CN112179818B - Pulverized coal fuel particle characteristic testing device - Google Patents
Pulverized coal fuel particle characteristic testing device Download PDFInfo
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- CN112179818B CN112179818B CN202011280337.4A CN202011280337A CN112179818B CN 112179818 B CN112179818 B CN 112179818B CN 202011280337 A CN202011280337 A CN 202011280337A CN 112179818 B CN112179818 B CN 112179818B
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- 239000002245 particle Substances 0.000 title claims abstract description 161
- 239000003245 coal Substances 0.000 title claims abstract description 120
- 239000000446 fuel Substances 0.000 title claims abstract description 25
- 238000012360 testing method Methods 0.000 title claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 46
- 238000003384 imaging method Methods 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 13
- 238000012805 post-processing Methods 0.000 claims abstract description 12
- 238000002474 experimental method Methods 0.000 claims abstract description 6
- 239000002817 coal dust Substances 0.000 claims description 38
- 239000011521 glass Substances 0.000 claims description 13
- 238000005485 electric heating Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 8
- 238000012545 processing Methods 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 5
- 239000000470 constituent Substances 0.000 claims description 3
- 238000004321 preservation Methods 0.000 claims description 3
- 230000000644 propagated effect Effects 0.000 claims description 3
- 238000002485 combustion reaction Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 7
- 230000001276 controlling effect Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
- G01N15/0227—Investigating particle size or size distribution by optical means using imaging; using holography
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/10—Devices for withdrawing samples in the liquid or fluent state
- G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/10—Devices for withdrawing samples in the liquid or fluent state
- G01N2001/1006—Dispersed solids
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/10—Devices for withdrawing samples in the liquid or fluent state
- G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
- G01N2001/2007—Flow conveyors
- G01N2001/2014—Pneumatic conveyors
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Abstract
The invention discloses a pulverized coal fuel particle characteristic testing device, which is characterized in that: the system comprises an acoustic wave generation system, a pulverized coal particle conveying system, a water bath temperature control system, a particle stripe imaging acquisition system and a data post-processing system; obtaining dimensionless data information of the number and the relative size of particles at different positions corresponding to position variables on the particle stripes by extracting light intensity information of the particle stripe pictures; the interval between two adjacent stripes on the grain stripe picture is obtained through experiments, and the grain diameter is obtained through calculation of a grain stripe interval formula; the frequency and the sound pressure intensity are changed for a plurality of times, the number proportion of different particle sizes of the pulverized coal particles under various frequency working conditions is obtained, and the more accurate pulverized coal fuel particle characteristics are obtained after the calculation of the summation average value. The invention provides a novel method for indirectly testing the particle size ratio of pulverized coal combustion particles (comprising particle size distribution and corresponding quantity ratio), which is convenient for synchronously testing the particle size distribution of conveyed pulverized coal on line.
Description
Technical Field
The invention relates to a pulverized coal fuel particle characteristic testing device, and belongs to the field of testing of the concentration of microparticles with different particle diameters.
Background
The characteristic of pulverized coal fuel particles, also called the granularity of pulverized coal fuel particles, specifically refers to the number ratio of particles with different particle sizes in pulverized coal of any sample. The weighing method of the multi-layer multi-mesh sieve commonly used in engineering has the advantages that the size of the test particle size range interval is larger, if a narrower division particle size range interval is used, the number of layers of the sieve can be obviously increased, the workload and construction difficulty of a test technology are greatly improved, and in a pneumatic coal conveying pipeline of a thermal power plant boiler, the accurate on-line test of the coal dust fuel particle characteristics is significant for guiding the efficient operation of the power plant boiler.
Disclosure of Invention
The invention aims to: in order to overcome the problems in the prior art, the invention provides the pulverized coal fuel particle characteristic testing device, the pulverized coal particle size distribution is calculated by controlling the pulverized coal particle stripe spacing through a variable, the pulverized coal fuel particle granularity is obtained by means of the one-to-one correspondence between the stripe picture light intensity and the quantity concentration, and the measurement accuracy is very high.
