CN111208044A - Engine tail jet flow particulate parameter monitoring device and method - Google Patents

Abstract

According to the device and the method for monitoring the parameters of the particulate matters of the engine tail jet flow, the scattered light and the radiant light of the particles of the high-speed tail jet flow are measured simultaneously, the parameter analysis and the source identification of the particle diameter, the concentration, the components and the like of the particulate matters of the engine tail jet flow are established, the algorithm of the radiation parameters such as the radiation temperature, the radiation rate, the radiation intensity and the like is used for monitoring the parameters and the sources of the particle diameter, the concentration, the components and the like of the particulate matters of the tail jet flow synchronously, the radiation parameters such as the radiation temperature, the radiation rate, the radiation intensity and the like are monitored simultaneously, the three-dimensional image of the particles is rapidly triggered to be measured and captured, the three-dimensional. The engine tail jet flow particle parameter monitoring device comprises a laser light source part, a light receiving detection part, a particle three-dimensional imaging part and a particle monitoring processing part. The particulate matter monitoring and processing part processes, saves and displays the parameters of the particulate matter of the tail jet flow of the engine.

Description

Engine tail jet flow particulate parameter monitoring device and method

Technical Field

The invention belongs to the technical field of aerospace, and relates to a device and a method for monitoring parameters of particulate matters of engine tail jet flow.

Background

The exhaust tail jet of the aerospace engines such as the aero-engine, the rocket engine, the ramjet engine and the novel engine is usually the combustion product of the jet pipe which is discharged at supersonic speed, and the combustion product can be further diffused and expanded at the outlet of the jet pipe to form a flow field which emits light and heat.

The engine is the heart of an aerospace aircraft, the technology is complex, and the reliability requirement is extremely high. The engine safety monitoring system not only needs to work under severe conditions of high temperature, large stress and the like, but also needs to change working conditions frequently, so that the engine safety monitoring is one of important contents of engine tests and operation. In the ground test and flight process of the engine, due to the influence of severe working conditions such as high temperature, high pressure, strong vibration and the like and factors such as fatigue, creep deformation, material aging and the like, the key structural components such as turbine blades, wheel discs and the like are inevitably damaged due to collision and abrasion or coating shedding, and particles enter tail jet flow and can emit ultraviolet and visible emission spectra with strong enough intensity at high temperature to show the characteristics of Mars, so that a technical approach is provided for the evaluation and real-time detection and diagnosis of the working state of the engine. The monitoring of the engine tail jet flow particulate matter parameters can provide important support for safety evaluation of the working state of the engine, and no effective monitoring means for the engine tail jet flow particulate matter parameters exists at present.

Disclosure of Invention

One of the purposes of the invention is to provide a device and a method for monitoring parameters of particulate matters of engine tail jet flow, which are characterized in that the scattered light and the radiation light of particles of the engine tail jet flow are measured at the same time, so that the analysis and the source identification of parameters such as particle size, concentration and components of the particulate matters of the engine tail jet flow are established, and the algorithm of radiation parameters such as radiation temperature, radiation rate and radiation intensity is established, so that the parameters and the sources of the particle size, concentration and components of the particulate matters of the tail jet flow and the radiation parameters such as radiation temperature, radiation rate and radiation intensity are synchronously monitored, and meanwhile, three-dimensional images are rapidly triggered to measure and capture three-dimensional images of the particles, so that the three-dimensional size and the surface morphology of the.

The invention provides a monitoring device for particulate matter parameters of engine tail jet, which is characterized by comprising a laser light source part, a laser light source part and a monitoring device, wherein the laser light source part is positioned on one side of the engine tail jet and is used for generating incident laser with different wavelengths; the light receiving and detecting part is positioned on the other side of the tail jet flow of the engine and is used for receiving the radiation light or the scattered light, converting the radiation light or the scattered light into an electric signal and sending a particle monitoring trigger signal; the particle three-dimensional imaging part starts to work after receiving the particle monitoring trigger signal and obtains a particle three-dimensional image through backlight imaging and three-dimensional projection reconstruction; and the particle monitoring and processing part is used for controlling the working modes of the laser light source part and the light receiving and detecting part, wherein the particle monitoring and processing part is respectively in communication connection with the laser light source part, the photoelectric detecting part and the particle three-dimensional imaging part and is used for processing, storing and displaying the parameters of particles of the tail jet flow of the engine.

The invention provides an engine tail jet flow particle parameter monitoring device which is characterized in that a laser light source part comprises a laser controller, a plurality of lasers, an optical fiber coupler and a collimator, a particle monitoring processing part controls the working mode, the laser wavelength and the laser output intensity parameter of the laser controller, the laser controller controls the opening and closing of the two working modes, the laser wavelength and the laser output intensity parameter through a control signal cable by a characteristic signal testing processing part, laser generated by the lasers is output to the optical fiber coupler through the optical fiber, the optical fiber coupler receives the laser generated by the lasers and couples the laser to an output optical fiber, and the collimator is connected with the optical fiber coupler and outputs the laser to irradiate a measuring area.

In addition, in the engine tail jet particulate matter parameter monitoring device provided by the invention, the device also has the following characteristics: wherein, the light receiving and detecting part comprises a filter attenuator, a light converging optical fiber coupler, an optical fiber, a collimator, a grating, a plurality of photoelectric detectors and a photoelectric detection processor, the filter attenuator has two controllable working modes of filtering and non-filtering, tail jet radiation light, laser generated by a laser source part or a mixture of the tail jet radiation light and the laser irradiate particles in a tail jet measuring area, the particle scattered light enters the optical fiber coupler after passing through the filter attenuator, the filter attenuator and the optical fiber coupler are arranged on the same straight line, the angle between the straight line and the irradiation direction of the laser emitted by the laser source part is an acute angle, the collimator is connected with the optical fiber coupler through the optical fiber, collimated laser which is collimated by the particle scattered light is irradiated on the grating, the grating receives the collimated laser and then divides the collimated laser into a plurality of beams according to the wavelength, the plurality of photoelectric detectors respectively receive the plurality of beams and then convert the optical signals into, the photoelectric detection processor collects electric signals output by the photoelectric detectors and converts the electric signals into digital signals, the intensities of light with different wavelengths are obtained and output to the particle monitoring processing part, and a particle monitoring trigger signal is sent to the particle three-dimensional imaging part.

In addition, in the engine tail jet particulate matter parameter monitoring device provided by the invention, the device also has the following characteristics: the particle three-dimensional imaging part comprises at least two groups of light paths, a particle three-dimensional imaging processor and a trigger, wherein each group of light paths is provided with a light source, a lens and an industrial camera, and the trigger triggers the particle three-dimensional imaging processor to work after receiving a particle monitoring trigger signal output by the light receiving and detecting part, so that the light source, the lens and the industrial camera on the light paths are controlled to work.

In addition, in the engine tail jet particulate matter parameter monitoring device provided by the invention, the device also has the following characteristics: the particle monitoring and processing part is connected with the laser controller and used for controlling the generation and the closing, the wavelength and the intensity of incident laser, the particle monitoring and processing part is connected with the filter attenuator and used for controlling the working mode of the filter attenuator, the particle monitoring and processing part is connected with the photoelectric detection processor and used for obtaining the intensity of radiation light or scattered light, and based on the established engine tail jet flow particle parameter analysis algorithm, tail jet flow particle parameters are synchronously obtained.

In addition, in the engine tail jet particulate matter parameter monitoring device provided by the invention, the device also has the following characteristics: the light receiving and detecting part comprises a filter attenuator, a light converging optical fiber coupler, an optical fiber, a collimator, a grating, a plurality of photoelectric detectors and a photoelectric detection processor, wherein the filter attenuator has two controllable working modes of filtering and non-filtering, the attenuation degree is adjustable, the particle monitoring and processing part is controlled by a control signal cable, tail jet radiation light, laser generated by a laser source part or mixed light of the tail jet radiation light and the laser generated by the laser source part irradiate particles in a tail jet measuring area to generate particle scattering light, the particle scattering light enters the optical fiber coupler after passing through the filter attenuator, the filter attenuator and the optical fiber coupler are in the same straight line direction and form a certain angle with the irradiation direction of the laser emitted by the laser source part, the optical fiber outputs the light to the collimator after receiving the light to irradiate the grating, the grating divides the light into a plurality of light splitting according to the wavelength, the plurality of photoelectric detectors respectively receive the plurality of light splitting and then convert the light signals into, the photoelectric detection processor converts the electric signals into digital signals, obtains the intensities of light with different wavelengths, outputs the light to the particle monitoring and processing part through the digital signal communication cable, and sends out particle monitoring trigger signals to the particle three-dimensional imaging part through the cable.

