JP2014115096A - Temperature detection method, temperature detection device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the local temperature more accurately when temperature is detected on the basis of the receiving light intensity.SOLUTION: A temperature detection method in which temperature is detected on the basis of the receiving light intensity includes: a light receiving intensity measuring step for inserting an optical fiber into an object domain of temperature detection and measuring the light receiving intensity along a light receiving direction of the optical fiber at every predetermined interval; and a temperature detection step for figuring out the temperature at every predetermined interval on the basis of the light receiving intensity obtained by the light receiving intensity measuring step.

Description

  The present invention relates to a temperature detection method, a temperature detection device, and a program.

  As a temperature detection method, for example, a method of calculating a temperature from received light intensity such as a two-color method is known. For example, Patent Document 1 describes that the flame temperature can be known from the emission characteristics of soot (soot or carbon) using the relation of Planck's radiation law.

Japanese Patent No. 3083633

When there are a plurality of heat sources, there is a possibility that the local temperature cannot be obtained accurately by the method of calculating the temperature from the received light intensity.
For example, when a temperature detection target region including a large number of heat sources (for example, each pulverized coal particle) such as in a furnace of a pulverized coal fired boiler is divided into predetermined pitches and the temperature of each pitch is obtained, the light receiving range is larger than the pitch. If it is larger (longer), heat sources located at other pitches such as adjacent pitches are included in the light receiving range. For this reason, when calculating the temperature from the received light intensity, there is a possibility that the overall temperature over a plurality of pitches may be calculated instead of the temperature for each pitch.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a temperature detection method, a temperature detection device, and a program capable of more accurately detecting a local temperature. .

  The present invention has been made to solve the above-described problems, and a temperature detection method according to an aspect of the present invention includes inserting an optical fiber into a target region and receiving light at predetermined intervals along the light receiving direction of the optical fiber. A received light intensity measuring step for measuring the intensity; and a temperature detecting step for obtaining a temperature at each predetermined interval based on the received light intensity obtained in the received light intensity measuring step.

  The temperature detection method according to another aspect of the present invention is the temperature detection method described above, wherein, in the temperature detection step, the temperature calculated from the light reception intensity obtained in the light reception intensity measurement step, and the predetermined The temperature of each section is detected in order based on the temperature of the section where the temperature has been detected among the sections for each interval.

  A temperature detection method according to another aspect of the present invention is the above-described temperature detection method, and is a light reception method for evaluating a change in received light intensity when the optical fiber is moved along the light receiving direction of the optical fiber. An intensity change evaluation step, wherein in the temperature detection step, the temperature at the measurement point at which the change in the received light intensity is evaluated to be sufficiently small in the received light intensity change evaluation step is detected, and the obtained temperature is used as the initial temperature. The temperature of each section is detected in order.

  A temperature detection method according to another aspect of the present invention is the above-described temperature detection method, and includes a temperature measurement step of measuring a temperature of the section set as an initial section. In the temperature detection step, The temperature obtained in the temperature measurement step is detected in order using the temperature obtained in the temperature measurement step as an initial temperature.

  A temperature detection method according to another aspect of the present invention is the above-described temperature detection method, and a flame surface temperature detection step of detecting a temperature of the flame surface when the target region includes a flame surface; And a temperature evaluation step for evaluating the temperature obtained in the temperature detection step based on the flame surface temperature obtained in the flame surface temperature detection step.

  The temperature detection method according to another aspect of the present invention is the above-described temperature detection method, wherein in the temperature detection step, the temperature is detected in each section obtained by dividing the substantial light receiving distance at the predetermined intervals. With respect to the already completed section, the radiant energy in the section is weighted by the transmittance according to the distance between the light receiving portion of the optical fiber and the section, and is excluded from the received light energy based on the received light intensity obtained in the received light intensity measurement step. Then, based on the obtained received light energy, the temperature of the section whose temperature is to be calculated is calculated.

  In addition, a temperature detection device according to another aspect of the present invention includes a received light intensity measuring unit that measures received light intensity at predetermined intervals along a light receiving direction of the optical fiber using an optical fiber inserted into a target region. And a temperature detection unit that obtains the temperature at each predetermined interval based on the received light intensity acquired by the received light intensity measurement unit.

  According to another aspect of the present invention, there is provided a program for measuring a received light intensity at predetermined intervals along a light receiving direction of the optical fiber by using an optical fiber inserted into a target area in a computer as a temperature detecting device. And a temperature detecting step for obtaining a temperature at each predetermined interval based on the received light intensity obtained in the received light intensity measuring step.

  According to the present invention, the local temperature can be detected more accurately.

It is a schematic block diagram which shows the function structure of the temperature detection apparatus in the 1st Embodiment of this invention. It is a schematic block diagram of the boiler containing the inside of a furnace as an example of the object area | region in the embodiment. It is explanatory drawing which shows the example of the area where the temperature detection part in the embodiment detects temperature. It is explanatory drawing which shows the example of the temperature detection object area in the temperature detection apparatus of the embodiment. It is a schematic block diagram which shows the function structure of the temperature detection apparatus in the 2nd Embodiment of this invention. It is explanatory drawing which shows the example of the substantial light reception distance of the optical fiber in the embodiment. It is explanatory drawing which shows the example of the area where the temperature detection part in the embodiment detects temperature. It is explanatory drawing which shows the example of the contribution in the same embodiment. It is a schematic block diagram which shows the function structure of the temperature detection apparatus in the 3rd Embodiment of this invention. It is a schematic block diagram which shows the function structure of the temperature detection apparatus in the 4th Embodiment of this invention.

