Thermophoresis probe sampling system for realizing continuous sampling of soot in combustion flame

Abstract

The invention relates to the technical field of soot measurement, in particular to a thermophoresis probe sampling system for continuously sampling soot in combustion flames, which comprises a double-layer storage cabinet, a control system and a sampling system, wherein the double-layer storage cabinet is used for integrating the whole set of measurement system, and the double-layer storage cabinet is movable and adapts to different experiment places; the control system is used for controlling stretching-in and taking-out of the probe and rotation of the turntable, so that multiple sampling at the same flame height is realized; the sampling system realizes the movement of the probe through the track, and is adaptive to soot sampling in combustion environments with different heights. The multi-time sampling of the soot particles at different heights of the flame in each combustion environment is realized, and particularly, the multi-time sampling of the soot particles at the same height in the flame has great significance for revealing soot generation in the combustion environment.

Description

Technical Field

[0001] The present invention relates to the technical field of soot measurement, and particularly relates to a thermophoretic probe sampling system for realizing continuous sampling of soot in a combustion flame. Background Art

[0002] Soot (also known as carbon black) is one of the main harmful products generated by incomplete combustion of various hydrocarbons. The generation of soot, including subsequent processes such as growth and aggregation, is a very complex process. And there are also very complex gas-phase reactions and chemical reactions among soot particles. Currently, various power equipment in human life involve hydrocarbons, such as automobile engines, aero-engines, thermal power generation, etc. The generation of soot is closely related to human life. At present, hydrocarbons are still the mainstream fuels for power equipment, combustion equipment, etc. The generation of soot is extremely harmful. From an industrial perspective, the generation of soot will lead to a decrease in fuel utilization rate, and the generation of soot in the engine will also cause blockage or even corrosion of some fine pores in the engine, resulting in problems such as a reduction in the engine's lifespan. And because soot itself has a certain adsorbability, it may adsorb some harmful substances in the air, such as various bacteria and viruses that are harmful to the human body, thus increasing the level of harmful substances in the air, which will cause great harm to the human body, such as cancer or even death. Therefore, it is quite important to understand the generation level of soot in combustion equipment. The combustion of hydrocarbons first generates precursors of soot, namely polycyclic aromatic hydrocarbons (PAHs). There are two subsequent behaviors of polycyclic aromatic hydrocarbons, pyrolysis and oxidation. Among them, pyrolysis will cause polycyclic aromatic hydrocarbons to pyrolyze into soot, and the degree of oxidation of polycyclic aromatic hydrocarbons is inversely proportional to the subsequent generation level of soot. In some combustion equipment, although most PAHs and soot particles will be oxidized, there are still a small number of soot particles discharged into the atmosphere. Therefore, it is necessary to understand the generation level of soot in various combustion equipment. Monitoring and reducing the soot emission level requires understanding the generation and oxidation mechanism of soot, and understanding the generation and oxidation mechanism of soot requires obtaining information on the particle size and concentration of soot.

[0003] The information of soot, such as soot concentration distribution, soot particle size, soot particle temperature, etc., can be obtained through experimental measurement means. Obtaining the information of soot helps to further understand the generation and oxidation mechanism of soot to monitor and reduce the generation level of soot. At present, the methods for measuring soot information at home and abroad are mainly divided into two categories: 1. Direct contact sampling method; 2. Non-contact optical diagnostic method. Among them, non-contact optical diagnostic techniques include extinction method, light scattering method, two-color method, laser-induced incandescence technique. Non-contact optical diagnostic techniques have been widely used due to their fast response, high measurement accuracy, etc. The extinction method and the light scattering method can only measure the average value within a certain optical path and cannot achieve accurate measurement of two-dimensional soot information. Although the two-color method can achieve accurate online measurement of two-dimensional soot information, it requires two sets of laser systems and needs to ensure that the two laser beams are on the same plane, with high operation difficulty. The laser-induced incandescence technique has the advantages of simple operation, fast time response, and can achieve accurate online measurement of soot information in a two-dimensional plane, so it has become the mainstream method for measuring soot by non-contact optical diagnostic techniques. The direct contact sampling method includes fiber sampling method, thermophoretic probe sampling method, dilution sampling method, etc. The direct contact sampling method has the advantages of simple operation, low cost, and can directly obtain soot particles, so it has been widely used in the field of soot particle size measurement. And the present invention provides a soot direct sampling system based on thermophoretic sampling technology, which can bring great convenience to the direct sampling of soot particles. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a thermophoretic probe sampling system for realizing continuous sampling of soot in a combustion flame. On the one hand, it can directly sample the soot generated in the combustion site, and on the other hand, it can simultaneously realize multiple samplings of soot at different flame heights.

