A system and method for testing the phase change of water vapor on the surface of carbon soot particles

Abstract

The present application relates to a kind of carbon smoke particle surface water vapor phase change test system and method, belong to phase change test technical field, carbon smoke particle sampling sub-system is used to provide primary carbon smoke particle or secondary carbon smoke particle to sample bin, temperature / pressure control subsystem is used to adjust the temperature and pressure of sample bin, so that sample bin is at predetermined temperature and predetermined pressure, predetermined humidity water vapor generation subsystem is used to provide predetermined humidity water vapor to sample bin, detection component is used to detect the phase change of predetermined humidity water vapor on the surface of primary carbon smoke particle or secondary carbon smoke particle at predetermined temperature and predetermined pressure, so that the temperature-pressure-humidity of sample bin can be realized coordinated control, carries out carbon smoke particle surface water vapor phase change test research under different temperature, humidity, pressure conditions.

Description

Technical Field

[0001] This invention relates to the field of phase change testing technology, and in particular to a test system and method for water vapor phase change on the surface of carbon soot particles. Background Technology

[0002] Soot particles can directly or indirectly alter the amount of solar radiation reaching the Earth's surface, thus impacting the climate. The aviation industry is the sole source of soot emissions from the upper troposphere. Aviation soot particles can act as icing nuclei in aircraft exhaust, forming ice crystals that influence the formation and distribution of contrails and cirrus clouds, thereby affecting the Earth's radiation balance and significantly impacting global climate. The complex microscopic morphology of soot particles, coupled with the adsorption of organic matter and sulfates from emissions onto their surfaces, alters their ability to ic and form clouds, further complicating these processes. These issues make it difficult to apply traditional research findings on icing and cloud formation to soot particles, hindering accurate assessments of their impact on atmospheric radiation and global climate. Different studies can even yield contradictory conclusions, creating a bottleneck in the development of relevant atmospheric models.

[0003] Currently, research on the water vapor phase transition on the surface of soot particles mainly employs two methods: online and offline. Online methods typically involve directly introducing soot particles into different types of environmental chambers, cloud chambers, and flow tubes for experiments. Offline methods usually place the collected soot particles on a cold stage for experiments, using optical microscopy and environmental scanning electron microscopy to observe the water vapor phase transition process on the soot particle surface in real time. However, current online and offline methods still struggle to simulate the temperature, humidity, and pressure conditions at high altitudes during cruising, making it difficult to support experimental research on the water vapor phase transition on the surface of soot particles under such conditions.

[0004] Therefore, there is an urgent need for a new experimental technique for water vapor phase change on the surface of carbon soot particles. Summary of the Invention

[0005] The purpose of this invention is to provide a test system and method for water vapor phase change on the surface of carbon soot particles, which can realize the coordinated control of temperature, pressure and humidity in the sample chamber of the hot and cold stage, simulate the temperature, humidity and pressure conditions of cruising at high altitude, and carry out experimental research on water vapor phase change on the surface of carbon soot particles under cruising at high altitude environmental conditions.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A carbon soot particle surface water vapor phase change test system, the test system comprising: a carbon soot particle sampling subsystem, a detection subsystem, a temperature / pressure control subsystem, and a predetermined humidity water vapor generation subsystem; the detection subsystem includes a hot and cold stage with a sample chamber and detection components;

[0008] The carbon soot particle sampling subsystem is used to provide primary or secondary carbon soot particles to the sample chamber.

[0009] The temperature / pressure control subsystem is used to regulate the temperature and pressure of the sample chamber, so that the sample chamber is at a predetermined temperature and predetermined pressure.

[0010] The predetermined humidity water vapor generation subsystem is used to provide water vapor with a predetermined humidity to the sample chamber;

[0011] The detection component is used to detect the phase change of water vapor at a predetermined humidity on the surface of primary or secondary soot particles at the predetermined temperature and pressure.

[0012] In some embodiments, the soot particle sampling subsystem includes a generating component and a sampling component; the generating component and the sampling component are connected by pipelines.

[0013] The generating component is used to generate the primary soot particles or the secondary soot particles;

[0014] The sampling component is used to sample the primary soot particles or the secondary soot particles and to provide the primary soot particles or the secondary soot particles to the sample chamber.

