JPH1082699A - Method and apparatus for mesuring two-dimensional temperature distribution of fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the instantaneous temperature distribution of two-dimensional area of a fluid to be detected without contact at a desired time, by calculating the ratio of measured fluorescence intensities of first and second images to first and second band lights in the same coordinates and obtaining temperature. SOLUTION: An observed light 35 is divided by a divisional mirror 12, transmitted light 351 is passed through a filter 211, photographed by a camera 221, and its reflected light 352 is photographed by a camera 222 via a filter 212. Video outputs 11, 12 of the cameras 221, 222 are input to an arithmetic means 40. If excitation light is emitted to gas obtained by mixing toluene as first fluorescent substance and diethyl ketone as second fluorescent substance, the toluene and diethyl ketone emit fluorescences of first and second band lights having different wavelengths. The means 40 calculates a ratio 11/12 of the fluorescent intensity from the outputs 11, 12 in a predetermined region of the cameras 221, 222, and decides a temperature in the region from the relationship between the ratio and the temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring method or a temperature measuring device capable of measuring a temperature distribution in a two-dimensional region of a fluid without contact.

[0002]

2. Description of the Related Art The most common method for measuring the temperature of a fluid such as a gas or a liquid is to use a thermocouple. However, in the method using a thermocouple, the temperature distribution must be in contact with the fluid to be measured and one thermocouple measures the temperature at or near one point. Can not be measured.

On the other hand, as a method for measuring the temperature of a test fluid in a non-contact manner, an optical measuring method is known. As an optical temperature measurement method, an infrared absorption / emission method is a simple method (Charles A. Amann, SAEpap).
er 850395 (1985) and the like). However, in this method, it is difficult to obtain, for example, a temperature distribution in an arbitrary two-dimensional cross section on the optical axis because the measured value includes all information on the optical axis of the absorbed / emitted light.

[0004] Further, CARS (Coherent Anti-Stokes spectroscopy) and Raman spectroscopy are also known, but these methods are also methods of measuring a temperature at a point, and it is difficult to obtain a temperature distribution in a two-dimensional area at the same time. (T. Michael Dayer, SAEpaper)
85036 (1985) etc.).

The laser-induced fluorescence method is known as a powerful method for measuring a two-dimensional temperature distribution (A.
Arnold, et al. , Ber. Bunseng
es. Phys. Chem. Vol. 96, No10,
1388 (1992)). In this method, a test fluid is irradiated with laser light having two different wavelengths, and a two-dimensional fluorescent image excited by the laser light is measured for each of the two laser lights. Then, a two-dimensional temperature distribution is measured from the intensity ratio of the fluorescent image and the Boltzmann distribution of molecules or radicals.

[0006]

However, since the laser-induced fluorescence method excites radicals such as OH, there is a problem in that the method is limited to a test fluid containing radicals, for example, temperature measurement of a combustion field. is there. In addition, there is a problem that a certain time is required for the measurement, and the temperature distribution of the test fluid in an instant or an extremely short time cannot be measured.
That is, since the wavelength bands of the respective fluorescences excited by the two laser beams are usually almost the same,
The two fluorescent images need to be measured at an interval.

Therefore, when measuring the temperature of an unsteady field where the temperature distribution changes with time, the instantaneous temperature distribution at a desired time cannot be measured. Therefore, for example, the temperature distribution in the cylinder of the operating engine cannot be measured. The present invention has been made in view of such a conventional problem, and provides a measuring method and a measuring apparatus capable of measuring a temperature distribution of a two-dimensional region of a test fluid at a desired time instantaneously without contact. It is something to offer.