[0005] In order to achieve the above object, the following technical solutions are provided:

[0006] A thermophoretic probe sampling system for realizing continuous sampling of soot in a combustion flame, characterized in that: it includes a double-layer storage cabinet, a control system and a sampling system; wherein, the double-layer storage cabinet is used to integrate the whole set of measurement systems, the double-layer storage cabinet is movable and adapted to different experimental sites; the control system is used to control the insertion, extraction of the probe and the rotation of the turntable to realize multiple samplings at the same flame height; the sampling system realizes the movement of the probe through a track and is adapted to the soot sampling in combustion environments at different heights.

[0007] Preferably, the double-layer storage cabinet is divided into two layers, with gas cylinders placed in the lower layer and the control system and the sampling system placed in the upper layer.

[0008] Preferably, the control system includes an air compression system, which includes two nitrogen cylinders, an air compressor, and a cylinder, and precisely controls the sampling time of the probe through a time relay.

[0009] Preferably, the sampling system uses a cold probe, and the probe is long enough to obtain soot particles across the entire flame.

[0010] Preferably, the sampling system realizes multiple samplings at the same flame height through gears, linear racks, and a turntable.

[0011] Preferably, the sampling system utilizes the thermophoretic phenomenon. When the cold probe extends into the combustion environment, high-temperature soot particles adhere to the probe surface due to the temperature gradient. After sampling, the soot particles are collected through a scanning electron microscope grid.

[0012] Preferably, rigid connection structures are provided at the four corners of the double-layer storage cabinet to reduce the influence of system vibration on the probe.

[0013] Preferably, the thermophoretic probe sampling system analyzes the distribution and shape of soot particles through a scanning electron microscope to realize the inversion of the soot particle size distribution in the flame region.

[0014] The principle of the thermophoretic probe is as follows: When the cold probe extends into the combustion environment, high-temperature soot particles will adhere to the probe surface along with the temperature gradient. After the probe completes one acquisition of soot particles, the soot particles are collected through a scanning electron microscope grid, and finally the particle size information of the soot particles is obtained based on the scanning electron microscope.

[0015] The present invention also provides a method for using a thermophoretic probe sampling system for continuous sampling of soot in a combustion flame, which is characterized by including the following steps:

[0016] Step 1: Move the double-layer storage cabinet carrying the sampling system to a predetermined position, specifically: Move the double-layer storage cabinet carrying the sampling system to a specific position suitable for measurement, which can ensure that the sampling system can sample soot particles in the combustion environment at an effective position and ensure the effectiveness of sampling;

[0017] Step 2: Check the placement of each component of the system, specifically: Check whether the placement of the gas cylinder, air compression system, and sampling system is reasonable and stable, which can avoid the sampling process being affected when the measurement system itself vibrates during the measurement process;

[0018] Step 3: Check whether the air pressure in the gas cylinder is normal and stable;

[0019] Step 4: Rigidly connect the four corners of the double-layer storage cabinet to the ground after checking each part of the sampling system. After completing the rigid connection, check again whether the system is stable;

[0020] Step Five: After completing the system check and rigid connection, check whether the air compression system and the time relay can work properly. The checking method is as follows: When the combustion device is not ignited, set the parameters of the time relay. The time for controlling the picking and sending of the probe can be set to 1 - 10 s to check whether the time relay and the air compression system can work properly; The control of both sets of air compression systems shall perform the above no-load running state check.

[0021] Step Six: After determining that the air compression system can work properly, move the sampling system to a suitable position, that is, the length of the cold probe is sufficient to pass through the entire flame area during the picking and sending process.