[0015] In some embodiments, the generating component includes: a carbon black aerosol generator, a secondary particulate matter oxidation reaction generator, a first valve, and a second valve; the carbon black aerosol generator and the secondary particulate matter oxidation reaction generator are connected by pipelines; both the carbon black aerosol generator and the secondary particulate matter oxidation reaction generator are connected by pipelines to the sampling component; the first valve is located on the pipeline between the carbon black aerosol generator and the sampling component; the second valve is located on the pipeline between the carbon black aerosol generator and the secondary particulate matter oxidation reaction generator.

[0016] The carbon black aerosol generator is used to generate the primary carbon soot particles;

[0017] The secondary particulate matter oxidation reaction generator is used to convert the primary carbon soot particles into the secondary carbon soot particles.

[0018] When the first valve is open and the second valve is closed, the sampling component is used to sample the primary carbon soot particles;

[0019] When the first valve is closed and the second valve is open, the sampling component is used to sample the secondary soot particles.

[0020] In some embodiments, the sampling component includes a sampler and a vacuum pump; the vacuum pump is connected to the air circuit of the sampler.

[0021] The sampler is used to sample the primary or secondary soot particles; the air pump is used to drive the movement of the primary or secondary soot particles, causing them to deposit on the hydrophobic sampling membrane inside the sampler; during the test, the hydrophobic sampling membrane is placed in the sample chamber to provide the primary or secondary soot particles to the sample chamber.

[0022] In some embodiments, the temperature / pressure control subsystem includes a temperature control component and a pressure control component;

[0023] The temperature control component is used to adjust the temperature of the sample chamber to keep the sample chamber at a predetermined temperature.

[0024] The pressure control component is used to adjust the pressure of the sample chamber so that the sample chamber is at a predetermined pressure.

[0025] In some embodiments, the temperature control component includes a hot and cold stage controller, a cooling sub-component, and a heating sub-component; the hot and cold stage controller is used to adjust the temperature of the sample chamber by controlling the heating sub-component and the cooling sub-component, so that the sample chamber is at a predetermined temperature;

[0026] The refrigeration sub-component includes a Dewar flask, a liquid nitrogen cooling pump, and a refrigeration element disposed inside the heating / cooling stage; the liquid nitrogen cooling pump is connected to the Dewar flask by pipeline; the Dewar flask stores liquid nitrogen; the liquid nitrogen cooling pump is used to pump the liquid nitrogen into the refrigeration element to cool and regulate the temperature of the sample chamber, so that the sample chamber is at a predetermined temperature.

[0027] The heating sub-component includes a water circulation pump and a heating element disposed inside the heating / cooling stage; the water circulation pump is used to cool the heating element; the heating element is used to heat and regulate the temperature of the sample chamber, so that the sample chamber is at a predetermined temperature.

[0028] In some embodiments, the pressure control component includes a vacuum pump and a pressure sensor; the pressure sensor is used to collect the pressure inside the sample chamber; the vacuum pump is used to evacuate the sample chamber according to the pressure, thereby adjusting the pressure of the sample chamber to a predetermined pressure.

[0029] In some embodiments, the predetermined humidity water vapor generating subsystem includes an air compressor, a water vapor generator, a mixing and heat-insulating container, a first mass flow controller, a second mass flow controller, and a humidity controller;

[0030] The air compressor is used to generate compressed air; the first mass flow controller is used to adjust the flow rate of the compressed air entering the mixing and insulation container;

[0031] The steam generator is used to generate steam; the humidity controller is used to detect the ambient humidity inside the sample chamber and control the second mass flow controller according to the ambient humidity to adjust the flow rate of steam entering the mixing and heat preservation container.

[0032] The mixing and heat-insulating container is used to mix the compressed air and the water vapor to obtain water vapor with a predetermined humidity, and to provide the water vapor with the predetermined humidity to the sample chamber.

[0033] In some embodiments, the detection component is a confocal Raman microscopy instrument.

[0034] A method for testing the water vapor phase transition on the surface of soot particles, utilizing the aforementioned testing system, the method comprising:

[0035] The carbon soot particle sampling subsystem provides primary or secondary carbon soot particles to the sample chamber.

[0036] The temperature and pressure of the sample chamber are regulated by a temperature / pressure control subsystem to keep the sample chamber at a predetermined temperature and pressure.

[0037] A predetermined humidity water vapor generation subsystem is used to supply water vapor with a predetermined humidity to the sample chamber.

[0038] Using a detection component, the phase transition of water vapor at a predetermined humidity on the surface of primary or secondary soot particles is detected at the predetermined temperature and pressure.

