CN115876830A - A kind of soot particle surface water vapor phase change test system and method - Google Patents

Abstract

The invention relates to a water vapor phase change test system and method on the surface of soot particles, belonging to the technical field of phase change tests. The soot particle sampling subsystem is used to provide primary soot particles or secondary soot particles to the sample chamber, and the temperature/ The pressure control subsystem is used to adjust the temperature and pressure of the sample chamber, so that the sample chamber is at a predetermined temperature and predetermined pressure. The predetermined humidity water vapor generation subsystem is used to provide water vapor with a predetermined humidity to the sample chamber. At a predetermined temperature and a predetermined pressure, detect the phase change of water vapor with a predetermined humidity on the surface of primary soot particles or secondary soot particles, so as to realize the coordinated control of temperature-pressure-humidity in the sample chamber, and carry out different temperature, humidity and pressure Experimental study on phase transition of water vapor on the surface of soot particles under high temperature conditions.

Description

A kind of soot particle surface water vapor phase change test system and method

technical field

The invention relates to the technical field of phase change tests, in particular to a system and method for testing the phase change of water vapor on the surface of soot particles.

Background technique

Soot particles can directly or indirectly change the solar radiation energy reaching the ground and affect the climate and environment. The aviation industry is the only emission source of soot at the top of the troposphere. Aviation soot particles can act as ice nuclei to form ice crystals in aircraft exhaust, which affects the formation and distribution of wake clouds and cirrus clouds, and then affects the earth's radiation balance, which has a major impact on global climate. Influence. The microscopic morphology of soot particles is complex, and the organic matter and sulfate in the emissions can be adsorbed on the surface of soot particles, which will lead to changes in the ice condensation and cloud formation capabilities of soot particles, and intensify the ice condensation and cloud formation process of soot particles complexity. These problems make it difficult for the traditional research results on ice condensation and cloud formation to be applied to soot particles, and it is impossible to accurately assess the impact of soot particles on atmospheric radiation and global climate. stuck in a bottleneck.

At present, the research on the phase transition of water vapor on the surface of soot particles is mainly carried out in two ways: online and offline. The online method usually directly introduces soot particles into different types of environmental chambers, cloud chambers, and flow tubes for testing. In the off-line method, the collected soot particles are usually placed on a cold bench for testing, and the phase transition process of water vapor on the surface of soot particles can be observed online in real time in combination with optical microscopy and environmental scanning electron microscopy. The current online and offline methods are still difficult to simulate the temperature, humidity, and pressure conditions of cruising high altitudes, and it is difficult to support the experimental research on the water vapor phase transition on the surface of soot particles under the environmental conditions of cruising high altitudes.

In view of this, there is an urgent need for a new test technology for water vapor phase transition on the surface of soot particles.

Contents of the invention

The purpose of the present invention is to provide a soot particle surface water vapor phase change test system and method, which can realize the coordinated control of the temperature, pressure and humidity of the sample chamber of the cold and hot platform, simulate the conditions of cruising high altitude temperature, humidity, and pressure, and carry out cruising high altitude environment Experimental study on phase transition of water vapor on the surface of soot particles under high temperature conditions.

To achieve the above object, the present invention provides the following scheme:

A soot particle surface water vapor phase change test system, the test system includes: a soot particle sampling subsystem, a detection subsystem, a temperature/pressure control subsystem and a predetermined humidity water vapor generation subsystem; the detection subsystem Including hot and cold stage with sample compartment and detection parts;

The soot particle sampling subsystem is used to provide primary soot particles or secondary soot particles to the sample chamber;

The temperature/pressure control subsystem is used to adjust the temperature and pressure of the sample chamber, so that the sample chamber is at a predetermined temperature and predetermined pressure;

The predetermined humidity water vapor generation subsystem is used to provide water vapor with a predetermined humidity to the sample chamber;

The detection component is used to detect the phase change of the water vapor with the predetermined humidity on the surface of the primary soot particle or the secondary soot particle under the predetermined temperature and the predetermined pressure.

In some embodiments, the soot sampling subsystem includes a generating component and a sampling component; the generating component and the sampling component are connected by pipelines;

The generating component is used to generate the primary soot particles or the secondary soot particles;

The sampling component is used to sample the primary soot particles or the secondary soot particles, and provide the primary soot particles or the secondary soot particles to the sample chamber.

