WO2024021052A1

WO2024021052A1 - Fuel atomization performance testing apparatus

Info

Publication number: WO2024021052A1
Application number: PCT/CN2022/109072
Authority: WO
Inventors: 刘子钰; 杨晓奕; 顾骁宇
Original assignee: 北京航空航天大学
Priority date: 2022-07-25
Filing date: 2022-07-29
Publication date: 2024-02-01
Also published as: CN115201151A

Abstract

The present application relates to a fuel atomization performance testing apparatus. In the apparatus, a fuel spraying unit is used for spraying fuel to be tested, to form a first atomization field and a second atomization field; a first atomization parameter acquisition unit comprises a first atomization field image acquisition subunit and a first atomization parameter testing subunit, the first atomization field image acquisition subunit is used for acquiring a corresponding first atomization field image when light passes through the first atomization field, and the first atomization field image comprises a shadow image corresponding to first-form fuel; the first atomization parameter testing subunit is used for performing image processing and data processing on the basis of the first atomization field image to obtain first atomization parameters; a second atomization parameter acquisition unit is used for testing second-form fuel of the second atomization field to obtain second atomization parameters of the second-form fuel. By using the apparatus, accurate measurement for fuel atomization effect can be implemented when the fuel atomization fields are rapidly changed.

Description

A fuel atomization performance testing device

Cross-references to related applications

This application is filed based on the Chinese patent application with application number 2022108769717, the filing date is July 25, 2022, and the invention name is "A fuel atomization performance testing device", and claims the priority of the Chinese patent application. The Chinese patent The entire contents of the application are incorporated by reference into this application in its entirety.

Technical field

The present application relates to the technical field of fuel performance testing, and in particular to a fuel atomization performance testing device.

Background technique

In the engine combustion chamber, the atomization quality of fuel determines its combustion efficiency, flame temperature distribution, emission indicators, etc., which directly affects the safety, performance and emission requirements of the engine. Taking aviation alternative fuels as an example, the "ready-to-use" nature of aviation alternative fuels requires that the structure and operating performance of aviation engines are not changed, and the safety, performance and emission requirements of the alternative fuels are not reduced. How to certify the "ready-to-use" atomization performance of aviation alternative fuels requires accurate evaluation of their atomization performance.

The aviation fuel atomization process forms a huge number of atomized droplets. Not only does the injection speed be high and the particle size distribution is wide, but the size and speed of the droplets will further change due to evaporation, collision, adhesion, etc. How to use the fuel in the fuel atomization process? Achieving accurate measurement of the fuel atomization effect when the atomization field changes rapidly is a problem that needs to be solved.

Contents of the invention

This application provides a fuel atomization performance testing device to solve the problem of achieving accurate measurement of the fuel atomization effect when the fuel atomization field changes rapidly.

According to one aspect of the present application, a fuel atomization performance testing device is provided, including: a fuel spray unit, a first atomization parameter acquisition unit corresponding to primary atomization, and a second atomization parameter acquisition unit corresponding to secondary atomization;

The fuel spray unit is used to spray the fuel to be tested to form a first atomization field and a second atomization field, wherein the second atomization field is composed of a second form of fuel, and the second form of fuel is composed of the The first form of fuel in the first atomization field is formed after fragmentation;

The first fog parameter acquisition unit includes a first fog field image acquisition sub-unit and a first fog parameter test sub-unit. The first fog field image acquisition sub-unit is used to acquire light passing through the first fog field image acquisition sub-unit. The first atomization field image corresponding to the atomization field, the first atomization field image includes the shadow image corresponding to the first form of fuel; the first atomization parameter testing subunit is used to determine the first atomization field image based on the first atomization field image. Perform image processing and data processing on a fog field image to obtain the first fog parameters;

The second atomization parameter acquisition unit is used to detect the second form of fuel in the second atomization field and obtain the second atomization parameter of the second form of fuel.

In some embodiments, the first fog field image acquisition subunit includes a light source that illuminates the first fog field, a concave reflector, and an image capture device, and the fog field is disposed on the concave reflector. Between the image capture device and the light source, the light source is used to illuminate the first atomization field and form reflected light reflected by the concave reflector to the image capture device. The image capture device uses The reflected light is captured to form the first atomization field image including a shadow image corresponding to the first form of fuel.