The particle three-dimensional imaging part comprises two or more groups of light paths arranged at an angle, a particle three-dimensional imaging processor and a trigger, wherein each group of light paths is provided with a light source, a lens and an industrial camera, the trigger receives a particle monitoring trigger signal output by the light receiving and detecting part through a cable and triggers the particle three-dimensional imaging processor to start working, so that the light source, the lens and the industrial camera on each group of light paths are controlled by the cable to work, projected digital images of particles on the groups of light paths of the particles are captured through backlight imaging of each group of light paths, the digital images are sent to the particle three-dimensional imaging processor through a digital signal communication cable to be processed, three-dimensional images of the particles are obtained through a three-dimensional reconstruction algorithm, parameters such as particle size, shape indication and the like are further obtained through.

The particle monitoring processing part is connected with a laser controller through a control signal cable to control the generation and closing, wavelength and intensity of incident laser, is connected with a filter attenuator through a control signal cable to control a filtering and non-filtering working mode, is connected with a photoelectric detection processor through a digital signal communication cable to obtain the intensity of radiation light or scattered light, synchronously obtains parameters such as particle diameter, concentration, components and sources of tail jet flow particle parameters based on an established engine tail jet flow particle parameter analysis algorithm, is connected with a particle three-dimensional imaging part through the digital signal communication cable to obtain particle three-dimensional images, further obtains the parameters such as particle size, indicating form and the like through image analysis, and determines the particle sources, so that the working safety state of the engine is evaluated through the tail jet flow particle parameters.

The invention provides a device for monitoring parameters of particulate matters of tail jet flow of an engine, which has the following characteristics: the engine tail jet flow particulate matter parameter monitoring device has three working modes of radiation measurement, particle measurement and synchronous measurement:

in the radiation measurement working mode of the engine tail jet flow particle parameter monitoring device, a laser light source part adopts a closed working mode, a light receiving detection part adopts a non-filtering working mode, and the light receiving detection part is used for collecting and obtaining tail jet flow radiation light and directly detecting the intensity of the tail jet flow radiation light with different wavelengths in ultraviolet, visible and infrared wave bands so as to obtain radiation parameters such as tail jet flow radiation temperature, radiation rate, radiation intensity and the like; in the particle measuring working mode of the engine tail jet flow particle parameter monitoring device, the laser light source part adopts an opening working mode, the light receiving and detecting part adopts a filtering working mode and is used for filtering tail jet flow radiation light and converging scattered laser light with different wavelengths, detecting the intensity of the scattered laser light with different wavelengths after the tail jet flow radiation light is filtered and obtaining the particle size and concentration parameters of tail jet flow particles, and further evaluating the working safety state of an engine through the tail jet flow particle parameters.

In the synchronous measurement working mode of the engine tail jet flow particle parameter monitoring device, the laser light source part adopts an open working mode, the light receiving and detecting part adopts a non-filtering working mode and is used for collecting and obtaining tail jet flow radiation light and scattered laser mixed light, detecting the intensity of the radiation light with different wavelengths and the scattered laser mixed light and synchronously obtaining particle parameters such as tail jet flow particle size, concentration, components and source identification and radiation parameters such as radiation temperature, radiation rate and radiation intensity.

When the engine tail jet flow particle parameter monitoring device adopts any one of the working modes, the light receiving detection part sends out a particle monitoring trigger signal to the particle three-dimensional imaging part to trigger the three-dimensional imaging part to work while detecting the radiation light or the scattered light, the particle projection digital image on a plurality of groups of light paths of the particles is captured through the backlight imaging of a plurality of groups of light paths, the digital image is sent to the particle three-dimensional imaging processor by using a digital signal communication cable to be processed, the particle three-dimensional image is obtained through a three-dimensional reconstruction algorithm, the particle size, the shape indication and other parameters are further obtained through image analysis, and the particle source is determined.

The invention provides a device for monitoring parameters of particulate matters of tail jet flow of an engine, which has the following characteristics: the working mode of the engine tail jet flow particle parameter monitoring device is determined according to the parameter types which can be obtained by the working mode by combining the engine test requirements, and the working modes of the laser light source part and the light receiving detection part are correspondingly determined; the selection of the laser wavelengths of the lasers of the laser source part and the filtering wavelength range of the filter attenuator of the light receiving detection part is usually in the blue-violet light band, in order to eliminate the influence of tail jet radiation light; the intensity of a plurality of lasers, the attenuation rate of a filter attenuator, the size of a light gathering area of a light gathering optical fiber coupler and the selection of the beam cross section size of laser are determined according to a tail jet flow area to be monitored and a scattering light intensity signal-to-noise ratio, the beam cross section size of the laser needs to cover the tail jet flow area to be monitored, the scattering light intensity signal-to-noise ratio is related to the particle size and the concentration of tail jet flow particles, the larger the particle size or the higher the particle concentration is, the larger the generated scattering light intensity is, and the higher the.

The selection of the multiple photodetector wavelengths is determined in conjunction with testing the wavelengths at which the data needs to be analyzed.

The filter attenuator and the light-converging optical fiber coupler in the light receiving detection part are arranged in pairs, can be used as a filter attenuator and a light-converging optical fiber coupler for single-point detection, and can also be used as an annular array type filter attenuator and a light-converging optical fiber coupler for annular multipoint detection, so that the scattered light of particles at different positions of large-size engine tail jet flow can be detected.

The particle three-dimensional imaging part is arranged at a position with a certain distance from the light receiving detection part, the distance between the particle three-dimensional imaging part and the light receiving detection part is determined by the movement speed of particles in tail jet flow, and in order to ensure that the light receiving detection part can send a particle monitoring trigger signal to the particle three-dimensional imaging part to trigger the three-dimensional imaging part to work and capture particle images when the light receiving detection part monitors the particles.

The invention provides a device for monitoring parameters of particulate matters of tail jet flow of an engine, which has the following characteristics: the particles in the tail jet flow tested by the engine tail jet flow particle parameter monitoring device can be particles generated by combustion of engine fuel, and can also be particles generated by inevitable damage to key structural components such as engine turbine blades, wheel discs and the like due to collision and abrasion or falling of a coating under severe working conditions in the ground test and the flight process of the engine.

A method for monitoring the particulate parameters of the engine tail jet flow by adopting any one of the above monitoring devices for the particulate parameters of the engine tail jet flow is characterized by comprising the following steps:

s1: arranging engine tail jet flow particulate matter parameter monitoring devices on two sides of engine tail jet flow;

s2: determining the working mode of the engine tail jet flow particulate matter parameter monitoring device;

s3: opening an engine tail jet flow particulate matter parameter monitoring device, and carrying out engine tail jet flow particulate matter parameter monitoring;

s4: parameters such as particle size, concentration and components, three-dimensional images and sources of particles are obtained in real time based on the established engine tail jet flow particle analysis algorithm, so that the working safety state of the engine is evaluated through the tail jet flow particle parameters.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: the monitoring method of the particulate matter parameters of the tail jet flow of the engine also comprises three methods corresponding to three working modes of radiation measurement, particle measurement and synchronous measurement adopted by the monitoring device of the particulate matter parameters of the tail jet flow of the engine:

corresponding to the radiation measurement working mode adopted by the engine tail jet flow particulate matter parameter monitoring device, the engine tail jet flow particulate matter parameter monitoring method adopts tail jet flow ultraviolet, visible and infrared wave band different wavelength tail jet flow radiation light intensity data obtained by a light receiving detection part, the data has two characteristics of tail jet flow radiation continuous characteristic and particle radiation characteristic spectral line, and the two characteristics are stripped: obtaining spectral line wavelength and spectral line intensity parameters according to particle radiation characteristic spectral lines, determining particle components and particle concentration through a particle component inversion algorithm, and analyzing according to the radiation characteristic spectral line wavelength, spectral line intensity, particle components and particle concentration information through a particle source identification algorithm to obtain particle sources; according to the continuous radiation characteristic of the tail jet flow, radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow are obtained through a radiation parameter inversion algorithm such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow; and further evaluating the working safety state of the engine through the parameters of the tail jet flow particles.

The particle measurement working mode adopted by the particle parameter monitoring and measuring device corresponding to the engine tail jet flow is characterized in that the particle parameter monitoring method of the engine tail jet flow adopts intensity data of scattered laser with different wavelengths for filtering tail jet flow radiation light obtained by a light receiving and detecting part, and light signals obtained by detection of the light receiving and detecting part in a test are intensity of the scattered laser with different wavelengths.