[0039] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0040] This invention provides a system and method for testing the phase transition of water vapor on the surface of soot particles, comprising: a soot particle sampling subsystem, a detection subsystem, a temperature / pressure control subsystem, and a predetermined humidity water vapor generation subsystem. The detection subsystem includes a hot and cold stage with a sample chamber and a detection component. The soot particle sampling subsystem provides primary or secondary soot particles to the sample chamber. The temperature / pressure control subsystem regulates the temperature and pressure of the sample chamber to maintain a predetermined temperature and pressure. The predetermined humidity water vapor generation subsystem provides water vapor with a predetermined humidity to the sample chamber. The detection component detects the phase transition of water vapor with a predetermined humidity on the surface of primary or secondary soot particles at the predetermined temperature and pressure using both optical microscopy and Raman spectroscopy. This allows for coordinated control of the sample chamber's temperature, pressure, and humidity, enabling experimental research on the phase transition of water vapor on the surface of soot particles under cruising high-altitude environmental conditions. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the experimental system provided in Embodiment 1 of the present invention;

[0043] Figure 2 This is a schematic diagram of the air inlet end of the sampler provided in Embodiment 1 of the present invention; Figure 2 (a) is a schematic diagram of the air intake end; Figure 2 (b) is a perspective view of the air intake end;

[0044] Figure 3 This is a schematic diagram of the support network for the sampler provided in Embodiment 1 of the present invention;

[0045] Figure 4 This is a schematic diagram of the exhaust end of the sampler provided in Embodiment 1 of the present invention; Figure 4 (a) is a schematic diagram of the exhaust end; Figure 4 (b) is a perspective view of the exhaust end;

[0046] Figure 5 This is a schematic diagram of the assembly result of the sampler provided in Embodiment 1 of the present invention; Figure 5 (a) is a schematic diagram of the assembled appearance; Figure 5 (b) is a perspective view after assembly.

[0047] Symbol explanation:

[0048] 1-Carbon black aerosol generator; 2-Particle size analyzer; 3-Secondary particulate matter oxidation reaction generator; 4-First valve; 5-Second valve; 6-Sampler; 7-Air pump; 8-Hydrophobic sampling membrane; 9-Heating and cooling stage with sample chamber; 10-Confocal Raman microscopy; 11-Raman spectrometer controller; 12-Heating and cooling stage controller; 13-Dewar flask; 14-Liquid nitrogen cooling pump; 15-Water circulation pump; 16-Vacuum pump; 17-Exhaust pipe; 18-Air compressor; 19-Water vapor generator; 20-First mass flow controller; 21-Second mass flow controller; 22-Mixing and heat-insulating container; 23-Humidity controller; 24-Air inlet; 25-Support mesh; 26-Exhaust end; 27-Card slot. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] The purpose of this invention is to provide a test system and method for water vapor phase change on the surface of carbon soot particles, which can realize the coordinated control of temperature, pressure and humidity in the sample chamber and carry out experimental research on water vapor phase change on the surface of carbon soot particles under different temperature, humidity and pressure conditions.

[0051] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] Example 1:

[0053] This embodiment provides a test system for water vapor phase change on the surface of soot particles, such as... Figure 1 As shown, the test system includes: a carbon soot particle sampling subsystem, a detection subsystem, a temperature / pressure control subsystem, and a predetermined humidity water vapor generation subsystem. The detection subsystem includes a hot and cold stage 9 with a sample chamber and detection components.

[0054] The carbon soot particle sampling subsystem is used to provide primary or secondary carbon soot particles to the sample chamber.

[0055] The temperature / pressure control subsystem is used to regulate the temperature and pressure of the sample chamber to keep the sample chamber at a predetermined temperature and pressure.

[0056] The predetermined humidity water vapor generation subsystem is used to provide water vapor with a predetermined humidity to the sample chamber.

[0057] The detection component is used to detect the phase change of water vapor at a predetermined humidity on the surface of primary or secondary soot particles at a predetermined temperature and pressure.

[0058] The soot particle sampling subsystem of this embodiment includes a generation component and a sampling component, which are connected by pipelines. The generation component is used to generate primary or secondary soot particles, and the sampling component is used to sample the primary or secondary soot particles and provide them to the sample chamber of the hot / cold stage 9.