[0008]

A first invention of the present application is a temperature measurement method for measuring a temperature distribution in a two-dimensional region of a fluid in a non-contact manner,
First band light Δλ1 having a center wavelength λ1 different from the wavelength of the excitation light
And a second fluorescent substance that emits fluorescence of a second band light Δλ2 having a center wavelength λ2 different from λ1 with respect to the same excitation light, wherein the first band light Δ
A sample in which the ratio between the fluorescence intensity I1 of λ1 and the intensity I2 of the second band light Δλ2 changes with temperature in a desired temperature region is prepared, and the first and second fluorescent materials are mixed with the test fluid, The test fluid is irradiated with the excitation light having the above-described wavelength extending in the range of the two-dimensional area S (x, y) to be measured, and a first image of the first band light Δλ1 in the area S and the The second band light Δ in the region S
The second image with respect to λ2 is measured, and the same coordinates (x,
The ratio R (x, y) of the measured intensity I1 (x, y) of the first image and the measured intensity I2 (x, y) of the second image in y).
And calculating the temperature T from the value of the ratio R to determine the temperature distribution T (x, y) of the region S.

In the present invention, the most remarkable thing is
The fluorescent wavelength band Δλ1 of the first fluorescent substance and the fluorescent wavelength band Δλ2 of the second fluorescent substance for the excitation light having the same wavelength are different, and the fluorescent intensity I1 of the first band light Δλ1 and the intensity of the second band light Δλ2. The ratio with I2 varies with temperature in the desired temperature range. That is, for example, as shown in FIG. 6, when the wavelength of the excitation light is λo, the wavelength between the wavelength of the first band light Δλ1 shown by the curve 61 and the wavelength of the second band light Δλ2 shown by the curve 62 is, for example, There is a difference that can be separated by an optical filter or the like.

There is a difference between the temperature characteristic of the fluorescent intensity I1 of the first fluorescent substance and the temperature characteristic of the fluorescent intensity I2 of the second fluorescent substance, and I1 / I2 (or I2 / I1) changes with the temperature T. I do. That is, as shown in FIG. 7, for example, there is a difference in the temperature characteristic between the fluorescence intensity F1 per unit concentration of the first fluorescent substance and the fluorescent intensity F2 per unit concentration of the second fluorescent substance. As shown at 63, the ratio between the fluorescence intensities F1 and F2 changes with temperature.

The intensity of the excitation light is Io, the concentration of the first fluorescent substance in the test fluid is C1, the concentration of the second fluorescent substance in the test fluid is C2, and the temperature of the first fluorescent substance is T per unit concentration. Assuming that the fluorescence intensity is F1 (T) and the fluorescence intensity per unit concentration at the temperature T of the second fluorescent substance is F2 (T), the above-mentioned fluorescence intensities I1 and I2 are as follows. I1 = K * Io * C1 * F1 (T) (1) I2 = K * Io * C2 * F2 (T) (2) In the above equation, K is a constant specific to the measuring device. It is.

The ratio R of the intensities I1 and I2 when the test fluid containing the first fluorescent substance having the concentration C1 and the second fluorescent substance having the concentration C2 is excited by the excitation light is given by the following equation. . R {(I1 / I2) = (C1 / C2) * {F1 (T) / F2 (T)} (3) As described above, F1 (T) / F2 (T) is constant with respect to temperature. But changes with temperature. Also, F
When 1 (T) / F2 (T) is replaced by a characteristic function F12 (T) defined by the following equation (4), the following is obtained.

F12 (T) ≡F1 (T) / F2 (T) (4) R≡ (I1 / I2) = (C1 / C2) * F12 (T) (5) F12 (T) ) = (I1 / I2) * (C1 / C2) (6) Since (C1 / C2) is a constant, the measured value (I
1 / I2) and F12 (T) are in a proportional relationship.
If (T) (or more directly the relationship between the measured value (I1 / I2) and the temperature T) is known in advance, the measured value (I1
/ I2), the temperature T can be obtained.