[0022] Step Seven: If the sampling environment is a stable laminar diffusion burner, first check whether the air pressures of the gas cylinders used by the burner, such as the fuel gas cylinder, the coflow gas cylinder, etc., are stable, and whether the electronic flowmeter can normally control the flame equivalence ratio.

[0023] Step Eight: Let the burner run with air for a period of time. During the air-running time of the burner, observe whether the flame generated by the flame burner is stable and whether there is any blockage on the surface of the burner.

[0024] Step Nine: After the burner burns stably for a period of time, set the parameters of the time relay. The set time parameter is 10 ms. After completing the time relay parameters, start the air compression system and sample the soot particles in the combustion environment according to actual needs.

[0025] Step Ten: After the probe finishes sampling, collect the soot particles using an electron microscope grid.

[0026] Steps Seven - Ten are the operation steps for a stable laminar diffusion burner sampling environment, but the operation steps are slightly different in some actual engineering bench applications. The sampling steps in some turbulent combustion environments with open optical windows, such as the combustion chamber of an aeroengine, the combustion chamber outlet, etc., are as follows:

[0027] As shown above, Steps One - Six remain the same. In the turbulent combustion environment:

[0028] Step Seven: Check whether the engineering bench is safe and stable. For example, check whether the components of the aeroengine combustion chamber are installed stably, and then check whether it can be normally ignited.

[0029] Step Eight: Stably place the sampling probe at the opening position of the optical window.

[0030] Step Nine: Set the parameters of the time relay, and only use the air compression system for controlling the picking and sending of the probe. The sampling time is set to 15 ms.

[0031] Step 10: After completing the parameter settings, ignite the fire to obtain soot particles. Subsequently, use a grid to collect the soot particles. By taking multiple samples, that is, repeating Step 9, the soot particles at different combustion stages in the turbulent combustion environment can be obtained.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. All components of the system involved in the present invention are simple to operate and have low costs. Among them, the storage cabinet, gas cylinder, air compressor, cylinder, time relay, cold probe, rigid connection structure, and the required straight rack, gear, slide rail, steel plate structure, etc. can all be purchased on the market or can be processed later by purchasing materials. This also greatly reduces the construction cost of the sampling system involved in the present invention. In addition, the present invention aims to provide a more efficient and convenient direct sampling system based on the sampling principle of the thermophoretic probe compared to traditional sampling methods. The sampling system mentioned in the present invention can achieve multiple samplings in a single experiment, which is of great significance for studying the behavior process of soot in the stable laminar combustion environment and the high-speed turbulent combustion environment, that is, it can provide certain technical and data support for revealing the generation and oxidation mechanism of soot.

[0034] 2. The present invention has certain advantages compared with the traditional thermophoretic probe sampling system. There are some technical problems in direct sampling during the actual experiments of measuring soot concentration and particle size. For the acquisition of soot particles, the sampling time of the cold probe is crucial, including the time for the cold probe to extend into and withdraw from the flame. The traditional sampling system samples the soot particles by controlling the time parameters of the time relay, and the following situations may occur: 1. The sampled particles are incomplete; 2. The soot particles on the probe overlap, resulting in the inability to separate the soot particles when observing the morphology of the soot particles with an electron microscope in the later stage; 3. It is impossible to obtain clearly visible soot particles. In addition, when actually analyzing the soot particle size in the flame, the traditional sampling method can only obtain the soot particles generated at a certain position and at a certain moment in the flame once, which is far from enough for revealing and understanding the generation and oxidation mechanism of soot. Therefore, the present invention aims at the direct sampling of soot particles and aims to improve the sampling efficiency of soot particles in the combustion flame. Achieving multiple samplings of soot particles at different heights in the flame in various combustion environments, especially achieving multiple samplings of soot particles at the same height in the flame is of great significance for revealing the generation of soot in this combustion environment. Whether it is a stable laminar diffusion burner or an unstable turbulent combustion environment, the soot sampling system proposed by the present invention has certain significance for revealing the generation and oxidation mechanism of soot and the soot generation level in the combustion environment. Description of the Drawings

[0035] The accompanying drawings are used to provide a further understanding of the present invention and form a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention.

