JP2019158440A - System and method for measuring microparticle - Google Patents

Abstract

To provide a system and a method for measuring a microparticle, capable of easily measuring microparticles existing in a large high temperature combustion field.SOLUTION: A system for measuring a microparticle includes: an irradiation part which irradiates two-phase flow, in which liquid or solid microparticles exist in the gas phase, with laser beams; and a measurement part for measuring the microparticles by detecting scattered light from the microparticles seeing from the microparticles.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a measurement system and a measurement method for measuring liquid or solid microparticles present in a gas phase.

  In a combustion facility such as a thermal power plant, fossil fuels such as coal and oil are burned in a combustion field such as a boiler furnace. In the combustion field, a turbulent flow field is formed in which solid particles such as pulverized coal that has been pulverized and liquid particles such as liquid droplets in which oil is dispersed float in the gas phase (air). Yes. It is known that the behavior of fine particles in such a turbulent flow field greatly affects the combustion efficiency.

  As a technique for measuring the behavior of fine particles in such a turbulent flow field, for example, Patent Document 1 is known. Patent Document 1 discloses a measurement system for simultaneously measuring the shape, diameter, and temperature of fine particles as the behavior of fine particles in a turbulent flow field.

  Here, FIG. 8 is a schematic diagram showing a microparticle measurement system 100 ′ of Patent Document 1. The measurement system 100 'includes a shadow Doppler optical system 110' for measuring the shape and diameter of the microparticles, and a Cassegrain optical system 120 'for measuring the temperature of the microparticles. In the shadow Doppler optical system 110 ′, based on the shadow formed by shielding the laser beams L1 and L2 by the particles in the flame B passing through the measurement region formed at the intersection of the two laser beams L1 and L2. The particle is imaged by the high-speed camera 112 ′, and the shape and diameter of the particle are measured based on the captured image signal. On the other hand, in the Cassegrain optical system 120 ′, two types of light intensities of specific wavelengths included in the detection light from the particles in the measurement region are measured by the spectroscope 122 ′, and the principle of the two-color thermometer is obtained by the arithmetic device 124 ′. Based on this, the temperature of the particles is measured.

JP 2012-13580 A

  In Patent Document 1, as described above, the shadow Doppler optical system 110 ′ for measuring the shape and diameter of the particles and the Cassegrain optical system 120 ′ for measuring the temperature of the particles are included. These two optical systems are configured as optical systems having casings independent of each other. Therefore, when measuring the microparticle which floats in the turbulent flow field in a large sized high temperature combustion field like a boiler furnace using the technique of patent document 1, it is necessary to provide the measurement window corresponding to each optical system. In particular, in the shadow Doppler optical system 110 ′, it is necessary to measure shadows on the side opposite to the irradiation direction of the two laser beams L1 and L2, and therefore it is necessary to provide measurement windows on the irradiation side and the light receiving side, respectively. is there. However, in a large-scale high-temperature combustion field such as a boiler furnace, the actual situation is that the measurement window is limitedly provided in a limited region in order to achieve good combustion efficiency. It is not easy to adopt.

  Moreover, in order to apply the technique of the said patent document 1 to a high temperature combustion field, it is necessary to protect from the high temperature atmosphere of a combustion field by accommodating an optical system in the protection housing | casing which has cooling performance. Therefore, in the above-mentioned Patent Document 1, it is necessary to accommodate each optical system in such a protective housing, and the apparatus configuration becomes large. Although it is conceivable to simplify the housing by moving the optical system away from the high-temperature combustion field, in this case, the effective solid angle expected from the microparticles to be measured is reduced. In this case, in particular, in the Cassegrain optical system 120 ′ using the principle of the two-color thermometer, the detection amount of the radiant light from the fine particles to be measured is reduced.

  Further, in Patent Document 1, since the shadow Doppler optical system 110 ′ and the Cassegrain optical system 120 ′ are independent from each other, when the refractive indexes on the optical paths of the respective optical systems are different, the substantial measurement position is shifted. Therefore, there is a possibility that accurate measurement cannot be performed.