<First Embodiment>
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic block diagram showing a functional configuration of a temperature detection device according to the first embodiment of the present invention. In FIG. 1, the temperature detection device 1 includes a received light intensity measurement unit 11 and a temperature detection unit 12.
The temperature detection device 1 measures the temperature of the target region at predetermined intervals.
The target region here is a region that is a target for detecting temperature. Below, although the case where an object field is in the furnace of a pulverized coal fired boiler is explained as an example, it is not restricted to this. The temperature detection device 1 can detect the temperature using various regions in which the temperature can be calculated from the received light intensity as target regions.

The received light intensity measuring unit 11 includes an optical fiber, and measures the received light intensity at predetermined intervals along the light receiving direction of the optical fiber using the optical fiber inserted into the target region.
In addition, the light here is an electromagnetic wave that is not limited to visible light, and may be infrared rays in particular. For example, when the temperature detection unit 12 detects the temperature using the two-color method, the received light intensity measurement unit 11 detects the received light intensity of infrared light having a wavelength of 1.35 micrometers (μm) and infrared light having a wavelength of 1.55 micrometers. The received light intensity may be measured.
The process performed by the received light intensity measurement unit 11 corresponds to an example of a process in the received light intensity measurement step.

The temperature detection unit 12 obtains a temperature for each predetermined interval based on the received light intensity acquired by the received light intensity measurement unit 11. In particular, the temperature detection unit 12 determines the temperature of each section based on the temperature calculated from the received light intensity acquired by the received light intensity measurement unit 11 and the temperature of the section where the temperature has been detected among the sections for each predetermined interval. Are detected in order.
The process performed by the temperature detection unit 12 corresponds to an example of a process in the temperature detection step.

Here, with reference to FIGS. 2-6, the process which the light reception intensity measurement part 11 and the temperature detection part 12 perform is demonstrated further.
FIG. 2 is a schematic configuration diagram of a boiler including the inside of a furnace as an example of the target region. In the figure, a burner 901, a furnace core tube 902, a heater chamber 903, and a viewing window 904 provided in the boiler 900 are shown. Further, the optical fiber included in the received light intensity measurement unit 11 is inserted into the boiler 900 from the viewing window 904.

The boiler 900 is a pulverized coal fired boiler, and generates heat by burning the pulverized coal.
The burner 901 mixes the pulverized coal and primary air supplied through the path AR11 and the secondary air supplied through the path AR12, diffuses them into the furnace of the core tube 902, and burns them.
The core tube 902 has a furnace as a combustion chamber in the core tube 902 itself, and burns pulverized coal from the burner 901 in the furnace. The inside of the furnace core tube 902 corresponds to an example of the target region, and the burning pulverized coal, the heated pulverized coal, and the heated furnace wall are heat sources. In particular, the temperature detection device 1 detects the particle temperature of pulverized coal in the furnace for each predetermined section.
The heater chamber 903 heats the inside of the furnace in order to burn the pulverized coal diffused in the furnace.
The observation window 904 is provided for observing the inside from the outside of the boiler 900, and in particular, serves as an insertion port when the optical fiber of the received light intensity measuring unit 11 is inserted into the furnace tube 902.

FIG. 3 is an explanatory diagram illustrating an example of a section in which the temperature detection unit 12 detects a temperature. The horizontal axis of the figure shows the distance from the burner, and the position of the furnace wall is shown on the right side of the figure.
In FIG. 3, measurement timings (0) to (4) are shown, and the tip, which is the light receiving portion of the optical fiber, of the light receiving intensity measuring unit 11 is moved backward by a distance D11. Distance D11 is corresponds to an example of the measurement interval, the temperature of each measurement interval is expressed as the temperature T ₁ through T _4. Further, the received light intensity in the measurement timing (0) - (4) are respectively a _I f0 _{~I f4.}
Note that the positions of the light receiving portions at the measurement timings (0) to (4) are denoted by P0 to P4, respectively.

The received light intensity of the optical fiber of the received light intensity measurement unit 11 is the received light intensity from all heat sources included in the received light range. Therefore, if the received light intensity is directly converted into temperature, the temperature for one section of the measurement interval cannot be detected. For example, the received light intensity _{If4 at} the measurement timing (4) is the received light intensity from the entire heat source located in the light receiving range from the furnace wall to the light receiving portion. Therefore, it is impossible to obtain a temperature T ₄ of the one section immediately measured distance from the light intensity I _f4.