[0059] Specifically, addressing the difficulty of existing experimental systems in investigating the influence of secondary oxidation levels on the phase transition process of water vapor on the surface of soot particles, this embodiment uses either primary or secondary soot particles to study the phase transition of water vapor on the surface of primary and secondary soot particles. In this embodiment, the generating components include: a carbon black aerosol generator 1, a secondary particulate oxidation reaction generator 3, a first valve 4, and a second valve 5. The carbon black aerosol generator 1 and the secondary particulate oxidation reaction generator 3 are connected by pipelines, and both are connected to the sampling component pipelines. The first valve 4 is located on the pipeline between the carbon black aerosol generator 1 and the sampling component, and the second valve 5 is located on the pipeline between the carbon black aerosol generator 1 and the secondary particulate oxidation reaction generator 3.

[0060] The carbon black aerosol generator 1 generates primary carbon soot particles, and the secondary particulate matter oxidation reaction generator 3 converts the primary carbon soot particles into secondary carbon soot particles. The first valve 4 and the second valve 5 control the flow direction of the primary carbon soot particles. When both valves 4 and 5 are closed, primary carbon soot particles cannot enter the sampling component or the secondary particulate matter oxidation reaction generator 3; in this case, the sampling component cannot sample either primary or secondary carbon soot particles. When both valves 4 and 5 are open, primary carbon soot particles can enter both the sampling component and the secondary particulate matter oxidation reaction generator 3; in this case, the sampling component can sample both primary and secondary carbon soot particles simultaneously. When the first valve 4 is open and the second valve 5 is closed, primary carbon soot particles can enter the sampling component but cannot enter the secondary particulate matter oxidation reaction generator 3; in this case, the sampling component can only sample primary carbon soot particles. When the first valve 4 is closed and the second valve 5 is open, primary carbon soot particles cannot enter the sampling component but can enter the secondary particulate matter oxidation reaction generator 3; in this case, the sampling component can only sample secondary carbon soot particles. Therefore, in order to obtain different types of soot particles, this embodiment opens the first valve 4 and closes the second valve 5 when it is necessary to sample the soot particles for the first time; and closes the first valve 4 and opens the second valve 5 when it is necessary to sample the soot particles for the second time.

[0061] Normally, the carbon black aerosol generator 1 produces primary carbon soot particle aerosol. In this embodiment, the generating component may further include a particle size analyzer 2, which is connected to the carbon black aerosol generator 1. The particle size analyzer 2 is located between the carbon black aerosol generator 1 and the first valve 4, and also between the carbon black aerosol generator 1 and the second valve 5. The particle size analyzer 2 is used to sieve the primary carbon soot particle aerosol produced by the carbon black aerosol generator 1 to obtain primary carbon soot particles within a specific particle size range. In this embodiment, secondary carbon soot particles with different oxidation degrees can also be obtained by adjusting the parameters of the secondary particulate matter oxidation reaction generator 3.

[0062] Specifically, the sampling components in this embodiment include a sampler 6 and a vacuum pump 7, with the vacuum pump 7 connected to the sampler 6 via an air path. The sampler 6 is used to sample primary or secondary soot particles generated by the generating component, and the vacuum pump 7 is used to drive the movement of the soot particles, causing them to deposit on the hydrophobic sampling membrane 8 inside the sampler 6. During the experiment, the hydrophobic sampling membrane 8 is placed in the sample chamber of the hot and cold stage 9 to provide soot particles to the sample chamber of the hot and cold stage 9.

[0063] like Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the sampler 6 in this embodiment includes an air inlet 24, a hydrophobic sampling membrane 8, a support net 25, and an exhaust end 26. With the direction of air intake as the inward direction, the air inlet 24 gradually expands from the outside to the inside, and the exhaust end 26 gradually contracts from the outside to the inside. The support net 25 is placed on the slot 27 of the exhaust end 26. The air inlet 24 and the exhaust end 26 are connected by threads and then the support net 25 is locked in place. The hydrophobic sampling membrane 8 is pasted on the support net 25.

[0064] The carbon soot particle sampling subsystem of this embodiment includes a carbon black aerosol generator 1, a particle size analyzer 2, a secondary particulate matter oxidation reaction generator 3, a first valve 4, a second valve 5, a sampler 6, and an air pump 7, which can generate and collect primary or secondary carbon soot particles.

[0065] The temperature / pressure control subsystem of this embodiment includes a temperature control component and a pressure control component. The temperature control component is used to adjust the temperature of the sample chamber of the hot and cold stage 9 so that the sample chamber of the hot and cold stage 9 is at a predetermined temperature. The pressure control component is used to adjust the pressure of the sample chamber of the hot and cold stage 9 so that the sample chamber of the hot and cold stage 9 is at a predetermined pressure.