Corresponding to the synchronous measurement working mode adopted by the engine tail jet flow particle parameter monitoring device, the engine tail jet flow particle parameter monitoring method adopts the intensity data of the radiation light and the scattering laser mixed light with different wavelengths obtained by the light receiving detection part, and the light signals obtained by the detection of the light receiving detection part in the test are the intensities of the radiation light and the scattering laser mixed light with different wavelengths, and have three characteristics of tail jet flow radiation continuity, particle radiation characteristic spectral line and scattering laser: obtaining spectral line wavelength and spectral line intensity parameters according to particle radiation characteristic spectral lines, determining particle components and particle concentration through a particle component inversion algorithm, and analyzing according to the radiation characteristic spectral line wavelength, spectral line intensity, particle components and particle concentration information through a particle source identification algorithm to obtain particle sources; according to the continuous radiation characteristic of the tail jet flow, radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow are obtained through a radiation parameter inversion algorithm such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow; according to the scattered laser characteristics, the scattered laser that causes for a plurality of lasers of laser light source portion to can obtain the mixed light superposition light intensity I' that different wavelengths correspond, the radiant light intensity in the mixed light needs to be deducted, thereby obtains accurate scattered laser light intensity I:

I＝I’-I_r

i' is the light intensity of the corresponding wavelength obtained by the test light receiving detection part, I_rThe radiation reference light intensity obtained by the interpolation of the intensity data of the peripheral wavelength radiation light is combined with the initial light intensity I₀And obtaining the particle diameter and concentration parameter of the tail jet flow particles by a synchronous inversion algorithm of the particle diameter and concentration parameter. Therefore, particle parameters such as particle size, concentration, components and source identification of the tail jet flow particles and radiation parameters such as radiation temperature, radiation rate and radiation intensity are synchronously obtained, and the working safety state of the engine is further evaluated through the parameters of the tail jet flow particles.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: the particle size and concentration parameter synchronous inversion algorithm is established on the basis of a particle angle scattering theory, and if incident light is completely polarized light, the distance between an observation point and scattering particles is L, and the included angle between a vibration surface and a scattering surface of the incident light is a polarization angle phi, the total scattering light intensity of the particles is I_s. Total scattered light intensity I_sIs composed of two parts: intensity of scattered light I generated perpendicular to the scattering surface_rAnd the intensity of the scattered light I generated in a direction parallel to the scattering surface_lI.e. I_s＝I_r+I_lWherein, in the step (A),

r is the particle size of the particles; theta is a scattering angle; s₁(theta) and s₂(theta) is an amplitude function related to the refractive index m and the dimensionless quantity α, but not to the polarization angle phi of the incident light, lambda is the wavelength of the incident light, I₀The intensity of the incident laser beam can be regarded as the intensity of the laser beam output from the laser light source unit.

The total scattered intensity I obtained in the case of incident light being fully polarized_sComprises the following steps:

i₁(theta) and i₂(theta) is an intensity function of the spherical particles, and is related to the scattering angle theta, the refractive index m, and the dimensionless parameter α, and is independent of the polarization angle phi of the incident light, whereas the dimensionless parameter α is related only to the wavelength lambda of the incident light and the particle size r of the particles_sMainly related to the scattering angle theta, the refractive index m, the wavelength lambda of the incident light and the particle size r of the particles. Thus, by measuring the angular scattering intensity of incident light at different wavelengths, different wavelengths λ can be established₁、λ₂、λ₃Lower angle scattered light intensity I_s,λ1、I_s,λ2、I_s,λ3Relationship with incident wavelength, particle size:

the particle size r can be calculated by solving the scattered light equation with different wavelengths.

Once the particle size is obtained, the particle number concentration N can be obtained through the quantitative relation between the angular scattering light intensity and the particle number concentration_v：

V is the volume of the detection zone.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: the particle component inversion algorithm is established in that the particle emits a sufficiently strong ultraviolet, visible or infrared band radiation spectrum characteristic spectral line in the high-temperature tail jet flow of the engine, and the particle component is determined through the characteristic spectral line.

The outer layer electrons of the atoms of the tail jet flow particles are in a ground state in a normal state, and after the atoms are excited by the outside of a high-temperature environment, the atoms in the excited state are in an extremely unstable state, and the outer layer electrons spontaneously jump from a high energy level to a low energy level and release photons. Atomic spontaneous emission radio frequencyRatio v and energy level difference (E)₁-E₂) In relation to, satisfy:

hν＝E₁-E₂

h is the Planck constant.

When the system is in a thermal equilibrium state, the distribution among the energy steady states of the atoms follows a boltzmann distribution:

N_nand N₁Number of atoms in excited and ground states, g_nAnd g₁Atomic number and statistical weight, E, for the excited and ground states, respectively_1nThe excitation energy required for the ground state to the excited state, k is the boltzmann constant, and T is the temperature at which the atoms are located. From this, the particle composition can be determined and the component concentration obtained by analysis of the characteristic spectral line wavelength and intensity.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: the particle source identification algorithm is mainly obtained based on a K-means clustering algorithm of tail jet flow radiation spectrum clustering analysis.

The basic idea of K-means clustering is to randomly select K data samples from a data set containing a large number of solid particle radiation spectrum samples as initial clustering centers, count the distance between each spectrum sample and the K initial clustering centers, divide all the spectrum data into the class represented by the clustering center closest to the spectrum sample, and update the K clustering centers according to the mean value of the newly generated spectrum samples in each class. If the change of the clustering center value in the adjacent iteration times exceeds the set threshold value, performing classification again on all the spectrum samples according to the new clustering center; and if the change of the clustering central value in the adjacent iteration times is smaller than a specified threshold value, the algorithm converges and a clustering result is output.

The K-means clustering algorithm flow is as follows:

(a) selecting an original data set of K-mean clustering, and randomly selecting K spectral samples from the original data set as an initial clustering center z₁,z₂,…,z_k；

(b) Calculating the distances from the sample data to k condensation points one by one (generally, Euclidean distance is used as the distance from the sample to the clustering center), and dividing n samples (or variables) into k classes according to the distance, wherein the Euclidean distance calculation formula is as follows:

x_iis the variable value of the ith variable of the sample x, y_iAre the variable values of the i variables of the sample y. If the distance from the spectrum sample to the original class is the shortest, the spectrum sample is still in the original class, otherwise, the spectrum sample is moved to the class which is the shortest;

(c) and (c) calculating the clustering center of each type of data in the k types, if the clustering center is not coincident with the initial clustering center, taking the clustering center as a new clustering center, repeating the step (b) until all the spectrum samples cannot move or each clustering center is not changed, and terminating the calculation process, thereby identifying the source of the engine tail jet flow particles.

Through a large amount of tail jet flow radiation spectral clustering analysis, specific wavelength characteristics of particle source identification can be obtained, so that the wavelength intensity data of radiation light of all wave bands does not need to be obtained, only a plurality of data of determined wavelengths are needed, and an engine tail jet flow particle parameter monitoring device and a particle source identification algorithm can be further simplified.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: the inversion algorithm of radiation parameters such as tail jet radiation temperature, radiation rate, radiation intensity and the like is established based on a Planck radiation law parameter fitting method.

The measured radiation intensities of the tail jet flow at different wavelengths are as follows:

epsilon is the average radiance of tail jet flow, and the value is a constant between 0 and 1; t is the field-of-view average thermodynamic temperature, k is the different wavelength probe response correction coefficient, which is related to the photoelectric probe response, the optical fiber transmission and the relevant parameters of the test system.

According to the measuring working condition and the calculation range, under the condition of lambda T < <2000 mu mT, the Planck radiation law can be simplified into a Wien relation:

taking logarithm at both ends of the equal sign of the above formula, making epsilon '═ ln epsilon, T ═ 1/T, and substituting epsilon' and T into the above formula to obtain:

establishing a multivariate function f (ε', t) using a polynomial y_iAnd (3) carrying out curve fitting:

y_iis measured by experiment to obtain a wavelength of lambda_iThe logarithm of the intensity of the radiation. According to the least square method, when the square sum of the deviation in the above formula is minimum, the corresponding values of epsilon 'and T are obtained through calculation, and the average temperature and radiance parameters obtained through experimental measurement can be obtained by substituting the formula epsilon' into ln epsilon and the formula T into 1/T.

On the basis of obtaining the radiation temperature and the radiation rate parameters of the tail jet flow, the radiation intensity of the tail jet flow with different wavelengths in all bands such as ultraviolet, visible and infrared bands can be calculated according to the Planck's law, and the total radiation intensity can be obtained through all-band integration.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: when any one of the methods is adopted in the engine tail jet flow particulate parameter monitoring method, when particulate matter is monitored, a three-dimensional imaging part is triggered to obtain a three-dimensional image of the particulate matter, and a three-dimensional reconstruction algorithm is obtained based on reconstruction of a plurality of groups of particle projection digital images on light paths.

If two groups of light paths are adopted and are arranged to be vertical, one group of light paths obtains horizontal projection and contains the appearance characteristics of particles in the horizontal direction, the other group of light paths obtains vertical projection and contains the appearance characteristics of particles in the vertical direction, and the three-dimensional images of the particles can be reconstructed through restoration of the horizontal and vertical projections.

If more groups of light paths are adopted, more particle projection images in the light path direction can be obtained, and therefore a particle three-dimensional image can be reconstructed more accurately.

After the three-dimensional image of the particles is obtained, the particle size distribution and the particle counting concentration parameters can be calculated according to image processing.

The source of the particles can be further confirmed by combining the engine working engineering according to the surface morphology of the particles.

