Mechanism research system and method for non-volatile combustible liquid aerosol

Abstract

The invention relates to the technical field of difficult-to-volatilize combustible liquid, in particular to a difficult-to-volatilize combustible liquid aerosol mechanism research system and method, and the system comprises an aerosol fogging device which is used for carrying out the pneumatic atomization of difficult-to-volatilize combustible liquid to form aerosol, the device comprises a gas-liquid conveying pipe section, a porous hollow ball, a spherical spray chamber and a hemispherical spray head, the system further comprises a transient aerosol turbulence test system, a transient concentration and particle size measurement system, an aerosol explosion experiment device and a data processing and analysis module. The dynamic change rule of the liquid drop size, concentration and turbulence intensity in the forming process of the non-volatile combustible liquid aerosol is disclosed systematically for the first time, the research blank in the field at home and abroad is filled, and a solid foundation is laid for the research of subsequent explosion characteristics.

Description

Technical Field

[0001] The present invention relates to the technical field of hardly volatile combustible liquids, and particularly relates to a mechanism research system and method for hardly volatile combustible liquid aerosol. Background Art

[0002] Hardly volatile combustible liquids are widely used in civil and chemical industries, such as common hydrocarbons, ethers, benzene, nitro compounds and their derivatives, etc. In industrial production, storage, transportation and other scenarios, if accidental leakage or splashing occurs, it will potentially be accompanied by cloud explosion disaster accidents. For the explosion limit of combustible liquids, generally only its pure gas phase concentration is used as the basis standard. However, at normal temperature and pressure, the saturated vapor concentration of a large number of high-boiling combustible liquids is lower than the lower explosion limit, and the explosion hazard of aerosol (cloud) in the real environment is extremely common. The explosion process of this saturated aerosol involves many transient physical characteristic factors, such as the droplet size of the aerosol, the gas-liquid two-phase concentration, and the turbulent characteristics that satisfy droplet suspension, etc., making the research on aerosol explosion extremely complex. At present, in the safety standards monitoring of dangerous substances both internationally and domestically, the mechanism research on the combustion and explosion of combustible liquid clouds is far from mature. Effectively preventing and controlling cloud explosion is the basis and an urgent issue to be solved in the field of production safety and public safety emergency response.

[0003] Currently, mature technical standards and industry codes have been established internationally in terms of gas-phase combustion and explosion. However, for gas-liquid two-phase aerosols, there is no unified specification due to the lack of scientific basis. Research shows that the explosion power of aerosol is higher than that of its corresponding pure gas phase and air mixture under certain conditions. Therefore, scholars from various countries have conducted exploratory research on aerosol explosion. The latest relevant standard, British Standard BS EN 60079-10-1, contains a new additional content, which provides some qualitative guiding opinions on the combustion and explosion hazards of aerosol and a small amount of quantitative methods. The Code of Practice of the Energy Institute of the UK also points out that: "Currently, there is no complete understanding of the aerosol formation mechanism and the classification method for related dangerous areas, and all this requires further research".

[0004] As early as the mid-20th century, with aerosol droplets as the research object (ignoring the gas-phase concentration of aerosols), a large number of scholars conducted experimental studies on aerosol explosions. Among them, the experimental results of Zabetakis, Burgoyne and Cohen, and Faeth and Olson showed that: when the particle size of aerosol droplets is less than 10 μm, its lower explosion limit concentration is similar to that of the pure gas phase, and it was pointed out that when the droplets are small (<10 μm), the flame propagation front can directly carry out mass and heat exchange with the droplets at the critical edge, directly resulting in the evaporation and gasification of the droplets. Therefore, it has essentially transformed into a gas-phase explosion phenomenon. When the droplet size is large (>10 μm), the mass and heat exchange between the flame propagation front and the droplets is not sufficient to completely evaporate the larger droplets, so it presents a diffusion combustion phenomenon of each droplet itself. In addition, under the same concentration conditions, the distance between droplets also affects the lower explosion limit concentration, that is, when the droplets are <10 μm, the distance between droplets is about 22 times their diameter, and when the droplets reach 40 μm, the distance between droplets will increase to 31 times their diameter, resulting in the inability to promote the diffusion combustion transfer of adjacent droplets due to the increase in the distance between droplets. Subsequently, it was concluded that when the droplet size is large (>10 μm), the lower explosion limit concentration of the aerosol increases.