  At least one embodiment of the present invention has been made in view of the above-described circumstances, and an object thereof is to provide a microparticle measurement system and a measurement method capable of simply measuring microparticles present in a large high-temperature combustion field. And

(1) In order to solve the above problems, a microparticle measurement system according to at least one embodiment of the present invention
An irradiation unit for irradiating laser light to a two-phase flow in which liquid or solid microparticles exist in the gas phase;
A measuring unit for measuring the microparticles by detecting the scattered light of the laser beam by the microparticles;
With
The irradiation unit and the measurement unit are arranged on one side when viewed from the fine particles.

  According to the configuration of (1) above, the microparticles are detected by detecting the scattered light of the laser beam by the measurement unit arranged on the same side as the irradiation unit that irradiates the laser beam to the microparticles to be measured. Is measured. In this way, the irradiation unit that irradiates the microparticles with laser light and the measurement unit that detects the scattered light of the laser light from the microparticles are arranged on one side when viewed from the microparticles. Even in a combustion field, it is possible to cope with a limited measurement window, and it is possible to easily measure fine particles.

(2) In some embodiments, in the configuration of (1) above,
The measurement unit receives the scattered light through an optical system including a magnification objective lens for collecting the scattered light.

  According to the configuration of (2) above, the scattered light from the microparticles is received by the measurement unit via the optical system including the magnifying objective lens. In the measurement unit, fine particles are detected by the scattered light collected by the optical system. Since the magnifying objective lens is included in the optical system, by adjusting the focal length, the imaging position of the microparticles can be adjusted, and the microparticles to be measured can be suitably extracted and measured.

(3) In some embodiments, in the configuration of (2) above,
The magnifying objective lens has a depth of field of 5 mm or less.

  According to the configuration of (3) above, by configuring the depth of field of the magnifying objective lens to be shallow, it is possible to suitably extract fine particles to be measured.

(4) In some embodiments, in any one of the above configurations (1) to (3),
The measurement unit includes a shape measurement unit that measures the shape of the microparticle based on the scattered light detected by the measurement unit.

  According to the configuration of (4) above, the measurement unit measures the shape of the microparticle based on the scattered light from the microparticle. In this case, a high-speed camera such as a PIV (Particle Tracking Velocity) camera can be employed as the shape measuring unit.

(5) In some embodiments, in the configuration of (4) above,
The measurement unit includes a spectroscopic unit that splits the scattered light into short wavelength light including the wavelength of the laser light and high wavelength light including a wavelength larger than the short wavelength light.
The shape measuring unit measures the shape of the microparticle based on the short wavelength light.

  According to the configuration of (5) above, the shape measurement of the microparticles is performed based on the short wavelength light including the wavelength of the laser light irradiated from the irradiation unit.

(6) In some embodiments, in any one of the above configurations (1) to (5),
The measurement unit continuously images the microparticles in synchronization with the irradiation timing of the laser light in the irradiation unit, and measures the flow velocity of the microparticles based on the displacement of the microparticles between imaging frames. Includes a flow rate measurement unit.

  According to the configuration of (6) above, the measurement unit measures the flow velocity of the microparticles based on the microparticle variation between frames imaged at a predetermined interval.

(7) In some embodiments, in the configuration of (6) above,
The measurement unit includes a spectroscopic unit that splits the scattered light into short wavelength light including the wavelength of the laser light and high wavelength light including a wavelength larger than the short wavelength light.
The flow velocity measurement unit measures the flow velocity of the microparticles based on the short wavelength light.

  According to the configuration of (7) above, the flow velocity measurement of the microparticles is performed based on the short wavelength light including the wavelength of the laser light irradiated from the irradiation unit.

(8) In some embodiments, in any one of the above configurations (1) to (7),
The measurement unit includes a temperature measurement unit that measures the temperature of the microparticles based on the principle of a two-color thermometer using light intensities of a plurality of specific wavelengths included in the scattered light.

  With configuration (8) above, the temperature of the microparticles can be measured by the principle of a two-color thermometer using the light intensities at a plurality of specific wavelengths included in the scattered light.

(9) In some embodiments, in the configuration of (8) above,
The measurement unit includes a spectroscopic unit that splits the scattered light into short wavelength light including the wavelength of the laser light and high wavelength light including a wavelength larger than the short wavelength light.
The temperature measurement unit measures the temperature of the microparticles based on the long wavelength light.

