determined absorption coefficient of the medium region, the actual flame temperature is obtained, and the actual flame temperature distribution matrix T is constructed. g .

[0037] Furthermore, in S4, the actual flame temperature and medium region absorption coefficient of each grid are substituted into the flame radiation intensity calculation model to obtain flame monochromatic radiation intensity data at wavelengths of 3μm-5μm.

[0038] Furthermore, in S4, from the monochromatic radiation intensity matrix I λ3 After removing the flame monochromatic radiation intensity data from the dataset, the monochromatic radiation intensity of the water-cooled wall was obtained. The flame radiation intensity calculation model was then reconstructed using the water-cooled wall monochromatic radiation intensity, yielding the following result:

[0039]

[0040]

[0041]

[0042] By inversely solving equation (4-7), the water-cooled wall temperature of each grid is obtained, and the water-cooled wall temperature matrix is ​​constructed:

[0043]

[0044]

[0045] In the formula, This represents the matrix of total radiation intensity received by the infrared detector at wavelength λ3. This represents the flame radiation intensity matrix received by the infrared detector at wavelength λ3, in W·m. -3 ·sr -1 ; For temperature T j Blackbody radiation energy matrix at wavelength λ3, W·m -3 .

[0046] This invention provides a system for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler, comprising:

[0047] The image acquisition module is used to acquire visible light and infrared images of a certain height section inside the furnace of a power plant boiler;

[0048] The radiation intensity calculation module is used to obtain the monochromatic radiation intensity matrix I of all pixels in the middle row of a visible light image at the corresponding wavelength, based on their R and G values. λ1 and I λ2 ; Obtain the monochromatic radiation intensity matrix I of the temperature of all pixels in the middle row of the infrared image at the corresponding wavelength. λ3 ;

[0049] The flame temperature distribution calculation module is used to calculate the flame temperature distribution using the monochromatic radiation intensity matrix I. λ1The initial flame temperature distribution matrix T is obtained by matrix reconstruction and inverse solution of the flame radiation intensity calculation model. j Using the monochromatic radiation intensity matrix I λ2 The matrix reconstruction and inverse solution of the flame radiation intensity calculation model yielded the medium region absorption coefficient matrix K. λ Cross-iteration, based on the determined medium region absorption coefficient matrix K λ Obtain the true flame temperature distribution matrix T g ;

[0050] The water-cooled wall temperature distribution calculation module is used to substitute real flame temperature distribution data and the absorption coefficient of the medium region into the flame radiation intensity calculation model to obtain the flame monochromatic radiation intensity data at infrared wavelengths; based on the flame radiation intensity calculation model, it calculates the monochromatic radiation intensity matrix I... λ3 After removing the flame monochromatic radiation intensity data at infrared wavelengths from the data, matrix reconstruction and inverse solving are performed to obtain the water-cooled wall temperature distribution matrix.

[0051] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the above-described method for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler. Alternatively, when the processor executes the computer program, it implements the functions of each module in the above-described system for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler.

[0052] Compared with the prior art, the present invention has at least the following beneficial effects:

[0053] This invention discloses a method for simultaneously detecting the two-dimensional flame and water-cooled wall temperature distribution of a power plant boiler. It utilizes image detection methods to acquire visible light and infrared images of the flame, obtaining radiation intensity information in both the visible and infrared spectral bands. The flame temperature distribution is reconstructed using the visible light radiation information, and the water-cooled wall temperature distribution is reconstructed using the infrared information, thus decoupling flame radiation and water-cooled wall radiation. This enables simultaneous detection of both flame and water-cooled wall temperature distributions. The image detection method of this invention can intuitively and rapidly monitor the rate of change and deviation of the heated surface wall temperature, preventing boiler tube rupture and leakage, and significantly improving the safety and economy of boiler operation.

[0054] This invention employs an image detector to achieve non-contact continuous measurement of flame temperature, offering advantages such as high accuracy, reliable equipment, and real-time measurement capabilities. Traditional thermocouple temperature measurement methods can only obtain single-point temperatures and cannot measure the temperature field. This invention, by measuring the temperature distribution across a two-dimensional cross-section of the flame, can directly monitor the flame center position and deviation, guiding furnace air distribution adjustments and thus preventing uneven temperature distribution in the water-cooled walls caused by uneven burning.