The technical scheme is as follows: in order to achieve the above purpose, the invention adopts the following technical scheme:
the utility model provides a buggy fuel particle characteristic testing arrangement which characterized in that: the system comprises an acoustic wave generation system, a pulverized coal particle conveying system, a water bath temperature control system, a particle stripe imaging acquisition system and a data post-processing system;
the sound wave generating system comprises a signal generator, a power amplifier, a sound wave guide tube and two identical Helmholtz sound sources arranged at two ends of the sound wave guide tube;
the Helmholtz sound source comprises a semi-closed structure which consists of a loudspeaker, a cavity, a through hole and a flat plate and is only connected with the outside through the through hole, and the loudspeaker and the flat plate are respectively positioned at two ends of the cavity; the inner diameter of the cavity is larger than that of the through hole; the through hole is arranged on the center of the flat plate;
the acoustic waveguide tube is a transparent circular tube, and the inner diameter of the acoustic waveguide tube is larger than that of the through hole; two identical Helmholtz sound sources are hermetically arranged at two ends of the sound waveguide tube through flat plates, and the two sound sources are used for ensuring that the through holes are communicated with the sound waveguide tube;
the signal generator, the power amplifier and the loudspeaker are sequentially connected into an electrical loop by using a lead, so that the output frequency of the signal generator and the output voltage amplitude of the power amplifier are regulated, the input frequency and the input voltage amplitude of the loudspeaker are regulated, after the sound wave radiated by the loudspeaker is regulated, two beams of large-amplitude sound waves which are propagated in opposite directions are radiated inwards from two ends of the sound waveguide tube after the sound wave is acted by the cavity and the through hole, the two beams of sound waves interfere in the sound waveguide tube to form a one-dimensional standing wave sound field with a plurality of sound pressure antinodes and sound pressure nodes, and the coal dust forms particle stripes at the sound pressure node positions of the standing wave sound field;
the pulverized coal particle conveying system is connected with the sound wave generating system and is used for conveying pulverized coal into the sound wave guide tube;
the water bath temperature control system is connected with the sound wave generation system and is used for heating coal dust in the sound wave guide tube;
the particle stripe imaging acquisition system is used for shooting a particle stripe picture of particle stripes in the acoustic waveguide tube;
the data post-processing system is connected with the particle stripe imaging acquisition system and is used for analyzing and processing the particle stripe pictures.
Preferably: the pulverized coal particle conveying system comprises a pulverized coal conveying pipeline, a pulverized coal fan, a pulverized coal air valve, an acoustic waveguide pipe and a pulverized coal conveying main pipeline, wherein the pulverized coal fan, the pulverized coal air valve, the acoustic waveguide pipe and the pulverized coal conveying main pipeline are connected into a sealed pulverized coal conveying loop through the pulverized coal conveying pipeline;
the pulverized coal is conveyed into the acoustic waveguide tube from the pulverized coal main pipeline through the pulverized coal conveying pipeline by utilizing the pulverized coal blower, and is conveyed back to the pulverized coal conveying main pipeline through the pulverized coal conveying pipeline after being subjected to the action of the standing wave sound field in the acoustic waveguide tube;
the outside of the pulverized coal conveying pipeline is subjected to heat preservation treatment, so that the pulverized coal is not cooled in the conveying process in the pulverized coal conveying pipeline;
an external heat source is additionally arranged on the pulverized coal conveying pipeline and is used for heating and preserving heat of pulverized coal when the temperature of the external environment is too low and the temperature of the pulverized coal conveying pipeline is too low.