  According to the configuration of (9) above, the temperature measurement of the fine particles is performed based on the high wavelength light including the wavelength of the laser light irradiated from the irradiation unit.

(10) In some embodiments, in any one of the above configurations (1) to (9),
A speckle killer is provided in the optical path between the irradiation unit and the two-layer flow.

  According to the configuration of (10) above, since the speckle killer is provided in the optical path between the irradiation unit and the two-layer flow, the speckle noise generated when the laser beam is irradiated to the fine particles is effectively reduced. , Accurate measurement is possible.

(11) In some embodiments, in any one of the above configurations (1) to (10),
The optical path between the irradiating unit and the two-layer flow is configured by a flexible tube.

  According to the configuration of (11) above, by configuring the optical path between the irradiation unit and the two-phase flow with a flexible tube (for example, an optical fiber), the optical path can be formed with a more flexible layout.

(12) In some embodiments, in any one of the above configurations (1) to (11),
The optical path of the laser light irradiated from the irradiation unit shares at least a part of the optical path of the scattered light from the fine particles.

  According to the configuration of (12) above, since the laser light from the irradiation unit and the scattered light from the microparticles have a common optical path, the irradiation direction to the microparticles and the light receiving direction of the scattered light are aligned. be able to. This eliminates the need for adjustment of the optical axis and the focal position in the optical system, thereby realizing a measurement system having more suitable operability.

(13) In order to solve the above-described problem, a method for measuring microparticles according to at least one embodiment of the present invention,
Irradiating laser light to a two-phase flow in which liquid or solid microparticles exist in the gas phase;
Measuring the microparticles by detecting the scattered light of the laser light by the microparticles on the same side as the laser beam as seen from the microparticles;
Is provided.

  According to the above method (13), the microparticles are measured by detecting the scattered light of the laser light on the same side as the irradiation direction of the laser light with respect to the microparticles to be measured. In this way, the irradiation of the laser beam and the detection of the scattered light are performed on one side as seen from the microparticles, so even a large high-temperature combustion field can be handled with a limited measurement window, and the microparticles can be easily Measurements can be made.

  According to at least one embodiment of the present invention, it is possible to provide a microparticle measurement system and a measurement method capable of easily measuring microparticles present in a large high-temperature combustion field.

It is a mimetic diagram showing roughly composition of combustion equipment 1 provided with a measurement system of fine particles concerning at least one embodiment of the present invention. FIG. 2 is a detailed view of the configuration of the measurement system in FIG. 1. It is a flowchart which shows the measuring method implemented with the measuring system of FIG. 2 for every process. It is an example of the 2 frame image imaged continuously by the flow velocity measurement unit. It is a modification of FIG. It is another modification of FIG. It is another modification of FIG. It is a schematic diagram which shows the measurement system of the microparticle of patent document 1.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
In addition, for example, expressions representing shapes such as quadrangular shapes and cylindrical shapes not only represent shapes such as quadrangular shapes and cylindrical shapes in a strict geometric sense, but also within the range where the same effect can be obtained. A shape including a chamfered portion or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

  First, with reference to FIG. 1, the whole structure of the combustion equipment 1 provided with the measurement system 100 of the microparticle which concerns on at least one embodiment of this invention is demonstrated. FIG. 1 is a schematic diagram schematically showing a configuration of a combustion facility 1 including a microparticle measurement system according to at least one embodiment of the present invention.

  The combustion facility 1 includes a combustion furnace 2 that combusts fuel, a flue 4 that guides combustion air generated in the combustion furnace 2, a reheater unit 6 that acquires thermal energy from the combustion air, and a combustion furnace 2. A combustion control device 8 for controlling the combustion state in the combustion furnace 2 by adjusting the supply of fuel and air to the inside, and a measurement system 100 for measuring fine particles contained in the combustion air in the combustion furnace 2; .

  The combustion furnace 2 is configured to be surrounded by a substantially box shape with a wall surface using a heat resistant material. In the combustion furnace 2, high-temperature combustion air is generated by burning fuel and air supplied from a combustion control device 8 described later. The combustion furnace 2 is open on the upper side in the vertical direction, and the opened portion is connected to the flue 4. The high-temperature combustion air generated in the combustion furnace 2 forms a flow path so as to be guided to the flue 4.