In some embodiments, performing image processing and data processing based on the first fog field image to obtain the first fog parameters includes:

Perform image extraction on the first fog field image to obtain a target image for identifying the fog cone angle;

Convert the target image into a grayscale image;

Data processing is performed based on the grayscale image to obtain at least one of a target value of the atomization cone angle, a target length of the atomized liquid film, and a target thickness of the atomized liquid film.

In some embodiments, image extraction of the first fog field image includes:

A rectangular image with the nozzle axis of the nozzle of the fuel spray unit as the center line in the first atomization field image is extracted as a target image for identifying the atomization cone angle.

In some embodiments, the data processing based on the grayscale image to obtain the target value of the atomization cone angle includes:

Select the median value of the grayscale value in the grayscale image as the threshold for identifying the atomization cone angle;

The grayscale values are taken along the horizontal direction at different heights in the grayscale image, and the pixels at each height whose grayscale value exceeds the threshold are determined as boundary pixels, and the left and right corresponding to each height are recorded. Boundary pixel points and right boundary pixel points, and obtain position information corresponding to the left boundary pixel point and position information corresponding to the right boundary pixel point;

Perform linear fitting based on the position information corresponding to the left boundary pixel point to obtain the slope of the left boundary of the atomization cone angle, and perform linear fitting based on the position information corresponding to the right boundary pixel point to obtain the The slope of the right boundary of the atomization cone angle;

According to the slope of the left boundary and the slope of the right boundary, obtain the value of the atomization cone angle corresponding to the grayscale image;

Calculate the average value of the atomization cone angle values corresponding to the plurality of grayscale images, and determine the average value as the target value of the atomization cone angle.

In some embodiments, performing data processing based on the grayscale image to obtain the target length of the atomized liquid film and the target thickness of the atomized liquid film includes:

Determine the gray value step threshold;

In the grayscale image, the grayscale value of each pixel is taken from left to right and from bottom to top, and the pixels whose grayscale value step exceeds the grayscale value step threshold in each pixel are The abscissa and ordinate are respectively determined as the pixel value of the length and the pixel value of the thickness of the atomized liquid film corresponding to the grayscale image;

Based on the preset subject matter, convert the pixel value of the length and thickness of the atomized liquid film into the length and thickness of the atomized liquid film corresponding to the grayscale image;

The length and thickness of the atomized liquid film corresponding to the plurality of grayscale images are averaged, and the average value is determined as the target length of the atomized liquid film and the target thickness of the atomized liquid film.

In some embodiments, the target object is a spherical object with a preset diameter suspended next to the nozzle of the fuel spray unit, and the center of the spherical object is on the same optical path as the nozzle axis of the nozzle. within the normal plane.

In some embodiments, the spray is a centrifugal nozzle.

In some embodiments, the device further includes: a test environment maintaining unit, configured to adjust the external environment of the fuel combustion performance testing device to maintain a preset test state before testing the combustion performance of the fuel to be tested. .

In some embodiments, detecting the second form of fuel in the second atomization field includes: using a laser Doppler testing method to detect the second form of fuel in the second atomization field.

Description of drawings

Figure 1 is a schematic diagram of a scene using a fuel atomization performance testing device to obtain the first atomization parameter provided by an embodiment of the present application;

Figure 2 is a schematic diagram of a scenario in which a fuel atomization performance testing device is used to obtain a second atomization parameter provided by an embodiment of the present application;

Figure annotation:

Fuel spray unit 10, first atomization parameter acquisition unit 11 corresponding to primary atomization, second atomization parameter acquisition unit 12 corresponding to secondary atomization, first atomization field image acquisition sub-unit 111, first atomization parameter Test subunit 112, light source 1111, concave reflector 1112, image capture device 1113, preset target 1114

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all implementations. example. The related embodiments described herein are illustrative in nature and are intended to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limitations of the present application. All other embodiments obtained by those skilled in the art based on the technical solutions and the examples provided in this application fall within the scope of protection of this application.

Unless otherwise stated, terms used in this application have their commonly understood meanings as generally understood by those skilled in the art. Unless otherwise stated, the values of each parameter mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the examples of this application).

A list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A or B" means only A; only B; or A and B. In another example, if the items A, B, and C are listed, then the phrase "at least one of A, B, or C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

For the fuel atomization performance test scenario, in order to achieve accurate measurement of the fuel atomization effect when the fuel atomization field changes rapidly, this application provides a fuel atomization performance test device. Examples are provided below to describe the device in detail.