In some embodiments, the generation component includes: a carbon black aerosol generator, a secondary particle oxidation reaction generator, a first valve, and a second valve; the carbon black aerosol generator and the secondary particle oxidation The reaction generator pipeline is connected; the carbon black aerosol generator and the secondary particle oxidation reaction generator are all connected with the sampling component pipeline; the first valve is located between the carbon black aerosol generator and the On the pipeline between the sampling components; the second valve is located on the pipeline between the carbon black aerosol generator and the secondary particle oxidation reaction generator;

The carbon black aerosol generator is used to generate the primary soot particles;

The secondary particle oxidation reaction generator is used to convert the primary soot particles into the secondary soot particles;

When the first valve is open and the second valve is closed, the sampling component is used to sample the primary soot particles;

When the first valve is closed and the second valve is opened, the sampling component is used to sample the secondary soot particles.

In some embodiments, the sampling component includes a sampler and an air pump; the air pump is connected to the air circuit of the sampler;

The sampler is used to sample the primary soot particles or the secondary soot particles; the air pump is used to drive the primary soot particles or the secondary soot particles to move, so that the primary Soot particles or the secondary soot particles are deposited on the hydrophobically treated sampling film in the sampler; during the test, the hydrophobically treated sampling film is placed in the sample chamber to provide The sample chamber provides the primary soot particles or the secondary soot particles.

In some embodiments, the temperature/pressure control subsystem includes a temperature control component and a pressure control component;

The temperature control part is used to adjust the temperature of the sample chamber so that the sample chamber is at a predetermined temperature;

The pressure control part is used to adjust the pressure of the sample chamber so that the sample chamber is at a predetermined pressure.

In some embodiments, the temperature control part includes a hot and cold stage controller, a cooling subassembly and a heating subassembly; Adjust the temperature of the sample chamber so that the sample chamber is at a predetermined temperature;

The refrigeration sub-components include a Dewar bottle, a liquid nitrogen cooling pump and a refrigeration element arranged inside the hot and cold table; the liquid nitrogen cooling pump is connected to the Dewar bottle pipeline; the Dewar bottle stores There is liquid nitrogen; the liquid nitrogen cooling pump is used to pump the liquid nitrogen into the refrigeration element, and adjust the temperature of the sample chamber to lower the temperature, so that the sample chamber is at a predetermined temperature;

The heating subcomponent includes a water circulation pump and a heating element arranged inside the hot and cold table; the water circulation pump is used to cool the heating element; the heating element is used to heat and adjust the temperature of the sample chamber, The sample chamber is brought to a predetermined temperature.

In some embodiments, the pressure control component includes a vacuum pump and an air pressure sensor; the air pressure sensor is used to collect the air pressure in the sample chamber; the vacuum pump is used to pump the sample chamber according to the air pressure, The pressure of the sample chamber is adjusted so that the sample chamber is at a predetermined pressure.

In some embodiments, the predetermined humidity water vapor generation subsystem includes an air compressor, a water vapor generator, a mixing insulation container, a first mass flow controller, a second mass flow controller, and a humidity controller;

The air compressor is used to generate compressed air; the first mass flow controller is used to adjust the flow of compressed air entering the mixing and heat preservation container;

The water vapor generator is used to generate water vapor; the humidity controller is used to detect the ambient humidity in the sample chamber, and control the second mass flow controller according to the ambient humidity to control Adjust the flow of water vapor inside;

The mixing and heat preservation container is used to mix the compressed air and the water vapor to obtain water vapor with a predetermined humidity, and provide the water vapor with a predetermined humidity to the sample chamber.

In some embodiments, the detection component is a confocal Raman microscope.

A kind of soot particle surface water vapor phase change test method, utilizes above-mentioned test system to work, and described test method comprises:

Using the soot particle sampling subsystem to provide primary soot particles or secondary soot particles to the sample chamber;

Using the temperature/pressure control subsystem to adjust the temperature and pressure of the sample chamber, so that the sample chamber is at a predetermined temperature and predetermined pressure;

using a predetermined humidity water vapor generation subsystem to provide water vapor with a predetermined humidity to the sample chamber;

The phase change of the water vapor with the predetermined humidity on the surface of the primary soot particle or the secondary soot particle is detected by the detection component under the predetermined temperature and the predetermined pressure.