  The reheater unit 6 includes a plurality of reheaters and is disposed on the combustion air flow path in the combustion furnace 2 and the flue 4. The reheater is composed of a tubular member in which liquid or gas is enclosed. The liquid or gas enclosed in the reheater acquires heat energy by exchanging heat with high-temperature combustion air, and becomes steam. The steam passes through a predetermined path from the reheater unit 6, and rotates a turbine (not shown) to convert thermal energy into electric energy or mechanical energy and output the steam.

  The combustion control device 8 controls the combustion state in the combustion furnace 2 by adjusting the fuel and air supplied into the combustion furnace 2. The combustion control device 8 includes a fuel supply unit 12 and an air supply unit 14 that supply fuel and air to the combustion furnace 2, respectively.

  The fuel supply unit 12 generates a pulverized coal burner (hereinafter referred to as “burner” as appropriate) 16 that burns fuel, a pulverized coal supply unit 18 that supplies pulverized coal as a fuel, and air blown to convey the fuel. A blower 20 to be adjusted, a flow rate adjusting valve 22 for adjusting the flow rate of the fuel, and a pipe 24 connecting them to each other.

  The pulverized coal supply unit 18 is a mechanism configured to supply fuel to the pipe 24. The pulverized coal supplied to the pipe 24 is conveyed through the pipe 24 by the blower 20, mixed with the air introduced from the main pipe 32 of the air supply unit 14 via the flow rate adjusting valve 22, and then supplied to the burner 16. The The burner 16 is a combustor installed such that the injection port is exposed to the inside of the combustion furnace 2, and injects fuel supplied via the pipe 24 and burns it in the combustion furnace 2.

  Note that the burners 16 are arranged at a plurality of locations in the combustion furnace 2, and are preferably laid out so that vortex air flows into the combustion furnace 2 by the air injected from each burner 16.

  The pulverized coal supply unit 18 may be a mechanism for pulverizing coal to generate pulverized coal, supplying the generated pulverized coal to the pipe 24, or storing the pulverized coal generated in advance, A mechanism for supplying the stored pulverized coal to the pipe 24 may be used.

  The air supply unit 14 includes a primary air supply unit 26 and a secondary air supply unit 28 that supply primary air and secondary air to the combustion furnace 2, respectively, and the primary air supply unit 26 and secondary air together with the fuel supply unit 12 described above. A blower 30 that is a blower or a fan that sends air to the supply unit 28 and a main pipe 32 that connects them are provided.

  The primary air supply unit 26 includes a first pipe 36 disposed so that the outlet 34 is exposed to the combustion furnace 2, and a flow rate adjustment valve 38 configured to adjust the flow rate of air in the first pipe 36. Prepare. The first pipe 36 is connected to the main pipe 32 via a flow rate adjusting valve 38, and is configured to be able to introduce air taken into the main pipe 32 by the blower 30 into the blowout port 34. The outlet 34 is provided on the downstream side of the burner 16 in the combustion air flow path in the combustion furnace 2. The flow rate adjustment valve 38 is disposed at a connection portion between the main pipe 32 and the first pipe 36, and adjusts the amount of air supplied from the main pipe 32 to the first pipe 36.

  The secondary air supply unit 28 includes a second pipe 42 disposed so that the outlet 40 is exposed to the combustion furnace 2, and a flow rate adjusting valve 44 configured to be able to adjust the flow rate of air in the second pipe 42. . The second pipe 42 is connected to the main pipe 32 via the flow rate adjustment valve 44, and is configured so that the air taken into the main pipe 32 by the blower 30 can be introduced into the outlet 40. The air outlet 40 is provided on the downstream side of the air outlet 34 in the flow path of the combustion air in the combustion furnace 2. The flow rate adjusting valve 44 is disposed at a connection portion between the main pipe 32 and the second pipe 42, and adjusts the amount of air supplied from the main pipe 32 to the second pipe 42.