Preferably: the water bath temperature control system comprises a transparent glass sleeve, a hot water conveying pipeline, a hot water circulating pump, a temperature sensor, a temperature control switch, a power supply, a water tank and electric heating devices, wherein the transparent glass sleeve is arranged outside the acoustic waveguide tube in a sealing manner, the temperature sensor is arranged in pulverized coal wind in the acoustic waveguide tube, the temperature control switch, the power supply, the water tank and the electric heating devices are arranged in the water tank;
connecting a hot water circulating pump, a water tank and a glass sleeve to a water circulating loop by using a hot water conveying pipeline, and ensuring that the hot water flowing in the glass sleeve uniformly heats coal dust in an acoustic waveguide;
connecting the electric heating, the temperature control switch and the power supply into a heating electric loop by using a wire, and connecting a temperature sensor to the temperature control switch;
the temperature sensor is used for controlling the on-off of the temperature control switch; when the temperature sensor detects that the coal dust temperature in the acoustic waveguide tube is lower than the coal dust temperature in the coal dust conveying pipeline, the temperature control switch is closed, electric heating starts to work, circulating water in the water tank is heated until the coal dust temperature detected by the temperature sensor is equal to the coal dust temperature in the coal dust conveying pipeline, and then the temperature control switch is opened, so that the coal dust temperature in the acoustic waveguide tube is equal to the coal dust temperature in the coal dust conveying pipeline.
Preferably: the particle stripe imaging acquisition system comprises a light source, particle stripes formed at the sound pressure node position in the sound wave guide tube under the action of a standing wave sound field, a lens, a camera with a micro-distance microscopic function and a computer;
the light source emits light to irradiate the particle stripes, the scattered light of the particle stripes is emitted into the camera through the lens to be shot into particle stripe pictures, and a computer connected with the camera records the particle stripe pictures shot by the camera;
and translating the light source, the lens and the camera to different sound pressure wave node positions along the axial direction of the sound wave guide tube, and shooting and recording particle stripe pictures corresponding to more than one sound pressure wave node.
Preferably: the data post-processing system performs the steps of:
1) Extracting light intensity information of the particle stripe picture, further performing dimensionless processing to obtain dimensionless light intensity information I which corresponds to position variables x on the particle stripe one by one, and taking the light intensity information I as dimensionless data information n of the relative sizes of the number of particles at different positions;
2) Measuring and calculating the distance D between two adjacent stripes on the grain stripe picture es Comprising a distance D between the centers of two stripes 2 And distance D between adjacent edges of two stripes 1 Wherein D is es Corresponding to x, I and n one by one to form a four-dimensional set x-I-n-D es ；
3) Respectively let D es Equal to D 1 And D 2 And the particle diameter d is calculated by taking the formula of the particle stripe spacing p Upper limit value d of (2) 2 And a lower limit value d 1 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the interval formula of the grain stripes is:
d in es Representing the measured spacing between two adjacent stripes; d, d p Represents the particle diameter of the constituent stripes; ρ a And ρ p Respectively representing the densities of the main stream gas medium and the particles in the non-uniform sound field; beta a And beta p Respectively representing the compressibility coefficients of the main stream gas medium and particles in the non-uniform sound field; k=2pi f/c represents wave number, f and c represent frequency and sound velocity of the non-uniform sound field, respectively; wherein, divide D es And d p All other variables can be obtained through routine experiments or table lookup;
d p and D es The X, the n and the I are also in one-to-one correspondence to form a five-dimensional set x-I-n-D es -d p Obtaining n and d p One-to-one correspondence;
4) Repeating the steps 1) -3) for each particle stripe picture of the sound pressure node to obtain a plurality of n-d equal to the number of each particle stripe picture p One-to-one correspondence, then particle diameter d p The dimensionless data information n of the equal grain stripe pictures are correspondingly added and averaged, namely, the dimensionless data information n is used as the quantity ratio of different grain sizes of coal powder particles obtained under a frequency working condition, namely, the characteristic of coal powder fuel particles under a certain frequency condition;
5) Changing the frequency and sound pressure intensity of the standing wave sound field, repeating the steps 1) to 4), obtaining the particle quantity ratio of different particle sizes of the pulverized coal under different frequency working conditions, and further, obtaining the particle size d under different frequency working conditions p And carrying out summation average treatment on the equal particle quantity ratio, and further obtaining the final pulverized coal fuel particle characteristics.