Therefore, the temperature detection unit 12 detects the temperature for one section from the received light intensity measured by the received light intensity measurement unit 11 by excluding components related to the temperature detected section.
Hereinafter, the process performed by the temperature detection unit 12 will be described in more detail. First, a mathematical expression (model) used by the temperature detection unit 12 to detect (calculate) the temperature will be described.
First, from the Lambert-Beer law, the transmittance _I 1 / _{I 0} divided by the transmitted light intensity _{I 1} incident light intensity _{I 0} is as shown in equation (1).

However, e shows the base of natural logarithm. Further, σ represents an absorption cross section. C represents the particle number density. D represents the optical path length.
Using the notation on the right side of the expression (1) for the transmittance, the light receiving intensity of the light having the wavelengths λ ₁ and λ ₂ (the radiation intensity received at the light receiving part) in the light receiving part of the optical fiber of the light receiving intensity measuring unit 11 ) I _λ1 and I _λ2 are expressed as shown in Equation (2).

However, n (n is a positive integer) indicates the number of heat sources in the furnace. _{Also, I iλ1 (1 ≦ i ≦} n) indicates from the i-th heat source, the radiation intensity of the light of wavelength lambda _1. In the description of the specification, superscripts and subscripts after the second stage are omitted. _{Also, I iλ2 (1 ≦ i ≦} n) indicates from the i-th heat source, the radiation intensity of the light of wavelength lambda _2. Further, d _i (1 ≦ i ≦ n) represents an optical path length from the i-th heat source to the light receiving portion.
Also, I _Wramuda1 shows from the furnace wall, the radiation intensity of the light of wavelength lambda _1. Also, I _Wramuda2 shows from the furnace wall, the radiation intensity of the light of wavelength lambda _2. Further, d _W indicates the optical path length from the furnace wall to the light receiving portion.
Here, the radiant intensity is the thermal radiation energy per unit solid angle per unit projected area that is emitted in a specific direction.
Here, the thermal radiation energy E _lambda light wavelength lambda, is represented by equation (3) using the circular constant [pi.

Here, I _λ indicates the radiation intensity of light having a wavelength λ.
Using equation (3), equation (2) can be transformed into equation (4).

Here, E _λ1 indicates the light reception energy of light having the wavelength λ ₁ (heat radiation energy received at the light receiving portion). Also, E _.lambda.2 shows light energy of a wavelength lambda ₂ of light. _{Also, E iλ1 (1 ≦ i ≦} n) indicates from the i-th heat source, the thermal radiation energy at a wavelength lambda ₁ of light. _{Also, E iλ2 (1 ≦ i ≦} n) indicates from the i-th heat source, the wavelength lambda ₂ of the thermal radiation energy of light. Also, E _Wramuda1 shows from the furnace wall, the thermal radiation energy at a wavelength lambda ₁ of light. Also, E _Wramuda2 shows from the furnace wall, the wavelength lambda ₂ of the thermal radiation energy of light.
Here, according to Planck's radiation law, the thermal radiant energy E _λ of the light having the wavelength _λ is expressed as in Equation (5).

Here, ε _λ indicates the spectral emissivity at the wavelength λ. T represents the true surface temperature of the heat source. C ₁ represents a first constant of radiation (plank). Also, _{C 2} is the radiation (Planck) shows a second constant.
Here, Equation (6) is established from the Wien approximation.

That is, when e ^{(C / λT)} is sufficiently larger than 1, e ^{(C / λT)} −1 can be approximated by e ^{(C / λT)} .
Applying the approximation rule of equation (6) to equation (5) yields equation (7).

  Using this equation (7), equation (4) can be transformed into equation (8).

Further, when the wavelengths λ ₁ and λ ₂ are close to each other, the wavelength dependence of the emissivity can be ignored, and can be approximated as shown in Expression (9).

From the equations (8) and (9), the ratio R (T) of the radiant heat energy between the wavelengths λ ₁ and λ ₂ is expressed as the equation (10).

Here, exp indicates a power of e.
Moreover, the conversion formula from the radiant intensity to the temperature in the two-color method is shown as the formula (11).

  By substituting equation (10) into equation (11), equation (12) is obtained.

However, in the formula (12), the subscripts 1 to n in the formula (8) are replaced with the subscripts i to 0.
The temperature detection unit 12 detects the temperature for one section of the measurement interval using the equation (12).
For example, in the example of FIG. 3, the temperature detection unit 12 is previously obtains the temperature T _w of the furnace wall.
And the temperature detection part 12 makes the value of the subscript i in Formula (12) 0 first. The temperature detection unit 12, the distance d _w from the position P0 to the furnace wall, and the temperature T _w of the furnace wall, the distance d ₀ to a section between the position P0 and the furnace wall from the position P0, the received light intensity The temperature T obtained from _If0 is substituted into equation (12). In addition, the values of the coefficients C ₁ , C ₂ , λ ₁ , λ ₂ , and σC (product of σ and C) in Expression (12) are all known.

Then, the unknown variable in the equation (12) is only the temperature T ₀ , and the temperature detection unit 12 acquires the temperature T ₀ by solving the equation (12).
The temperature T _w of the furnace wall is measured by providing a thermometer for example a furnace wall. Further, the distance d ₀ to a section between the position P0 and the furnace wall from the position P0 is left to the small section setting negligibly the section width, for example, half the distance from the position P0 to the furnace wall Is the distance d ₀ . The same applies to the other sections described below.