[0055] During the operation of a power plant boiler, the combustion state of some representative sections can reflect the entire combustion characteristics of the furnace, such as the section where the burner is located, the section where the flue gas temperature is located at the bottom of the screen, and the section at the furnace outlet. By detecting the temperature distribution of these two-dimensional sections, the combustion state of the entire furnace can be characterized with fewer detection devices, reducing equipment investment and improving system reliability. Attached Figure Description

[0056] Figure 1 This is a system for simultaneously detecting the two-dimensional flame temperature and water-cooled wall temperature distribution in a power plant boiler, as described in a specific embodiment of the present invention.

[0057] Figure 2 The image is captured by a visible light detector in a specific embodiment of the present invention;

[0058] Figure 3 The image is captured by the infrared detector in a specific embodiment of the present invention;

[0059] Figure 4 This refers to the calibration data of the visible light detector in a specific embodiment of the present invention;

[0060] Figure 5 This refers to the calibration data of the infrared detector in a specific embodiment of the present invention;

[0061] Figure 6 This is the two-dimensional temperature distribution of the flame detected in a specific embodiment of the present invention;

[0062] Figure 7 This is a two-dimensional temperature distribution of the water-cooled wall detected in a specific embodiment of the present invention.

[0063] Figure 8 This refers to the water-cooled wall temperature measurement accuracy in a specific embodiment of the present invention. Detailed Implementation

[0064] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0065] like Figure 1 As shown, the walls surrounding the furnace of a power plant boiler are water-cooled walls, with a flowing working fluid inside to cool the water-cooled wall tubes. The center of the furnace contains a pulverized coal flame, the temperature of which is higher than that of the water-cooled walls. This invention provides a method for simultaneously detecting the two-dimensional flame and water-cooled wall temperature distributions in a power plant boiler. The specific steps are as follows:

[0066] S1 is equipped with an image detector at a certain height section inside the furnace of the power plant boiler. The visible light detector and the infrared detector respectively capture images of the flame inside the furnace and receive radiation from the flame and the water-cooled wall inside the furnace.

[0067] Among them, the visible light detector has a light-sensing wavelength of 380-780nm, and the captured images are as follows: Figure 2 As shown, each pixel in the image contains red, green, and blue primary color signal values; the infrared detector has a photosensitive wavelength of 3-5µm, and the captured image is as follows. Figure 3 As shown, each pixel in the image represents a temperature signal;

[0068] S2 calibrates the visible light detector and the infrared detector, obtaining the relationship curves with radiation intensity:

[0069] To recover the boundary radiation intensity received by the detector from the distorted image signal, a blackbody furnace was used to calibrate the visible light detector and the infrared detector, resulting in calibration curves for the visible light detector and the infrared detector, as shown below. Figure 4 , 5 As shown, the calibration curve fitting formulas for visible light detectors and infrared detectors are obtained. The specific form of the formulas will vary depending on the detector model.

[0070] Specifically: The calibration curve of a visible light detector is the fitting relationship between the red and green primary color signal values ​​of each pixel in a visible light image and the monochromatic radiation intensity at the corresponding wavelength, as shown below. Figure 4 As shown, the details are as follows:

[0071] I λ1 =10422.8×(R / S);

[0072] I λ2 =6630.9×(G / S);

[0073] Where R represents the red primary color signal value, G represents the green primary color signal value, S represents the detector exposure time, and I represents the red primary color signal value. λ1 This represents the monochromatic radiation intensity at wavelength λ1, where wavelength λ1 is the characteristic wavelength corresponding to the red primary color; I λ2 This represents the monochromatic radiation intensity at wavelength λ2, where wavelength λ2 is the characteristic wavelength corresponding to the green primary color.

[0074] The calibration curve of an infrared detector is the fitting relationship between the temperature signal of each pixel in an infrared image and the monochromatic radiation intensity at the corresponding wavelength, as shown in the figure. Figure 5 As shown, the details are as follows:

[0075] I λ3 = -7.65 + 3.39 × T - 62143.76 × T 2 +54.97×T 3 -0.016×T 4

[0076] Among them, I λ3This represents the monochromatic radiation intensity at an infrared wavelength λ3, where λ3 is the wavelength through which the center of the infrared detector passes.