[0066] Specifically, the temperature control component in this embodiment includes a hot and cold stage controller 12, a cooling sub-component, and a heating sub-component. The hot and cold stage controller 12 adjusts the temperature of the sample chamber of the hot and cold stage 9 by controlling the heating sub-component and the cooling sub-component, so that the sample chamber of the hot and cold stage 9 is at a predetermined temperature.

[0067] The cooling sub-component of this embodiment includes a Dewar flask 13, a liquid nitrogen cooling pump 14, and a cooling element disposed inside the heating / cooling stage 9. The liquid nitrogen cooling pump 14 and the Dewar flask 13 are connected by pipeline. The Dewar flask 13 stores liquid nitrogen, and the liquid nitrogen cooling pump 14 is used to pump the liquid nitrogen into the cooling element disposed inside the heating / cooling stage 9 to cool the sample chamber of the heating / cooling stage 9. That is, the cooling function is achieved by liquid nitrogen to cool and regulate the temperature of the sample chamber of the heating / cooling stage 9, so that the sample chamber of the heating / cooling stage 9 is at a predetermined temperature.

[0068] The heating sub-component in this embodiment includes a water circulation pump 15 and a heating element disposed inside the heating and cooling stage 9. The water circulation pump 15 is used to cool the heating element disposed inside the heating and cooling stage 9, and the heating element is used to heat and regulate the temperature of the sample chamber of the heating and cooling stage 9 so that the sample chamber of the heating and cooling stage 9 is at a predetermined temperature.

[0069] Specifically, the pressure control component in this embodiment includes a vacuum pump 16 and a pressure sensor. The pressure sensor can be a pressure sensor mounted on the vacuum pump 16. The pressure sensor is used to collect the air pressure inside the sample chamber of the hot and cold stage 9. The vacuum pump 16 is used to evacuate the sample chamber of the hot and cold stage 9 according to the air pressure, thereby adjusting the pressure of the sample chamber of the hot and cold stage 9 to a predetermined pressure, so as to achieve the function of controlling the ambient pressure in the sample chamber of the hot and cold stage 9. The pressure control component in this embodiment may also include an exhaust pipe 17, which is connected to the air outlet of the vacuum pump 16 to discharge excess gas from the sample chamber of the hot and cold stage 9.

[0070] The temperature / pressure control subsystem of this embodiment includes a hot / cold stage controller 12, a Dewar flask 13, a liquid nitrogen cooling pump 14, a water circulation pump 15, a vacuum pump 16, and an exhaust pipe 17. The hot / cold stage controller 12 is connected to the sample chamber of the hot / cold stage 9, the Dewar flask 13 is connected to the liquid nitrogen cooling pump 14, the liquid nitrogen cooling pump 14, the water circulation pump 15, and the vacuum pump 16 are connected to the sample chamber of the hot / cold stage 9, and the exhaust pipe 17 is connected to the vacuum pump 16. It can be used to control the temperature and pressure inside the sample chamber of the hot / cold stage 9.

[0071] The predetermined humidity steam generation subsystem of this embodiment includes an air compressor 18, a steam generator 19, a mixing and insulated container 22, a first mass flow controller 20, a second mass flow controller 21, and a humidity controller 23. Both the air compressor 18 and the steam generator 19 are connected to the mixing and insulated container 22 via piping. Specifically, the air compressor 18 is connected to the first mass flow controller 20, and the steam generator 19 is connected to the second mass flow controller 21. The first mass flow controller 20 and the second mass flow controller 21 are both connected to the mixing and insulated container 22, which is connected to the sample chamber of the hot and cold stage 9.

[0072] An air compressor 18 generates compressed air, and a first mass flow controller 20 adjusts the flow rate of the compressed air entering the mixing and insulated container 22 to regulate the compressed air flow rate. A steam generator 19 generates steam, and a humidity controller 23 detects the ambient humidity inside the sample chamber of the heating and cooling stage 9 and controls a second mass flow controller 21 based on the ambient humidity to adjust the flow rate of the steam entering the mixing and insulated container 22 to control the steam flow rate. The mixing and insulated container 22 mixes the compressed air and steam to obtain steam with a predetermined humidity and provides the steam with the predetermined humidity to the sample chamber of the heating and cooling stage 9. In this embodiment, the mixing and insulated container 22 can also insulate the steam with the predetermined humidity.