In addition, the method for monitoring the parameters of the particulate matters in the tail jet flow of the engine provided by the invention can also have the following characteristics: the method for evaluating the working safety state of the engine through the parameters of the tail jet flow particles comprises the steps of determining the types of the particles by monitoring the parameters of the tail jet flow particles, determining the source of the particles, and determining the combustion and safe operation conditions of the test fuel of the engine by combining the particle size and the concentration parameters of the particles.

Action and Effect of the invention

The invention relates to a device and a method for monitoring parameters of particulate matters of engine tail jet flow, which have the following effects:

(1) according to the invention, by measuring the radiation energy distribution of the tail jet flow in ultraviolet, visible and infrared bands and the angular scattering light intensity of laser with different wavelengths after passing through the tail jet flow to be detected, an engine tail jet flow particle parameter analysis algorithm is established, particle parameters such as particle size, concentration, components, source identification and the like of tail jet flow particles are synchronously obtained, the occurrence of the particles is rapidly judged through photoelectric detection, then three-dimensional imaging of the particles is synchronously triggered, the three-dimensional size and surface form of the particles are further determined, the particle source is determined, and thus the working safety state of the engine is evaluated through the tail jet flow particle parameters.

(2) The particle photoelectric detection is adopted to quickly obtain the optical signal of the particles in the tail jet flow, the data processing is extremely quick, the long-term monitoring of the particles can be realized, and therefore the three-dimensional imaging of the particles is synchronously triggered, the capture of the particles with quick motion of the tail jet flow is met, and the omission detection can be avoided.

(3) When the synchronous measurement working mode is adopted, the intensity data of the mixed light of the radiant light and the scattered laser with different wavelengths is obtained by detection, and the intensity data of the scattered laser in the mixed light can be obtained by data conversion, so that the synchronous test of particle parameters such as the particle size, the concentration, the components and the source identification of tail jet flow particles and the radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity is realized. And the particle size and concentration measurement accuracy can be improved through the combined solution of multi-wavelength scattered light.

(4) The laser wavelength, the intensity, the working mode, the filtering wavelength range of the filter attenuator of the light receiving detection part, the attenuation rate, the working mode, the selection of the data wavelength and the like of a plurality of lasers of the laser light source part need to be selected and determined by combining parameters such as the particle size parameter range of the tail jet flow of the engine, the particle concentration parameter concentration, the radiation characteristic of the tail jet flow and the like, the wavelength of the laser is generally blue-violet light, the measurement of the laser scattering light intensity can be ensured not to be influenced by the radiation light, and the particle size and concentration parameter test precision is improved.

Drawings

FIG. 1 is a schematic view of a device for monitoring parameters of particulate matters in tail jet flow of an engine in an embodiment;

FIG. 2 is a schematic diagram of an arrangement of an annular array type filter attenuator and a light converging fiber coupler for annular multipoint detection of a light receiving detection part of the engine tail jet flow particle parameter monitoring device in the embodiment;

FIG. 3 is a typical data processing diagram of three operation modes of monitoring particulate matter parameters of engine tail jet flow in the embodiment;

FIG. 4 is a schematic diagram of three-dimensional reconstruction particles projected by two sets of perpendicular optical paths in the method for monitoring parameters of particulate matters in tail jet flow of an engine in the embodiment.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the efficacy of the invention easy to understand, the following embodiments are combined with the accompanying drawings to specifically describe the device and the method for monitoring the parameters of the engine tail jet flow particles.

As shown in fig. 1, the present embodiment provides an engine tail jet particulate parameter monitoring device, which includes a laser light source unit 2, a light receiving and detecting unit 3, a three-dimensional particulate imaging unit 4, and a particulate monitoring and processing unit 5.

The testing device comprises a laser light source part 2 and a light receiving and detecting part 3 which are correspondingly arranged on two sides of a tail jet flow 12 of an engine 11.

The laser light source unit 2 is located on the side of the tail jet 12 of the engine 11 and generates incident laser light having different wavelengths.

The light receiving and detecting part 3 is positioned at the other side of the tail jet flow 12 of the engine 11 and is used for receiving the radiated light or the scattered light, converting the radiated light or the scattered light into an electric signal and sending out a particle monitoring trigger signal.

The particle three-dimensional imaging part 4 starts to work after receiving the particle monitoring trigger signal, and obtains a particle three-dimensional image through backlight imaging and three-dimensional projection reconstruction.

The particle monitoring and processing part 5 is used for controlling the working modes of the laser light source part 2 and the light receiving and detecting part 3, and processing, storing and displaying the parameters of the particles of the tail jet flow of the engine.

The laser light source unit 2 includes a laser controller 21, a plurality of lasers 22, 23, and 24, a fiber coupler 27, and a collimator 29.

The particle monitoring and processing part 5 controls the working mode of the laser controller 21, the wavelengths of the lasers 22, 23 and 24 and the laser output intensity parameter through the control signal cable 51, and the laser controller 21 has two working modes of opening and closing.

The laser controller 21 and the lasers 22, 23, and 24 are connected in parallel through a cable 25, respectively, and are configured to control the lasers 22, 23, and 24 with different wavelengths to generate laser light.

The laser light generated by the lasers 22, 23, 24 is output to the optical fiber coupler 27 through the optical fiber 26, the optical fiber coupler 27 receives the laser light generated by the lasers 22, 23, 24 and couples the laser light to the output optical fiber 28, and is connected with the collimator 29, and the collimator 29 outputs the laser light 20 to irradiate the measuring area.

The light reception detecting unit 3 includes a filter attenuator 31, a light collecting fiber coupler 32, an optical fiber 33, a collimator 34, a grating 36, a plurality of photodetectors 362, 364, 366, and a photodetector processor 38.

The filter attenuator 31 has two controllable operation modes of filtering and non-filtering, and the attenuation degree is adjustable, and is controlled by the particulate matter monitoring processing part 5 through the control signal cable 52.

The radiation light of the tail jet 12, the laser light generated by the laser light source unit 2, or a mixture thereof irradiates the particles 131 in the measurement region of the tail jet 12 to generate particle scattered light 30, and the particle scattered light passes through the filter attenuator 31 and enters the optical fiber coupler 32, and the filter attenuator 31 and the optical fiber coupler 32 are aligned in the same direction and form a certain angle with the irradiation direction of the laser light 20 emitted from the laser light source unit 2. The fiber coupler 32 receives the light and outputs the light to the collimator 34 through the fiber 33 to emit light 35, irradiates the grating 36, the grating 36 receives the light 35 and then divides the light into multiple beams 361, 363, 365 according to the wavelength, and the multiple photodetectors 362, 364, 366 receive the multiple beams 361, 363, 365 respectively and then convert the light signals into electrical signals to output the electrical signals to the photodetector processor 38 through the cable 37.

The photoelectric detection processor 38 converts the electrical signal into a digital signal, obtains the intensities of light with different wavelengths, outputs the digital signal to the particle monitoring processing part 5 through the digital signal communication cable 53, and sends a particle monitoring trigger signal to the particle three-dimensional imaging part 4 through the cable 47.

The particle three-dimensional imaging section 4 includes a plurality of sets of angularly arranged optical paths, a particle three-dimensional imaging processor 43, and a trigger 44.

In the embodiment, the three-dimensional particle imaging part 4 has two sets of orthogonally arranged light paths (411-.

The trigger 44 receives the particle monitoring trigger signal output by the light receiving and detecting part 38 through the cable 47, and triggers the particle three-dimensional imaging processor 43 to start working, so as to control the light source, the lens and the industrial camera on each set of optical paths to work through the cables 45 and 46, capture the projection digital image of the particles 132 on the multiple sets of optical paths through the backlight imaging of each set of optical paths, send the projection digital image to the particle three-dimensional imaging processor 43 for processing by using the digital signal communication cables 45 and 46, obtain the three-dimensional image of the particles 132 through the three-dimensional reconstruction algorithm, further obtain the parameters such as particle size, shape and the like through image analysis, clarify the particle source, and transmit the parameters to the particle monitoring and processing part 5 through the cable.

The particle monitoring and processing part 5 is connected with a laser controller 21 through a control signal cable 51 to control the generation and closing, wavelength and intensity of incident laser, is connected with a filter attenuator 31 through a control signal cable 52 to control the working modes of filtering and non-filtering, is connected with a photoelectric detection processor 38 through a digital signal communication cable 53 to obtain the intensity of radiation light or scattered light, synchronously obtains parameters such as the particle diameter, concentration, components and sources of tail jet flow particle parameters based on the established engine tail jet flow particle parameter analysis algorithm, is connected with the particle three-dimensional imaging part 4 through a digital signal communication cable 54 to obtain particle three-dimensional images, further obtains the parameters such as particle size, indication form and the like through image analysis, determines the particle sources, and accordingly evaluates the working safety state of the engine through the tail jet flow parameters.