In the method of the present invention, the test fluid is irradiated with excitation light (for example, spread in the area S in a sheet shape) extending in the range of the two-dimensional area S (x, y) to be measured. . Then, a first image of the region S with the first band light Δλ1 and a second image of the region S with the second band light Δλ2 are measured. Subsequently, a ratio R (x, y) between the measured intensity I1 (x, y) of the first image and the measured intensity I2 (x, y) of the second image at the same point (x, y) is calculated.
As a result, the value of F12 (T) at each position (x, y) is known from the above equation (5) or (6), and the distribution T (x, y) of the temperature T in the two-dimensional area S (x, y) is obtained. ) Can be determined.

According to the measuring method of the present invention, the first band light Δλ1
And the second band light Δλ2 are different bands,
The fluorescence emitted from the test fluid is separated into the first band light Δλ1 and the second band light Δλ2 by a band filter or the like, and the first image and the second image at the same time can be measured simultaneously. Therefore, it is possible to measure a two-dimensional temperature distribution at a desired time (instant or very short time).

That is, in the conventional laser-induced fluorescence method, the wavelength bands of the respective fluorescences excited by two laser beams are almost the same, so that the two fluorescent images are spaced at a fixed time interval. In contrast to only being able to separately collect data, the present invention allows two image data to be collected at the same time, and as a result, instantaneous temperature measurement is possible. As described above, according to the present invention, it is possible to provide a measuring method capable of measuring the instantaneous temperature distribution of a test fluid in a two-dimensional region at a fixed time without contact.

On the other hand, the second invention of the present application is a temperature measuring device for measuring the temperature distribution of a two-dimensional region of a fluid in a non-contact manner, wherein the first band light Δ1 having a center wavelength λ1 different from the wavelength of the excitation light.
a first fluorescent substance that emits fluorescence of λ1, and a second band light Δλ2 of a center wavelength λ2 different from λ1 for the same excitation light.
A second fluorescent substance that emits fluorescence of the first band light Δλ1 and the intensity I2 of the second band light Δλ2.
And a fluorescent substance mixing means for mixing the first fluorescent substance and the second fluorescent substance with the test fluid, and a two-dimensional area S ( a light source for irradiating the test fluid with the excitation light extending in the range of (x, y), a first image for the first band light Δλ1 in the region S, and a light source for the second band light Δλ2 in the region S Image measurement means for measuring the second image, and measurement of the measurement intensity I1 (x, y) of the first image and the measurement of the second image at the same coordinates (x, y) in response to the output signal of the image measurement means Intensity I2 (x,
and calculating means for calculating a temperature T from the value of the ratio R and determining a temperature distribution T (x, y) of the region S. Fluid 2
It is in the measuring device of dimensional temperature distribution.

A second aspect of the present invention is an apparatus for performing the method of the first aspect of the present invention, wherein a fluorescent substance mixing means for mixing the first fluorescent substance and the second fluorescent substance and a two-dimensional area S (x, y) are provided. A light source for irradiating the test fluid with excitation light that spreads, image measurement means for measuring the first image and the second image, and intensity I1 (x, y) upon receiving an output signal from the image measurement means. And calculating means for calculating the ratio R (x, y) to the intensity I2 (x, y) and determining the temperature distribution T (x, y) as described above. As a result, it is possible to provide a measuring device capable of measuring the instantaneous two-dimensional temperature distribution of the test fluid at a fixed time without contact in the same manner as the first invention.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 As shown in FIG. 1, this embodiment is a temperature measuring apparatus 1 for measuring a two-dimensional temperature distribution of a test fluid 81 in a heating constant volume container 80 in a non-contact manner. Then, curves 611 to 614 in FIG.
As shown at 620, a first fluorescent substance that emits fluorescence of the first band light Δλ1 having a center wavelength λ1 different from the wavelength λo (not shown) of the excitation light, and a center wavelength λ2 different from the above λ1 for the same excitation light. A second fluorescent substance that emits fluorescence of the second band light Δλ2 is prepared, and the first fluorescent substance and the second fluorescent substance are combined with the first band light Δλ1 as shown by a curve 630 in FIG. Fluorescence intensity I1 and second band light Δλ2 intensity I
It is assumed that the ratio to 2 changes with the temperature T in a desired temperature range.