[0036] Figure 1 It is a schematic diagram of the structure and physical object of the Gülder burner in the present invention;

[0037] Figure 2 It is a schematic diagram of the thermophoresis principle in the present invention;

[0038] Figure 3 It is a schematic diagram of the air compression system in the present invention;

[0039] Figure 4 It is a schematic diagram of the double-layer storage cabinet in the present invention;

[0040] Figure 5 It is a top view of the double-layer storage cabinet and a front view schematic diagram of the roller structure in the present invention;

[0041] Figure 6 It is a schematic diagram of the probe structure in the present invention;

[0042] Figure 7 It is a schematic diagram of the probe control structure in the present invention;

[0043] Figure 8 It is a schematic diagram of the probe sampling structure and the console structure in the present invention. As shown in the figure: 1. Rotating disk for loading probes; 2. Probe structure; 3. Gear structure; 4. Straight rack; 5. Vertical shaft; 6. Straight rod; 7. Bearing; 8. Meshing gear; 9. First slide rail; 10. Fixed steel plate; 11. Ring structure; 12. Carrying platform; 13. Pulley; 14. Second slide rail; 15. Pin hole; 16. Pin. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] Embodiment 1

[0046] Based on the principle of thermophoretic probe sampling, the present invention constructs a direct sampling system for soot particles that can achieve multiple samplings in a single experiment in different combustion environments. Among them, through a double-layer storage cabinet, the integration of each part of the system can be realized. The movable double-layer storage cabinet can make the whole system have better flexibility and can place the measurement system according to the specific experimental site. Through the rigid connection of the four corners to the ground, the inevitable vibration impact on the front probe caused by the rapid start and stop of the cylinder in the air compression system during the sampling process can be reduced, and the impact generated by the rapid start and stop of the cylinder may lead to a decrease in the spatial resolution and detection efficiency of the probe. The sampling system of the present invention is different from the traditional sampling system. The present invention can realize the insertion and extraction of the probe into and from the flame environment through two sets of air compression systems and a time relay system (control system). In addition, by loading four sampling probes on a rotatable turntable, multiple samplings can be achieved at the same flame height within an approximately continuous time period in a single experiment. The two sets of air compression systems and time relay systems in the present invention will realize the rotation of the turntable and the extraction and insertion of the probe in the flame, and the two control systems are independent of each other. Soot undergoes complex gas-phase reactions and a series of subsequent chemical behaviors in the flame. By realizing multiple samplings of soot particles at the same flame height in a short time through the present invention, it is helpful to analyze the generation and growth of soot particles at a certain position in the flame within an approximately continuous time period. This is particularly significant for the generation and growth of soot in high-speed turbulent combustion environments. For example, in some engines such as automotive engines and aero engines, the generation of soot will cause engine corrosion, clogging of fine pores, etc. Therefore, realizing continuous sampling and analysis of soot in turbulent combustion environments plays an important role in revealing the soot generation situation during engine operation, thereby providing certain data support for engine structure design. Thus, the soot sampling system proposed by the present invention is of great significance for further revealing the growth level and generation and oxidation mechanism of soot.

[0047] In the traditional direct sampling system, only single sampling of the probe can be achieved. For some standard burners (such as Mckenna, Gülder, or Santoro, etc.), the instability of the flame will bring great uncertainty to the results of multiple measurements of single sampling, which will bring certain errors to the subsequent result analysis, and it is impossible to achieve multiple short-time measurements of soot particles in some turbulent combustion environments. The sampling system involved in the present invention can greatly reduce the measurement error caused by flame jitter to the sampling results in laminar flames through multiple samplings in a single experiment.

[0048] The double-layer storage cabinet involved in the present invention has a simple structure and low cost. The integration of each component in the system can be realized only through a double-layer storage cabinet with a door-opening and closing function, which is extremely convenient for the application of this measurement system to different combustion scenarios.

[0049] The air compression system involved in the present invention includes two nitrogen cylinders, which can be fixed at the lower layer of the double-layer storage cabinet. Fixing can prevent the system vibration during the measurement using the sampling system from affecting the compression system. Nitrogen is selected as the gas source of the air compression system because nitrogen is stable and will not bring other adverse effects to the measurement process. The double-layer storage cabinet involved in the present invention is equipped with retractable rigid connection structures at its four corners while enabling the measurement system to be movable. This is conducive to reducing the vibration impact on the probe caused by the rapid start and stop of the air compression system during the measurement, and the rigid connection is beneficial to reducing the errors brought by the impact generated by the rapid start and stop of the system to the detection efficiency, spatial resolution, etc. of the probe.