Further, the engine tail jet flow particulate matter parameter monitoring device has three working modes of radiation measurement, particle measurement and synchronous measurement:

in the radiation measurement working mode of the engine tail jet flow particle parameter monitoring device, a laser light source part adopts a closed working mode, a light receiving detection part adopts a non-filtering working mode, and the light receiving detection part is used for collecting and obtaining tail jet flow radiation light and directly detecting the intensity of the tail jet flow radiation light with different wavelengths in ultraviolet, visible and infrared wave bands so as to obtain radiation parameters such as tail jet flow radiation temperature, radiation rate, radiation intensity and the like;

in the particle measuring working mode of the engine tail jet flow particle parameter monitoring device, the laser light source part adopts an opening working mode, the light receiving and detecting part adopts a filtering working mode and is used for filtering tail jet flow radiation light and converging scattered laser light with different wavelengths, detecting the intensity of the scattered laser light with different wavelengths after the tail jet flow radiation light is filtered and obtaining the particle size and concentration parameters of tail jet flow particles, and further evaluating the working safety state of an engine through the tail jet flow particle parameters.

In the synchronous measurement working mode of the engine tail jet flow particle parameter monitoring device, the laser light source part adopts an open working mode, the light receiving and detecting part adopts a non-filtering working mode and is used for collecting and obtaining tail jet flow radiation light and scattered laser mixed light, detecting the intensity of the radiation light with different wavelengths and the scattered laser mixed light and synchronously obtaining particle parameters such as tail jet flow particle size, concentration, components and source identification and radiation parameters such as radiation temperature, radiation rate and radiation intensity.

When the engine tail jet flow particle parameter monitoring device adopts any one of the working modes, the light receiving detection part sends out a particle monitoring trigger signal to the particle three-dimensional imaging part to trigger the three-dimensional imaging part to work while detecting the radiation light or the scattered light, the particle projection digital image on a plurality of groups of light paths of the particles is captured through the backlight imaging of a plurality of groups of light paths, the digital image is sent to the particle three-dimensional imaging processor by using a digital signal communication cable to be processed, the particle three-dimensional image is obtained through a three-dimensional reconstruction algorithm, the particle size, the shape indication and other parameters are further obtained through image analysis, and the particle source is determined.

Further, the working mode of the engine tail jet flow particle parameter monitoring device is determined according to the parameter types which can be obtained by the working mode by combining the engine test requirements, and correspondingly determines the working modes of the laser light source part and the light receiving detection part.

The selection of the laser wavelengths of the lasers of the laser source part and the filtering wavelength range of the filter attenuator of the light receiving detection part is usually in the blue-violet light band, in order to eliminate the influence of tail jet radiation light;

the intensity of a plurality of lasers, the attenuation rate of a filter attenuator, the size of a light gathering area of a light gathering optical fiber coupler and the selection of the beam cross section size of laser are determined according to a tail jet flow area to be monitored and a scattering light intensity signal-to-noise ratio, the beam cross section size of the laser needs to cover the tail jet flow area to be monitored, the scattering light intensity signal-to-noise ratio is related to the particle size and the concentration of tail jet flow particles, the larger the particle size or the higher the particle concentration is, the larger the generated scattering light intensity is, and the higher the.

The selection of the multiple photodetector wavelengths is determined in conjunction with testing the wavelengths at which the data needs to be analyzed.

The filter attenuator and the light-converging optical fiber coupler in the light receiving detection part are arranged in pairs, can be used as a filter attenuator and a light-converging optical fiber coupler for single-point detection, and can also be used as an annular array type filter attenuator and a light-converging optical fiber coupler for annular multipoint detection, so that the scattered light of particles at different positions of large-size engine tail jet flow can be detected.

Fig. 2 is a schematic layout diagram of the ring array type filter attenuator and the light converging fiber coupler for ring multi-point detection of the light receiving detection portion, as shown in fig. 2, incident laser irradiates the engine tail jet flow, and scattered light is received by the ring array type filter attenuator and the light converging fiber coupler for multi-point detection of the light receiving detection portion, so as to ensure that particle scattered light at different positions of the engine tail jet flow is detected, wherein the incident laser may be volume light.

The particle three-dimensional imaging part 4 is arranged at a position with a certain distance from the light receiving detection part, the distance between the particle three-dimensional imaging part 4 and the light receiving detection part 3 is determined by the movement speed of the particles 131 in the tail stream, in order to ensure that the light receiving detection part 3 can monitor the particles, and simultaneously, a particle monitoring trigger signal is sent to the particle three-dimensional imaging part 4 to trigger the three-dimensional imaging part to work so as to capture the images of the particles 132, wherein the particles 131 and the particles 132 are indicated by the same particles at different time positions.

Further, particles in the tail jet flow tested by the engine tail jet flow particle parameter monitoring device can be particles generated by combustion of engine fuel, and can also be particles generated by inevitable damage to key structural components such as engine turbine blades, wheel discs and the like due to rubbing or falling of a coating under severe working conditions in the ground test and the flight process of the engine.

The embodiment also provides a method for monitoring parameters of particulate matters of engine tail jet, which comprises the following steps:

s1: arranging engine tail jet flow particulate matter parameter monitoring devices on two sides of engine tail jet flow;

s2: determining the working mode of the engine tail jet flow particulate matter parameter monitoring device;

s3: opening an engine tail jet flow particulate matter parameter monitoring device, and carrying out engine tail jet flow particulate matter parameter monitoring;

s4: parameters such as particle size, concentration and components, three-dimensional images and sources of particles are obtained in real time based on the established engine tail jet flow particle analysis algorithm, so that the working safety state of the engine is evaluated through the tail jet flow particle parameters.

Further, three working modes of radiation measurement, particle measurement and synchronous measurement are adopted by the engine tail jet flow particle parameter monitoring device, and the engine tail jet flow particle parameter monitoring method also comprises three methods:

corresponding to the radiation measurement working mode adopted by the engine tail jet flow particulate matter parameter monitoring device, the engine tail jet flow particulate matter parameter monitoring method adopts tail jet flow ultraviolet, visible and infrared wave band different wavelength tail jet flow radiation light intensity data obtained by a light receiving detection part, as shown in fig. 3(a), the data has two characteristics of tail jet flow radiation continuous characteristic and particle radiation characteristic spectral line, and the two characteristics are separated: obtaining spectral line wavelength and spectral line intensity parameters according to particle radiation characteristic spectral lines, determining particle components and particle concentration through a particle component inversion algorithm, and analyzing according to the radiation characteristic spectral line wavelength, spectral line intensity, particle components and particle concentration information through a particle source identification algorithm to obtain particle sources; according to the continuous radiation characteristic of the tail jet flow, radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow are obtained through a radiation parameter inversion algorithm such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow; and further evaluating the working safety state of the engine through the parameters of the tail jet flow particles.

Corresponding to the particle measurement working mode adopted by the engine tail jet particle parameter monitoring and measuring device, the engine tail jet particle parameter monitoring method adopts the intensity data of different wavelengths of scattering laser of the filtered tail jet radiation light obtained by the light receiving and detecting part, as shown in fig. 3(b), the light signals obtained by the light receiving and detecting part in the test are the intensities of the different wavelengths of scattering laser, for a plurality of lasers of the laser light source part, a plurality of signal peak values are provided, so that the different wavelengths of laser scattering light intensity I is obtained, the tail jet particle diameter and the concentration parameter are synchronously obtained by a particle diameter and concentration parameter synchronous inversion algorithm, and the working safety state of the engine is further evaluated by the tail jet particle parameter.

Corresponding to the synchronous measurement mode adopted by the engine tail jet flow particle parameter monitoring device, the engine tail jet flow particle parameter monitoring method adopts intensity data of the radiation light and the scattered laser mixed light with different wavelengths obtained by the light receiving detection part, as shown in fig. 3(c), the intensity data is an optical signal obtained by the detection of the light receiving detection part in the test, namely the intensity of the radiation light and the scattered laser mixed light with different wavelengths, and has three characteristics of tail jet flow radiation continuity, particle radiation characteristic spectral line and scattered laser, in fig. 3(c), I' is the light intensity of the corresponding wavelength obtained by the test photoelectric detection part, I_rAnd the radiation reference light intensity is obtained by interpolating the intensity data of the peripheral wavelength radiation light.

Obtaining spectral line wavelength and spectral line intensity parameters according to particle radiation characteristic spectral lines, determining particle components and particle concentration through a particle component inversion algorithm, and analyzing according to the radiation characteristic spectral line wavelength, spectral line intensity, particle components and particle concentration information through a particle source identification algorithm to obtain particle sources;

according to the continuous radiation characteristic of the tail jet flow, radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow are obtained through a radiation parameter inversion algorithm such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow; according to the scattered laser characteristics, the scattered laser that causes for a plurality of lasers of laser light source portion to can obtain the mixed light superposition light intensity I' that different wavelengths correspond, the radiant light intensity in the mixed light needs to be deducted, thereby obtains accurate scattered laser light intensity I:

I＝I’-I_r

i' obtained by testing light-receiving detecting partLight intensity of corresponding wavelength, I_rThe radiation reference light intensity obtained by the interpolation of the intensity data of the peripheral wavelength radiation light is combined with the initial light intensity I₀And obtaining the particle diameter and concentration parameter of the tail jet flow particles by a synchronous inversion algorithm of the particle diameter and concentration parameter. Therefore, particle parameters such as particle size, concentration, components and source identification of the tail jet flow particles and radiation parameters such as radiation temperature, radiation rate and radiation intensity are synchronously obtained, and the working safety state of the engine is further evaluated through the parameters of the tail jet flow particles.