Also, the value of σC is calculated, for example, from actual measurement of transmittance in the furnace. Alternatively, the temperature detection unit 12 acquires the radiation intensity and the light reception intensity at a certain distance, and uses the Lambert-Beer law to transmit the transmittances e ^{(−σCdw) 1} , e ^{(−σCd0) 2,. (−σCdi)} may be obtained.

Next, the temperature detection unit 12 sets the value of the subscript i in Equation (12) to 1. The temperature detecting section 12, as in the case of the determining the temperature _{T 0, d w, T w} , d 0, T 0, the values of _{d 1,} and the temperature T obtained from the received light intensity _{I f1} Substitute into equation (12).
Then, the unknown variable is only the temperatures _{T 1} in the formula (12), the temperature detecting section 12, by solving equation (12), acquires the temperature _{T 1} of.

Furthermore, the temperature detection unit 12 sets the value of the subscript i in Equation (12) to 2. Further, the temperature detection unit 12 receives each value of d _w , T _w , d ₀ , T ₀ , d ₁ , T ₁ , d ₂ , and light reception in the same manner as in the case of obtaining the temperatures T ₀ and T _1. The temperature T obtained from the intensity _If2 is substituted into the equation (12).
Then, the unknown variable is only the temperature _{T 2} in the formula (12), the temperature detecting section 12, by solving equation (12), acquires the temperature _{T 2.}
Similarly, the temperature detector _12, T _{3, T} 4, will get a ... in order.

FIG. 4 is an explanatory diagram illustrating an example of a temperature detection target section in the temperature detection device 1. In the example of the figure, the temperature detecting device 1, the temperature _T of the section of each measurement interval of the light-receiving intensity _0, T _{1, T} 2, _{T 3,} T 4, detects the · · · _{T n.} As described with reference to FIG. 3, the temperature sensing device 1, the temperature _{T 0, T 1, T 2} , T 3, T 4, it will detect the order of · · · _{T n.}

As described above, the received light intensity measurement unit 11 measures the received light intensity at predetermined intervals along the light receiving direction of the optical fiber using the optical fiber inserted into the target region. And the temperature detection part 12 calculates | requires the temperature for every predetermined interval based on the received light intensity which the received light intensity measurement part acquired.
Thereby, the temperature detection part 12 can detect the temperature for every predetermined interval. In this regard, the temperature detection unit 12 can detect the local temperature more accurately.

Further, the temperature detection unit 12 is configured to calculate the temperature of each section based on the temperature calculated from the received light intensity measured by the received light intensity measurement unit 11 and the temperature of the section in which the temperature has been detected among the sections for each predetermined interval. Are detected in order.
Thereby, the temperature detection part 12 can reduce the influence of the temperature in the area which has detected temperature, and can detect the temperature of the area for temperature detection more correctly.

  In the above description, the temperature detection unit 12 detects the temperature using a model based on the two-color method. However, the model used by the temperature detection unit 12 is not limited to this, and the temperature can be detected from the received light intensity. Any model can be used. For example, the temperature detection unit 12 may detect the temperature using a model based on the monochromatic method.

  In the above description, the temperature detection unit 12 substitutes the detected temperature into the model to reduce the influence of the temperature in the section in which the temperature has been detected. However, the temperature detection unit 12 You may make it reduce the influence of the temperature in the area where temperature was detected using the detected light reception intensity | strength. For example, the temperature detection unit 12 subtracts the component of light reception from the section in which the temperature has been detected from the light reception intensity measured by the light reception intensity measurement unit 11, and the light reception intensity from the section that is the temperature detection target. And the received light intensity obtained may be converted into temperature.

  Note that the temperature detection apparatus 1 may perform temperature detection for each section as in the example of FIG. 4 a plurality of times while shifting the measurement position. Thereby, the temperature detection apparatus 1 can detect the temperature of each part in a two-dimensional mesh or a three-dimensional mesh.

<Second Embodiment>
FIG. 5 is a schematic block diagram showing a functional configuration of the temperature detection device according to the second embodiment of the present invention. In the figure, the temperature detection device 2 includes a light reception intensity measurement unit 11, a temperature detection unit 22, a pulverized coal concentration acquisition unit 23, a substantial light reception distance acquisition unit 24, and a light reception intensity change evaluation unit 25. .
5, parts having the same functions corresponding to the respective parts in FIG. 1 are denoted by the same reference numerals (11), and description thereof is omitted.

Similar to the temperature detection device 1 (FIG. 1), the temperature detection device 2 detects the temperature of the target region at predetermined intervals. However, the temperature detection device 2 is different from the temperature detection device 1 in that temperature detection is performed by setting a substantial light receiving distance.
The received light intensity change evaluation unit 25 evaluates the change in received light intensity when the optical fiber of the received light intensity measurement unit 11 is moved along the light receiving direction of the optical fiber. For example, when the received light intensity measurement unit 11 measures the received light intensity at every measurement interval, the received light intensity change evaluation unit 25 evaluates the change in the received light intensity at each measurement interval. More specifically, the received light intensity change evaluation unit 25 has a sufficiently small change in the received light intensity when the magnitude of the change in the received light intensity at each measurement interval is equal to or smaller than a predetermined threshold value for a predetermined number of times. And evaluate.
The process performed by the received light intensity change evaluation unit 25 corresponds to an example of a process in the received light intensity change evaluation step.