[0005] For the lower limit of aerosols with droplet sizes greater than 20 μm, the experimental device and ignition method have a great influence on it. Burgoyne et al. conducted ignition experiments on quiescent, monodisperse aerosols in a flame tube (similar to a Hartmann tube). It was found that when igniting at the bottom of the tube, the flame propagation mode develops vertically upward. And due to the sedimentation factor of the droplets, the lower limit of the aerosol decreases as the droplet size increases. On the contrary, when igniting at the top of the tube, the lower limit of the aerosol increases as the droplet size increases.

[0006] Anson, Rao and Lefebvre studied momentum-dominated aerosols and obtained the experimental results of the lower explosion limit of aerosols formed by dynamic spraying, and its lower explosion limit increases with the increase of droplet size.

[0007] Williams predicted that there is a "transition range" in the range of 8 μm < d < 15 μm for the aerosol particle size, and pointed out that in this region, the explosion intensity of the aerosol will show a sharp increase. Polymeropoulos studied and predicted the combustion rate of monodisperse aerosols by theoretical calculation methods, and found that there is an obvious increase in the droplet combustion rate in the range of 5 μm to 15 μm. Bowen et al. also conducted a series of experimental studies on the explosion intensity of kerosene aerosols and their pure gas phase in a 2.5 m3 rectangular space device.

[0008] Liu Xueling et al. studied a series of experimental research results on the lower explosion limit, explosion pressure and temperature of transient unsaturated aerosols of low-boiling hydrocarbon liquids (C5-C9 alkane liquids, JP-10, ether, etc.) based on their self-developed and designed aerosol transient concentration and particle size measurement system and research theory and methods.

[0009] Zhang Qi and other teams from the State Key Laboratory of Explosion Science and Technology at Beijing Institute of Technology have continued to conduct a series of studies on low-boiling combustible liquid clouds in recent years under different ignition methods and flame structures.

[0010] Wang Yue et al. analyzed and studied the combustion and explosion laws of low-boiling combustible liquid ether clouds in a zero-turbulence field.

[0011] Through the exploratory research of domestic and foreign experts and scholars and myself, it is found that:

[0012] (1) Most of the international and domestic standards related to the explosion of combustible liquid aerosols are mainly based on their liquid-phase concentration, ignoring their internal gas-phase concentration; for the concentration of non-volatile combustible liquid aerosols, it is often composed of the saturated gas-phase concentration + droplet group (liquid-phase concentration).

[0013] (2) For non-volatile combustible liquid aerosols, since the saturated gas-phase concentration is often lower than its explosion limit, it indirectly shows that the explosion of non-volatile combustible liquids is the result of the combined action of the saturated gas-phase concentration + droplet group (liquid-phase concentration).

[0014] (3) As we all know, there is no air movement without dust. Clouds are suspended and do not settle quickly due to the turbulent movement generated by air movement. The inducement of combustible cloud explosion disasters is air movement turbulence, which is both the cause and the result. Real clouds are generated by two environments: strong convection and zero turbulence (isotropic turbulence). The characteristics of isotropic turbulence are like the wind that will not stop when the tree wants to be still. It can not only induce the formation of clouds but also lead to different explosion characteristics due to the difference between its turbulent integral scale and the characteristics of strong convection.

[0015] Therefore, the present invention will further carry out research on the explosion mechanism of saturated aerosols of non-volatile combustible liquids. The development of this research has important practical guiding significance for preventing the explosion disasters of high-boiling combustible liquid aerosols and the industrial safety production of high-boiling combustible liquids in the region. Summary of the Invention

[0016] The purpose of the present invention is to provide a mechanism research system and method for non-volatile combustible liquid aerosols, clarify the influence mechanism of the internal corresponding parameters of non-volatile combustible liquid aerosols on the explosion limit, ignition energy and explosion intensity, and establish relevant experimental and theoretical models. It provides an important scientific basis and theoretical basis for preventing, controlling and reducing aerosol explosion disasters, and for the division, standards and specifications of national aerosol dangerous areas.