  The distribution control means 46 adjusts the opening degree of the flow rate adjusting valves 22, 38, 44, thereby allowing the air taken in by the blower 30 to the fuel supply unit 12, the primary air supply unit 26 and the secondary air supply unit 28. And distribute at a predetermined ratio.

  In the combustion furnace 2, there is combustion air as a two-phase fluid in which pulverized coal that is fine particles (particles having a particle size of several mm or less) floats in air that is a gaseous medium. The measurement system 100 has such pulverized coal in combustion air as a measurement target, and is a system that measures based on an optical technique using laser light in particular. On the wall surface of the combustion furnace 2, there is provided a measurement window 2a through which laser light can be transmitted from the outside to the inside of the combustion furnace 2, and the measurement system 100 is disposed outside the measurement window 2a. As will be described later, the measurement system 100 can arrange the irradiation side and the light receiving side of the laser beam used for measurement in one direction as viewed from the combustion furnace 2 where the pulverized coal to be measured exists, and thus the wall surface of the combustion furnace 2 The number of measurement windows 2a provided in the battery is small.

  FIG. 2 is a detailed view of the configuration of the measurement system 100 of FIG. 1, and FIG. 3 is a flowchart showing the measurement method implemented by the measurement system 100 of FIG. The measurement system 100 includes an irradiation unit 110 that emits laser light, and a measurement unit 120 that measures microparticles by detecting scattered light from the microparticles.

  The irradiation unit 110 emits laser light as measurement light (step S1). In the present embodiment, the second harmonic (wavelength: 532 nm) of the YAG laser is used as the laser light, and in particular, a pulse laser that is repeatedly irradiated at a predetermined time interval t is used.

  Laser light from the irradiation unit 110 is emitted through the first optical system 112 toward the combustion air in the combustion furnace 2 in which fine particles to be measured exist. The first optical system 112 is an optical system that defines an optical path between the irradiation unit 110 and the combustion air, and the laser light from the irradiation unit 110 passes through a measurement window 2 a provided on the wall surface of the combustion furnace 2. It is configured to reach the combustion air in the combustion furnace 2.

  The first optical system 112 may include at least one optical element as necessary. In the example of FIG. 2, the first optical system 112 includes a plurality of mirrors 114a and 114b as optical elements, and an optical path through which the laser light from the irradiation unit 110 propagates is defined.

  When the laser light emitted from the measurement window 2a reaches the combustion air in the combustion furnace 2, it is scattered by the pulverized coal in the combustion air. Scattered light from the pulverized coal is received by the measuring unit 120 outside the combustion furnace 2 via the second optical system 116. The second optical system 116 is an optical system that defines an optical path between the combustion air and the measurement unit 120, and scattered light from the pulverized coal is measured via the measurement window 2 a provided on the wall surface of the combustion furnace 2. Configured to reach 120.

  The second optical system 116 may include at least one optical element as necessary. In the example of FIG. 2, the second optical system 116 includes, as an optical element, a magnifying objective lens 118 for condensing scattered light on the measurement unit 120. In the measurement unit 120, pulverized coal is imaged by the scattered light collected by the second optical system 116. Since the second optical system 116 includes the magnifying objective lens 118, the focal position is adjusted to adjust the imaging position of the fine particles, and the fine particles to be measured are preferably extracted and measured. can do.

  The magnification objective lens 118 has a depth of field of 5 mm or less. By configuring the magnifying objective lens 118 to have a shallow depth of field in this way, it is possible to suitably extract fine particles to be measured.

  Note that the magnification objective lens 118 can be selected from a microscope lens, a long working distance microscope lens, a macro lens, and a Cassegrain lens according to the purpose, and the focal length and the like may be set by appropriately combining them.

  The second optical system 116 may include an image guide 122 according to the distance L from the image side end surface of the magnifying objective lens 118 to the measurement unit 120. The image guide 122 is, for example, the back focus of the magnifying objective lens when the distance L is several tens of mm, and is GRIN (Gradient Index Lens) when the distance L is several tens to 500 mm or less. In the case of 500 mm to 3000 mm, it is an image fiber.