An embodiment of the present application provides a fuel atomization performance testing device. FIG. 1 is a schematic diagram of the fuel atomization performance testing device provided in this embodiment. The device provided in this embodiment will be described in detail below with reference to FIG. 1 . The examples involved in the following description are used to explain the principle of the method and are not intended to limit actual use.

As shown in Figure 1, the fuel atomization performance testing device provided by this embodiment includes: a fuel spray unit 10, a first atomization parameter acquisition unit 11 corresponding to primary atomization, and a second atomization parameter corresponding to secondary atomization. Get unit 12.

The fuel spray unit 10 is used to spray the fuel to be tested to form a first atomization field and a second atomization field, wherein the second atomization field is composed of a second form of fuel, and the second form of fuel is composed of The first form of fuel in the first atomization field is formed after fragmentation. Fuel atomization is a process in which the fuel flows from the atomizing nozzle into the ambient gas at high speed and is broken into discrete droplets. This process not only includes the jet breakup process (also called primary atomization), but the broken droplets will continue to split. Fine atomized droplets (also called secondary atomization) are formed, and the atomization performance of the fuel is determined by these two processes. That is, during the above-mentioned atomization process, the fuel forms a liquid film and atomization cone angle at its nozzle through the atomization nozzle (if the atomization cone angle is reduced, the length of the liquid film becomes longer, which will lead to a reduction in the combustion efficiency of the fuel). The film and atomization cone angle are broken and broken into liquid filaments, liquid flakes or large droplets under the action of aerodynamic force, and then through secondary atomization, the liquid filaments, liquid flakes or large droplets formed by the above-mentioned primary atomization are further broken. into fine atomized droplets. In this embodiment, the above-mentioned first atomization parameter refers to the atomization cone angle, atomization liquid film length, atomization liquid film thickness and other parameter values in the first atomization, and the second atomization parameter refers to the second atomization The speed, diameter and other parameters of the fine atomized droplets. The above-mentioned first form of fuel is the above-mentioned liquid film, atomization cone angle, liquid filament, liquid sheet or large droplets, etc., and the above-mentioned second form of fuel is the above-mentioned fine atomized liquid droplets.

The first fog parameter acquisition unit 11 includes a first fog field image acquisition sub-unit 111 and a first fog parameter testing sub-unit 112. The first fog field image acquisition sub-unit 111 is used to acquire light passing through the first The first atomization field image corresponding to the atomization field, the first atomization field image includes the shadow image corresponding to the first form of fuel; the first atomization parameter testing sub-unit 112 is used to perform image processing based on the first atomization field image Processing and data processing to obtain the first atomization parameters, such as the atomization cone angle, atomization liquid film length, and atomization liquid film thickness in one atomization.

The second atomization parameter acquisition unit 12 is used to detect the second form of fuel in the second atomization field and obtain the second atomization parameter of the second form of fuel, for example, measure and obtain the fine atomization liquid in the secondary atomization. Drop speed, diameter and other parameters. In this embodiment, a laser Doppler testing method can be specifically used to detect the second form of fuel in the second atomization field. For example, a phase Doppler dynamic particle analyzer (PDA) is used to measure the liquid spray. The droplet size and three-dimensional velocity field are based on the pre-designed grid distribution to measure the flow field information of the velocity field, particle size and concentration field of each atomized droplet particle, for example, laser irradiation to atomization For droplet particles, the detector receives scattered light from three color beams, including green light, blue light, and violet light, and calculates the particle velocity through frequency difference, the diameter of the droplet through phase difference, and the concentration through the number of particles and droplet diameter. Specifically, the laser light emitted by the laser generator is divided into two parallel incident laser beams through a spectrometer. After passing through a convex lens, they intersect at the focal point of the lens to form a measurement point. When the atomized droplets pass through the measurement point, the measurement is caused by light scattering. The interference fringes change at the point. The frequency of change of the interference fringe in unit time is measured by the detector, and the droplet velocity is calculated. Based on the maximum amplitude and minimum amplitude of the Doppler signal wave measured by the detector, the atomized droplet at the measurement point is calculated. diameter. In this embodiment, in order to obtain a sufficient number of samples and reduce the measurement error, no less than a predetermined number of effective samples are collected at each measurement point, and the measured data are calculated and processed to obtain the particle size, particle size, and particle size of different fuels during atomization. Characteristics of droplet velocity, concentration, etc. along the spatial distribution.