[0073] It should be noted that the humidity controller 23 in this embodiment can adjust the second mass flow controller 21 according to the difference between the predetermined humidity and the measured ambient humidity. Since the water vapor mass flow rate is positively correlated with humidity under the condition of constant air mass flow rate and humidity below 100%, the water vapor flow rate can be changed to make the mixed gas reach the predetermined humidity, thus obtaining water vapor with the predetermined humidity. At the same time, the humidity controller 23 in this embodiment can detect the humidity in the sample chamber of the hot and cold stage 9 in real time, and combine it with the predetermined humidity to control the water vapor flow rate, realizing closed-loop control, so that the water vapor in the sample chamber of the hot and cold stage 9 is always maintained at the predetermined humidity. The water vapor with the predetermined humidity in the mixing and insulation container 22 is introduced into the sample chamber of the hot and cold stage 9. Based on this embodiment, not only can the phase change process of water vapor on the surface of soot particles be observed, but the critical humidity condition for phase change can also be explored.

[0074] The predetermined humidity water vapor generation subsystem of this 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 and heat preservation container 22, and a humidity controller 23, which can provide water vapor with different relative humidity to the sample chamber of the hot and cold stage 9.

[0075] The sample chamber of the hot and cold stage 9 in this embodiment is a relatively sealed sample chamber with adjustable temperature, pressure and humidity.

[0076] In this embodiment, the detection component can be a confocal micro Raman spectrometer 10. The confocal micro Raman spectrometer 10 acquires optical microscopic images based on its built-in optical microscope to determine the position of soot particles. Based on this, Raman spectral analysis of the soot particles can be performed. Furthermore, the microscopic mechanism and laws of the phase transition process of water vapor on the surface of soot particles can be explored using both optical microscopy observation and Raman spectral analysis. For example, when water vapor undergoes a phase transition on the surface of soot particles, the optical microscope can observe the phase transition process. Based on the size changes of particles and water or ice on their surface in the optical microscopic image, the freezing rate under different experimental conditions can be revealed. When water vapor undergoes a phase transition on the surface of soot particles, the Raman spectrum measured by the confocal micro Raman spectrometer 10 will also change. Based on the changes in the position of the spectral peak, the critical environmental conditions when water vapor undergoes a phase transition on the surface of soot particles can be revealed, and the microscopic mechanism of this process can be explored.

[0077] The confocal micro Raman spectrometer 10 in this embodiment can realize the functions of observing particle position and spectral analysis. This embodiment can also be equipped with a Raman spectrometer controller 11, which is a computer for configuring and analyzing the parameters of the confocal micro Raman spectrometer 10 and is used to control the confocal micro Raman spectrometer 10.

[0078] It should be noted that the size of a single soot particle is usually less than 1 μm, making it 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 experimental system in this embodiment is mainly for micron-sized soot particle agglomerates.

[0079] 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.

[0080] Based on the structure of the above-described experimental system, the experimental steps in this embodiment are as follows:

[0081] 1) Determine the opening and closing of the secondary particulate matter oxidation generator 3, the first valve 4, and the second valve 5 according to the experimental requirements: When conducting a primary carbon soot particle surface water vapor phase change test, open the first valve 4, close the second valve 5, and shut down the secondary particulate matter oxidation generator 3; when conducting a secondary carbon soot particle surface water vapor phase change test, close the first valve 4, open the second valve 5, and start the secondary particulate matter oxidation generator 3.

[0082] 2) Start the carbon black aerosol generator 1 and the vacuum pump 7. Primary or secondary carbon soot particle samples within a specific particle size range move and deposit on the hydrophobic sampling membrane 8 in the sampler 6 under the action of the vacuum pump 7, thereby obtaining the hydrophobic sampling membrane 8 with attached carbon soot particles.

[0083] 3) After sampling, turn off carbon black aerosol generator 1, first valve 4 (or second valve 5 and secondary particulate matter oxidation reaction generator 3) and vacuum pump 7 in sequence, and take out the hydrophobic sampling membrane 8 with carbon soot particles attached from the sampler 6.

[0084] 4) Place the hydrophobically treated sampling membrane 8 with attached carbon soot particles in the sample chamber of the hot and cold stage 9, place the hot and cold stage 9 on the platform of the confocal micro Raman spectrometer 10, and start the confocal micro Raman spectrometer 10 and the Raman spectrometer controller 11.

[0085] 5) Start the hot and cold stage controller 12, water circulation pump 15, and liquid nitrogen cooling pump 14, and set the temperature of the sample chamber of the hot and cold stage 9 according to the test requirements.