  The measurement unit 120 measures the fine particles by detecting the scattered light of the laser light from the fine particles (step S2). Particularly in the present embodiment, the measurement unit 120 includes a shape measurement unit 124 that measures the shape of the microparticles, a flow rate measurement unit 126 that measures the flow rate of the microparticles, a temperature measurement unit 128 that measures the temperature of the microparticles, including. The shape measuring unit 124, the flow velocity measuring unit 126, and the temperature measuring unit 128 receive three parameters of the shape, flow velocity, and temperature of the microparticles by capturing the scattered light from the microparticles via the second optical system 116. Are configured to allow simultaneous measurement.

  On the downstream side of the image guide 122, dichroic mirrors 130a and 130b are arranged as a spectroscopic unit for splitting scattered light from fine particles. Each of the dichroic mirrors 130a and 130b is an optical element capable of dispersing light in a predetermined wavelength band. In the dichroic mirror 130a, the short wavelength light including the wavelength of the laser light out of the scattered light from the minute particles is dispersed and is incident on the shape measuring unit 124 and the flow velocity measuring unit 126. In the present embodiment, since the laser beam is the second harmonic (wavelength: 532 nm) of the YAG laser, the dichroic mirror 130a splits light having a wavelength shorter than 620 nm, for example.

  In the present embodiment, the shape measuring unit 124 and the flow velocity measuring unit 126 are integrally configured as an imaging device that can continuously capture images at frame intervals synchronized with the pulse period of the laser light emitted from the irradiation unit 110. As such an imaging apparatus, for example, a PIV camera can be adopted. The exposure time for each frame is, for example, several ms.

  The shape measuring unit 124 measures the shape of the microparticles included in the combustion air based on the image captured based on the incident light (short wavelength light included in the scattered light from the microparticles). Such shape measurement can be performed by, for example, acquiring an image at a certain moment with the shape measuring unit 124, recognizing the microparticles included in the image, and specifying the contour.

  The flow velocity measuring unit 126 measures the flow velocity of the microparticles included in the combustion air based on the image captured based on the incident light (short wavelength light included in the scattered light from the microparticles). Such a flow velocity measurement may be performed based on the displacement of microparticles between frames by, for example, continuously imaging in synchronization with the irradiation timing of the laser light from the irradiation unit 110 by the flow velocity measurement unit 126. .

  Here, FIG. 4 is an example of a two-frame image continuously captured by the flow velocity measuring unit 126. FIGS. 4A and 4B respectively show images in different frames that are continuously imaged in synchronism with the irradiation timing of the laser beam from the irradiation unit 110, and the same minute particles are imaged. (In FIG. 4B, the positions of the microparticles in FIG. 4A are indicated by broken lines). As can be seen by comparing these two frame images, it is specified that the minute particles are moved by the displacement x during the time difference Δt that is the frame interval. In the flow velocity measuring unit 126, by performing such image analysis, the flow velocity of the microparticles is measured by dividing the displacement x by the time difference Δt.

から温度の算出が行われる。 2 and 3, the transmitted light of the dichroic mirror 130a becomes high wavelength light (radiation light) including a wavelength larger than the short wavelength light. That is, in the above example, light having a wavelength higher than 620 nm passes through the dichroic mirror 130a and enters the dichroic mirror 130b. In the dichroic mirror 130b, the high-wavelength light is further spectrally separated and is incident on TCP (Two Color Pyrometry) detectors 132a and 132b constituting the temperature measuring unit 128, respectively. The TCP detectors 132a and 132b detect light intensities Iλ1 and Iλ2 at specific wavelengths λ1 and λ2, respectively. The light intensities Iλ1 and Iλ2 detected by the TCP detectors 132a and 132b are input to an analysis device (not shown) and based on the principle of a two-color thermometer,

From this, the temperature is calculated.

  The TCP detectors 132a and 132b use a point measuring device such as a photomultiplier tube or an avalanche photodiode when the microparticles to be measured are small (several hundred μm or less) and the radiation intensity is weak. Also good. On the other hand, when the fine particles to be measured are large (about 1 mm or more) and sufficient radiation intensity can be obtained, a camera may be used.

  Further, by comparing the particle shape measured by the shape measuring unit 124 with the temperature measured by the temperature measuring unit 128, the volatile combustion light emission is removed depending on whether or not the black body radiation intensity is appropriate. Also good. For example, soot contained in the combustion air has a low radiation intensity for the temperature, and may be handled separately from the fine particles to be measured.