According to the specific embodiments provided by the invention, the invention discloses the following technical effects:

The present invention is used to provide a soot particle surface water vapor phase change test system and method, including: soot particle sampling subsystem, detection subsystem, temperature/pressure control subsystem and predetermined humidity water vapor generation subsystem, detection subsystem The system includes a hot and cold stage with a sample chamber and detection components. The soot particle sampling subsystem is used to provide primary soot particles or secondary soot particles to the sample chamber, and the temperature/pressure control subsystem is used to adjust the temperature and pressure of the sample chamber so that the sample chamber is at a predetermined temperature and predetermined pressure The predetermined humidity water vapor generation subsystem is used to provide predetermined humidity water vapor to the sample chamber, and the detection part is used to detect the predetermined humidity of water vapor at a predetermined temperature and predetermined pressure based on optical microscope observation and Raman spectral analysis. The phase change of the surface of the primary soot particles or the secondary soot particles can realize the coordinated control of the temperature-pressure-humidity of the sample chamber, and carry out the experimental research on the phase change of the surface of the soot particles under the cruising high-altitude environmental conditions.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the structural representation of the test system provided by embodiment 1 of the present invention;

Fig. 2 is the schematic diagram of the intake end of the sampler provided by Embodiment 1 of the present invention; Fig. 2 (a) is the appearance schematic diagram of the intake end; Fig. 2 (b) is the perspective view of the intake end;

Fig. 3 is the schematic diagram of the supporting net of the sampler provided by embodiment 1 of the present invention;

Fig. 4 is the schematic view of the exhaust end of the sampler provided by Embodiment 1 of the present invention; Fig. 4 (a) is the appearance schematic diagram of the exhaust end; Fig. 4 (b) is the perspective view of the exhaust end;

Fig. 5 is a schematic diagram of the assembly result of the sampler provided by Example 1 of the present invention; Fig. 5(a) is a schematic diagram of the appearance after assembly; Fig. 5(b) is a perspective view after assembly.

Symbol Description:

1-carbon black aerosol generator; 2-particle size sieving instrument; 3-secondary particle oxidation reaction generator; 4-first valve; 5-second valve; 6-sampler; 7-air pump; 8 - Hydrophobic treated sampling film; 9- hot and cold stage with sample chamber; 10- confocal Raman microscope; 11- Raman spectrometer controller; 12- cold and hot stage controller; 13- Dewar bottle; 14- Liquid nitrogen cooling pump; 15-water circulation pump; 16-vacuum pump; 17-exhaust pipe; 18-air compressor; 19-steam generator; 20-first mass flow controller; 21-second mass flow controller ; 22-mixing insulation container; 23-humidity controller; 24-intake end; 25-support net; 26-exhaust end;

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The purpose of the present invention is to provide a soot particle surface water vapor phase change test system and method, which can realize the coordinated control of sample chamber temperature-pressure-humidity, and carry out the soot particle surface water vapor phase change under different temperature, humidity and pressure conditions Experimental Research.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

This embodiment is used to provide a soot particle surface water vapor phase change test system, as shown in Figure 1, the test system includes: soot particle sampling subsystem, detection subsystem, temperature/pressure control subsystem and predetermined The humidity water vapor generation subsystem, the detection subsystem includes a hot and cold platform 9 with a sample chamber and detection components.

The soot particle sampling subsystem is used to provide primary soot particles or secondary soot particles to the sample chamber.

The temperature/pressure control subsystem is used to adjust the temperature and pressure of the sample chamber, so that the sample chamber is at a predetermined temperature and predetermined pressure.

The predetermined humidity water vapor generating subsystem is used to provide predetermined humidity water vapor to the sample chamber.

The detecting part is used for detecting the phase change of the water vapor with the predetermined humidity on the surface of the primary soot particle or the secondary soot particle under the predetermined temperature and predetermined pressure.

The soot particle sampling subsystem of this embodiment includes a generation component and a sampling component, and the generation component and the sampling component are connected by pipelines. The generating part is used to generate primary soot particles or secondary soot particles, and the sampling part is used to sample the primary soot particles or secondary soot particles, and provide the primary soot particles or secondary soot particles to the sample chamber of the hot and cold stage 9. Secondary soot particles.

Specifically, it is difficult to explore the influence of the degree of secondary oxidation on the phase transition process of water vapor on the surface of soot particles in the existing test system. The soot particles in this embodiment can be primary soot particles or secondary soot particles, which can be studied The phase change of water vapor on the surface of primary soot particles and the phase change of water vapor on the surface of secondary soot particles. At this point, the generation components of this embodiment include: carbon black aerosol generator 1, secondary particle oxidation reaction generator 3, first valve 4 and second valve 5, carbon black aerosol generator 1 and secondary particle oxidation The reaction generator 3 is connected to the pipeline, the carbon black aerosol generator 1 and the secondary particle oxidation reaction generator 3 are connected to the sampling component pipeline, and the first valve 4 is located between the carbon black aerosol generator 1 and the sampling component. On the pipeline, the second valve 5 is located on the pipeline between the carbon black aerosol generator 1 and the secondary particle oxidation reaction generator 3 .