The beneficial effects are that: the invention has the remarkable beneficial effects that:
according to the pulverized coal fuel particle characteristic testing device, the particle characteristics of the pulverized coal particles which are gathered into stripes in a one-dimensional standing wave sound field are controlled through variables, and the particle sizes of the particles are calculated under the condition that the stripe intervals are measured through experiments by means of a nonlinear relational expression between the stripe particle intervals and the particle sizes of the particles; and the quantity ratio of particles with corresponding sizes is reflected by combining the light intensity of the particle stripes, and the pulverized coal fuel particle granularity with high accuracy is obtained through multiple experiments. The invention provides a novel method for indirectly testing the particle size ratio of pulverized coal combustion particles (comprising particle size distribution and corresponding quantity ratio), which is convenient for synchronously testing the particle size distribution of conveyed pulverized coal on line.
Drawings
FIG. 1 is a schematic diagram of a pulverized coal fuel particle characteristic testing apparatus according to the present invention;
FIG. 2 is a schematic diagram of a water bath temperature control system of the present invention;
FIG. 3 is a schematic diagram of an acoustic wave generation system and particle stripe according to the present invention;
FIG. 4 is a schematic diagram of a particle streak imaging acquisition system of the present invention;
FIG. 5 is a schematic diagram of a pulverized coal particle transport system according to the present invention;
FIG. 6 is a schematic diagram of a Helmholtz acoustic source of the present invention;
FIG. 7 is a schematic diagram of a data post-processing segment according to the present invention;
in the figure: 11-a signal generator; a 12-power amplifier; 13-Helmholtz sound source; 131-a speaker; 132-cavity; 133-through holes; 134-plate; 14-an acoustic waveguide; 15-standing wave sound field; 21-a pulverized coal conveying pipeline; 22-coal dust blower; 23-pulverized coal air valve; 24-a main pulverized coal conveying pipeline; 31-glass sleeve; 32-a hot water delivery pipe; 33-a hot water circulation pump; 34-a temperature sensor; 35-a temperature control switch; 36-a power supply; 37-sink; 38-electric heating; 41-a light source; 42-grain streaks; 43-lens; 44-a camera; 45-computer.
Detailed Description
The invention will be further described with reference to fig. 1 to 7.
The utility model provides a buggy fuel particle characteristic testing arrangement which characterized in that: the system comprises an acoustic wave generation system, a pulverized coal particle conveying system, a water bath temperature control system, a particle stripe imaging acquisition system and a data post-processing system;
the sound wave generating system comprises a signal generator 11, a power amplifier 12, a sound wave guide tube 14 and two identical Helmholtz sound sources 13 arranged at two ends of the sound wave guide tube 14.
The Helmholtz sound source 13 includes a semi-closed structure composed of a speaker 131, a cavity 132, a through hole 133 and a flat plate 134, which is connected to the outside only by the through hole 133, wherein the speaker 131 and the flat plate 134 are respectively located at both ends of the cavity 132; the inner diameter of the cavity 132 is larger than the inner diameter of the through hole 133; the through hole 133 is provided at the center of the flat plate 134.
The acoustic waveguide tube 14 is a transparent circular tube, and the inner diameter of the acoustic waveguide tube 14 is larger than the inner diameter of the through hole 133; two identical Helmholtz sources 13 are sealingly mounted at both ends of the acoustic waveguide 14 by means of flat plates 134, ensuring that the through holes 133 communicate with the acoustic waveguide 14.
The signal generator 11, the power amplifier 12 and the loudspeaker 131 are sequentially connected into an electrical loop by using wires, so that the input frequency and the input voltage amplitude of the loudspeaker 131 can be further adjusted by adjusting the output frequency of the signal generator 11 and the output voltage amplitude of the power amplifier 12; after the sound wave radiated by the loudspeaker 131 acts through the cavity 132 and the through hole 133, two beams of large-amplitude sound waves which are propagated in opposite directions are radiated inwards from two ends of the sound wave guide tube 14, the two beams of sound waves interfere in the sound wave guide tube 14 to form a one-dimensional standing wave sound field 15 with a plurality of sound pressure antinodes and sound pressure nodes, and the pulverized coal forms particle stripes 42 at the sound pressure node positions of the standing wave sound field 15.