[0017] To achieve the above technical objectives and effects, the present invention is realized through the following technical solutions:

[0018] A mechanism research system for non-volatile combustible liquid aerosol, comprising:

[0019] An aerosol atomization device for forming aerosol by pneumatic atomization of non-volatile combustible liquid, said device comprising a gas-liquid delivery pipe section, a porous hollow sphere, a spherical spray chamber and a hemispherical nozzle;

[0020] A transient aerosol turbulence measurement system for measuring the turbulence intensity during the aerosol formation process, said system comprising a particle matching probability method and a Monte Carlo numerical simulation method, and realizing the matching calculation of flow field particles in combination with particle tracking velocimetry (PTV);

[0021] A transient concentration and particle size measurement system for measuring the particle size distribution and concentration of aerosol, said system being designed based on the principle of optical total scattering method and having a key method for processing transient aerosol concentration and particle size data;

[0022] An aerosol combustion and explosion experiment device for determining the explosion parameters of aerosol, said device comprising a cast iron explosion tank body and an ignition system, and being able to measure parameters such as explosion limit, minimum ignition energy, explosion pressure and pressure rise rate;

[0023] A data processing and analysis module for integrating aerosol turbulence intensity, particle size distribution, concentration and explosion parameter data, and establishing an aerosol formation and explosion mechanism model in combination with multiphase flow theory and explosion mechanics theory.

[0024] Further, the aerosol atomization device realizes the secondary atomization of the liquid through the first pulsation and the second pulsation of high-pressure gas to form aerosol; the first pulsation action carries out the continuous liquid out of the liquid storage chamber and forms an annular liquid film in the gas-liquid delivery pipe section; the second pulsation action disperses the annular liquid film from multiple angles through the porous hollow sphere and the spherical spray chamber to form uniform aerosol droplets.

[0025] Further, the transient aerosol turbulence measurement system realizes the matching calculation of flow field particles through the particle matching probability method, and solves the key technologies of high-speed flow field, operation efficiency and calculation accuracy; the system further comprises:

[0026] A multi-plane turbulence measurement module for measuring the change of aerosol turbulence field at different positions;

[0027] A data visualization module for generating transient aerosol turbulence cloud images and analyzing the turbulence integral scale and pulsation characteristics.

[0028] Furthermore, the transient concentration and particle size measurement system measures the particle size distribution and concentration of aerosol droplets in real time; the data processing module can compare and verify the measurement results with a known standard system (such as the German HELOS-VARIO system) to ensure the accuracy and reliability of the data; and generate a dynamic curve of the aerosol particle size and concentration changing with time, providing data support for the aerosol diffusion and change characteristic model.

[0029] Furthermore, the aerosol combustion and explosion experimental device includes:

[0030] A cast iron explosion tank body, which is used to provide a stable experimental environment and ensure the accuracy of explosion parameters;

[0031] An ignition system, including a high-voltage electrode and an ignition controller, which is used to precisely control the ignition energy and ignition time;

[0032] An explosion parameter measurement module, which is used to record parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate, and flame propagation rate.

[0033] On the other hand, the present invention proposes a mechanism research method for non-volatile combustible liquid aerosols based on the above system, including the following steps:

[0034] S1: Aerosol atomization: The non-volatile combustible liquid is atomized into an aerosol through an aerosol atomization device by pneumatic atomization, controlling the gas-liquid ratio and spray pressure to obtain aerosol samples with different particle size distributions and concentrations;

[0035] S2: Turbulence intensity measurement: Use a transient aerosol turbulence test system to measure the turbulence intensity during the aerosol formation process and record the turbulence integral scale and pulsation characteristics;

[0036] S3: Particle size and concentration measurement: Use a transient concentration and particle size measurement system to measure the particle size distribution and concentration of the aerosol and generate a dynamic curve of the aerosol droplet size and concentration changing with time;

[0037] S4: Combustion and explosion experiment: Conduct an ignition experiment in the aerosol combustion and explosion experimental device to measure parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate, and flame propagation rate of the aerosol;

[0038] S5: Data analysis: Based on the experimental data, combined with the multiphase flow theory and explosion mechanics theory, establish an aerosol formation and explosion mechanism model to reveal the influence mechanism of aerosol particle size, concentration, and turbulence on the explosion limit, ignition energy, and explosion intensity.

[0039] Furthermore, in step S1, through the first pulsation and second pulsation of high-pressure gas, the secondary atomization of the liquid is realized to form an aerosol, which specifically includes the following sub-steps:

[0040] S1.1: The first pulsation action carries the liquid out of the liquid storage chamber to form an annular liquid film;

[0041] S1.2: The second pulsation action disperses the annular liquid film at multiple angles through the porous hollow sphere and the spherical spray chamber to form uniform aerosol droplets.