The carbon black aerosol generator 1 is used to generate primary soot particles, the secondary particle oxidation reaction generator 3 is used to convert primary soot particles into secondary soot particles, and the first valve 4 and the second valve 5 are used to control The flow direction of the primary soot particles, when both the first valve 4 and the second valve 5 are closed, the primary soot particles cannot enter the sampling part, nor can they enter the secondary particle oxidation reaction generator 3, and the sampling part cannot sample once Soot particles, and secondary soot particles cannot be sampled; when the first valve 4 and the second valve 5 are all opened, the primary soot particles can enter the sampling part, and can also enter the secondary particle oxidation reaction generator 3, at this time The sampling part can sample primary soot particles and secondary soot particles at the same time; when the first valve 4 is opened and the second valve 5 is closed, the primary soot particles can enter the sampling part, but cannot enter the secondary particle oxidation reaction generator 3 , the sampling part can only sample soot particles once; when the first valve 4 is closed and the second valve 5 is opened, the primary soot particles cannot enter the sampling part, but can enter the secondary particle oxidation reaction generator 3, at this time , the sampling component can only sample secondary soot particles. Therefore, in order to obtain different types of soot particles, the present embodiment will open the first valve 4 and close the second valve 5 when sampling the primary soot particles; Close the first valve 4 and open the second valve 5.

Generally speaking, what carbon black aerosol generator 1 produces is primary soot particle aerosol, and the generation part of present embodiment can also comprise particle size sieving instrument 2, particle size sieving instrument 2 and carbon black aerosol generator 1 is connected, the particle size sieving instrument 2 is located between the carbon black aerosol generator 1 and the first valve 4, and is also located between the carbon black aerosol generator 1 and the second valve 5, and the particle size sieving instrument 2 is used The primary soot particle aerosol generated by the carbon black aerosol generator 1 is screened to obtain primary soot particles in a specific particle size range. In this embodiment, secondary soot particles with different oxidation degrees can also be obtained by adjusting the parameters of the secondary particle oxidation reaction generator 3 .

Specifically, the sampling component in this embodiment includes a sampler 6 and an air pump 7 , and the air pump 7 is connected to the sampler 6 through an air path. The sampler 6 is used to sample the primary soot particles or secondary soot particles generated by the generating components, and the air pump 7 is used to drive the movement of the soot particles, so that the soot particles are deposited in the sampler 6 after hydrophobic treatment. On the membrane 8, during the test, the hydrophobically treated sampling membrane 8 was placed in the sample compartment of the hot and cold platform 9 to provide soot particles to the sample compartment of the hot and cold platform 9.

As shown in Fig. 2, Fig. 3, Fig. 4 and Fig. 5, the sampler 6 of the present embodiment comprises an inlet port 24, a hydrophobically treated sampling membrane 8, a support net 25 and an exhaust port 26, so that the movement of the inlet port The direction is inward, the intake end 24 gradually expands from the outside to the inside, and the exhaust end 26 gradually shrinks from the outside to the inside. After the connection, the support net 25 is just stuck, and the hydrophobically treated sampling membrane 8 is pasted on the support net 25 .

The soot particle sampling subsystem of the present embodiment comprises a carbon black aerosol generator 1, a particle size sieving instrument 2, a secondary particulate matter oxidation reaction generator 3, a first valve 4, a second valve 5, a sampler 6 and an extraction The air pump 7 can generate and collect primary soot particles or secondary soot particles.

The temperature/pressure control subsystem of the present embodiment includes a temperature control part and a pressure control part, and the temperature control part is used to adjust the temperature of the sample chamber of the cold and hot stage 9, so that the sample chamber of the cold and hot stage 9 is at a predetermined temperature and pressure The control part is used to adjust the pressure of the sample chamber of the hot and cold stage 9, so that the sample chamber of the cold and hot stage 9 is at a predetermined pressure.

Specifically, the temperature control part of the present embodiment includes a hot and cold stage controller 12, a cooling subassembly, and a heating subassembly. The temperature is adjusted so that the sample compartment of the hot and cold stage 9 is at a predetermined temperature.