The pulverized coal concentration acquisition unit 23 obtains the pulverized coal concentration in the pulverized coal fired boiler furnace as the target region. The process performed by the pulverized coal concentration acquisition unit 23 corresponds to an example of a process in the pulverized coal concentration acquisition step.
The substantial light receiving distance acquiring unit 24 obtains the substantial light receiving distance of the optical fiber based on the pulverized coal concentration acquired by the pulverized coal concentration acquiring unit 23.
For example, the pulverized coal concentration acquisition unit 23 acquires the amount of pulverized coal that the burner 901 diffuses into the furnace, so that the pulverized coal concentration (the amount of pulverized coal per unit volume obtained by dividing the amount of pulverized coal by the capacity of the furnace). To get. And the substantial light reception distance acquisition part 24 acquires a substantial light reception distance based on the relationship between the pulverized coal density | concentration previously obtained by simulation etc. and a substantial light reception distance.
The process performed by the substantial light reception distance acquisition unit 24 corresponds to an example of a process in the substantial light reception distance acquisition step.

The substantial light receiving distance here is a distance from the light receiving portion that indicates a range to be handled as a substantial target of temperature detection in the temperature detection performed by the temperature detection device 2 (temperature detection unit 22).
FIG. 6 is an explanatory diagram showing an example of a substantial light receiving distance of the optical fiber. In the example of the figure, the substantial light receiving range of the optical fiber of the light receiving intensity measuring unit 11 is indicated by a cone.

The optical fiber can also receive light emitted from a heat source located farther than the substantial light receiving range, but as the Lambert-Beer law indicates, the longer the distance from the heat source to the light receiving part (that is, the optical path) The longer the length), the smaller the amount of light received from the heat source. Therefore, a heat source having a certain optical path length or longer can be excluded from the detection target as an error in temperature detection performed by the temperature detection device 2.
The substantial light receiving distance is a reference distance for excluding the heat source from the detection target in the temperature detection. The substantial light receiving distance is set by the user of the temperature detection device 2 based on, for example, the transmittance in the target region and the accuracy of the temperature that the temperature detection device 2 should detect.

Similar to the temperature detection unit 12, the temperature detection unit 22 detects the temperature at each measurement interval.
However, the temperature detection unit 22 detects the temperature at the measurement point evaluated by the received light intensity change evaluation unit 25 when the change in the received light intensity is sufficiently small, and sequentially detects the temperature of each section using the obtained temperature as the initial temperature. In this respect, it differs from the temperature detector 12. Moreover, the temperature detection part 22 calculates | requires the temperature for every predetermined interval based on the substantial light reception distance which the substantial light reception distance acquisition part 24 acquired. More specifically, the temperature detection unit 22 determines the radiant energy in the section of the section in which the temperature is detected among the sections obtained by dividing the substantial light receiving distance at predetermined intervals, the light receiving portion of the optical fiber, and the section. The temperature of the section for which the temperature is to be obtained based on the obtained light reception energy, excluding the light reception energy based on the light reception intensity measured by the light reception intensity measuring unit 11 Is calculated.
The process performed by the temperature detection unit 22 corresponds to an example of a process in the temperature detection step.

FIG. 7 is an explanatory diagram illustrating an example of a section in which the temperature detection unit 22 detects a temperature. The horizontal axis of the figure shows the distance from the burner.
In FIG. 7, measurement timings (0a), (0b), and (1) to (4) are shown, and the tip, which is the light receiving portion of the optical fiber, of the light receiving intensity measuring unit 11 is retracted by a distance D11. The distance D12 corresponds to an example of a measurement interval, and the temperature for each measurement interval is expressed as temperatures T _{0 to} T ₄ . The distance D12 is set to a distance obtained by dividing the substantial light receiving distance into m (m is a positive integer). In the example of FIG. 7, m = 4.
Further, the received light intensity in the measurement timing (0) - (4) are respectively a _I f0 _{~I f4.}
Note that the received light intensity I _{f0 to If 4} , the temperatures T _{0 to} T _4, and the measurement timings (1) to (4) in FIG. 7 may be different from those in FIG.

Similar to the temperature detection unit 12, the temperature detection unit 22 detects the temperature for one section from the received light intensity measured by the received light intensity measurement unit 11 by excluding components related to the temperature detected section.
Here, it is assumed that contributions to the received light intensity of the radiated light from the intervals of the measurement intervals obtained by equally dividing the substantial light receiving distance by m are A1 to Am.