[0042] Furthermore, in step S2, the matching calculation of the flow field particles is realized by the particle matching probability method, which specifically includes the following sub-steps:

[0043] S2.1: Measure the changes in the aerosol turbulence field at different positions to generate a transient aerosol turbulence cloud map;

[0044] S2.2: Analyze the influence of the turbulence integral scale and pulsation characteristics on the suspension and explosion intensity of aerosol droplets.

[0045] Furthermore, in step S3, a transient concentration and particle size measurement system designed based on the principle of optical total scattering method is used to measure the particle size distribution and concentration of aerosol droplets in real time, and compare the measurement results with a known standard system (such as the German HELOS-VARIO system) for verification to ensure the accuracy and reliability of the data.

[0046] Furthermore, in step S4, through the cast iron explosion tank body and the ignition system, parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate, and flame propagation rate of the aerosol are measured, which specifically includes the following sub-steps:

[0047] S4.1: Measure the explosion limit and minimum ignition energy of the aerosol under different particle size distributions and concentrations;

[0048] S4.2: Record the explosion pressure and pressure rise rate, and analyze the dynamic changes in the explosion intensity of the aerosol;

[0049] S4.3: Measure the flame propagation rate and study the flame structure characteristics of the aerosol explosion.

[0050] Furthermore, in step S5, based on the experimental data, combined with the multiphase flow theory and the explosion mechanics theory, an aerosol formation and explosion mechanism model is established, which specifically includes the following sub-steps:

[0051] S5.1: Reveal the influence mechanism of aerosol particle size, concentration, and turbulence on the explosion limit, ignition energy, and explosion intensity;

[0052] S5.2: Establish a quantitative relationship model between the aerosol explosion limit, ignition energy, explosion intensity and droplet size, concentration, and turbulence intensity;

[0053] S5.3: Provide a scientific basis for the prevention and control of aerosol explosion disasters.

[0054] Advantages of the present invention:

[0055] Through the independently developed aerosol atomization device, the present invention combines the first pulsation and the second pulsation of high-pressure gas to achieve efficient secondary atomization of the hardly volatile combustible liquid, forming uniform aerosol droplets. The first pulsation of the present invention carries out the continuous liquid out of the liquid storage chamber, forming an annular liquid film in the gas-liquid conveying pipe section; the second pulsation disperses the annular liquid film from multiple angles through the porous hollow sphere and the spherical spray chamber, forming uniform aerosol droplets. This process is based on the multiphase flow theory and the pneumatic atomization principle, ensuring the controllability of the particle size distribution and concentration of the aerosol droplets. At the same time, through the transient aerosol turbulence test system and the transient concentration and particle size measurement system, the turbulence intensity, particle size distribution and concentration during the aerosol formation process are accurately measured. Among them, the particle matching probability method and the Monte Carlo numerical simulation solve the key technologies of high-speed flow field, operation efficiency and calculation accuracy, and the optical full scattering method realizes the non-contact measurement of the transient aerosol concentration and particle size, ensuring the accuracy and reliability of the data. The formation of aerosol depends on the processes of droplet breakup, dispersion and suspension, and the turbulence intensity is the key factor affecting droplet suspension and distribution. Through multi-angle atomization and accurate measurement, the present invention systematically reveals for the first time the dynamic change laws of droplet size, concentration and turbulence intensity during the formation process of hardly volatile combustible liquid aerosol, filling the research gap at home and abroad in this field and laying a solid foundation for the subsequent research on explosion characteristics.

[0056] Through the aerosol combustion and explosion experimental device, the present invention measures parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate and flame propagation rate of the aerosol under different particle size distributions, concentrations and turbulence intensities. The cast iron explosion tank body of the present invention provides a stable experimental environment to ensure the accuracy of explosion parameters; the ignition system accurately controls the ignition energy and ignition time through the high-voltage electrode and the ignition controller; the explosion parameter measurement module records parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate and flame propagation rate. The explosion characteristics of the aerosol are affected by the coupling of droplet size, concentration and turbulence intensity. Small-sized droplets are more likely to evaporate to form combustible gas, increasing the explosion risk; high-concentration aerosol increases the total amount of combustibles, enhancing the explosion intensity; the turbulence intensity affects droplet distribution and flame propagation rate. When the droplet size is 5-15 μm, the explosion intensity of the aerosol increases significantly, which is consistent with the theoretical predictions of Williams and Polymeropoulos. Based on the experimental data, the present invention combines the multiphase flow theory and the explosion mechanics theory to establish an aerosol formation and explosion mechanism model, including a quantitative relationship model between the aerosol explosion limit, ignition energy, explosion intensity and droplet size, concentration and turbulence intensity. This model can accurately predict the explosion characteristics of the aerosol under different conditions, providing a scientific basis for the assessment and control of aerosol explosion risk and having important practical application value.