In this embodiment, the first fog field image acquisition sub-unit 111 includes a light source 1111 that illuminates the first fog field, a concave reflector 1112, and an image capture device 1113. The fog field is disposed between the concave reflector and the image capture device. Between the devices, the light source is used to illuminate the first atomization field to form reflected light that is reflected by the concave reflector to the image capturing device. The image capturing device is used to capture the reflected light to form a shadow corresponding to the first form of fuel. The first fog field image of the image. For example, the above-mentioned light source can be an LED point light source with a luminous flux greater than 1000LM. The diameter of the concave reflector can be 203mm and the focal length can be 800mm. The image capture device can be a camera, because light will be reflected when passing through atomized liquid films and droplets. and refraction. Therefore, the image obtained by focusing the light will have shadows at the corresponding positions of the atomized liquid film and droplets. Therefore, the shadow image in the first atomized field image captured above can carry the atomization of the fuel to be measured. Performance information.

In this embodiment, the above-mentioned first fog parameter testing sub-unit performs image processing and data processing based on the first fog field image to obtain the first fog parameter, which may specifically refer to:

First, image extraction is performed on the first atomization field image to obtain a target image for identifying the atomization cone angle; in this embodiment, this process specifically refers to extracting the nozzle of the fuel spray unit from the first atomization field image. The rectangular image with the central axis of the nozzle as the center line is extracted as the target image for identifying the atomization cone angle.

Secondly, convert the target image into a grayscale image, for example, enlarge the target image and convert it into a grayscale image.

Then, perform data processing based on the above grayscale image to obtain at least one of the target value of the atomization cone angle, the target length of the atomized liquid film, and the target thickness of the atomized liquid film.

In this embodiment, the above-mentioned data processing based on the grayscale image is used to obtain the target value of the atomization cone angle, which may specifically refer to:

First, select the median value of the gray value in the grayscale image as the threshold for identifying the fog cone angle;

Secondly, the grayscale value is taken along the horizontal direction at different heights in the grayscale image. Since there is an obvious step at the edge of the atomized liquid film, that is, the grayscale value of the liquid film area and the grayscale value of the air area exist. There is an obvious difference, so the pixels whose gray value at the edge of the liquid film exceeds the above threshold among the pixels at each height are determined as boundary pixels, the left boundary pixels and right boundary pixels corresponding to each height are recorded, and the left boundary pixel is obtained The position information corresponding to the point and the position information corresponding to the right boundary pixel point;

Then, a linear fitting is performed based on the position information corresponding to the left boundary pixel point to obtain the slope of the left boundary of the atomization cone angle, and a linear fitting is performed based on the position information corresponding to the right boundary pixel point to obtain the right slope of the atomization cone angle. the slope of the boundary;

Again, based on the slope of the left boundary, the slope of the right boundary, and the geometric relationship between the slope and the angle, calculate the value of the atomization cone angle corresponding to the above grayscale image;

Finally, the atomization cone angle values corresponding to the multiple grayscale images are averaged, and the average value is determined as the target value of the atomization cone angle. For example, multiple first fog field images can be captured through an image capture device, the Pillow image processing module in Python can be used to batch process the multiple first fog field images, and extracted from each first fog field image. After extracting the above grayscale image and processing each grayscale image in the above manner, multiple atomization cone angle values corresponding to each grayscale image are obtained, and the average value of the multiple atomization cone angle values is calculated, This average value is used as the target value of the atomization cone angle.

In this embodiment, the above-mentioned data processing based on the grayscale image is used to obtain the target length of the atomized liquid film and the target thickness of the atomized liquid film, which may specifically refer to:

First, the grayscale value step threshold is determined. In this embodiment, the median value of the grayscale value in the grayscale image is selected as the grayscale value step threshold.