  Here, the optical distances from the image guide 122 to the shape measuring unit 124, the flow velocity measuring unit 126, and the temperature measuring unit 128 (TCP detectors 132a and 132b) are configured to be equal to each other. Thereby, the object side imaging positions of the shape measuring unit 124, the flow velocity measuring unit 126, and the temperature measuring unit 128 coincide with each other, and measurement data of the same target space can be acquired.

  Further, an optical filter (for example, a band) for transmitting measurement light in a frequency band to be measured on the incident side of the shape measuring unit 124, the flow velocity measuring unit 126, and the temperature measuring unit 128 (TCP detectors 132a and 132b). A path filter) may be arranged.

  In such a microparticle measurement system 100, the irradiation unit 110 and the measurement unit 120 are arranged on one side when viewed from the microparticles to be measured, and the shape of the microparticles is obtained only by optical access from one direction. Flow rate and temperature can be measured simultaneously. Thereby, even when the measurement window 2a is provided on the wall surface of the combustion furnace 2, the limited measurement window 2a can be used as shown in FIG. Therefore, the measurement system 100 that can be easily introduced into the combustion furnace 2 where the installation space of the measurement window 2a is limited can be constructed. Further, by measuring the shape, flow velocity, and temperature through the same second optical system 116, it is possible to suppress the measurement position shift due to the change in the refractive index of the medium, and it is possible to perform simple but accurate measurement. .

  FIG. 5 is a modification of FIG. This modification is different from the above-described embodiment in that the speckle killer 140 is included in the first optical system 112 that forms an optical path between the irradiation unit 110 and the combustion air that is the measurement target (the above-described embodiment). The components corresponding to the embodiments will be denoted by the same reference numerals, and redundant description will be omitted).

By including the speckle killer 140 in the first optical system 112 in this way, speckle noise generated when irradiating the fine particles in the combustion air with the laser light from the irradiation unit 110 can be effectively reduced. Accurate measurement is possible. Thereby, for example, when the concentration of fine particles in the combustion air is dilute (several thousand particles / m ³ ), the resolution limited by the speckle pattern can be improved from several tens of μm to several μm.

  FIG. 6 shows another modification of FIG. This modification is different from the above-described embodiment in that the optical path constituting the first optical system 112 between the irradiation unit 110 and the combustion air to be measured is configured by the flexible tube 150 (note that the above-described embodiment) The components corresponding to the embodiments will be denoted by the same reference numerals, and redundant description will be omitted).

  In this way, by configuring the optical path constituting the first optical system 112 with the flexible tube 150, as compared with the case where the first optical system 112 is configured with the mirrors 114a and 114b as shown in FIG. The measurement system 100 can be introduced with a flexible layout according to the structure. As the flexible tube, for example, an optical fiber or the like can be adopted. In this modification, the laser light is irradiated to the microparticles via the irradiation lens 152 provided at the tip of the flexible tube 150. It is configured. This modified example is easier to handle than other embodiments, and for example, it can be easily applied to fine particles having a low reflectance.

  FIG. 7 shows another modification of FIG. In this modification, the optical path of the laser light irradiated from the irradiation unit 110 shares at least a part of the optical path of the scattered light from the microparticles. That is, at least a part of the first optical system 112 and the second optical system 116 is configured to be shared. Specifically, the laser light from the irradiation unit 110 passes through the speckle killer 140 through the flexible tube 150a, and is further irradiated from the irradiation lens 154 through the flexible tube 150b. Irradiation light from the irradiation lens 154 is irradiated from the image guide 122 through the magnifying objective 118 to the combustion air to be measured by the half mirror 156 installed between the image guide 122 and the dichroic mirror 130a. The The scattered light from the minute particles enters the half mirror 156 via the magnifying objective lens 118 and the image guide 122, and a part of the light transmitted through the half mirror 156 enters the dichroic mirror 130a.

  Thus, in this modification, since the laser beam from the irradiation unit 110 and the scattered light from the microparticles have a common optical path, the irradiation direction to the microparticles and the light receiving direction of the scattered light are aligned. Can do. This eliminates the need for adjustment of the optical axis and the focal position in the optical system, thereby realizing a measurement system having more suitable operability.