[0057] Through the independently developed transient aerosol turbulence test system and transient concentration and particle size measurement system, the present invention realizes the accurate measurement of aerosol turbulence intensity, particle size distribution, and concentration. In the specific technical content, the particle matching probability method and Monte Carlo numerical simulation solve the key technologies of high-speed flow field, operation efficiency, and calculation accuracy; the multi-plane turbulence test module measures the changes in the aerosol turbulence field at different positions to generate transient aerosol turbulence cloud maps; the data visualization module analyzes the turbulence integral scale and pulsation characteristics, revealing the influence of turbulence on the suspension and explosion intensity of aerosol droplets. The transient concentration and particle size measurement system is designed based on the principle of optical total scattering method, which can measure the particle size distribution and concentration of aerosol droplets in real time, and compare and verify the measurement results with known standard systems (such as the German HELOS-VARIO system) to ensure the accuracy and reliability of the data. Through non-contact measurement and high-precision data processing, the measurement problems of high-speed flow field and complex environment in aerosol experiments are solved, improving the research efficiency and data reliability. The matching calculation of flow field particles is realized through the particle matching probability method, solving the technical problem of particle tracking velocimetry (PTV) in high-speed flow fields; the dynamic curves of aerosol particle size and concentration changing with time generated by the transient concentration and particle size measurement system provide data support for the aerosol diffusion and change characteristic model. These advanced technical means provide reliable technical support for aerosol explosion research and promote the technological progress of related fields.

[0058] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0060] Figure 1 It is a schematic diagram of the aerosol turbulence patterns formed by two spraying methods;

[0061] Figure 2 It is a schematic diagram of the composition of the transient aerosol turbulence intensity test system and the experiment;

[0062] Figure 3 It is a schematic diagram of the hardware of the transient aerosol turbulence intensity test and different test planes;

[0063] Figure 4 It is a turbulence cloud map of different spraying periods at plane number 2 of the transient aerosol turbulence intensity test;

[0064] Figure 5It is a schematic diagram of the hardware composition of the transient concentration and particle size measurement system;

[0065] Figure 6 It is a schematic diagram of the software interface of the transient concentration and particle size measurement system;

[0066] Figure 7 It is a schematic diagram of the result of the particle size distribution comparison report between the transient concentration and particle size measurement system and the German HELOS-VARIO particle size detection system;

[0067] Figure 8 is a schematic diagram of the pulsating atomization principle; (a) Pulsating spray system; (b) Atomization schematic diagram; (c) Hemispherical nozzle; (d) Porous hollow sphere; In the figure: 1-Manual valve; 2-High-pressure gas chamber; 3-Solenoid valve; 4-Non-return valve; 5-Liquid storage chamber; 6-Gas-liquid delivery pipe section; 7-Porous hollow sphere; 8-Spherical spray chamber; 9-Hemispherical nozzle; 10-Liquid injection hole; 11-Trigger control system;

[0068] Figure 9 It is a schematic diagram of the aerosol combustion and explosion experiment device;

[0069] Figure 10 It is a schematic diagram of the spherical tank experiment assembly system for measuring the particle size, concentration field, turbulent flow field, and explosion parameters of clouds and fog;

[0070] Figure 11 It is a schematic diagram of the lower explosion limit trend of n-alkane aerosol with the same particle size (~22μm);

[0071] Figure 12 It is a schematic diagram of the comparison of the lower explosion limit of n-alkane combustible liquid aerosol with different particle sizes;

[0072] Figure 13 It is a schematic diagram of the explosion overpressure and maximum pressure rise rate of n-pentane aerosol with the same concentration and different particle sizes; 1. Pure gas phase, SMD<1μm; 2. Particle size SMD = ~9μm; 3. Particle size SMD = ~15μm; 4. Particle size SMD = ~21μm;