Furthermore, the particle size and concentration parameter synchronous inversion algorithm is based on the particle angle scattering theory, assuming that the incident light is completely polarized light, the distance between the observation point and the scattering particles is L, the included angle between the vibration surface of the incident light and the scattering surface is the polarization angle phi, and then the total scattering light intensity of the particles is I_s. Total scattered light intensity I_sIs composed of two parts: intensity of scattered light I generated perpendicular to the scattering surface_rAnd the intensity of the scattered light I generated in a direction parallel to the scattering surface_lI.e. I_s＝I_r+I_lWherein, in the step (A),

r is the particle size of the particles; theta is a scattering angle; s₁(theta) and s₂(theta) is an amplitude function related to the refractive index m and the dimensionless quantity α, but not to the polarization angle phi of the incident light, lambda is the wavelength of the incident light, I₀The intensity of the incident laser beam can be regarded as the intensity of the laser beam output from the laser light source unit.

The total scattered intensity I obtained in the case of incident light being fully polarized_sComprises the following steps:

i₁(theta) and i₂(theta) is an intensity function of the spherical particles, and is related to the scattering angle theta, the refractive index m, and the dimensionless parameter α, and is independent of the polarization angle phi of the incident light, whereas the dimensionless parameter α is related only to the wavelength lambda of the incident light and the particle size r of the particles_sMainly related to the scattering angle theta, the refractive index m, the wavelength lambda of the incident light and the particle size r of the particles. Thus, by measuring the angular scattering intensity of incident light at different wavelengths, different wavelengths λ can be established₁、λ₂、λ₃Lower angle scattered light intensity I_s,λ1、I_s,λ2、I_s,λ3Relationship with incident wavelength, particle size:

the particle size r can be calculated by solving the scattered light equation with different wavelengths.

Once the particle size is obtained, the particle number concentration N can be obtained through the quantitative relation between the angular scattering light intensity and the particle number concentration_v：

V is the volume of the detection zone.

Further, the particle component inversion algorithm is established in that the particle emits a sufficiently strong ultraviolet, visible or infrared band radiation spectrum characteristic spectral line in the high-temperature tail jet flow of the engine, and the particle component is determined through the characteristic spectral line.

The outer layer electrons of the atoms of the tail jet flow particles are in a ground state in a normal state, and after the atoms are excited by the outside of a high-temperature environment, the atoms in the excited state are in an extremely unstable state, and the outer layer electrons spontaneously jump from a high energy level to a low energy level and release photons. Atomic spontaneous emission frequency v and energy level difference (E)₁-E₂) In relation to, satisfy:

hν＝E₁-E₂

h is the Planck constant.

When the system is in a thermal equilibrium state, the distribution among the energy steady states of the atoms follows a boltzmann distribution:

N_nand N₁Number of atoms in excited and ground states, g_nAnd g₁Atomic number and statistical weight, E, for the excited and ground states, respectively_1nThe excitation energy required for the ground state to the excited state, k is the boltzmann constant, and T is the temperature at which the atoms are located. From this, the particle composition can be determined and the component concentration obtained by analysis of the characteristic spectral line wavelength and intensity.

Further, the particle source identification algorithm is mainly obtained based on a K-means clustering algorithm of tail jet flow radiation spectrum clustering analysis.

The basic idea of K-means clustering is to randomly select K data samples from a data set containing a large number of solid particle radiation spectrum samples as initial clustering centers, count the distance between each spectrum sample and the K initial clustering centers, divide all the spectrum data into the class represented by the clustering center closest to the spectrum sample, and update the K clustering centers according to the mean value of the newly generated spectrum samples in each class. If the change of the clustering center value in the adjacent iteration times exceeds the set threshold value, performing classification again on all the spectrum samples according to the new clustering center; and if the change of the clustering central value in the adjacent iteration times is smaller than a specified threshold value, the algorithm converges and a clustering result is output.

The K-means clustering algorithm flow is as follows:

(a) selecting an original data set of K-mean clustering, and randomly selecting K spectral samples from the original data set as an initial clustering center z₁,z₂,…,z_k；

(b) Calculating the distances from the sample data to k condensation points one by one (generally, Euclidean distance is used as the distance from the sample to the clustering center), and dividing n samples (or variables) into k classes according to the distance, wherein the Euclidean distance calculation formula is as follows:

x_iis the variable value of the ith variable of the sample x, y_iAre the variable values of the i variables of the sample y. If the distance from the spectrum sample to the original class is the shortest, the spectrum sample is still in the original class, otherwise, the spectrum sample is moved to the class which is the shortest;

(c) and (c) calculating the clustering center of each type of data in the k types, if the clustering center is not coincident with the initial clustering center, taking the clustering center as a new clustering center, repeating the step (b) until all the spectrum samples cannot move or each clustering center is not changed, and terminating the calculation process, thereby identifying the source of the engine tail jet flow particles.

Through a large amount of tail jet flow radiation spectral clustering analysis, specific wavelength characteristics of particle source identification can be obtained, so that the wavelength intensity data of radiation light of all wave bands does not need to be obtained, only a plurality of data of determined wavelengths are needed, and an engine tail jet flow particle parameter monitoring device and a particle source identification algorithm can be further simplified.

Further, an inversion algorithm of radiation parameters such as tail jet radiation temperature, radiation rate and radiation intensity is established based on a Planck's radiation law parameter fitting method.

The measured radiation intensities of the tail jet flow at different wavelengths are as follows:

epsilon is the average radiance of tail jet flow, and the value is a constant between 0 and 1; t is the field-of-view average thermodynamic temperature, k is the different wavelength probe response correction coefficient, which is related to the photoelectric probe response, the optical fiber transmission and the relevant parameters of the test system.

According to the measuring working condition and the calculation range, under the condition of lambda T < <2000 mu mT, the Planck radiation law can be simplified into a Wien relation:

taking logarithm at both ends of the equal sign of the above formula, making epsilon '═ ln epsilon, T ═ 1/T, and substituting epsilon' and T into the above formula to obtain:

establishing a multivariate function f (ε', t) using a polynomial y_iAnd (3) carrying out curve fitting:

y_iis measured by experiment to obtain a wavelength of lambda_iThe logarithm of the intensity of the radiation. According to the least square method, when the square sum of the deviation in the above formula is minimum, the corresponding values of epsilon 'and T are obtained through calculation, and the average temperature and radiance parameters obtained through experimental measurement can be obtained by substituting the formula epsilon' into ln epsilon and the formula T into 1/T.

On the basis of obtaining the radiation temperature and the radiation rate parameters of the tail jet flow, the radiation intensity of the tail jet flow with different wavelengths in all bands such as ultraviolet, visible and infrared bands can be calculated according to the Planck's law, and the total radiation intensity can be obtained through all-band integration.

Further, when any one of the radiation measurement, particle measurement and synchronous measurement is adopted in the engine tail jet flow particle parameter monitoring method, when particles are monitored, the three-dimensional imaging part is triggered to obtain particle three-dimensional images, and the three-dimensional reconstruction algorithm is obtained based on the reconstruction of the particle projection digital images on multiple groups of light paths.

If two sets of optical paths are adopted, the two sets of optical paths are arranged to be vertical, as shown in fig. 4, one set of optical paths obtains horizontal projection, namely the particle projection on the zoy plane, and contains the appearance characteristics of the particles in the horizontal direction, the other set of optical paths obtains vertical projection, namely the particle projection on the xoy plane, and contains the appearance characteristics of the particles in the vertical direction, and the particle three-dimensional image can be reconstructed through restoration of the horizontal and vertical projections.

If more groups of light paths are adopted, more particle projection images in the light path direction can be obtained, and therefore a particle three-dimensional image can be reconstructed more accurately.

After the three-dimensional image of the particles is obtained, the particle size distribution and the particle counting concentration parameters can be calculated according to image processing.

The source of the particles can be further confirmed by combining the engine working engineering according to the surface morphology of the particles.

Further, the method for evaluating the working safety state of the engine through the parameters of the tail jet flow particles is to determine the types of the particles by monitoring the parameters of the tail jet flow particles, determine the source of the particles and judge the combustion and safe operation conditions of the test fuel of the engine by combining the particle size and the concentration parameters of the particles.