The cooling sub-components of this embodiment include a Dewar bottle 13 , a liquid nitrogen cooling pump 14 and refrigeration elements arranged inside the cold and hot table 9 , and the liquid nitrogen cooling pump 14 and the Dewar bottle 13 are connected by pipelines. Liquid nitrogen is stored in the Dewar bottle 13, and the liquid nitrogen cooling pump 14 is used to pump the liquid nitrogen into the refrigeration element arranged inside the hot and cold table 9, and cool down the sample chamber of the hot and cold table 9, that is, realize the cooling by liquid nitrogen. The cooling function is used to lower the temperature of the sample compartment of the hot and cold platform 9, so that the sample compartment of the hot and cold platform 9 is at a predetermined temperature.

The heating subassembly of the present embodiment includes a water circulation pump 15 and a heating element arranged inside the hot and cold platform 9. The water circulation pump 15 is used to cool the heating element arranged inside the hot and cold platform 9, and the heating element is used for cooling and heating of the hot and cold platform 9. The temperature of the sample chamber is adjusted by heating, so that the sample chamber of the hot and cold stage 9 is at a predetermined temperature.

Specifically, the pressure control part of the present embodiment includes a vacuum pump 16 and an air pressure sensor. The air pressure sensor can be an air pressure sensor equipped on the vacuum pump 16. The air pressure sensor is used to collect the air pressure in the sample chamber of the hot and cold platform 9. The vacuum pump 16 is used for According to the air pressure, the sample chamber of the cold and hot stage 9 is pumped, and the pressure of the sample chamber of the cold and hot stage 9 is adjusted so that the sample chamber of the cold and hot stage 9 is at a predetermined pressure, so as to control the sample chamber of the cold and hot stage 9 function of the ambient pressure. The pressure control part of this embodiment may also include an exhaust pipe 17, which is connected to the gas outlet of the vacuum pump 16, and is used to discharge excess gas in the sample compartment of the hot and cold stage 9.

The temperature/pressure control subsystem of the present embodiment comprises cold and hot table controller 12, Dewar bottle 13, liquid nitrogen cooling pump 14, water circulation pump 15, vacuum pump 16 and exhaust pipe 17, and cold and hot table controller 12 and heating and cooling The sample chamber of platform 9 is connected, and Dewar bottle 13 is connected with liquid nitrogen cooling pump 14, and liquid nitrogen cooling pump 14, water circulation pump 15, vacuum pump 16 are connected with the sample chamber of cold and hot platform 9, and exhaust pipe 17 is connected with vacuum pump 16, It can be used to control the temperature and pressure in the sample compartment of the hot and cold stage 9.

The predetermined humidity water vapor generation subsystem of the present embodiment comprises an air compressor 18, a water vapor generator 19, a mixing and heat preservation container 22, a first mass flow controller 20, a second mass flow controller 21 and a humidity controller 23, and the air Compressor 18 and steam generator 19 are all connected with mixing and heat preservation container 22 pipelines. Specifically, the air compressor 18 is connected to the first mass flow controller 20, the steam generator 19 is connected to the second mass flow controller 21, and the first mass flow controller 20 and the second mass flow controller 21 are connected together. Mixing heat preservation container 22, the mixing heat preservation container 22 links to each other with the sample chamber of cold and hot stage 9.

The air compressor 18 is used to generate compressed air, and the first mass flow controller 20 is used to adjust the flow rate of the compressed air entering the mixing and heat preservation container 22 to adjust the flow rate of the compressed air. The water vapor generator 19 is used to generate water vapor, and the humidity controller 23 is used to detect the ambient humidity in the sample chamber of the hot and cold platform 9, and controls the second mass flow controller 21 according to the ambient humidity to enter the mixed heat preservation container 22. The flow of water vapor is adjusted to control the flow of water vapor. The mixing and heat preservation container 22 is used to mix the compressed air and water vapor to obtain water vapor with a predetermined humidity, and provide the water vapor with a predetermined humidity to the sample compartment of the hot and cold stage 9 . The mixing and heat preservation container 22 of this embodiment can also insulate water vapor with a predetermined humidity.

It should be noted that the humidity controller 23 of this embodiment can adjust the second mass flow controller 21 according to the difference between the predetermined humidity and the measured ambient humidity. There is a positive correlation between the steam mass flow rate and the humidity, so the mixed gas can reach a predetermined humidity by changing the water vapor flow rate to obtain water vapor with a predetermined humidity. Simultaneously, the humidity controller 23 of this embodiment can detect the humidity situation in the sample chamber of the hot and cold stage 9 in real time, and control the water vapor flow in conjunction with the predetermined humidity to realize closed-loop control, so that the water vapor in the sample chamber of the hot and cold stage 9 is always Keep at predetermined humidity. The water vapor of the predetermined humidity in the mixed heat preservation container 22 is passed into the sample chamber of the cold and hot stage 9 . Based on this embodiment, not only the phase change process of water vapor on the surface of soot particles can be observed, but also the critical humidity condition of the phase change can be explored.