[0073] Figure 14 It is a schematic diagram of the explosion flame propagation delay time of n-pentane aerosol;

[0074] Figure 15 It is the overall technical roadmap of the present invention. Specific implementation mode

[0075] 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0076] Example 1

[0077] A mechanism research system for a non-volatile flammable liquid aerosol described in this example includes:

[0078] An aerosol atomization device for forming an aerosol by pneumatic atomization of a non-volatile flammable liquid. The device includes a gas-liquid delivery pipe section, a porous hollow sphere, a spherical spray chamber, and a hemispherical nozzle;

[0079] A transient aerosol turbulence test system for measuring the turbulence intensity during aerosol formation. The system includes a particle matching probability method and a Monte Carlo numerical simulation method, and combines particle tracking velocimetry (PTV) to achieve the matching calculation of flow field particles;

[0080] A transient concentration and particle size measurement system for measuring the particle size distribution and concentration of the aerosol. The system is designed based on the principle of optical total scattering method and has a key method for processing transient aerosol concentration and particle size data;

[0081] An aerosol combustion and explosion experimental device for determining the explosion parameters of the aerosol. The device includes a cast iron explosion tank and an ignition system, and can measure parameters such as the explosion limit, minimum ignition energy, explosion pressure, and pressure rise rate;

[0082] A data processing and analysis module for integrating aerosol turbulence intensity, particle size distribution, concentration, and explosion parameter data, and combining the multiphase flow theory and explosion mechanics theory to establish an aerosol formation and explosion mechanism model.

[0083] In this example, the aerosol atomization device includes: a manual valve, a high-pressure gas chamber, a solenoid valve, a check valve, a liquid storage chamber, a gas-liquid delivery pipe section, a porous hollow sphere, a spherical spray chamber, a hemispherical nozzle, a liquid injection hole, and a trigger control system;

[0084] Example 2

[0085] (1) Aerosol turbulence measurement method. Liquid and solid particles such as aerosols and dust are suspended and do not settle quickly due to the turbulent agitation generated by pneumatics. The inducement for the explosion disaster of flammable aerosols is pneumatic turbulence; as Figure 1 shown, there will be two phenomena during aerosol formation: strong convection formed by single spraying ( Figure 1 left figure, shown) and zero turbulence formed by opposite spraying ( Figure 1 right figure, shown). Among them, the characteristics of zero turbulence (isotropic turbulence) are like a tree that wants to be still but the wind keeps blowing. Its turbulent pulsation not only induces the formation of aerosols, but also leads to different explosion intensities and aerosol results induced by strong convection due to different turbulent integral scales. This example will combine two aerosol turbulence patterns to carry out experimental research on atomization parameters under different physical fields.

[0086] The measurement of aerosol turbulence will enable the self-developed transient aerosol turbulence test system platform - as Figure 2 , 3 shown, by using the technical advantages of PTV to accurately characterize the flow field, combining the characteristics of the aerosol flow field and the observation requirements, a transient aerosol turbulence measurement system has been successfully developed. Through the particle matching probability method, the matching calculation of the particles in the system flow field is realized, and the key design technologies such as high-speed flow field, operation efficiency, and calculation accuracy are solved. Through the system reliability verification and system applicability verification by the Monte Carlo numerical simulation method, the transient aerosol turbulence test results are reliable, realizing the non-contact observation of the transient aerosol flow field, and providing a new way for the in-depth study of the interaction between aerosol turbulence and explosion. As Figure 4 shown, it is the turbulent cloud images of transient aerosol at different time periods formed by the opposite spraying in the tank body.

[0087] (2) Measurement methods for droplet size and concentration. The measurement of droplet size and concentration will enable the self-developed transient concentration and particle size measurement system platform designed based on the principle of optical total scattering method, which has the key processing methods for transient aerosol concentration and particle size measurement data, providing an important observation means for the in-depth study of the aerosol explosion mechanism. As Figure 5 , shown in Figure 6, are the hardware system and software interface of the transient concentration and particle size measurement system platform respectively. As Figure 7 shown, the data comparison report results between the self-developed transient concentration and particle size measurement system and the German HELOS-VARIO particle size detection system reach consistency.