[0050] The air compression system involved in the present invention further includes an air compressor, a cylinder, and a time relay. The start and stop of the cylinder are controlled by the time relay, that is, the sampling time of the probe is controlled. Since the sampling time has a great influence on the sampling result, the control time of the time relay needs to be accurately adjusted, and the independent control of two sets of time relays is required to achieve the diversity of the sampling methods of the sampling system mentioned in the present invention.

[0051] The sampling system involved in the present invention can achieve multiple samplings in a single experiment in the flame, that is, based on gears, straight racks, turntables, etc., multiple samplings of soot particles in the flame are carried out continuously at the same flame height.

[0052] The sampling system involved in the present invention uses a commonly used cold probe on the market, but it is necessary to ensure that the probe is long enough. Under the condition that the probe is long enough, soot particles across the entire flame can be obtained. In some complex combustion environments with optical windows having an opening structure, a long enough probe can obtain soot particles in the turbulent combustion environment.

[0053] The sampling system involved in the present invention uses a scanning electron microscope grid to collect the soot particles obtained by sampling. The selection of the grid should have certain corrosion resistance and stability.

[0054] The sampling principle of the sampling system involved in the present invention is as follows: Soot particles generated in the combustion environment have different sizes and temperatures. When a cold probe is inserted into the combustion environment, soot particles with different temperatures will undergo thermophoretic motion due to the temperature gradient. The thermophoretic phenomenon refers to the phenomenon that particles move from the high-temperature part to the low-temperature part in a gas with a temperature gradient because gas molecules in the higher-temperature part collide with the particles with higher kinetic energy. Specifically: 1. Temperature gradient: In a non-isothermal field, gas molecules have higher average kinetic energy in the high-temperature region and lower average kinetic energy in the low-temperature region. 2. Collision effect: Due to the temperature difference, when gas molecules in the high-temperature region collide with suspended particles, they will transfer more kinetic energy to the particles, resulting in a net force acting on the particles. The direction of this force is from high temperature to low temperature. 3. Particle movement: The action of this net force causes the particles to gradually move from the high-temperature region to the low-temperature region, forming the thermophoretic phenomenon. Based on this, soot particles in the combustion environment will adhere to the surface of the cold probe.

[0055] After the sampling system involved in the present invention completes sampling, it uses an electron microscope grid to collect soot particles, and then uses a scanning electron microscope to analyze the distribution, shape, etc. of the soot particles. By obtaining the information of soot particles at different flame heights and analyzing it, the inversion of the soot particle size distribution in the entire flame region can be achieved.

[0056] The probe structure on the turntable involved in the present invention has a detachable function, and loading a longer probe can achieve the sampling of soot in some complex combustion environments with optical windows.

[0057] Embodiment 2

[0058] As Figure 1 shown, Figure 1 is the structure of the combustion system and Gülder burner selected for measurement in this sampling system. Among them, Figure 1 the left side is the schematic diagram of the Gülder burner structure, and the right side is the physical picture of the Gülder burner. As a stable diffusion burner, the Gülder burner can stably provide soot generation. In actual experiments, the sampling system involved in the present invention is used to sample the flame soot particles of the Gülder burner under different flame equivalence ratio conditions.

[0059] As Figure 2 shown, Figure 2 is the schematic diagram of the principle of thermoelectrophoresis involved in this sampling system. The thermophoretic principle has been described in Embodiment 1 and will not be elaborated here. As Figure 2 shown, soot particles generated in the combustion environment move towards the cold probe due to thermophoretic motion and are finally collected by the cold probe. The formula in the figure represents the principle of thermophoresis, where u T represents particle motion, D Trepresents the diameter of the particles, gradT g represents the temperature gradient of the particles, T g represents the particle temperature magnitude.