The pulverized coal particle conveying system is connected with the sound wave generating system and is used for conveying pulverized coal into the sound wave guide tube 14, and comprises a pulverized coal conveying pipeline 21, a pulverized coal fan 22, a pulverized coal air valve 23, the sound wave guide tube 14 and a pulverized coal conveying main pipeline 24, wherein the pulverized coal fan 22, the pulverized coal air valve 23, the sound wave guide tube 14 and the pulverized coal conveying main pipeline 24 are connected into a sealed pulverized coal conveying loop through the pulverized coal conveying pipeline 21.
The pulverized coal is conveyed from the pulverized coal main pipe 24 to the acoustic waveguide 14 through the pulverized coal conveying pipe 21 by the pulverized coal blower 22, and is conveyed back to the pulverized coal main pipe 24 through the pulverized coal conveying pipe 21 after being subjected to the standing wave sound field 15 in the acoustic waveguide 14.
The outside of the pulverized coal conveying pipeline 21 is subjected to heat preservation treatment, so that the pulverized coal is not cooled in the conveying process in the pulverized coal conveying pipeline 21, and therefore, when the temperature of the external environment is too low and the temperature of the pulverized coal conveying pipeline 21 is too low, an external heat source can be additionally arranged on the pulverized coal conveying pipeline 21 to heat and preserve heat of the pulverized coal.
The water bath temperature control system is connected with the sound wave generation system and is used for heating coal dust in the sound wave guide tube 14, and comprises a transparent glass sleeve 31, a hot water conveying pipeline 32, a hot water circulating pump 33, a temperature sensor 34, a temperature control switch 35, a power supply 36, a water tank 37 and an electric heater 38, wherein the transparent glass sleeve 31 is arranged outside the sound wave guide tube 14 in a sealing mode, the temperature sensor 34 is arranged in coal dust wind in the sound wave guide tube 14, and the electric heater 38 is arranged in the water tank 37.
The hot water circulation pump 33, the water tank 37 and the glass tube 31 are connected to a water circulation circuit by the hot water delivery pipe 32, so that the hot water flowing through the glass tube 31 can uniformly heat the coal dust in the acoustic waveguide 14.
The electric heating 38, the temperature control switch 35 and the power supply 36 are connected by wires to form a heating electric circuit, and the temperature sensor 34 is connected to the temperature control switch 35.
The temperature sensor 34 is used for controlling the on and off of the temperature control switch 35; when the temperature sensor 34 detects that the coal dust temperature in the acoustic waveguide 14 is lower than the coal dust temperature in the coal dust conveying pipeline 21, the temperature control switch 35 is closed, the electric heating 38 starts to work, the circulating water in the water tank 37 is heated until the temperature sensor 34 detects that the coal dust temperature in the acoustic waveguide 14 is equal to the coal dust temperature in the coal dust conveying pipeline 21, and then the temperature control switch 35 is opened, so that the coal dust temperature in the acoustic waveguide 14 is equal to the coal dust temperature in the coal dust conveying pipeline 21.
The particle fringe imaging acquisition system is used for taking a particle fringe image of a particle fringe 42 in the acoustic waveguide 14, and comprises a light source 41, the particle fringe 42 formed at the sound pressure node position in the acoustic waveguide 14 under the action of the standing wave sound field 15, a lens 43, a camera 44 with a micro-distance microscopic function and a computer 45.
The light source 41 emits light to irradiate the particle stripe 42, the scattered light of the particle stripe 42 is emitted into the camera 44 through the lens 43 to be shot into a particle stripe picture, and the particle stripe picture shot by the camera 44 is recorded by the computer 45 connected with the camera 44.
The light source 41, the lens 43 and the camera 44 are translated to different sound pressure wave node positions along the axial direction of the sound wave guide 14, and particle stripe pictures corresponding to a plurality of sound pressure wave nodes are shot and recorded.
The data post-processing system is connected with the particle stripe imaging acquisition system and is used for analyzing and processing the particle stripe pictures, and the data post-processing steps are sequentially executed, wherein the data post-processing steps comprise:
1) The light intensity information of the grain stripe picture is extracted, dimensionless processing is further carried out, light intensity information I which corresponds to position variables x on grain stripes in a one-to-one mode in a dimensionless mode is obtained, and the light intensity information I is used as dimensionless data information n of the number of grains at different positions and the size of the grains is relatively large.