The predetermined humidity water vapor generation subsystem of the present embodiment includes an air compressor 18, a water vapor generator 19, a first mass flow controller 20, a second mass flow controller 21, a mixing heat preservation container 22 and a humidity controller 23, which can be Water vapor with different relative humidity is provided for the sample compartment of the hot and cold stage 9.

The sample compartment of the hot and cold stage 9 in this embodiment is a relatively airtight sample compartment with adjustable temperature, pressure and humidity.

The detection component of this embodiment can be a confocal micro-Raman spectrometer 10. The confocal micro-Raman spectrometer 10 acquires an optical microscopic image based on its own optical microscope, so as to determine the position of the soot particles through the optical microscopic image. On this basis, it can The Raman spectrum analysis of soot particles can further explore the microscopic mechanism and law of the phase transition process of water vapor on the surface of soot particles based on optical microscope observation and Raman spectrum analysis. For example, when water vapor is on the surface of soot particles When the phase transition occurs, the optical microscope can observe the phase transition process. Based on the size change of the particle and its surface water or ice in the optical microscopic image, it can reveal the ice condensation rate under different experimental conditions; when the water vapor is on the surface of the soot particle When a phase transition occurs, the Raman spectrum measured by the confocal micro-Raman spectrometer 10 will also change. Based on the change in the position of the spectral peak, etc., the critical environmental conditions for the phase transition of water vapor on the surface of soot particles can be revealed, and the mechanism of the process can be explored. microscopic mechanism.

The confocal micro-Raman spectrometer 10 of this embodiment itself can realize the functions of observing the particle position and spectral analysis, and this embodiment can also be provided with a Raman spectrometer controller 11, which is to configure and analyze the parameters of the confocal micro-Raman spectrometer 10 A computer is used to control the confocal Raman microscope 10 .

It should be pointed out that the size of a single soot particle is usually below 1 μm, and it is difficult for an optical microscope to clearly distinguish a single soot particle, and it is also difficult for a laser spot to focus on a single soot particle. Therefore, the test system in this embodiment is mainly aimed at micron-sized soot Agglomerates of particles.

The detection subsystem of this embodiment includes a hot and cold stage 9 with a sample chamber, a confocal micro Raman spectrometer 10 and a Raman spectrometer controller 11, which can be used to detect the phase transition of water vapor on the surface of soot particles.

Based on the structure of the above-mentioned test system, the test steps of the present embodiment are as follows:

1) Determine the switches of the secondary particle oxidation reaction generator 3, the first valve 4, and the second valve 5 according to the test requirements: when carrying out a water vapor phase change test on the surface of soot particles, open the first valve 4 and close the second valve. Valve 5 closes the secondary particle oxidation reaction generator 3; when carrying out the secondary soot particle surface water vapor phase change test, closes the first valve 4, opens the second valve 5, and starts the secondary particle oxidation reaction generator 3.

2) Start the carbon black aerosol generator 1 and the air pump 7, and the primary soot particle sample or the secondary soot particle sample of a specific particle size range moves under the action of the air pump 7 and is deposited in the sampler 6 after hydrophobic treatment On the sampling film 8, so as to obtain the hydrophobically treated sampling film 8 attached with soot particles.

3) After the sampling is finished, close the carbon black aerosol generator 1, the first valve 4 (or the second valve 5 and the secondary particle oxidation reaction generator 3), the air pump 7 in sequence, and take out the attached carbon from the sampler 6 Hydrophobically treated sampling film of smoke particles8.

4) Place the hydrophobically treated sampling film 8 attached to the soot particles in the sample compartment of the hot and cold stage 9, place the hot and cold stage 9 on the platform of the confocal micro-Raman spectrometer 10, start the confocal micro-Raman spectrometer 10 and Raman spectrometer controller 11.

5) Start the hot and cold table controller 12, the water circulation pump 15, and the liquid nitrogen cooling pump 14, and set the temperature of the sample compartment of the hot and cold table 9 according to the test requirements.

6) The vacuum pump 16 and the humidity controller 23 are connected to the hot and cold stage 9, and the humidity controller 23 goes deep into the sample chamber of the hot and cold stage 9, and can directly measure the ambient humidity in the sample chamber of the hot and cold stage 9, and adjust it according to the needs of the test. The vacuum pump 16 makes the ambient pressure in the sample compartment of the hot and cold stage 9 meet the test requirements.