Secondly, in the grayscale image, take the grayscale value of each pixel from left to right and from bottom to top, and compare the abscissa and vertical coordinates of the pixels whose grayscale value exceeds the grayscale value step threshold in each pixel. The coordinates are respectively determined as the pixel value of the length and the pixel value of the thickness of the atomized liquid film corresponding to the above grayscale image. Then, based on the preset target, the pixel values of the length and thickness of the above-mentioned atomized liquid film are converted into the length and thickness of the atomized liquid film corresponding to the above-mentioned grayscale image; in this embodiment, as shown in Figure 1 shown. The above-mentioned preset target 1114 is a spherical object with a preset diameter suspended next to the nozzle of the fuel spray unit. The center of the spherical object and the nozzle axis of the nozzle are in the same normal plane of the optical path (irradiation light), so that Make the change rate of image enlargement or reduction consistent. With this setting, after obtaining the pixel value of the length and thickness of the above-mentioned atomized liquid film, it can be compared with the pixel value of the above-mentioned spherical object hanging next to the nozzle. Calculate the ratio to obtain the true length and thickness of the atomized liquid film.

Finally, the length and thickness of the atomized liquid film corresponding to multiple grayscale images are averaged, and the average value is determined as the target length of the atomized liquid film and the target thickness of the atomized liquid film. Similar to the above method of calculating the target value of the atomization cone angle, multiple first atomization field images can be captured through an image capture device, and the Pillow image processing module in Python is used to batch process the multiple first atomization field images. The above-mentioned grayscale image is extracted from each first atomization field image, and after each grayscale image is processed in the above manner, the length and thickness of multiple atomized liquid films corresponding to each grayscale image are obtained. The lengths and thicknesses of the plurality of atomized liquid films are averaged, and the average values are used as the target length and the target thickness of the atomized liquid film.

In this embodiment, the nozzle of the above-mentioned fuel spray unit is a centrifugal nozzle. The centrifugal nozzle has a simple structure and reliable operation. It has the ability to atomize fuel in the ambient atmosphere and can eliminate the influence of ambient gas flow during the atomization process. Interference in the fuel atomization process is helpful to reflect the impact of different fuel properties on atomization performance.

In this embodiment, the above-mentioned fuel atomization performance testing device also includes a test environment maintaining unit, which is used to adjust the internal environment of the fuel atomization performance testing device to maintain it in a standard state (i.e., before testing the atomization performance of the fuel to be tested). Standard atmospheric conditions), and maintain the air temperature, humidity, density, and flow state unchanged, eliminating the impact of the environment on fuel atomization performance.

The fuel atomization performance testing device provided by this embodiment includes: a fuel spray unit, a first atomization parameter acquisition unit corresponding to primary atomization, and a second atomization parameter acquisition unit corresponding to secondary atomization; the fuel spray unit is used for The fuel to be tested is sprayed to form a first atomization field and a second atomization field, wherein the second atomization field is composed of the second form of fuel, and the second form of fuel is fragmented by the first form of fuel in the first atomization field. After forming; the first fog parameter acquisition unit includes a first fog field image acquisition sub-unit and a first fog parameter test sub-unit, the first fog field image acquisition sub-unit is used to acquire light passing through the first fog field The first atomization field image corresponding to when , obtain the first atomization parameter; the second atomization parameter acquisition unit is used to detect the second form of fuel in the second atomization field, and obtain the second atomization parameter of the second form of fuel. Since the shadow image in the first atomization field image can carry the atomization performance information of the fuel to be tested, and the device can perform efficient batch processing of the first atomization field image through image processing, thereby being able to quickly analyze the fuel atomization field. Meets the demand for atomization parameter measurement under changing conditions. By using this device, the fuel atomization effect can be accurately measured when the fuel atomization field changes rapidly, and the atomization flow field will not be affected during the measurement process. interference. After changing the performance of traditional aviation fuel by adding typical alternative components, using the above fuel atomization performance test device can clearly identify the difference in atomization performance between the alternative jet fuel and traditional petroleum-based jet fuel caused by the change in performance. This device not only satisfies the "ready-to-use" evaluation process of aviation alternative fuels, but also provides usage strategies for the suitability of fuels and engines.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art will , without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make some changes or modifications to equivalent embodiments with equivalent changes. In essence, any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims

A fuel atomization performance testing device, characterized in that it includes: a fuel spray unit, a first atomization parameter acquisition unit corresponding to primary atomization, and a second atomization parameter acquisition unit corresponding to secondary atomization;

The fuel spray unit is used to spray the fuel to be tested to form a first atomization field and a second atomization field, wherein the second atomization field is composed of a second form of fuel, and the second form of fuel is composed of the The first form of fuel in the first atomization field is formed after fragmentation;