In one embodiment of the invention, the center of the particle stripe is taken as an origin, and a coordinate axis is established along the axial direction of the acoustic waveguide, so that the position variable x on the particle stripe can be obtained; in other embodiments of the invention, the coordinate axes may be placed in other positions by translation, as long as the position variable x on the grain stripe is obtained.
In one embodiment of the invention, the particle number corresponding to some special light intensity is measured by adopting other experimental methods, and a relation curve of the light intensity information I and the particle number n is made by an experimental fitting method and is similar to Gaussian function distribution; in other embodiments of the invention, other methods may be used as long as a relation between the obtained light intensity information I and the number of particles n can be achieved.
2) Measuring and calculating the distance D between two adjacent stripes on the grain stripe picture es Comprising a distance D between the centers of two stripes 2 And distance D between adjacent edges of two stripes 1 Also comprises a step D of 2 And D 1 The corresponding spacing at each location x on the stripe can be obtained, where D es Corresponding to x, I and n one by one to form a four-dimensional set x-I-n-D es 。
In one embodiment of the invention, the corresponding spacing at each location x on the stripe may be used with respect to x, D 2 And D 1 Is represented by a function of (a); in other embodiments of the present invention, other methods may be employed as long as the corresponding spacing at each location x on the stripe is enabled.
3) Respectively let D es Equal to D 1 And D 2 The particle diameter d is calculated by taking the formula of the particle stripe spacing p Upper limit value d of (2) 2 And a lower limit value d 1 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the interval formula of the grain stripes is:
wherein D is es Representing the measured spacing between two adjacent stripes; d, d p Represents the particle diameter of the constituent stripes; ρ a And ρ p Respectively representing the densities of the main stream gas medium and the particles in the non-uniform sound field; beta a And beta p Respectively representing the compressibility coefficients of the main stream gas medium and particles in the non-uniform sound field; k=2pi f/c represents wave number, f and c represent frequency and sound velocity of the non-uniform sound field, respectively; wherein, divide D es And d p Other variables than this can be derived by routine experimentation or look-up tables.
And similarly, substituting the corresponding interval at each position x on the stripe into a particle stripe interval formula, and calculating the particle diameter at each position x on the stripe.
Further, d p And D es The X, the n and the I are also in one-to-one correspondence to form a five-dimensional set x-I-n-D es -d p The method comprises the steps of carrying out a first treatment on the surface of the Further, n and d can be obtained p One-to-one correspondence of (a).
4) Repeating the steps 1) to 3) for particle stripe pictures of each sound pressure node to obtain a plurality of n-d equal to the number of the particle stripe pictures p One-to-one correspondence, further to the particle diameter d p The dimensionless data information n of the equal particle stripe pictures are correspondingly added and averaged, namely, the number of the particles with different particle diameters of the pulverized coal under a frequency working condition is taken as the ratio of the number of the particles with different particle diameters of the pulverized coal under a certain frequency condition, namely, the characteristic of the pulverized coal fuel particles under a certain frequency condition.
5) The frequency and sound pressure intensity of the standing wave sound field are changed for a plurality of times, the steps 1) to 4) are repeated for a plurality of times, the number proportion of different particle sizes and particles of the pulverized coal under various frequency working conditions is obtained, and further, the particle size d under different frequency working conditions is obtained p Equal particle count ratio for sum-averagingAnd (5) value processing to obtain more accurate coal powder fuel particle characteristics.
The foregoing is only a preferred embodiment of the invention, it being noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.