[0077] S3 divides the two-dimensional cross-section of the furnace into m grids to obtain spatial elements; divides the wall into n grids to obtain wall elements; and divides the detector into P imaging elements. Considering the response characteristics of the two detectors to the received radiation wavelength, the radiation intensity received by the two detectors in a certain line-of-sight direction mainly includes the radiation intensity from the flame and the radiation intensity from the water-cooled wall, expressed as:

[0078] I λ (i)=I λ , v (i)+I λ , s (i) (1)

[0079] In the formula, I λ (i) represents the monochromatic radiation intensity received by the two detectors in the i-th imaging unit, I λ，v (i) represents the intensity of monochromatic radiation received from the flame, I λ，s (i) represents the received monochromatic radiation intensity from the water-cooled wall, in W·m -3 ·sr -1 For the detailed derivation process, please refer to the reference "Principles and Technology of Visual Detection of Flames Inside Furnaces".

[0080]

[0081]

[0082] In the formula, R d,gIλ (ji), R d,wIλ (ji) represents the proportion of monochromatic radiation energy emitted by the j-th wall element and spatial element that is received by the i-th imaging element per unit area and unit angle; k λ m is the absorption coefficient of the medium region. -1 , ε w T is the wall emissivity; g T w ΔV represents the temperature of the space element (i.e., the flame temperature) and the temperature of the wall element, respectively. g ,,ΔS w Let C1 and C2 represent the volume of the spatial unit and the area of ​​the wall unit, respectively. C1 and C2 are Planck constants with values ​​of 3.742 × 10⁻⁶. -16 W / m 2 and 1.4388×10 -2 m·K.

[0083] S4 calculates the monochromatic radiation intensity from the flame. Based on the monochromatic radiation intensity from the flame, the absorption coefficient of the medium region, and the blackbody radiation energy, the actual flame temperature distribution is obtained, as follows:

[0084] S4.1 For visible light detectors, since the flame temperature is much higher than the water-cooled wall temperature, the flame radiation in the visible light region is much greater than the water-cooled wall radiation. Therefore, the radiation share from the water-cooled wall can be ignored in the monochromatic radiation intensity received by the detector, and formula (1) can be simplified to the following formula:

[0085]

[0086] S4.2 uses a visible light detector to capture images of the flame, and extracts the R and G values ​​of the middle row of pixels from the flame image, such as... Figure 2 and Figure 3 For all pixels corresponding to the red line in the middle, the R and G values ​​are then converted into monochromatic radiation intensity I at the corresponding wavelength based on the calibration curve fitting formula of the visible light detector established in S2. λ1 and I λ2 Specifically, I is calculated based on the R-value and the fitted relationship. λ1 I is calculated based on the G value and the fitted relationship. λ2 ;

[0087] S4.3 Given a uniformly distributed optical parameter across the entire field as the absorption coefficient k of the medium region. λ The initial values ​​for the iteration are obtained according to formulas (4-1) to (4-3), using the monochromatic radiation intensity matrix. Matrix reconstruction of formula (4) yields the initial flame temperature distribution matrix T. j ;

[0088]

[0089]

[0090]

[0091] In the formula, This is a monochromatic radiation temperature imaging matrix. For temperature T j Blackbody radiation energy matrix at wavelength λ1, W·m -3 σ is the Boltzmann constant, with a value of 1.380649 × 10⁻⁶. -23 J / K, k λ m is the absorption coefficient of the medium region. -1 .

[0092] The inverse solution of formula (4-1) is as follows:

[0093]

[0094]

[0095] In the formula, D is an identity matrix with diagonal elements of 1.

[0096] S4.4 Utilizing monochromatic radiation intensity I λ2 By reconstructing the matrix of formula (4), the absorption coefficient matrix of the medium region is obtained.

[0097]

[0098]

[0099]

[0100] The initial flame temperature distribution T j Substituting into formulas (4-4) to (4-6), the inverse solution of formula (4-4) is as follows:

[0101]

[0102] In the formula, This is called the medium region absorption coefficient imaging matrix; Let be the absorption coefficient matrix of the medium region, representing the set of absorption coefficients of all media, and σ be the Boltzmann constant.

[0103] The calculations of S4.5 are iterated over S4.3 and S4.4 until the reconstructed value of the absorption coefficient in the medium region no longer changes, at which point the iteration converges, and the true flame temperature distribution matrix T can be obtained. g The result is as follows Figure 6 As shown.