Effects and effects of the embodiments

The device and the method for monitoring the parameters of the particulate matters of the tail jet flow of the engine have the following effects:

(1) according to the embodiment, the distribution of the radiation energy of the tail jet flow in ultraviolet, visible and infrared bands is measured, the angle scattering light intensity of laser with different wavelengths after passing through the tail jet flow to be detected is measured, an engine tail jet flow particle parameter analysis algorithm is established, particle parameters such as the particle size, concentration, components, source identification and the like of tail jet flow particles are obtained singly or synchronously, the occurrence of the particles is rapidly judged through photoelectric detection, then three-dimensional imaging of the particles is triggered synchronously, the three-dimensional size and surface form of the particles are further determined, the particle source is determined, and therefore the working safety state of the engine is evaluated through the tail jet flow particle parameters.

(2) The particle photoelectric detection is adopted to quickly obtain the optical signal of the particles in the tail jet flow, the data processing is extremely quick, and the long-term monitoring of the particles can be realized, so that the three-dimensional imaging of the particles is synchronously triggered, the capture of the particles with quick motion of the tail jet flow is met, and the missing detection can be avoided.

(3) When the synchronous measurement working mode is adopted, the intensity data of the mixed light of the radiant light and the scattered laser with different wavelengths is obtained through detection, and the intensity data of the scattered laser in the mixed light can be obtained through data conversion, so that the synchronous test of particle parameters such as the particle size, the concentration, the components and the source identification of tail jet flow particles and radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity is realized. And the particle size and concentration measurement accuracy can be improved through the combined solution of multi-wavelength scattered light.

(4) The laser wavelength, the intensity, the working mode, the filtering wavelength range of the filter attenuator of the light receiving detection part, the attenuation rate, the working mode, the selection of the data wavelength and the like of a plurality of lasers of the laser light source part need to be selected and determined by combining parameters such as the particle size parameter range of the tail jet flow of the engine, the particle concentration parameter concentration, the radiation characteristic of the tail jet flow and the like, the wavelength of the laser is generally blue-violet light, the measurement of the laser scattering light intensity can be ensured not to be influenced by the radiation light, and the measurement accuracy of the particle size and the concentration parameter is improved.

The above embodiments are preferred examples of the present invention, and are not intended to limit the scope of the present invention.

Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Claims (10)

1. A monitoring device for particulate matter parameters of tail jet of an engine estimates the working safety state of the engine through the particulate matter parameters of the tail jet,

the engine tail jet particulate matter parameter monitoring device has three kinds of working methods of radiation measurement, particle measurement and synchronous measurement, synchronously monitors parameters and sources such as particle size, concentration and components of tail jet particulate matter, and radiation parameters such as radiation temperature, radiance and radiation intensity, and simultaneously rapidly triggers three-dimensional image measurement to capture particle three-dimensional images to evaluate the working safety state of the engine, and comprises the following steps:

the laser light source part is positioned on one side of the tail jet flow of the engine and is used for generating incident laser with different wavelengths;

the light receiving and detecting part is positioned on the other side of the tail jet flow of the engine and is used for receiving the radiation light or the scattered light, converting the radiation light or the scattered light into an electric signal and sending a particle monitoring trigger signal;

the particle three-dimensional imaging part starts to work after receiving the particle monitoring trigger signal and obtains a particle three-dimensional image through backlight imaging and three-dimensional projection reconstruction; and

a particle monitoring and processing part for controlling the working modes of the laser light source part and the light receiving and detecting part,

the particle monitoring and processing part is respectively in communication connection with the laser light source part, the photoelectric detection part and the particle three-dimensional imaging part, controls the working modes of the laser light source part and the photoelectric detection part according to three working modes of radiation measurement, particle measurement and synchronous measurement, and processes, stores and displays the parameters of particles of engine tail jet flow, thereby evaluating the working safety state of the engine.

2. The engine exhaust jet particulate matter parameter monitoring device according to claim 1, characterized in that:

wherein the laser light source part comprises a laser controller, a plurality of lasers, an optical fiber coupler and a collimator,

the particle monitoring and processing part controls the working mode of the laser controller, the wavelength of the laser and the laser output intensity parameters,

the laser controller is controlled by the characteristic signal testing and processing part through a control signal cable to open and close two working modes, the wavelength of the laser and the output intensity parameter of the laser,

the laser light generated by the laser is output to the optical fiber coupler through the optical fiber,

the fiber coupler receives laser light generated by the laser and couples the laser light to an output fiber,

and the collimator is connected with the optical fiber coupler and outputs laser to irradiate the measuring area.

3. The engine exhaust jet particulate matter parameter monitoring device according to claim 1, characterized in that:

wherein the light receiving and detecting part comprises a filter attenuator, a light converging optical fiber coupler, an optical fiber, a collimator, a grating, a plurality of photoelectric detectors and a photoelectric detection processor,

the filter attenuator has two controllable modes of operation, filtered and unfiltered,

particle scattered light generated by irradiating particles in the tail jet flow measuring region with the tail jet flow radiation light, the laser light generated by the laser light source part or the mixed light of the tail jet flow radiation light and the laser light enters the optical fiber coupler after passing through the filter attenuator,

the filter attenuator and the optical fiber coupler are arranged on the same straight line, the angle between the straight line and the irradiation direction of the laser emitted by the laser source part is an acute angle,

the collimator is connected with the optical fiber coupler through an optical fiber, collimated laser which is obtained by collimating the particle scattered light is irradiated on the grating,

the grating receives the collimated laser and then divides the collimated laser into a plurality of beams according to the wavelength,

the plurality of photodetectors respectively receive the plurality of beams of light split and convert the optical signals into electrical signals to be output through cables,

the photoelectric detection processor collects the electric signals output by the plurality of photoelectric detectors, converts the electric signals into digital signals, obtains the intensities of light with different wavelengths, outputs the light to the particle monitoring processing part, and sends out particle monitoring trigger signals to the particle three-dimensional imaging part.

4. The engine exhaust jet particulate matter parameter monitoring device according to claim 1, characterized in that:

wherein the particle three-dimensional imaging part comprises at least two groups of light paths, a particle three-dimensional imaging processor and a trigger,

each group of light paths is provided with a light source, a lens and an industrial camera,

and after receiving the particle monitoring trigger signal output by the light receiving and detecting part, the trigger triggers the particle three-dimensional imaging processor to work, so that the light source, the lens and the industrial camera on the light path are controlled to work.

5. The engine exhaust jet particulate matter parameter monitoring device according to claim 3, characterized in that:

wherein the particulate matter monitoring and processing part is connected with the laser controller and is used for controlling the generation and the closing, the wavelength and the intensity of incident laser,

the particulate matter monitoring and processing part is connected with the filter attenuator and is used for controlling the working mode of the filter attenuator,

the particle monitoring and processing part is connected with the photoelectric detection processor and is used for acquiring the intensity of the radiation light or the scattered light and synchronously obtaining the parameters of the tail jet flow particles based on the established parameter analysis algorithm of the particles of the tail jet flow of the engine.

6. A method for monitoring particulate parameters of an engine exhaust jet by using the particulate parameter monitoring device of the engine exhaust jet according to any one of claims 1 to 5, comprising the steps of:

s1: arranging engine tail jet flow particulate matter parameter monitoring devices on two sides of engine tail jet flow;

s2: determining the working mode of the engine tail jet flow particulate matter parameter monitoring device;

s3: opening an engine tail jet flow particulate matter parameter monitoring device, and carrying out engine tail jet flow particulate matter parameter monitoring;

s4: parameters such as particle size, concentration and components, three-dimensional images and sources of particles are obtained in real time based on the established engine tail jet flow particle analysis algorithm, so that the working safety state of the engine is evaluated through the tail jet flow particle parameters.