Claims (4)
1. The utility model provides a buggy fuel particle characteristic testing arrangement which characterized in that: the system comprises an acoustic wave generation system, a pulverized coal particle conveying system, a water bath temperature control system, a particle stripe imaging acquisition system and a data post-processing system;
the sound wave generation system comprises a signal generator (11), a power amplifier (12), a sound waveguide tube (14) and two identical Helmholtz sound sources (13) arranged at two ends of the sound waveguide tube (14);
the Helmholtz sound source (13) comprises a semi-closed structure which consists of a loudspeaker (131), a cavity (132), a through hole (133) and a plate (134) and is only formed by connecting the through hole (133) with the outside, wherein the loudspeaker (131) and the plate (134) are respectively positioned at two ends of the cavity (132); the inner diameter of the cavity (32) is larger than the inner diameter of the through hole (133); the through hole (133) is arranged on the center of the flat plate (134);
the sound waveguide tube (14) is a transparent round tube, and the inner diameter of the sound waveguide tube (14) is larger than the inner diameter of the through hole (133); two identical Helmholtz sound sources (13) are hermetically arranged at two ends of the sound waveguide tube (14) through flat plates (134) for ensuring that the through holes (133) are communicated with the sound waveguide tube (14);
the signal generator (11), the power amplifier (12) and the loudspeaker (131) are sequentially connected into an electrical loop through wires, the electrical loop is used for guaranteeing that through adjusting the output frequency of the signal generator (11) and the output voltage amplitude of the power amplifier (12), the input frequency and the input voltage amplitude of the loudspeaker (131) are adjusted, after the sound waves radiated by the loudspeaker (131) are acted by the cavity (132) and the through hole (133), two large-amplitude sound waves which are propagated in opposite directions are radiated inwards from two ends of the sound waveguide tube (14), the two sound waves interfere in the sound waveguide tube (14) to form a one-dimensional standing wave sound field (15) with a plurality of sound pressure antinodes and sound pressure nodes, and the coal dust forms particle stripes (42) at the sound pressure node positions of the standing wave field (15);
the pulverized coal particle conveying system is connected with the sound wave generating system and is used for conveying pulverized coal into the sound wave guide tube (14);
the water bath temperature control system is connected with the sound wave generation system and is used for heating coal dust in the sound wave guide tube (14);
the particle stripe imaging acquisition system is used for taking a particle stripe picture of a particle stripe (42) in the acoustic waveguide (14);
the data post-processing system is connected with the particle stripe imaging acquisition system and is used for analyzing and processing the particle stripe pictures;
the data post-processing system performs the steps of:
1) Extracting light intensity information of the particle stripe picture, further performing dimensionless processing to obtain dimensionless light intensity information I which corresponds to position variables x on the particle stripe one by one, and taking the light intensity information I as dimensionless data information n of the relative sizes of the number of particles at different positions;
2) Measuring and calculating the distance D between two adjacent stripes on the grain stripe picture es Comprising a distance D between the centers of two stripes 2 And distance D between adjacent edges of two stripes 1 Wherein D is es Corresponding to x, I and n one by one to form a four-dimensional set x-I-n-D es ；
3) Respectively let D es Equal to D 1 And D 2 And the particle diameter d is calculated by taking the formula of the particle stripe spacing p Upper limit value d of (2) 2 And a lower limit value d 1 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, the interval formula of the grain stripes is:
d in es Representing the measured spacing between two adjacent stripes; d, d p Represents the particle diameter of the constituent stripes; ρ a And ρ p Respectively representing the densities of the main stream gas medium and the particles in the non-uniform sound field; beta a And beta p Respectively representing the compressibility coefficients of the main stream gas medium and particles in the non-uniform sound field; k=2pi f/c represents wave number, f and c represent frequency and sound velocity of the non-uniform sound field, respectively; wherein, divide D es And d p All other variables can be obtained through routine experiments or table lookup;
d p and D es The X, the n and the I are also in one-to-one correspondence to form a five-dimensional set x-I-n-D es -d p Obtaining n and d p One-to-one correspondence;
4) Repeating the steps 1) -3) for each particle stripe picture of the sound pressure node to obtain a plurality of n-d equal to the number of each particle stripe picture p One-to-one correspondence, then particle diameter d p The dimensionless data information n of the equal grain stripe pictures are correspondingly added and averaged, namely, the dimensionless data information n is used as the quantity ratio of different grain sizes of coal powder particles obtained under a frequency working condition, namely, the characteristic of coal powder fuel particles under a certain frequency condition;
5) Changing the frequency and sound pressure intensity of the standing wave sound field, repeating the steps 1) to 4), obtaining the particle quantity ratio of different particle sizes of the pulverized coal under different frequency working conditions, and further, obtaining the particle size d under different frequency working conditions p And carrying out summation average treatment on the equal particle quantity ratio, and further obtaining the final pulverized coal fuel particle characteristics.