Then, the first and second fluorescent substances are mixed in a predetermined concentration with the test fluid in advance by a fluorescent substance mixing means (not shown) and stored in the heating constant volume container 80. The temperature measuring device 1 includes the above-described fluorescent substance mixing means,
As shown in the figure, the two-dimensional area S (x,
a light source 11 for irradiating the test fluid with sheet-like excitation light extending in the range of y), a first image for the first band light Δλ1 in the region S, and the second band light Δλ2 in the region S Receiving the output signal of the image measurement means 20 and the measurement intensity I1 (x, y) of the first image at the same coordinates (x, y) and the second image Of calculating the ratio R (x, y) to the measured intensity I2 (x, y) of the above and calculating the temperature T from the magnitude of the ratio R to determine the temperature distribution T (x, y) of the region S Means 40.

The following is a supplementary explanation for each.
This example is an example in which the temperature of air as a test fluid in the heating constant volume container 80 is measured. Inside the heating constant volume container 80, 0.31 mol / m ³ of toluene as a first fluorescent substance and 2.3 of diethyl ketone as a second fluorescent substance are added to air.
It is filled with air mixed with 7 mol / m ³ .

The excitation light emitted from the light source 11 is YAG
The fourth harmonic of the laser (wavelength 266 nm). Then, the beam-shaped radiation light 31 is converted by the lenses 111 and 112 into parallel light 32 having a spread including a predetermined area S, enters the container from the quartz window 801 of the heating constant volume container 80, and enters the window. 802 emits light. An observation window 803 for transmitting light is provided at the bottom of the heating constant volume container 80, and a split mirror 12 made of a half mirror or a dichroic mirror is provided below the observation window 803.

The observation light 35 incident on the split mirror 12 is
Light 351 split by the split mirror 12 and transmitted through the split mirror 12 is captured by the first camera 221 through the first filter 211. On the other hand, the light 352 reflected by the split mirror 12 passes through the second filter 212,
Photographed by the camera 222. The first filter 211 is a band filter that transmits the first band light Δλ1, and the second filter 212 is a band filter that transmits the second band light Δλ2.

Video outputs (first and second images) I1 (x, y), I2 of the first and second cameras 221, 222
(X, y) is input to the calculating means 40. In the figure, reference numeral 41 denotes a display of the calculating means 40. FIG. 2 shows the temperature characteristics 611 to 614 of the fluorescence spectrum when the above-mentioned excitation light is irradiated to a gas in which air is mixed with 0.31 mol / m ³ of toluene as a first fluorescent substance.
And diethyl ketone 2.3 as a second fluorescent substance in air.
A temperature characteristic 620 of a fluorescence spectrum when the gas mixed with 7 mol / m ³ is irradiated with the excitation light is shown (the change in the fluorescence intensity of diethyl ketone due to the temperature is small, and is collectively indicated by a curve 620).

As can be seen from the figure, toluene emits fluorescence of the first band light Δλ1 having a wavelength of about 280-320 nm, and diethyl ketone emits second fluorescence having a wavelength of about 340-500 nm.
The fluorescent light of the band light Δλ2 is emitted. The first and second filters 211 and 212 are band filters that transmit the first band light Δλ1 and the second band light Δλ2, respectively. Also, the temperature characteristics 611 to 614 and 620 of the fluorescence intensities I1 and I2 shown in the figure are greatly different, and the ratio I1 / I2 of the fluorescence intensities greatly changes depending on the temperature.

The calculating means 40 calculates the ratio of the two intensities from the video outputs I1 (x, y) and I2 (x, y) for the predetermined area S (x, y) of the first and second cameras 221 and 222. R (x, y) is calculated. A curve 630 in FIG. 3 is an example showing the relationship between the magnitude of the ratio R and the temperature T. Then, the arithmetic unit 40 determines the temperature T (x, y) in the region S from the relationship between the magnitude of the ratio R and the temperature T (curve 630) and R (x, y).