7. The method of monitoring parameters of particulate matter of engine exhaust jet according to claim 6, characterized by:

the engine tail jet flow particulate matter parameter monitoring method comprises three methods:

corresponding to the radiation measurement working mode adopted by the engine tail jet flow particulate matter parameter monitoring device, the engine tail jet flow particulate matter parameter monitoring method adopts tail jet flow ultraviolet, visible and infrared wave band different wavelength tail jet flow radiation light intensity data obtained by a light receiving detection part, the data has two characteristics of tail jet flow radiation continuous characteristic and particle radiation characteristic spectral line, and the two characteristics are stripped: obtaining spectral line wavelength and spectral line intensity parameters according to particle radiation characteristic spectral lines, determining particle components and particle concentration through a particle component inversion algorithm, and analyzing according to the radiation characteristic spectral line wavelength, spectral line intensity, particle components and particle concentration information through a particle source identification algorithm to obtain particle sources; according to the continuous radiation characteristic of the tail jet flow, radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow are obtained through a radiation parameter inversion algorithm such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow; further evaluating the working safety state of the engine through the parameters of the tail jet flow particles,

corresponding to the particle measurement working mode adopted by the engine tail jet particle parameter monitoring and measuring device, the engine tail jet particle parameter monitoring method adopts the intensity data of different wavelengths of scattered laser of filtered tail jet radiation light obtained by a light receiving and detecting part, and obtains light signals for the light receiving and detecting part in the test, namely the intensity of the scattered laser with different wavelengths, for a plurality of lasers of a laser light source part, a plurality of signal peak values are provided, so that the scattering light intensity I of the laser with different wavelengths is obtained, the particle diameter and concentration parameter of the tail jet particle are synchronously obtained by a particle diameter and concentration parameter synchronous inversion algorithm, and further the working safety state of the engine is evaluated by the particle parameter of the tail jet,

corresponding to the synchronous measurement working mode adopted by the engine tail jet flow particle parameter monitoring device, the engine tail jet flow particle parameter monitoring method adopts the intensity data of the radiation light and the scattering laser mixed light with different wavelengths obtained by the light receiving detection part, and the light signals obtained by the detection of the light receiving detection part in the test are the intensities of the radiation light and the scattering laser mixed light with different wavelengths, and have three characteristics of tail jet flow radiation continuity, particle radiation characteristic spectral line and scattering laser: obtaining spectral line wavelength and spectral line intensity parameters according to particle radiation characteristic spectral lines, determining particle components and particle concentration through a particle component inversion algorithm, and analyzing according to the radiation characteristic spectral line wavelength, spectral line intensity, particle components and particle concentration information through a particle source identification algorithm to obtain particle sources; according to the continuous radiation characteristic of the tail jet flow, radiation parameters such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow are obtained through a radiation parameter inversion algorithm such as the radiation temperature, the radiation rate and the radiation intensity of the tail jet flow; according to the scattered laser characteristics, the scattered laser that causes for a plurality of lasers of laser light source portion to can obtain the mixed light superposition light intensity I' that different wavelengths correspond, the radiant light intensity in the mixed light needs to be deducted, thereby obtains accurate scattered laser light intensity I:

I＝I’-I_r

i' is the light intensity of the corresponding wavelength obtained by the test light receiving detection part, I_rThe radiation reference light intensity obtained by the interpolation of the intensity data of the peripheral wavelength radiation light is combined with the initial light intensity I₀And obtaining the particle diameter and concentration parameter of the tail jet flow particles by a synchronous inversion algorithm of the particle diameter and concentration parameter. Therefore, particle parameters such as particle size, concentration, components and source identification of the tail jet flow particles and radiation parameters such as radiation temperature, radiation rate and radiation intensity are synchronously obtained, and the working safety state of the engine is further evaluated through the parameters of the tail jet flow particles.

8. The method of monitoring parameters of particulate matter of engine exhaust jet according to claim 6, characterized by:

the particle size and concentration parameter synchronous inversion algorithm is established on the basis of a particle angle scattering theory, assuming that incident light is completely polarized light, the distance between an observation point and scattering particles is L, and an included angle between a vibration surface of the incident light and a scattering surface is a polarization angle phi, so that the total scattering light intensity of the particles is I_s. Total scattered light intensity I_sIs composed of two parts: intensity of scattered light I generated perpendicular to the scattering surface_rAnd the intensity of the scattered light I generated in a direction parallel to the scattering surface_lI.e. I_s＝I_r+I_lWherein, in the step (A),

r is the particle size of the particles; theta is a scattering angle; s₁(theta) and s₂(theta) is an amplitude function related to the refractive index m and the dimensionless quantity α, but not to the polarization angle phi of the incident light, lambda is the wavelength of the incident light, I₀The intensity of the incident laser beam can be regarded as the intensity of the laser beam output from the laser light source unit,

the total scattered intensity I obtained in the case of incident light being fully polarized_sComprises the following steps:

i₁(theta) and i₂(theta) is an intensity function of the spherical particles, is related to the scattering angle theta, the refractive index m and the dimensionless parameter α, is independent of the polarization angle phi of the incident light, whereas the dimensionless parameter α is related only to the wavelength lambda of the incident light and the particle size r of the particles,

total scattered light intensity I_sMainly related to the scattering angle theta, the refractive index m, the wavelength lambda of the incident light and the particle diameter r of the particles,

by measuring the angular scattering intensity of incident light at different wavelengths, different wavelengths λ can be established₁、λ₂、λ₃Lower angle scattered light intensity I_s,λ1、I_s,λ2、I_s,λ3Relationship with incident wavelength, particle size:

the particle size r can be calculated by solving the scattered light equation with different wavelengths,

once the particle size is obtained, the intensity of the light can be scattered by the angleQuantitative correlation with particle number concentration to obtain particle number concentration N_v：

V is the volume of the detection zone.

9. The method of monitoring parameters of particulate matter of engine exhaust jet according to claim 6, characterized by:

wherein, the particle component inversion algorithm is established in that the particle emits a sufficiently strong ultraviolet, visible or infrared wave band radiation spectrum characteristic spectral line in the high-temperature tail jet flow of the engine, the particle component is determined through the characteristic spectral line,

the outer layer electrons of the atoms of the tail jet flow particles are in a ground state in a normal state, and after the atoms are excited by the outside of a high-temperature environment, the atoms in the excited state are in an extremely unstable state, and the outer layer electrons spontaneously jump from a high energy level to a low energy level and release photons. Atomic spontaneous emission frequency v and energy level difference (E)₁-E₂) In relation to, satisfy:

hν＝E₁-E₂

h is the Planck constant.

When the system is in a thermal equilibrium state, the distribution among the energy steady states of the atoms follows a boltzmann distribution:

N_nand N₁Number of atoms in excited and ground states, g_nAnd g₁Atomic number and statistical weight, E, for the excited and ground states, respectively_1nThe excitation energy required for the ground state to the excited state, k is the boltzmann constant, and T is the temperature at which the atoms are located. From which the particle composition can be determined and the composition concentration obtained by analysis of the characteristic spectral line wavelengths and intensities,

the particle source identification algorithm is mainly obtained based on a K-means clustering algorithm of tail jet flow radiation spectral clustering analysis,

the basic idea of K-means clustering is to randomly select K data samples from a data set containing a large number of solid particle radiation spectrum samples as initial clustering centers, count the distance between each spectrum sample and the K initial clustering centers, divide all the spectrum data into the class represented by the clustering center closest to the spectrum sample, and update the K clustering centers according to the mean value of the newly generated spectrum samples in each class. If the change of the clustering center value in the adjacent iteration times exceeds the set threshold value, performing classification again on all the spectrum samples according to the new clustering center; if the change of the clustering central value in the adjacent iteration times is less than the specified threshold value, the algorithm converges and outputs a clustering result,

the K-means clustering algorithm flow is as follows:

(a) selecting an original data set of K-mean clustering, and randomly selecting K spectral samples from the original data set as an initial clustering center z₁,z₂,…,z_k；

(b) Calculating the distances from the sample data to k condensation points one by one (generally, Euclidean distance is used as the distance from the sample to the clustering center), and dividing n samples (or variables) into k classes according to the distance, wherein the Euclidean distance calculation formula is as follows:

x_iis the variable value of the ith variable of the sample x, y_iAre the variable values of the i variables of the sample y. If the distance from the spectrum sample to the original class is the shortest, the spectrum sample is still in the original class, otherwise, the spectrum sample is moved to the class which is the shortest;

(c) calculating the cluster center of each class of data in the k classes, if the cluster center is not coincident with the initial cluster center, taking the cluster center as a new cluster center, repeating the step (b) until all the spectrum samples can not move or each cluster center is not changed any more, terminating the calculation process, thereby identifying the source of the engine tail jet flow particles,

through a large amount of tail jet flow radiation spectral clustering analysis, specific wavelength characteristics of particle source identification can be obtained, so that the wavelength intensity data of radiation light of all wave bands does not need to be obtained, only a plurality of data of determined wavelengths are needed, and an engine tail jet flow particle parameter monitoring device and a particle source identification algorithm can be further simplified.

10. The method of monitoring parameters of particulate matter of engine exhaust jet according to claim 6, characterized by:

when the particles are monitored, the three-dimensional imaging part is triggered to obtain a particle three-dimensional image, the three-dimensional reconstruction algorithm is obtained by reconstructing a particle projection digital image on a plurality of groups of light paths,

if two groups of light paths are adopted and arranged to be vertical, one group of light paths obtains horizontal projection and contains the appearance characteristics of the particles in the horizontal direction, the other group of light paths obtains vertical projection and contains the appearance characteristics of the particles in the vertical direction, and the three-dimensional images of the particles can be reconstructed through the restoration of the horizontal and vertical projections,

if a plurality of groups of light paths are adopted, more particle projection images in the light path direction can be obtained, so that a particle three-dimensional image can be more accurately reconstructed,

after obtaining a three-dimensional image of the particles, counting the particle size distribution and the particle counting concentration parameters according to the image processing,

the source of the particles is identified by combining engine operation engineering according to the surface morphology of the particles.

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