[0104] S5 calculates the monochromatic radiation intensity of the flame at infrared wavelength λ3 based on the actual flame temperature data and the absorption coefficient of the medium region obtained in S4. The monochromatic radiation intensity of the flame at infrared wavelength λ3 is then subtracted from the total radiation intensity received by the infrared detector at wavelength λ3 to obtain the temperature distribution of the water-cooled wall. Specifically:

[0105] S5.1 In the 3-5μm band, there is no gas emission and absorption, and the radiation properties of the flame can be approximately considered to be consistent with those of the visible light band. Therefore, by substituting the actual flame temperature distribution and medium region absorption coefficient obtained in S4 into formula (4), the monochromatic radiation intensity of the flame at the infrared wavelength λ3 can be calculated.

[0106] S5.2 uses an infrared detector to capture images of the furnace interior, extracts the temperature value of the middle row of pixels from the images, and then converts the temperature signal into monochromatic radiation intensity I at the corresponding wavelength according to the calibration curve fitting formula of the infrared detector established in S2.λ3 Since the radiation from the wall and the flame are of equal magnitude in the infrared band, the radiation intensity received by the infrared detector includes both flame radiation and water-cooled wall radiation, thus satisfying:

[0107] I λ3 (i)=I λ3，v (i)+I λ3，s (i) (8)

[0108] S5.3 The monochromatic radiation intensity of the water-cooled wall for each pixel is obtained by filtering out the flame radiation portion received by the infrared detector at wavelength λ3 from the total radiation intensity received by the infrared detector at wavelength λ3, and the monochromatic radiation intensity matrix I of the water-cooled wall is constructed. λ3 From the monochromatic radiation intensity matrix I of the water-cooled wall λ3 The water-cooled wall temperature distribution was obtained through reconstruction:

[0109]

[0110]

[0111]

[0112] Solving equation (4-7) inversely yields equations (9) and (10), providing the water-cooled wall temperature for each pixel. A water-cooled wall temperature matrix is ​​then established, and the results are as follows: Figure 7 As shown:

[0113]

[0114]

[0115] In the formula, I λ3 I represents the matrix of total radiation intensity received by the infrared detector at wavelength λ3. λ3,v This represents the flame radiation intensity matrix received by the infrared detector at wavelength λ3, in W·m. -3 ·sr -1 ; For temperature T j Blackbody radiation energy matrix at wavelength λ3, W·m -3 .

[0116] Preferably, the visible light detector and the infrared detector are fixedly installed on the furnace wall to capture images of the furnace in real time, quickly reconstruct the flame temperature and water-cooled wall temperature distribution, and the two-dimensional temperature distribution refresh time is less than 5 seconds.

[0117] Preferably, in a specific embodiment of the present invention, the number of visible light detectors and infrared detectors can be four or more.

[0118] according to Figure 8 As shown, when the number of visible light detectors and infrared detectors is 2, the maximum deviation of the water-cooled wall temperature measurement result from the thermocouple measurement value is less than 30℃, and the error is less than 5%. When the number of visible light detectors and infrared detectors increases, the temperature measurement error will be further reduced.

[0119] The present invention also provides a system for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler, comprising:

[0120] The image acquisition module is used to acquire visible light and infrared images of a certain height section inside the furnace of a power plant boiler;

[0121] The radiation intensity calculation module is used to obtain the monochromatic radiation intensity matrix I of all pixels in the middle row of a visible light image at the corresponding wavelength, based on their R and G values. λ1 and I λ2 ; Obtain the monochromatic radiation intensity matrix I of the temperature of all pixels in the middle row of the infrared image at the corresponding wavelength. λ3 ;

[0122] The flame temperature distribution calculation module is used to calculate the flame temperature distribution using the monochromatic radiation intensity matrix I. λ1 The initial flame temperature distribution matrix T is obtained by matrix reconstruction and inverse solution of the flame radiation intensity calculation model. j Using the monochromatic radiation intensity matrix I λ2 The matrix reconstruction and inverse solution of the flame radiation intensity calculation model yielded the medium region absorption coefficient matrix K. λ Cross-iteration, based on the determined medium region absorption coefficient matrix K λ Obtain the true flame temperature distribution matrix T g ;

[0123] The water-cooled wall temperature distribution calculation module is used to substitute real flame temperature distribution data and the absorption coefficient of the medium region into the flame radiation intensity calculation model to obtain the flame monochromatic radiation intensity data at infrared wavelengths; based on the flame radiation intensity calculation model, it calculates the monochromatic radiation intensity matrix I... λ3 After removing the flame monochromatic radiation intensity data at infrared wavelengths from the data, matrix reconstruction and inverse solving are performed to obtain the water-cooled wall temperature distribution matrix.