FIG. 8 is an explanatory diagram illustrating an example of the degree of contribution.
The horizontal axis of the figure shows the distance from the light receiving portion to each section. The vertical axis indicates the contribution.
According to Lambert-Beer's law, the farther the distance from the light receiving portion is, the smaller the contribution is set.
Here, the received light intensity _{I f1} at the measurement timing (1), when the contribution of the radiant intensity _{I 1} from the temperature _{T 1} of the section to _{A 1,} the contribution of the radiant intensity _{I 0} from the section of the temperature _{T 0} is (1-A ₁ ), which is expressed as in Equation (13).

Therefore, when the light reception intensity change evaluation unit 25 evaluates that the change in the light reception intensity is sufficiently small in the measurement timings (0a) and (0b), the temperature detection unit 22 determines the measurement timings (0a) and (0b). based on the received light intensity _{I f0} in), calculates the temperature _{T 0} as the initial temperature.
Then, the temperature detection unit 22 excludes the influence of the radiation intensity I ₀ from the section of the temperature T ₀ according to the contribution (1-A ₁ ) from the received light intensity I _{f1 at} the measurement timing (1), and the temperature T ₁ is calculated.

Next, the received light intensity _{I f2} at the measurement timing (2), the contribution of the radiant intensity _{I 2} from the temperature _{T 2} zone and _{A 1,} the contribution of the radiant intensity _{I 1} from the temperature _{T 1} of section A ₂ . Then, the contribution degree of the radiation intensity I ₀ from the section of the temperature T ₀ is (1−A ₁ −A ₂ ), which is expressed as in Expression (14).

Therefore, the temperature detecting unit 22, the received light intensity _{I f2} at the measurement timing (2), in accordance with the contribution _{A 2} and _(1-A 1 -A _2), the radiant intensity _{I 1} from the temperature _{T 1} of section The temperature T ₂ is calculated by excluding the influence and the influence of the radiation intensity I ₀ from the section of the temperature T ₀ .

Furthermore, the received light intensity _{I f3} at the measurement timing (3), the temperature _{T 3,} T 2, each radiation intensity _{I 3,} contribution of I 2, _{I 1} from _{T 1} of the section, each _{A 1, A} 2, and a _3. Then, the contribution of the radiation intensity I ₀ from the section of the temperature T ₀ is (1−A ₁ −A ₂ −A ₃ ), which is expressed by the equation (15).

Therefore, the temperature detecting unit 22, the received light intensity _{I f3} at the measurement timing (3), depending on the contribution _to the exclusion of the influence of the I _3, I 2, _{I 1,} to calculate the temperature _{T 3.}
When formulas (13) to (15) are generalized, they are represented as formula (16).

However, i is a positive integer of 1 ≦ i ≦ m−1.
Further, the received light intensity I _fi when the region of the initial temperature is not included is expressed as in Expression (17).

However, i is a positive integer with m ≧ i.
For example, similar to the temperature detecting portion 12 detects the temperature of one section based on the equation (12), the temperature detecting unit 22 detects the temperature T _i of one section on the basis of the equation (18) .

However, i is a positive integer with m ≧ i.
That is, among the sections obtained by dividing the substantial light receiving distance into m, the temperatures T _{i−1 to} T _{i−m + 1} of the m−1 section excluding the section closest to the light receiving portion are known, and the temperature detection unit As in the case of the temperature detector 12, 22 substitutes each temperature and distance into the equation (18). Then, the temperature detecting section 22 obtains an expression that only the temperature T _i is in the unknown variables, acquires the temperature T _i by solving this equation.
In addition, even when the section of the initial temperature T ₀ is included in each section obtained by dividing the substantial light receiving distance into m, the temperature detection unit 22 calculates the temperature of the section that is a temperature detection target based on the equation (18). To detect. In this case, the temperature T ₀ is substituted for all the sections of the initial temperature T ₀ .

As described above, the received light intensity change evaluation unit 25 evaluates the change in received light intensity when the optical fiber is moved along the light receiving direction of the optical fiber. Then, the temperature detection unit 22 detects the temperature at the measurement point evaluated by the received light intensity change evaluation unit 25 when the change in the received light intensity is sufficiently small, and sequentially detects the temperature of each section using the obtained temperature as the initial temperature. .
As described above, the temperature detection unit 22 detects the temperature of each section based on the initial temperature, so that the temperature detection unit 22 can detect the temperature of each section even when the temperature of the boundary portion such as the temperature of the furnace wall is unknown. Can be detected. Further, the temperature detection unit 22 does not need to start temperature detection in the vicinity of the boundary portion such as the furnace wall, and the temperature detection unit 22 detects the temperature from an arbitrary section evaluated by the light reception intensity change evaluation unit 25 when the change in the light reception intensity is sufficiently small. Can start.
Further, the light reception intensity change evaluating unit 25 can detect a section where the temperature change is gentle by detecting a section where the change in the light reception intensity is sufficiently small. Thereby, the temperature change in the sections other than the section that is the temperature detection target becomes gentle, and the temperature detection unit 22 can detect the temperature in the sections other than the section that is the temperature detection target more accurately.