The calculation means 40 displays the result on the display 41. As described above, in this example,
The first image and the second image are simultaneously measured by the first camera 221 and the second camera 222, and a two-dimensional temperature distribution can be measured instantaneously or in a very short time. The first fluorescent material is benzene,
A hydrocarbon having a benzene ring such as styrene can be used. The second fluorescent substance includes ketones such as acetone and methyl ethyl ketone and aldehydes in addition to the above-mentioned diethyl ketone.

In addition to the fourth harmonic (266 nm) of the YAG laser, a KrF excimer laser (248 nm) and a XeCl excimer laser (3
08 nm) or a dye laser (or a harmonic thereof) that emits light in the absorption wavelength range of the first and second fluorescent substances.

Embodiment 2 As shown in FIG. 4, this embodiment is different from Embodiment 1 in that a stereoscope 24 is used to measure the first image and the second image with one camera 23. It is an example of one embodiment. That is, the observation light 35 is transmitted to the stereoscope 2
4 is directly incident on the first filter 211 and the second filter 212, and is photographed by one camera 23 from the mirrors 241 to 244 via the lens 245.

The first image passed through the first filter 211 is detected in a half area of the detection surface of the camera 23, and the second image passed through the second filter 212 is detected by the camera 2
No. 3 is detected in the remaining 1/2 area of the detection surface. Then, the calculating means 40 calculates the intensity ratio between the same coordinates in the first image detected in the half area and the second image detected in the remaining half area, and calculates the two-dimensional temperature distribution. T
(X, y) is obtained. For others, Embodiment 1
Is the same as

Embodiment 3 This embodiment is another embodiment for measuring a two-dimensional temperature distribution in a cross section perpendicular to the axis in the engine cylinder. As shown in FIG. 5, the engine cylinder 51 is provided with quartz glass windows 511 and 512 for transmitting the sheet-like excitation light 34 and an emission window 513 for the observation light 35, and a piston 52.
Window 521 made of quartz glass through which observation light 35 is transmitted
Is provided. Then, the observation light 35 transmitted through the window 521 becomes
The direction is changed by a mirror 531, and the light is emitted from the emission window 513.

The test fluid is isooctane as a fuel, and benzene as the first fluorescent substance and acetone as the second fluorescent substance are mixed. The light source is a KrF excimer laser (wavelength: 248 nm), not shown, which forms a sheet-like excitation light 34 and transmits the excitation light 34 to a window 511 of the engine cylinder 51.
From. The excitation light 34 passes through the engine cylinder 51, whereby the first fluorescent material and the second fluorescent material in the fuel are excited, and the first band light Δλ1 (wavelength of about 280 nm to 3
20 nm) and the second band light Δλ2 (wavelength of about 340 nm to 5
00 nm).

The first band light Δλ1 and the second band light Δλ2
Is transmitted through the window 521 of the piston 51, changes its direction by the mirror 531 and exits through the exit window 513. Then, the observation light 35 is split into two by the split mirror 12 as in FIG.
A first image and a second image are respectively captured by the first camera 221 and the second camera 222 through the second filter 212. And the outputs of the cameras 221 and 222 are
The temperature distribution T (x, y) in the section perpendicular to the axis of the engine cylinder 51 is obtained by the same procedure as in the first embodiment and input to the calculating means 40 in the same procedure.

Then, in order to measure the instantaneous temperature distribution at a desired timing of the engine, the excitation light 34 is oscillated in a pulse shape (in this example, the light emission time is about 20 ns).
Then, the shutters of the cameras 221 and 222 are set to the excitation light 3.
4 is operated at high speed in synchronization with the oscillation of
00 ns or less). As a result, the instantaneous two-dimensional temperature distribution T in the engine cylinder 51 at a desired timing of the engine is obtained.
(X, y) can be obtained. For others,
This is the same as the first embodiment.

[0035]

As described above, according to the present invention, it is possible to obtain a measuring method and a measuring apparatus which can measure the temperature distribution of a two-dimensional area of a test fluid at a fixed time instantaneously without contact. Can be.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a temperature measuring device according to a first embodiment.