7) Turn on the air compressor 18, and adjust the first mass flow controller 20 according to the required compressed air flow.

8) start the water vapor generator 19, humidity controller 23, the humidity controller 23 is used to detect the ambient humidity in the sample chamber of the hot and cold platform 9, and control the second mass flow controller 21 according to the ambient humidity, to enter the mixed heat preservation The flow of water vapor in the container 22 is adjusted to control the flow of water vapor.

9) Water vapor with a predetermined humidity is introduced into the sample chamber of the hot and cold stage 9, and the position of the soot particles is observed based on the confocal micro Raman spectrometer 10 and Raman spectrum analysis is performed. When the water vapor undergoes a phase change on the surface of the soot particles, the optical microscope The phase transition process can be observed, and the Raman spectrum measured by the confocal micro-Raman spectrometer 10 will also change. Based on optical microscope observation and Raman spectrum analysis, the critical environmental conditions when water vapor undergoes phase transition on the surface of soot particles can be judged , and explore the microscopic mechanism of the process.

10) After the test ends, turn off the steam generator 19, the air compressor 18, the first mass flow controller 20, the second mass flow controller 21, the humidity controller 23, the hot and cold table controller 12, and the water circulation pump 15 in sequence , liquid nitrogen cooling pump 14, vacuum pump 16, confocal micro-Raman spectrometer 10 and Raman spectrometer controller 11, the cold and hot stage 9 is taken off from the platform of the confocal micro-Raman spectrometer 10, and the sample chamber of the cold and hot stage 9 is taken out A hydrophobically treated sampling membrane 8 with soot particles attached to it.

The main purpose of this embodiment is to overcome the deficiencies in the prior art, and propose a soot particle surface water vapor phase change test system, which can realize the coordinated control of the temperature-pressure-humidity of the sample chamber of the cold and hot platform 9, and simulate the high-altitude temperature of cruising, Humidity and pressure conditions, carry out experimental research on the phase transition of water vapor on the surface of soot particles under cruising high-altitude environmental conditions. Aiming at the problem that it is difficult to guarantee the accuracy of judging the icing situation based on a single method, the test system of this embodiment can observe and detect the phase transition process of water vapor on the surface of soot particles through an optical microscope and a Raman spectrometer respectively. Two methods judge the critical environmental conditions when water vapor undergoes phase transition on the surface of soot particles and explore the micro-mechanism of the process; It is of great significance for revealing the microcosmic nature of soot particle icing and cloud formation and developing high-precision icing models.

Example 2:

This embodiment is used to provide a soot particle surface water vapor phase change test method, using the test system described in Example 1 to work, the test method includes: using the soot particle sampling subsystem to provide a soot particle to the sample chamber Particles or secondary soot particles; use the temperature/pressure control subsystem to adjust the temperature and pressure of the sample chamber, so that the sample chamber is at a predetermined temperature and predetermined pressure; use the predetermined humidity water vapor generation subsystem to provide the sample chamber with a predetermined humidity Water vapor: using detection components at a predetermined temperature and predetermined pressure to detect the phase transition of water vapor with a predetermined humidity on the surface of primary soot particles or secondary soot particles.

What each embodiment in this specification focuses on is the difference from other embodiments, and the same and similar parts of the various embodiments can be referred to each other.

In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in specific implementation methods and application ranges. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. A soot particle surface vapor phase change test system is characterized in that the test system comprises: the system comprises a soot particle sampling subsystem, a detection subsystem, a temperature/pressure control subsystem and a preset humidity steam generation subsystem; the detection subsystem comprises a cold-hot table with a sample bin and a detection part;

the soot sampling subsystem is used for providing primary soot particles or secondary soot particles to the sample bin;

the temperature/pressure control subsystem is used for adjusting the temperature and the pressure of the sample chamber to enable the sample chamber to be at a preset temperature and a preset pressure;

the water vapor generation subsystem with the preset humidity is used for providing water vapor with the preset humidity to the sample bin;

the detection component is used for detecting the phase change condition of the water vapor with the preset humidity on the surface of the primary soot particles or the secondary soot particles under the preset temperature and the preset pressure.

2. The testing system of claim 1, wherein the soot sampling subsystem includes a generation component and a sampling component; the generating component is connected with the sampling component in a pipeline way;

the generating component is used for generating the primary soot particles or the secondary soot particles;

the sampling part is used for sampling the primary soot particles or the secondary soot particles and providing the primary soot particles or the secondary soot particles to the sample bin.