[0086] 6) Connect the vacuum pump 16 and humidity controller 23 to the hot and cold stage 9. The humidity controller 23 is inserted into the sample chamber of the hot and cold stage 9 and can directly measure the ambient humidity inside the sample chamber of the hot and cold stage 9. Adjust the vacuum pump 16 according to the test requirements so that the ambient pressure inside the sample chamber of the hot and cold stage 9 meets the test requirements.

[0087] 7) Turn on the air compressor 18 and adjust the first mass flow controller 20 according to the required compressed air flow rate.

[0088] 8) Start the water vapor generator 19 and humidity controller 23. The humidity controller 23 is used to detect the ambient humidity in the sample chamber of the hot and cold stage 9, and controls the second mass flow controller 21 according to the ambient humidity to adjust the flow rate of water vapor entering the mixing and heat preservation container 22 in order to control the water vapor flow rate.

[0089] 9) Water vapor with a predetermined humidity is introduced into the sample chamber of the heating and cooling stage 9. The position of the soot particles is observed and Raman spectroscopy is performed based on the confocal micro Raman spectrometer 10. When water vapor undergoes a phase transition on the surface of soot particles, the phase transition process can be observed by an optical microscope. The Raman spectrum measured by the confocal micro Raman spectrometer 10 will also change. Based on the two methods of optical microscope observation and Raman spectroscopy analysis, the critical environmental conditions when water vapor undergoes a phase transition on the surface of soot particles can be determined, and the microscopic mechanism of this process can be explored.

[0090] 10) After the experiment, turn off the steam generator 19, air compressor 18, first mass flow controller 20, second mass flow controller 21, humidity controller 23, hot and cold stage controller 12, water circulation pump 15, liquid nitrogen cooling pump 14, vacuum pump 16, confocal micro Raman spectrometer 10 and Raman spectrometer controller 11 in sequence. Remove the hot and cold stage 9 from the platform of the confocal micro Raman spectrometer 10 and take out the hydrophobic sampling membrane 8 with carbon soot particles attached to the sample chamber of the hot and cold stage 9.

[0091] The main objective of this embodiment is to overcome the shortcomings of existing technologies and propose a water vapor phase transition experimental system for soot particles. This system enables coordinated control of temperature, pressure, and humidity in the sample chamber of the hot and cold stage 9, simulating the temperature, humidity, and pressure conditions under high-altitude cruising conditions to conduct experimental research on water vapor phase transition on the surface of soot particles under these conditions. Addressing the issue that the accuracy of judging icing conditions using a single method is difficult to guarantee, this embodiment's experimental system can observe and detect the phase transition process of water vapor on the surface of soot particles using both an optical microscope and a Raman spectrometer. Based on these two methods, the critical environmental conditions for water vapor phase transition on the surface of soot particles can be determined, and the microscopic mechanism of this process can be explored. Furthermore, this embodiment's experimental system can also investigate the influence of the degree of secondary oxidation on the phase transition process of water vapor on the surface of soot particles, which is of great significance for revealing the microscopic nature of soot particle condensation and cloud formation and for developing high-precision condensation models.

[0092] Example 2:

[0093] This embodiment provides a method for testing the phase transition of water vapor on the surface of soot particles. It utilizes the testing system described in Embodiment 1. The testing method includes: providing primary or secondary soot particles to a sample chamber using a soot particle sampling subsystem; adjusting the temperature and pressure of the sample chamber using a temperature / pressure control subsystem to maintain a predetermined temperature and pressure; providing water vapor with a predetermined humidity to the sample chamber using a predetermined humidity water vapor generation subsystem; and detecting the phase transition of the water vapor with the predetermined humidity on the surface of the primary or secondary soot particles using a detection component at the predetermined temperature and pressure.

[0094] Each embodiment in this specification focuses on the differences from other embodiments. For the same or similar parts between the embodiments, please refer to each other.