FIG. 2 is a diagram showing the relationship between the fluorescence wavelength and the fluorescence intensity of a first fluorescent substance and a second fluorescent substance of Embodiment 1 at different temperatures.

FIG. 3 is a diagram illustrating a relationship between a temperature R and a ratio R between an intensity I1 of a first band light Δλ1 and an intensity I2 of a second band light Δλ2 in the first embodiment.

FIG. 4 is a system configuration diagram of a temperature measurement device according to a second embodiment.

FIG. 5 is a system configuration diagram of a temperature measuring device according to a third embodiment.

FIG. 6 is a diagram schematically showing a relationship between a wavelength of excitation light of a first fluorescent substance and a second fluorescent substance and a fluorescent wavelength and a fluorescent intensity;

FIG. 7 shows the fluorescence intensity F1 per unit concentration of the first fluorescent substance.
FIG. 7 is a diagram illustrating an example of a relationship between the fluorescence intensity F2 per unit concentration of the second fluorescent substance and the temperature.

FIG. 8 shows a ratio F12 between F1 and F2 in FIG.
The fluorescent intensity I1 of the fluorescent substance and the fluorescent intensity I2 of the second fluorescent substance
The figure which shows an example of the aspect of the change with respect to temperature of the ratio with respect to.

[Explanation of symbols]

 1. . . 10. temperature measuring device, . . Light source, 15. . . Image measurement means, 40. . . Arithmetic means,

Claims (2)

[Claims] 1. A temperature measuring method for non-contact measurement of a temperature distribution in a two-dimensional region of a fluid, wherein the first fluorescent substance emits fluorescence of a first band light Δλ1 having a center wavelength λ1 different from a wavelength of excitation light. And a second fluorescent substance that emits fluorescence of the second band light Δλ2 having a center wavelength λ2 different from the above λ1 with respect to the same excitation light, wherein the fluorescence intensity I1 of the first band light Δλ1 and the second band light Δλ2 A sample whose ratio with the intensity I2 changes with temperature in a desired temperature region is prepared, and the first and second fluorescent materials are mixed with the test fluid, and the two-dimensional region S (x, irradiating the test fluid with the excitation light having the wavelength extending in the range of y), the first image corresponding to the first band light Δλ1 in the region S and the second image corresponding to the second band light Δλ2 in the region S. 2 and the same coordinates (x, y )) And the measured intensity I2 of the first image and the measured intensity I2 of the second image.
A fluid R is characterized by calculating a ratio R (x, y) with respect to (x, y), obtaining a temperature T from the value of the ratio R and determining a temperature distribution T (x, y) of the region S. A method for measuring a two-dimensional temperature distribution. 2. A temperature measuring device for measuring a temperature distribution in a two-dimensional region of a fluid in a non-contact manner, wherein the first fluorescent material emits fluorescence of a first band light Δλ1 having a center wavelength λ1 different from a wavelength of excitation light. And a second fluorescent substance that emits fluorescence of the second band light Δλ2 having a center wavelength λ2 different from the above λ1 with respect to the same excitation light, wherein the fluorescence intensity I1 of the first band light Δλ1 and the second band light Δλ2 And a fluorescent substance mixing means for mixing the first fluorescent substance and the second fluorescent substance with the test fluid, and a two-dimensional element to be measured. A light source for irradiating the test fluid with the excitation light spread over a range of a region S (x, y); a first image for the first band light Δλ1 in the region S; and a second band in the region S Light Δλ
Image measuring means for measuring the second image with respect to 2 and the same coordinates (x, y) upon receiving an output signal of the image measuring means
And the measured intensity I1 (x, y) of the first image at
A ratio R (x, y) to the measured intensity I2 (x, y) of the image is calculated, and a temperature T is obtained from the value of the ratio R to obtain the area S.
Calculating means for determining the temperature distribution T (x, y) of the fluid.