[0060] Such as Figure 3 shown, Figure 3 As shown, it is a schematic diagram of air compression and time control involved in the sampling system of the present invention. The movement of the control rod can be controlled by a two-way cylinder. Among them, the time relay is used to set the movement speed of the two-way cylinder, that is, to control the speed of the control rod. The air compressor can accurately control the air pressure to ensure the normal movement of the two-way cylinder.

[0061] Such as Figure 4 shown, Figure 4 is a double-layer storage cabinet involved in this sampling system. This storage cabinet is divided into two layers, and each layer realizes the integration of the components of the sampling system. Among them, two gas cylinders are placed on the first layer of the storage cabinet to provide gas sources for two sets of air compression systems. There is a circular opening connecting the first layer and the second layer to realize the connection between the air compression system in the second layer and the gas cylinders. The opening directions of the cabinet doors of the first layer and the second layer are as shown by the black arrows in Figure 4 . The installation of the cabinet doors is conducive to the efficient use of the sampling system and can prevent substances such as dust in the air from polluting the sampling system. Pulley wheels are installed at the four corners of the sampling system to realize the mobility of the sampling system, which is conducive to moving the sampling system according to the actual engineering environment to adapt to the sampling operations in different experimental environments.

[0062] Such as Figure 5 shown, where (a) and (b) are respectively the top views of the second layer and the first layer of the storage cabinet. It can be seen from the figure that the first layer of the storage cabinet is mainly used to place the gas cylinders required for two sets of control systems. The grooves A and B and the buckles shown in the figure can ensure the stable installation of the gas cylinders. In addition, the openable and closable nature of the push-button buckle can improve the installation stability of the gas cylinders while facilitating the replacement of the gas cylinders at any time. The installation position of the gas cylinders can be further stabilized through a rigid and stable rectangular structure (the top view is rectangular, and it is actually a cuboid structure connected to the cabinet wall of the storage cabinet). There is also space on the first layer of the storage cabinet that can place components such as plug-in boards and power supplies. This part of the space can place component structures according to the actual space requirements of the experimental site. The second layer of the storage cabinet is mainly used to place the thermophoretic probe sampling system, the control system for controlling the thermophoretic probe sampling system, the guide rail, etc. Among them, the thermophoretic probe sampling system is installed on the guide rail, which is conducive to moving the thermophoretic probe sampling system according to the actual engineering bench environment and the flame position. In addition, a fixing device is designed between the thermophoretic probe sampling system and the storage cabinet to fix the position of the thermophoretic probe sampling system during sampling. An opening is provided between the first layer and the second layer of the storage cabinet to connect the control system in the second layer and the gas cylinders. As shown in Figure c, rollers are installed at the four corners of the storage cabinet, and telescopic steel pipe structures are installed in four directions of each roller to realize the rigid connection between the storage cabinet and the ground.

[0063] As shown Figure 6 in the figure, the specific structures of the probe and the grid are as Figure 6 (a). The placement position of the grid is close to that of the probe. By means of a telescopic rod structure, the detection positions of the probe and the electron microscope grid can be changed to adapt to different combustion environments, and this structure can improve the sampling and collection efficiency of soot particles. Figure 6 (b) shows a schematic diagram of the disk structure for loading four probes. Four sampling probes are loaded on a disk, and the sampling probe structure is fixed to the disk by four screws. The four screws are detachable to realize the replacement of the sampling probe structure, thus simplifying the operation of replacing the probe that has reached the service life.