Moreover, the pulverized coal concentration acquisition part 23 calculates | requires pulverized coal density | concentration, when an object area | region is in the furnace of a pulverized coal fired boiler. And the substantial light reception distance acquisition part 24 calculates | requires the substantial light reception distance of an optical fiber based on the pulverized coal density | concentration which the pulverized coal density | concentration acquisition part 23 acquired.
Thereby, the temperature detection part 22 can detect the temperature of each area based on a substantial light receiving distance.
By detecting the temperature of each section based on the substantial light receiving distance, the temperature detection unit 22 does not need to calculate the influence of the section far from the substantial light receiving distance. In this respect, the load on the temperature detection unit 22 can be reduced.

In addition, the temperature detection unit 22 sets the radiant energy in the section to the distance between the light receiving portion of the optical fiber and the section of the section in which the temperature is detected among the sections obtained by dividing the substantial light receiving distance at predetermined intervals. The temperature is obtained based on the obtained light reception energy by weighting with the corresponding transmittance and excluding the light reception energy based on the light reception intensity measured by the light reception intensity measuring unit 11.
For example, the temperature detection unit 22 substitutes the temperature of each known section into the equation (18), thereby radiating the temperature from each known section with respect to the temperature based on the received light intensity measured by the temperature detection unit 12. Clarify the effects of energy. And the temperature detection part 22 excludes the influence of the radiant energy from each area where temperature is known by solving the equation (18) in which each temperature is substituted, and calculates the temperature of the section that is the temperature detection target. calculate.
As described above, the temperature detection unit 22 can detect the temperature more accurately by performing the weighting according to the distance between the light receiving portion and the section with respect to the influence from each section in which the temperature is known.

  In the above description, the temperature detection unit 22 detects the temperature using a model based on the two-color method. However, the model used by the temperature detection unit 22 is not limited to this, and the temperature can be detected from the received light intensity. Any model can be used. For example, the temperature detection unit 22 may detect the temperature using a model based on the monochromatic method.

  In the above description, the temperature detection unit 22 substitutes the detected temperature into the model to reduce the influence of the temperature in the section in which the temperature has been detected. However, the temperature detection unit 22 You may make it reduce the influence of the temperature in the area where temperature was detected using the detected light reception intensity | strength. For example, the temperature detection unit 22 subtracts the light reception component from the section in which the temperature has been detected from the light reception intensity measured by the light reception intensity measurement unit 11, and the light reception intensity from the section that is the temperature detection target. And the received light intensity obtained may be converted into temperature.

  As in the case of the temperature detection device 1, the temperature detection device 2 may perform the temperature detection for each section as in the example of FIG. 4 a plurality of times while shifting the measurement position. Thereby, the temperature detection apparatus 2 can detect the temperature of each part in a two-dimensional mesh or a three-dimensional mesh.

<Third Embodiment>
FIG. 9 is a schematic block diagram showing a functional configuration of the temperature detection device according to the third embodiment of the present invention. In the figure, the temperature detection device 3 includes a light reception intensity measurement unit 11, a pulverized coal concentration acquisition unit 23, a substantial light reception distance acquisition unit 24, a temperature detection unit 32, and a temperature measurement unit 35.
9, parts having the same functions corresponding to the respective parts in FIG. 5 are denoted by the same reference numerals (11, 23, 24), and description thereof is omitted.

  Similar to the temperature detection device 2 (FIG. 5), the temperature detection device 3 sets a substantial light receiving distance and detects the temperature of the target region at predetermined intervals. However, while the temperature detection device 2 detects an interval where the temperature change is small and sets the initial temperature, the temperature detection device 3 actually measures the initial temperature using a temperature measurement method other than the received light intensity.

The temperature measurement unit 35 includes, for example, a thermocouple, and measures (actually measures) the temperature of each section set as the initial section. The process performed by the temperature measurement unit 35 corresponds to an example of a process in the temperature measurement step.
Similar to the temperature detection unit 22, the temperature detection unit 32 sequentially detects the temperature of each section. However, the temperature detection unit 32 differs from the temperature detection unit 22 in that the temperature actually measured by the temperature measurement unit 35 is used as the initial temperature. The process performed by the temperature detection unit 32 corresponds to an example of a process in the temperature detection step.

  As described above, even when the temperature measurement unit 35 cannot detect a section with a small temperature change by measuring the temperature of the section set as the initial section, the temperature detection unit 32 detects the temperature of each section. can do.

<Fourth Embodiment>
FIG. 10 is a schematic block diagram showing a functional configuration of the temperature detection device according to the fourth embodiment of the present invention. In the figure, the temperature detection device 4 includes a received light intensity measurement unit 11, a temperature detection unit 12, a flame surface temperature detection unit 46, and a temperature evaluation unit 47.
10, parts having the same functions corresponding to the parts in FIG. 1 are denoted by the same reference numerals (11, 12), and description thereof is omitted.

Similar to the temperature detection device 1 (FIG. 1), the temperature detection device 4 detects the temperature of the target region at predetermined intervals. However, the temperature detection device 4 is different from the temperature detection device 1 in that the detected temperature is evaluated.
The flame surface temperature detection unit 46 detects the temperature of the flame surface in the boiler furnace as the target region. The process performed by the flame surface temperature detection unit 46 corresponds to an example of a process in the flame surface temperature detection step.