2. The pulverized coal fuel grain characteristics testing device according to claim 1, wherein: the pulverized coal particle conveying system comprises a pulverized coal conveying pipeline (21), a pulverized coal fan (22), a pulverized coal air valve (23), an acoustic waveguide pipe (14) and a pulverized coal conveying main pipeline (24), wherein the pulverized coal conveying pipeline (21) is used for connecting the pulverized coal fan (22), the pulverized coal air valve (23), the acoustic waveguide pipe (14) and the pulverized coal conveying main pipeline (24) into a sealed pulverized coal conveying loop;
the pulverized coal is conveyed into the acoustic waveguide tube (14) from the pulverized coal main pipeline (24) through the pulverized coal conveying pipeline (21) by utilizing the pulverized coal blower (22), and is conveyed back to the pulverized coal conveying main pipeline (24) through the pulverized coal conveying pipeline (21) after being subjected to the action of the standing wave sound field (15) in the acoustic waveguide tube (14);
the outside of the pulverized coal conveying pipeline (21) is subjected to heat preservation treatment, so that the pulverized coal is not cooled in the conveying process in the pulverized coal conveying pipeline (21);
an external heat source is additionally arranged on the pulverized coal conveying pipeline (21) and is used for heating and preserving heat for pulverized coal when the temperature of the external environment is too low and the temperature of the pulverized coal conveying pipeline (21) is too low.
3. The pulverized coal fuel grain characteristics testing device according to claim 1, wherein: the water bath temperature control system comprises a transparent glass sleeve (31), a hot water conveying pipeline (32), a hot water circulating pump (33), a temperature sensor (34), a temperature control switch (35), a power supply (36), a water tank (37) and an electric heater (38) which are arranged in the water tank (37), wherein the transparent glass sleeve is arranged outside the acoustic waveguide (14), the temperature sensor (34) is arranged in pulverized coal wind in the acoustic waveguide (14);
a hot water circulation pump (33), a water tank (37) and a glass sleeve (31) are connected into a water circulation loop by a hot water conveying pipeline (32) for ensuring that hot water flowing in the glass sleeve (31) uniformly heats coal dust in an acoustic waveguide (14);
connecting an electric heating circuit (38), a temperature control switch (35) and a power supply (36) into a heating electric loop by using wires, and connecting a temperature sensor (34) to the temperature control switch (35);
a temperature sensor (34) is used for controlling the on-off of a temperature control switch (35); when the temperature sensor (34) detects that the coal dust temperature in the acoustic waveguide tube (14) is lower than the coal dust temperature in the coal dust conveying pipeline (21), the temperature control switch (35) is closed, the electric heating (38) starts to work, the circulating water in the water tank (37) is heated until the coal dust temperature detected by the temperature sensor (34) is equal to the coal dust temperature in the coal dust conveying pipeline (21), and then the temperature control switch (35) is opened, so that the coal dust temperature in the acoustic waveguide tube (14) is equal to the coal dust temperature in the coal dust conveying pipeline (21).
4. The pulverized coal fuel grain characteristics testing device according to claim 1, wherein: the particle stripe imaging acquisition system comprises a light source (41), particle stripes (42) formed at the sound pressure node positions in the sound wave guide tube (14) under the action of the standing wave sound field (15), a lens (43), a camera (44) with a micro-distance microscopic function and a computer (45);
the light source (41) emits light to irradiate the particle stripes (42), the scattered light of the particle stripes (42) is emitted into the camera (44) through the lens (43) to be shot into particle stripe pictures, and a computer (45) connected with the camera (44) records the particle stripe pictures shot by the camera (44);
and the light source (41), the lens (43) and the camera (44) are translated to different sound pressure wave node positions along the axial direction of the sound wave guide tube (14) and are used for shooting and recording particle stripe pictures corresponding to more than one sound pressure wave node.
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