[0095] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A system for testing phase change of water vapor on a surface of a soot particle, comprising: a soot particle generator; a soot particle collection device; a water vapor source; and a temperature control device. The test system comprises a carbon soot particle sampling subsystem, a detection subsystem, a temperature / pressure control subsystem and a predetermined humidity water vapor generation subsystem; the detection subsystem comprises a cold-hot stage with a sample chamber and a detection component; The carbon soot particle sampling subsystem is configured to provide the sample chamber with primary carbon soot particles or secondary carbon soot particles; The temperature / pressure control subsystem is configured to adjust the temperature and pressure of the sample chamber so that the sample chamber is at a predetermined temperature and a predetermined pressure; The predetermined humidity water vapor generation subsystem is configured to provide the sample chamber with water vapor of a predetermined humidity; The detection component is configured to detect the phase change of the water vapor of the predetermined humidity on the surface of the primary carbon soot particles or the secondary carbon soot particles at the predetermined temperature and the predetermined pressure; The carbon soot particle sampling subsystem comprises a generation component and a sampling component; the generation component and the sampling component are connected by pipelines; The generation component is configured to generate the primary carbon soot particles or the secondary carbon soot particles; The sampling component is configured to sample the primary carbon soot particles or the secondary carbon soot particles and provide the sample chamber with the primary carbon soot particles or the secondary carbon soot particles; The generation component comprises 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 reaction generator are connected by pipelines; the carbon black aerosol generator and the secondary particle oxidation reaction generator are both connected with the sampling component by pipelines; the first valve is located on the pipeline between the carbon black aerosol generator and the sampling component; 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 configured to generate the primary carbon soot particles; The secondary particle oxidation reaction generator is configured to convert the primary carbon soot particles into the secondary carbon soot particles; When the first valve is opened and the second valve is closed, the sampling component is configured to sample the primary carbon soot particles; When the first valve is closed and the second valve is opened, the sampling component is configured to sample the secondary carbon soot particles.

2. The test system of claim 1, wherein, The sampling component comprises a sampler and a suction pump; the suction pump is connected with the sampler by a gas path; The sampler is configured to sample the primary carbon soot particles or the secondary carbon soot particles; the suction pump is configured to drive the primary carbon soot particles or the secondary carbon soot particles to move so that the primary carbon soot particles or the secondary carbon soot particles are deposited on a hydrophobic treated sampling membrane in the sampler; during a test, the hydrophobic treated sampling membrane is placed in the sample chamber to provide the sample chamber with the primary carbon soot particles or the secondary carbon soot particles.

3. The test 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 configured to adjust the temperature of the sample chamber so that the sample chamber is at a predetermined temperature; The pressure control component is configured to adjust the pressure of the sample chamber so that the sample chamber is at a predetermined pressure.

4. The test system of claim 3, wherein, The temperature control component comprises a cold-hot stage controller, a refrigeration sub-component and a heating sub-component; the cold-hot stage controller is used to adjust the temperature of the sample chamber by controlling the heating sub-component and the refrigeration sub-component, so that the sample chamber is at a predetermined temperature; The refrigeration sub-component comprises a dewar flask, a liquid nitrogen cooling pump and a refrigeration element arranged inside the cold-hot stage; the liquid nitrogen cooling pump and the dewar flask are connected by pipeline; The dewar flask stores liquid nitrogen; the liquid nitrogen cooling pump is used to pump the liquid nitrogen into the refrigeration element to adjust the temperature of the sample chamber, so that the sample chamber is at a predetermined temperature; The heating sub-component comprises a water circulating pump and a heating element arranged inside the cold-hot stage; the water circulating pump is used to cool the heating element; the heating element is used to adjust the temperature of the sample chamber, so that the sample chamber is at a predetermined temperature.

5. The test system of claim 3, wherein, The pressure control component comprises 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 air out of the sample chamber according to the air pressure to adjust the pressure of the sample chamber, so that the sample chamber is at a predetermined pressure.

6. The test system of claim 1, wherein, The predetermined humidity water vapor generation subsystem comprises an air compressor, a water vapor generator, a mixed heat preservation 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 mixed heat preservation container; The water vapor generator is used to generate water vapor; the humidity controller is used to detect the environmental humidity in the sample chamber and control the second mass flow controller according to the environmental humidity to adjust the flow of water vapor entering the mixed heat preservation container; The mixed 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.

7. The test system of claim 1, wherein The detection component is a confocal microscopic Raman spectrometer.

8. A method for testing the phase change of water vapor on the surface of carbon smoke particles, using the test system according to any one of claims 1 to 7, characterized in that, The test method comprises: providing primary soot particles or secondary soot particles to the sample chamber by using a soot particle sampling subsystem; adjusting the temperature and pressure of the sample chamber by using a temperature / pressure control subsystem, so that the sample chamber is at a predetermined temperature and a predetermined pressure; providing water vapor with a predetermined humidity to the sample chamber by using a predetermined humidity water vapor generation subsystem; detecting the phase change of the water vapor with a predetermined humidity on the surface of the primary soot particles or the secondary soot particles at the predetermined temperature and the predetermined pressure by using a detection component.

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