The temperature evaluation unit 47 evaluates the temperature detected by the temperature detection unit 12 based on the flame surface temperature detected by the flame surface temperature detection unit 46. For example, the temperature evaluation unit 47 compares the flame surface temperature detected by the flame surface temperature detection unit 46 with the temperature detected by the temperature detection unit 12 for the section corresponding to the flame surface, and the temperature difference is greater than a predetermined threshold value. In such a case, a message indicating that the temperature detected by the temperature detection device 4 may be inaccurate is presented to the user (for example, display or voice output).
The process performed by the temperature evaluation unit 47 corresponds to an example of a process in the temperature evaluation step.

As described above, the flame surface temperature detection unit 46 detects the temperature of the flame surface when the target region includes the flame surface. And the temperature evaluation part 47 evaluates the temperature which the temperature detection part 12 detected based on the flame surface temperature which the flame surface temperature detection part 46 detected.
Thereby, the temperature evaluation part 47 can determine whether the temperature detected by the temperature detection part 12 is accurate. If it is determined that the temperature detected by the temperature detector 12 may not be accurate, for example, a warning can be given to the user.

  In addition, you may implement combining 4th Embodiment, 2nd Embodiment, or 3rd Embodiment. For example, the temperature detection device 2 or the temperature detection device 3 may include a flame surface temperature detection unit 46 or a temperature evaluation unit 47.

It should be noted that a program for realizing all or part of the functions of the temperature detection device 1, 2, 3 or 4 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system. The processing of each unit may be performed by executing. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

1, 2, 3, 4 Temperature detection device 11 Light reception intensity measurement unit 12, 22, 32 Temperature detection unit 23 Pulverized coal concentration acquisition unit 24 Substantial light reception distance acquisition unit 25 Light reception intensity change evaluation unit 35 Temperature measurement unit 46 Flame surface temperature Detection unit 47 Temperature evaluation unit

Claims (9)

A light-receiving intensity measuring step of inserting an optical fiber into a target region and measuring the light-receiving intensity at predetermined intervals along the light-receiving direction of the optical fiber;
Based on the received light intensity obtained in the received light intensity measurement step, a temperature detecting step for obtaining a temperature at each predetermined interval;
The temperature detection method characterized by comprising.   In the temperature detecting step, based on the temperature calculated from the received light intensity obtained in the received light intensity measuring step and the temperature of the section in which the temperature has been detected among the sections for each predetermined interval, the temperature of each section The temperature detection method according to claim 1, wherein the temperature is detected in order. A light-receiving intensity change evaluation step for evaluating a change in light-receiving intensity when the optical fiber is moved along the light-receiving direction of the optical fiber;
In the temperature detection step, the temperature at the measurement point evaluated that the change in the received light intensity is sufficiently small in the received light intensity change evaluation step is detected, and the temperature of each section is sequentially detected using the obtained temperature as the initial temperature. The temperature detection method according to claim 2. A temperature measuring step for measuring the temperature of the section set as the initial section;
The temperature detection method according to claim 2, wherein in the temperature detection step, the temperature of each section is detected in order using the temperature obtained in the temperature measurement step as an initial temperature. A flame surface temperature detecting step for detecting a temperature of the flame surface when the target region includes a flame surface; and
The temperature evaluation step of evaluating the temperature obtained in the temperature detection step based on the flame surface temperature obtained in the flame surface temperature detection step is provided. The temperature detection method as described in any one of Claims. A pulverized coal concentration acquisition step for obtaining a pulverized coal concentration when the target region is in a furnace of a pulverized coal fired boiler;
Based on the pulverized coal concentration obtained in the pulverized coal concentration acquisition step, comprising a substantial light receiving distance obtaining step for obtaining a substantial light receiving distance of the optical fiber,
6. The temperature detection step determines the temperature at each predetermined interval based on the substantial light reception distance obtained in the substantial light reception distance acquisition step. 6. The temperature detection method described in 1. In the temperature detection step, for each section in which the temperature is detected among the sections obtained by dividing the substantial light receiving distance at predetermined intervals, the radiant energy in the section is set to the distance between the light receiving portion of the optical fiber and the section. Weighted with the corresponding transmittance, excluded from the received light energy based on the received light intensity obtained in the received light intensity measurement step, based on the obtained received light energy, the temperature of the section for which the temperature is to be obtained The temperature detection method according to claim 6, wherein the temperature detection method is calculated. Using an optical fiber inserted into the target region, a received light intensity measuring unit that measures the received light intensity at predetermined intervals along the light receiving direction of the optical fiber;
Based on the received light intensity acquired by the received light intensity measuring unit, a temperature detecting unit for obtaining a temperature at each predetermined interval;
A temperature detection apparatus comprising: To a computer as a temperature detection device,
Using an optical fiber inserted into the target region, a received light intensity measuring step for measuring the received light intensity at predetermined intervals along the light receiving direction of the optical fiber;
Based on the received light intensity obtained in the received light intensity measurement step, a temperature detecting step for obtaining a temperature at each predetermined interval;
A program for running

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