JPS6014013A - Observation method for combustion surface - Google Patents

Abstract

PURPOSE:To enable observation of a combustion surface which is under combustion, by a method wherein a combustion body is irradiated with a light beam wavelength thereof is not contained in a combustion flame, and light reflected by the combustion body and a combustion flame are observed through a filter through which only said wavelength passes. CONSTITUTION:Light beam with a wavelength substantially not contained in light emitted from the combustion flame of a combustion body 1 is emitted as a laser light 3 by, for example, a laser device 2, and is guided to a beam expander 5 through a mirror 4. A proper spread angle is formed therein, and the surface of the combustion body 1 is irradiated therewith. A laser light 6 and a combustion flame, which are reflected by the combustion surface, are caused to pass through an interference surface, are caused to pass through an interference filter 7 through which only the laser light passes, and an image is formed by a camera 8 or a television camera to observe the combustion surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of observing the surface condition of a combustion surface.

A possible method for observing the surface condition of the combustion surface is to use a camera or a television camera. However, the burning surface is covered with combustion flame, and its flame brightness is so strong that it simply cannot be seen by the camera.

Even with a television camera, only the flames could be observed, and the burning surface could not be observed.

This IP was created in view of the above circumstances, and EMt
- The aim is to develop a method that allows observation of the surface of the fuel inside.

That is, the present invention irradiates the combustion object with light (for example, laser light) having a wavelength that is not substantially included in the light emitted from the combustion flame of the combustion object, and the irradiated light is applied to the surface of the combustion object. This is a method in which only the combustion surface can be observed by observing the reflected light and the combustion flame with a camera, 7-rep camera, etc., through a filter that allows only the light of the wavelengths mentioned above to pass through.

The method of the present invention will be explained below with reference to illustrative examples.

In this method, the burning surface of a burning object 1 (for example, solid fuel) is observed, and first, a laser beam 3 is emitted from a laser device 2. This laser light 3 has a wavelength that is substantially not included in the light emitted from the combustion flame of the combustion object, that is, it is not included at all or is included only slightly. This laser beam 3 is guided to a beam expander 5 via a mirror 4,
Here, an appropriate spread is made to provide an angle υ, and the laser beam 6 reflected from the combustion surface and the combustion flame that irradiates the surface of the combustion object 1 are passed through an interference filter 7 that transmits only the laser beam.
The combustion surface is observed by imaging it with a camera 8 or a dervikamen.

Here, the brightness 13r of the combustion surface under laser illumination is expressed by the following formula O BT, = ρM×τB×ρp X (Po/Ao)
ρIF...(1) However, ρM: Mirror reflectance τB = Beam expander transmittance ρ): Reflectance of combustion surface Po: Laser light output (W) Ao: Laser on the fuel surface Cross-sectional area of light (ch &
) ρIF: Transmittance of interference filter In order to guide the Rayleigh beam to a desired position, two mirrors are normally required, and ρM”0.6.

Also, since a beam expander usually uses two lenses, τE-Q,6. Since the reflectance of the fuel surface is about 5% even for a black surface, ρPΣ0.05 is obtained. Laser output is 0.5 W if argon laser is used
An output of about Q PoΣ0.5 (W) can be easily obtained.

The cross-sectional area of the laser beam needs to match the size of the fuel, but considering the size of the fuel, which is about 15m1lφ in diameter, A
o= πx 1.52/4 = 1.8 (i). The transmittance of an interference filter is usually about 70 cm, but due to manufacturing errors, the center wavelength of the interference filter and the laser wavelength are usually different, so the transmittance will be low, so it is necessary to consider ρrr = about -0.1. There is. Substituting the above values into formula (1), BL Yu0.6 Xo, 6 Xo, 05 X (0,5/
1.8)XO,-1=5×10-'(W,/c++t
) ・・・・−(2) On the other hand, the maximum value Bλ(T) of the brightness spectrum of the combustion flame is determined theoretically and given by the following formula〇where λ: Wavelength [μ: Micron] T: Flame temperature [0K ] CH-3,74X 10'(W・tt'/ctl)
C2=1.44
The brightness BIF(T) when observed through 20 interference filters with a half-width (Δλ+) of λmax) is given by the following equation, assuming that the flame temperature is 1500°.

In the above equation, ρIF(λ) indicates the wavelength dependence of the transmittance of the interference filter.

From the comparison of formula (2) and formula (3), BIF (1500) /BL Yu2.6%...
(5) As can be seen from equation (5), the brightness BL of the fuel surface when laser illumination and an interference filter are used is approximately 40 times the brightness BIF of the combustion flame seen through the interference filter. Therefore, the combustion flame is virtually erased from the observation image, and only the combustion surface can be observed. BL
shows.

As described above, according to the present invention, the combustion flame is eliminated and the combustion surface, which could not be observed conventionally, can be observed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of the method of the present invention, and FIG.
The wavelength dependence of the maximum value Bλ(T) of the brightness spectrum of the combustion flame in the case of 00° and the fuel surface brightness Br by argon laser illumination. FIG. 1... Burning object, 2... Laser device, 3, 6...
Laser light, 4...Mirror, 5...Beam ekinupanda, 7 pass filter, 8...Camera. Applicant Sub-Agent Patent Attorney Takeshi Suzue Figure 1

Claims (1)

[Claims] Light having a wavelength that is not substantially included in the light emitted from the combustion flame of the combustion object is irradiated toward the combustion object, and the reflected light of the irradiated light on the surface of the combustion object and the combustion flame are reflected at the wavelength of the combustion object. A method for observing a combustion surface, which is characterized by observing through a filter that allows only light to pass through.