The first fog parameter acquisition unit includes a first fog field image acquisition sub-unit and a first fog parameter test sub-unit. The first fog field image acquisition sub-unit is used to acquire light passing through the first fog field image acquisition sub-unit. The first atomization field image corresponding to the atomization field, the first atomization field image includes the shadow image corresponding to the first form of fuel; the first atomization parameter testing subunit is used to determine the first atomization field image based on the first atomization field image. Perform image processing and data processing on a fog field image to obtain the first fog parameters;

The second atomization parameter acquisition unit is used to detect the second form of fuel in the second atomization field and obtain the second atomization parameter of the second form of fuel.
The device according to claim 1, wherein the first fog field image acquisition subunit includes a light source that illuminates the first fog field, a concave reflector, and an image capture device, and the fog field Disposed between the concave reflector and the image capture device, the light source is used to illuminate the first atomization field and form reflected light reflected by the concave reflector to the image capture device. , the image capturing device is used to capture the reflected light to form the first atomization field image including the shadow image corresponding to the first form of fuel.
The device according to claim 1, characterized in that, performing image processing and data processing based on the first fog field image to obtain the first fog parameter includes:

Perform image extraction on the first fog field image to obtain a target image for identifying the fog cone angle;

Convert the target image into a grayscale image;

Data processing is performed based on the grayscale image to obtain at least one of a target value of the atomization cone angle, a target length of the atomized liquid film, and a target thickness of the atomized liquid film.
The device according to claim 3, wherein the image extraction of the first fog field image includes:

A rectangular image with the nozzle axis of the nozzle of the fuel spray unit as the center line in the first atomization field image is extracted as a target image for identifying the atomization cone angle.
The device according to claim 3, characterized in that, performing data processing based on the grayscale image to obtain the target value of the atomization cone angle includes:

Select the median value of the grayscale value in the grayscale image as the threshold for identifying the atomization cone angle;

The grayscale values are taken along the horizontal direction at different heights in the grayscale image, and the pixels at each height whose grayscale value exceeds the threshold are determined as boundary pixels, and the left and right corresponding to each height are recorded. Boundary pixel points and right boundary pixel points, and obtain position information corresponding to the left boundary pixel point and position information corresponding to the right boundary pixel point;

Perform linear fitting based on the position information corresponding to the left boundary pixel point to obtain the slope of the left boundary of the atomization cone angle, and perform linear fitting based on the position information corresponding to the right boundary pixel point to obtain the The slope of the right boundary of the atomization cone angle;

According to the slope of the left boundary and the slope of the right boundary, obtain the value of the atomization cone angle corresponding to the grayscale image;

Calculate the average value of the atomization cone angle values corresponding to the plurality of grayscale images, and determine the average value as the target value of the atomization cone angle.
The device according to claim 3, wherein the data processing based on the grayscale image to obtain the target length of the atomized liquid film and the target thickness of the atomized liquid film includes:

Determine the gray value step threshold;

In the grayscale image, take the grayscale value of each pixel from left to right and from bottom to top, and select the pixels whose grayscale value step exceeds the grayscale value step threshold in each pixel. The abscissa and ordinate are respectively determined as the pixel value of the length and the pixel value of the thickness of the atomized liquid film corresponding to the grayscale image;

Based on the preset subject matter, convert the pixel value of the length and thickness of the atomized liquid film into the length and thickness of the atomized liquid film corresponding to the grayscale image;

The length and thickness of the atomized liquid film corresponding to the plurality of grayscale images are averaged, and the average value is determined as the target length of the atomized liquid film and the target thickness of the atomized liquid film.
The device according to claim 6, wherein the target object is a spherical object with a preset diameter suspended next to the nozzle of the fuel spray unit, and the center of the spherical object is in contact with the nozzle. The nozzle axis is in the same normal plane of the optical path.
The device according to any one of claims 4 and 7, characterized in that the nozzle is a centrifugal nozzle.
The device according to claim 1, characterized in that the device further includes: a test environment holding unit for adjusting the fuel atomization performance testing device before testing the atomization performance of the fuel to be tested. The internal environment is maintained in the preset test state.
The device according to claim 1, wherein detecting the second form of fuel in the second atomization field includes:

The second form of fuel in the second atomization field is detected using a laser Doppler testing method.