  Needless to say, the above-described embodiments and modifications can be appropriately combined.

  As described above, according to the above-described embodiments, it is possible to provide a microparticle measurement system and a measurement method that can easily measure microparticles present in a large-scale high-temperature combustion field.

  At least one embodiment of the present invention can be used in a measurement system and a measurement method for measuring liquid or solid microparticles present in a gas phase.

DESCRIPTION OF SYMBOLS 1 Combustion equipment 2 Combustion furnace 2a Measurement window 4 Flue 8 Combustion control device 12 Fuel supply part 14 Air supply part 16 Burner 18 Pulverized coal supply part 24 Pipe 26 Primary air supply unit 28 Secondary air supply unit 100 Measurement system 110 Irradiation part 112 First optical system 114a, 114b Mirror 130a, 130b Dichroic mirror 116 Second optical system 118 Magnifying objective lens 120 Measuring unit 122 Image guide 124 Shape measuring unit 126 Flow velocity measuring unit 128 Temperature measuring unit 132a, 132b TCP detector 140 Spec Lucifer 150 Flexible tube 152,154 Irradiation lens 156 Half mirror

Claims (13)

An irradiation unit for irradiating laser light to a two-phase flow in which liquid or solid microparticles exist in the gas phase;
A measuring unit for measuring the microparticles by detecting the scattered light of the laser beam by the microparticles;
With
The said irradiation part and the said measurement part are the measurement systems of a microparticle arrange | positioned seeing from the said microparticle.   The microparticle measurement system according to claim 1, wherein the measurement unit receives the scattered light via an optical system including a magnifying objective lens for collecting the scattered light.   The microparticle measurement system according to claim 2, wherein the magnifying objective lens has a depth of field of 5 mm or less.   4. The microparticle measurement system according to claim 1, wherein the measurement unit includes a shape measurement unit that measures the shape of the microparticles based on scattered light detected by the measurement unit. 5. The measurement unit includes a spectroscopic unit that splits the scattered light into short wavelength light including the wavelength of the laser light and high wavelength light including a wavelength larger than the short wavelength light.
The microparticle measurement system according to claim 4, wherein the shape measurement unit measures the shape of the microparticles based on the short wavelength light.   The measurement unit continuously images the microparticles in synchronization with the irradiation timing of the laser light in the irradiation unit, and measures the flow velocity of the microparticles based on the displacement of the microparticles between imaging frames. The microparticle measurement system according to any one of claims 1 to 5, comprising a flow velocity measurement unit. The measurement unit includes a spectroscopic unit that splits the scattered light into short wavelength light including the wavelength of the laser light and high wavelength light including a wavelength larger than the short wavelength light.
The microparticle measurement system according to claim 6, wherein the flow velocity measurement unit measures the flow velocity of the microparticles based on the short wavelength light.   The said measurement part contains the temperature measurement part which measures the temperature of the said microparticle by the principle of a two-color thermometer using the light intensity of the several specific wavelength contained in the said scattered light, The any one of Claim 1 to 7 The microparticle measurement system according to one item. The measurement unit includes a spectroscopic unit that splits the scattered light into short wavelength light including the wavelength of the laser light and high wavelength light including a wavelength larger than the short wavelength light.
The microparticle measurement system according to claim 8, wherein the temperature measurement unit measures the temperature of the microparticles based on the long wavelength light.   The microparticle measurement system according to any one of claims 1 to 9, further comprising a speckle killer disposed in an optical path between the irradiation unit and the two-layer flow.   The optical system between the said irradiation part and the said two-layer flow is a microparticle measurement system as described in any one of Claim 1 to 10 comprised with a flexible tube.   12. The microparticle measurement system according to claim 1, wherein an optical path of the laser light irradiated from the irradiation unit shares at least a part of an optical path of the scattered light from the microparticles. . Irradiating laser light to a two-phase flow in which liquid or solid microparticles exist in the gas phase;
Measuring the microparticles by detecting the scattered light of the laser light by the microparticles on the same side as the laser beam as seen from the microparticles;
A method for measuring fine particles.

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