[0064] As shown Figure 7 in the figure Figure 7 is a schematic diagram of the probe control structure. Figure 7 (a) represents the front view of the probe control structure, and the components are as follows: 1. A rotating disk for loading the probe, used to load and fix the probe; 2. The probe structure, which includes a telescopic rod, a cold probe, and an electron microscope grid for collecting soot particles; 3. A gear structure, used to realize the rotation of the rotating disk 1 for loading the probe; 4. A straight rack, adapted to the gear structure 3, used to realize the rotation of the gear structure 3. The structure of the second half of the straight rack is the same as that of the straight rod 6. The straight rack is connected to the control system B, and the movement of the straight rack is realized through the air compression system and the time relay mentioned in the first embodiment, and the movement direction is as shown by the arrow in the figure. The forward and reset of the straight rack can be controlled through the control system B; 5. A vertical shaft, the vertical shaft 5 is used to connect the rotating disk 1 and the gear structure 3. The top of the vertical shaft 5 is fixedly connected to the rotating disk 1 for loading the probe. The vertical shaft 5 and the gear structure 3 are connected by a bearing 7, so that the gear can rotate at the same height. This setting can improve the sampling system when sampling at different heights; 6. A straight rod, the straight rod 6 is fixed to the lower end of the vertical shaft 5 by a screw, and this straight rod 6 is connected to the control system A. The movement direction of the straight rod 6 is as shown in the figure. The probe system can be controlled to extend into and withdraw from the flame through the control system A to improve the sampling efficiency of the system; 7. A bearing, the bearing 7 can prevent the gear from having an axial offset during operation, so as to stabilize the rotation of the rotating disk and reduce the error caused by the probe position offset during sampling; 8. A meshing gear, a meshing gear structure, which is used to connect the vertical shaft 5 and the gear structure 3 with the bearing 7. This connection method helps to improve the stability of the sampling structure. In the shaft connection technology involved in the present invention, a detachable stepped interference connection method is preferably used to improve the structural stability and the service life of the structure, but the connection method is not limited to the method mentioned in the present invention. The meshing gear 8 shows the specific structures of the gear structure 3 and the vertical shaft 5, that is Figure 7(b), the present invention uses meshing gears as the motion structure, which can greatly improve the accuracy of sampling. The top view of the probe sampling structure is as shown in Figure 7 (c). The straight rack 4 and the straight rod 6 are controlled by control system B and control system A respectively, and the two control systems do not interfere with each other. Control system B controls the rotation of the rotating disk by controlling the straight rack, and control system A controls the straight rod to achieve the control of the lateral distance of the sampling probe.

[0065] As shown in Figure 8 . Figure 8 The schematic diagrams of the probe structure and the console structure are given. Fig. 8(a) in the figure is the front view. In the figure, 9 represents the first slide rail. The function of the first slide rail 9 is to enable the probe to sample in flames at different heights. The control schematic diagrams of the straight rack 4 and the straight rod 6 are as shown in Fig. 3 in the figure. The fixed steel plate 10 can move on the first slide rail 9 to adapt to the sampling at different flame heights. Two circular ring structures 11 are designed on the fixed steel plate 10. The function of the circular ring structure 11 is to stably control Figure 7 the movement directions of the straight rack 4 and the straight rod 6 in it to reduce the sampling error caused by the position deviation of the sampling probe; the bearing platform 12 is a supporting structure; the second pulley 13 can move the entire console structure, and the pulley 13 can slide on the second slide rail 14. This operation is as described in the schematic diagram of the second layer of the storage cabinet in Figure 5 . Thus, the diversity of the placement position of the probe sampling system can be realized to adapt to the measurement position requirements of different combustion environments. Fig. 8(b) in the figure is the side view. It can be seen from the figure that the fixed steel plate 10 moves on the first slide rail 9, so as to realize the function of sampling the probe at different axial heights. There are pin holes 15 on the fixed steel plate 10, and the fixed steel plate 10 is fixed on the first slide rail 9 through the pin 16. This operation can ensure the stability of the sampling probe in height during sampling, thereby reducing the sampling error caused by the jitter of the sampling position.

[0066] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A thermophoresis probe sampling system for continuous sampling of soot in a combustion flame, characterized in that: It includes a double-layer storage cabinet, a control system and a sampling system; wherein the double-layer storage cabinet is used to integrate the entire measurement system, and the double-layer storage cabinet is movable and adaptable to different experimental sites; the control system is used to control the insertion and removal of the probe and the rotation of the turntable to achieve multiple sampling at the same flame height; the sampling system realizes the movement of the probe through a track, and is adapted to carbon soot sampling in combustion environments at different heights.

2. A thermophoresis probe sampling system for realizing continuous sampling of soot in a combustion flame according to claim 1, characterized in that: The double-layer storage cabinet is divided into two layers, the lower layer is used to place gas cylinders, and the upper layer is used to place control systems and sampling systems.