[0124] The present invention also provides a terminal device, comprising: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the method for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler; or, when the processor executes the computer program, it implements the functions of each module in the system for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler.

[0125] A computer program can be divided into one or more modules / units, one or more modules / units are stored in memory and executed by a processor to complete the present invention.

[0126] Terminal devices can be computing devices such as desktop computers, laptops, handheld computers, and cloud servers. Terminal devices may include, but are not limited to, processors and memory.

[0127] The processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0128] The memory can be used to store computer programs and / or modules. The processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory, and by calling the data stored in the memory.

[0129] If the modules / units integrated into the terminal device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.

[0130] Based on this understanding, all or part of the processes in the above-described embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms.

[0131] Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in computer-readable media can be appropriately added to or removed according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

Claims

1. A method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler, characterized in that, The specific steps are as follows: S1 simultaneously acquires visible light and infrared images at a certain height section inside the furnace of the power plant boiler; S2 obtains the monochromatic radiation intensity matrix of the R values ​​of all pixels in the middle row of the visible light image at the corresponding wavelength. I λ1 ; Obtain the monochromatic radiance matrix of the G values ​​of all pixels in the middle row of a visible light image at the corresponding wavelength. I λ2 ; Obtain the monochromatic radiation intensity matrix of the temperature of all pixels in the middle row of the infrared image at the corresponding wavelength. I λ3 ; S3 utilizes a monochromatic radiation intensity matrix I λ1 The initial flame temperature distribution matrix is ​​obtained by matrix reconstruction and inverse solution of the flame radiation intensity calculation model. ; Using monochromatic radiation intensity matrix I λ2 The matrix of the flame radiation intensity calculation model is reconstructed and inversely solved to obtain the absorption coefficient matrix of the medium region. Cross-iteration, based on the determined absorption coefficient matrix of the medium region. Obtain the true flame temperature distribution matrix T g ; S4 substitutes the actual flame temperature distribution data and the absorption coefficient of the medium region into the flame radiation intensity calculation model to obtain the flame monochromatic radiation intensity data at infrared wavelengths; from the monochromatic radiation intensity matrix I λ3 The monochromatic radiation intensity of the flame under infrared wavelength is removed from the data to obtain the monochromatic radiation intensity of the water-cooled wall. The monochromatic radiation intensity of the water-cooled wall is used to perform matrix reconstruction and inverse solution of the flame radiation intensity calculation model to obtain the water-cooled wall temperature distribution matrix.

2. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 1, characterized in that, In S1, an image detector is arranged at a certain height section inside the furnace of the power plant boiler. The image detector includes a visible light detector and an infrared detector.

3. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 1, characterized in that, In S2, a fitting relationship is established between the R and G values ​​of each pixel in the visible light image and the monochromatic radiation intensity at the corresponding wavelength. This fitting relationship is then used to obtain the monochromatic radiation intensity matrix corresponding to the R and G values ​​of all pixels in the middle row of the visible light image. I λ1 and I λ2 .

4. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 1, characterized in that, In S2, a fitting relationship is established between the temperature signal of each pixel in the infrared image and the monochromatic radiation intensity at the corresponding wavelength. Based on the fitting relationship, a monochromatic radiation intensity matrix corresponding to the temperature values ​​of all pixels in the middle row of the infrared image is obtained. I λ3 .

5. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 1, characterized in that, In S3, the two-dimensional cross-section of the furnace is divided into m By dividing the grid into grids, spatial units are obtained; Divide the wall into n grids to obtain wall elements; detector Divided into P imaging units, from a certain line of sight, the first... i Ignoring the radiation share from the water-cooled wall in the radiation intensity received by each imaging unit, the specific calculation model for flame radiation intensity is as follows: （4） in, I λ ( i ) indicates the first i The radiation intensity received by each imaging unit, R d,gIλ ( ji ) indicates the first j The monochromatic radiation emitted by each wall unit and space unit is... i The share of data received per unit area and per unit angle by each imaging unit The absorption coefficient of the medium region. T g C1 and C2 represent the temperature of a space cell, respectively, and the volume of the space cell. C1 and C2 are Planck constants.

6. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 5, characterized in that, In S3 (1) Using the monochromatic radiation intensity matrix I λ1 Matrix reconstruction was performed on the flame radiation intensity calculation model to obtain: (4-1) (4-2) (4-3) in, This is a monochromatic radiation temperature imaging matrix; For temperature wavelength λ Blackbody radiation energy matrix at 1, σ Boltzmann's constant, Let the absorption coefficient of the medium be the optical parameter with uniform distribution across the entire field. Initial value for iteration; wavelength λ 1 represents the characteristic wavelength corresponding to the red primary color; Solving equation (4-1) inversely yields the initial flame temperature for each pixel. The initial flame temperature matrix is ​​constructed. : (5) (6) In the formula, D It is an identity matrix with diagonal elements all equal to 1. (2) Using the monochromatic radiation intensity matrix I λ2 Matrix reconstruction was performed on the flame radiation intensity calculation model to obtain: (4-4) (4-5) (4-6) Initial flame temperature of each pixel By introducing formula (4-4) and solving it inversely, the absorption coefficient matrix of the medium region is obtained. : (7) in, This is called the medium region absorption coefficient imaging matrix; This is the absorption coefficient matrix of the medium region. σ λ is the Boltzmann constant; wavelength λ2 is the characteristic wavelength corresponding to the green primary color; (3) Perform cross-iteration of steps (1) and (2) until the reconstructed values ​​of the medium region absorption coefficients of each grid no longer change, and construct a determined medium region absorption coefficient matrix. Based on the determined absorption coefficient of the medium region, the actual flame temperature is obtained, and a matrix representing the actual flame temperature distribution is constructed. T g .

7. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 5, characterized in that, In S4, the actual flame temperature and medium region absorption coefficient of each grid are substituted into the flame radiation intensity calculation model to obtain flame monochromatic radiation intensity data at wavelengths of 3μm-5μm.

8. The method for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler according to claim 7, characterized in that, In S4, from the monochromatic radiation intensity matrix I λ3 After removing the flame monochromatic radiation intensity data from the dataset, the monochromatic radiation intensity of the water-cooled wall was obtained. The flame radiation intensity calculation model was then reconstructed using the water-cooled wall monochromatic radiation intensity, yielding the following result: (4-7) (4-8) (4-9) By inversely solving equation (4-7), the water-cooled wall temperature of each grid is obtained, and the water-cooled wall temperature matrix is ​​constructed: (8) (9) In the formula, Indicates the infrared detector at wavelength λ The complete radiation intensity matrix received under condition 3. Indicates the infrared detector at wavelength λ The received flame radiation intensity matrix under 3; For temperature wavelength λ Blackbody radiation energy matrix under 3, wavelength λ 3 represents the wavelength passing through the center of the infrared detector.

9. A system for simultaneously detecting the temperature distribution of a two-dimensional flame and water-cooled wall in a power plant boiler, characterized in that, include: The image acquisition module is used to acquire visible light and infrared images of a certain height section inside the furnace of a power plant boiler; The radiation intensity calculation module is used to obtain the monochromatic radiation intensity matrix of all pixels in the middle row of a visible light image at the corresponding wavelength, based on their R and G values. I λ1 and I λ2 Obtain the monochromatic radiation intensity matrix of all pixels in the middle row of an infrared image at the corresponding wavelength. I λ3 ; The flame temperature distribution calculation module is used to calculate the flame temperature distribution using a monochromatic radiation intensity matrix. I λ1 The initial flame temperature distribution matrix is ​​obtained by matrix reconstruction and inverse solution of the flame radiation intensity calculation model. Using the monochromatic radiation intensity matrix I λ2 The matrix of the flame radiation intensity calculation model is reconstructed and inversely solved to obtain the absorption coefficient matrix of the medium region. Cross-iteration, based on the determined absorption coefficient matrix of the medium region. Obtain the true flame temperature distribution matrix T g ; The water-cooled wall temperature distribution calculation module is used to substitute the actual flame temperature distribution data and the absorption coefficient of the medium region into the flame radiation intensity calculation model to obtain the flame monochromatic radiation intensity data under infrared wavelength. Based on the flame radiation intensity calculation model, from the monochromatic radiation intensity matrix I λ3 After removing the flame monochromatic radiation intensity data at infrared wavelengths from the data, matrix reconstruction and inverse solving are performed to obtain the water-cooled wall temperature distribution matrix.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler as described in any one of claims 1-8; or, when the processor executes the computer program, it implements the functions of each module in the system for simultaneously detecting the temperature distribution of a two-dimensional flame and a water-cooled wall in a power plant boiler as described in claim 9.

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