3. The testing system of claim 2, wherein the generating means comprises: the device comprises a carbon black aerosol generator, a secondary particulate oxidation reaction generator, a first valve and a second valve; the carbon black aerosol generator is connected with the secondary particle oxidation reaction generator through a pipeline; the carbon black aerosol generator and the secondary particle oxidation reaction generator are both connected with the sampling component through pipelines; the first valve is positioned on a pipeline between the carbon black aerosol generator and the sampling component; the second valve is located on a pipeline between the soot aerosol generator and the secondary particulate matter oxidation reaction generator;

the carbon black aerosol generator is used for generating the primary carbon smoke particles;

the secondary particulate matter oxidation reaction generator is used for converting the primary soot particles into the secondary soot particles;

the sampling component is used for sampling the primary soot particles when the first valve is opened and the second valve is closed;

when the first valve is closed and the second valve is opened, the sampling part is used for sampling the secondary soot particles.

4. The testing system of claim 2, wherein said sampling component comprises a sampler and a suction pump; the air pump is connected with the air path of the sampler;

the sampler is used for sampling the primary soot particles or the secondary soot particles; the air suction pump is used for driving the primary soot particles or the secondary soot particles to move, so that the primary soot particles or the secondary soot particles are deposited on the sampling membrane subjected to hydrophobic treatment in the sampler; in testing, the hydrophobically treated sampling membrane is placed in the sample compartment to provide the primary soot or the secondary soot to the sample compartment.

5. The testing system of claim 1, wherein the temperature/pressure control subsystem comprises a temperature control component and a pressure control component;

the temperature control component is used for adjusting the temperature of the sample cabin so that the sample cabin is at a preset temperature;

the pressure control component is used for adjusting the pressure of the sample chamber to enable the sample chamber to be at a preset pressure.

6. The testing system of claim 5, wherein said temperature control component comprises a hot and cold stage controller, a refrigeration sub-component, and a heating sub-component; the cold and hot table controller is used for adjusting the temperature of the sample bin by controlling the heating sub-component and the refrigerating sub-component so that the sample bin is at a preset temperature;

the refrigerating sub-component comprises a Dewar flask, a liquid nitrogen cooling pump and a refrigerating element arranged inside the cold and hot table; the liquid nitrogen cooling pump is connected with the Dewar flask pipeline; liquid nitrogen is stored in the Dewar flask; the liquid nitrogen cooling pump is used for pumping the liquid nitrogen into the refrigeration element, and cooling and adjusting the temperature of the sample bin to enable the sample bin to be at a preset temperature;

the heating sub-component comprises a water circulating pump and a heating element arranged inside the cold and hot table; the water circulating pump is used for cooling the heating element; the heating element is used for heating and adjusting the temperature of the sample chamber, so that the sample chamber is at a preset temperature.

7. The testing system of claim 5, wherein the pressure control component comprises a vacuum pump and an air pressure sensor; the air pressure sensor is used for collecting air pressure in the sample bin; the vacuum pump is used for exhausting air to the sample bin according to the air pressure and adjusting the pressure of the sample bin to enable the sample bin to be at a preset pressure.

8. The testing system of claim 1, wherein said predetermined humidity water vapor generation subsystem comprises an air compressor, a water vapor generator, a mixing and holding vessel, a first mass flow controller, a second mass flow controller, and a humidity controller;

the air compressor is used for generating compressed air; the first mass flow controller is used for adjusting the flow of the compressed air entering the mixing heat-preserving container;

the water vapor generator is used for generating water vapor; the humidity controller is used for detecting the environmental humidity in the sample bin, controlling the second mass flow controller according to the environmental humidity and adjusting the flow of the water vapor entering the mixing heat-preserving container;

the mixing heat-preserving container is used for mixing the compressed air and the water vapor to obtain water vapor with preset humidity, and providing the water vapor with the preset humidity for the sample bin.

9. The assay system of claim 1, wherein the detection component is a confocal micro-raman spectrometer.

10. A soot surface water vapor phase transition test method operated by the test system of any one of claims 1 to 9, the test method comprising:

providing primary soot particles or secondary soot particles to the sample bin by using a soot particle sampling subsystem;

adjusting the temperature and the pressure of the sample chamber by using a temperature/pressure control subsystem to enable the sample chamber to be at a preset temperature and a preset pressure;

providing water vapor of a predetermined humidity to the sample compartment with a predetermined humidity water vapor generation subsystem;

and detecting the phase change condition of the water vapor with the preset humidity on the surface of the primary soot particles or the secondary soot particles by using a detecting component at the preset temperature and the preset pressure.

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