3. A thermophoresis probe sampling system for realizing continuous sampling of soot in a combustion flame according to claim 1, characterized in that: The control system includes an air compression system, which includes two nitrogen bottles, an air compressor and a cylinder, and the sampling time of the probe is accurately controlled by a time relay.

4. A thermophoresis probe sampling system for realizing continuous sampling of soot in a combustion flame according to claim 1, characterized in that: The sampling system uses a cold probe, and the probe length is long enough to obtain soot particles in the entire flame transverse direction.

5. The thermophoresis probe sampling system for realizing continuous sampling of soot in combustion flames according to claim 1, characterized in that: The sampling system realizes multiple sampling at the same flame height through gears, spur racks and a rotating disk.

6. The thermophoresis probe sampling system for realizing continuous sampling of soot in a combustion flame according to claim 1, characterized in that: The sampling system utilizes the thermophoresis phenomenon. When the cold probe is extended into the combustion environment, the high-temperature soot particles adhere to the probe surface due to the temperature gradient. After the sampling is completed, the soot particles are collected by the scanning electron microscope grid.

7. The thermophoresis probe sampling system for realizing continuous sampling of soot in a combustion flame according to claim 1, characterized in that: The four corners of the double-layer storage cabinet are provided with rigid connection structures to reduce the influence of system vibration on the probe.

8. The thermophoresis probe sampling system for realizing continuous sampling of soot in a combustion flame according to claim 1, characterized in that: The thermophoresis probe sampling system analyzes the distribution and shape of soot particles through a scanning electron microscope to achieve the inversion of soot particle size distribution in the flame area.

9. A method for using a thermophoresis probe sampling system for continuous sampling of soot in a combustion flame, characterized in that: The steps include: Step 1: Move the double-layer storage cabinet equipped with the sampling system to a predetermined position, specifically: move the double-layer storage cabinet equipped with the sampling system to a specific position suitable for measurement. This operation can ensure that the sampling system can sample the soot particles in the combustion environment at an effective position and ensure the effectiveness of the sampling; Step 2: Check the placement of each component of the system, specifically: check whether the placement of the gas cylinder, air compression system, and sampling system is reasonable and stable. This operation can avoid the sampling process being affected when the measurement system itself vibrates during the measurement process; Step 3: Check whether the gas cylinder pressure is normal and stable; Step 4: After checking all parts of the sampling system, rigidly connect the four corners of the double-layer storage cabinet to the ground. After completing the rigid connection, check again whether the system is stable; Step 5: After completing the system inspection and rigid connection, check whether the air compression system and the time relay can work normally. The inspection method is: when the combustion device is not ignited, set the parameters of the time relay, where the time of the control probe can be set to 1-10s to check whether the time relay and the air compression system can work normally; the control of the two sets of air compression systems are checked in the above empty running state; Step 6: After confirming that the air compression system can work normally, move the sampling system to a suitable position, that is, the length of the cold probe is sufficient to pass through the entire flame area during the collection and delivery process; Step 7: If the sampling environment is a stable laminar diffusion burner, first check whether the gas pressure of the gas cylinders used by the burner, such as fuel gas cylinders and stream gas cylinders, is stable, and whether the electronic flow meter can normally control the flame equivalence ratio; Step 8: Let the burner burn for a while. During the burner burning time, observe whether the flame is stable and whether there is any blockage on the burner surface. Step 9: After the burner has been burning stably for a period of time, set the parameters of the time relay, where the time parameter is set to 10ms. After completing the time relay parameters, start the air compression system to sample the soot particles in the combustion environment according to actual needs; Step 10: After the probe completes sampling, use the electron microscope grid to collect the soot particles; Step 11: If the sampling environment is a turbulent combustion environment, check whether the engineering bench is safe and stable, such as whether the components of the aircraft engine combustion chamber are installed stably, and then check whether it can be ignited normally; Step 12: Place the sampling probe stably at the opening of the optical window; Step 13: Set the time relay parameters, use only the air compression system to control the probe, and set the sampling time to 15ms; Step 14: After completing the parameter setting, ignite the fire to obtain soot particles, and then use a grid to collect the soot particles. By sampling multiple times, that is, repeating step nine, soot particles at different combustion stages in a turbulent combustion environment can be obtained.

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