[0088] (3) Aerosol atomization method. The self-developed pulsating spray system is enabled, as shown in Figure 8(a). The first pulsating action of the high-pressure gas carries the continuous liquid out of the liquid storage chamber, and enters the gas-liquid delivery pipe section at different gas-liquid flow rates to form an annular liquid film; then it enters the spherical spray chamber, and the annular liquid film flows along the spherical wall under the action of gas expansion. A part of the expanded central gas column enters the porous hollow sphere and is discharged through the small holes on its surface to form the second pulsation of the high-pressure gas, and the other part of the gas forms a cyclone acting on the inner side of the liquid film; finally, the liquid film on the inner wall of the spray chamber is dispersed and ejected from multiple spray holes on the surface of the spherical spray chamber under the multi-angle action of the secondary pulsation and the inner cyclone, forming secondary atomization, as shown in Figure 8(b). In the pulsating atomization principle, the formation process of the aerosol is based on the multi-phase flow theory and the pneumatic atomization principle, and the secondary pulsating atomization is completed by the cooperation of the gas-liquid delivery pipe section (annular liquid film area), the spherical spray chamber with porous hollow spheres (secondary pulsation area) and the hemispherical porous nozzle (forming secondary atomization based on the secondary pulsation), as Figure 8(c) , 8(d) shown.

[0089] Secondly, based on the above-mentioned beneficial atomization results, the explosion parameters of saturated aerosol (parameters such as explosion limit, minimum ignition energy, explosion intensity, etc.) under various parameter conditions are obtained through the ignition experiment of the cast iron explosion tank, and then the explosion mechanism and its characteristic laws of saturated aerosol are revealed. As Figure 9 shown, the aerosol combustion and explosion experimental device of a cast iron cylindrical tank which is the same as that for measuring the aerosol particle size and concentration. As Figure 10 shown, it is the experimental total system of a spherical tank for measuring the cloud particle size and concentration field, turbulent flow field, and explosion parameters.

[0090] This embodiment completes the law of the lower explosion limit of low-boiling-point alkane n-alkane aerosol, as Figure 11 、 12 shown. The results show that except for the aerosol of n-pentane (C5H12) having its independent explosion characteristics, there is a linear relationship between the lower explosion limits of the aerosols of n-hexane (C6H14), n-heptane (C7H16), n-octane (C8H18) and n-decane (C10H22):

[0091]

[0092] wherein, is the total concentration of aerosol (g / m3), n is the number of C elements in n-alkane;

[0093] The lower explosion limits (LELs) of n-alkanes all increase with the increase of particle size; for the LELs of the aerosols of n-pentane (C5H12), n-hexane (C6H14) and n-heptane (C7H16), the corresponding gas-phase concentrations in the aerosols all increase with the increase of particle size; while for the LELs of the aerosols of n-octane (C8H18) and n-decane (C10H22), the corresponding gas-phase concentrations in the aerosols change weakly with the increase of particle size.

[0094] This embodiment will expand the research on the laws of the lower explosion limit, minimum ignition energy, explosion intensity, etc. of high-boiling-point combustible liquid aerosol.

[0095] Finally, based on the above experimental research results, combined with the theoretical analysis of multiple related disciplines such as multiphase flow theory and explosion mechanics theory, the formation and explosion mechanism and its laws of the gas-liquid two-phase aerosol of difficult-to-volatilize combustible liquids are obtained.

[0096] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A mechanism research system for a non-volatile combustible liquid aerosol, characterized in that, Including: An aerosol atomization device for pneumatically atomizing a non-volatile combustible liquid to form an aerosol. The device includes a gas-liquid delivery pipe section, a porous hollow sphere, a spherical spray chamber, and a hemispherical nozzle; A transient aerosol turbulence measurement system for measuring the turbulence intensity during the aerosol formation process. The system includes a particle matching probability method and a Monte Carlo numerical simulation method, and combines particle tracking velocimetry (PTV) to achieve the matching calculation of flow field particles; A transient concentration and particle size measurement system for measuring the particle size distribution and concentration of the aerosol. The system is designed based on the principle of optical total scattering method and has a key method for processing transient aerosol concentration and particle size data; An aerosol combustion and explosion experiment device for measuring the explosion parameters of the aerosol. The device includes a cast iron explosion tank body and an ignition system, and can measure parameters such as the explosion limit, minimum ignition energy, explosion pressure, and pressure rise rate; A data processing and analysis module for integrating aerosol turbulence intensity, particle size distribution, concentration, and explosion parameter data, and combining multiphase flow theory and explosion mechanics theory to establish an aerosol formation and explosion mechanism model.

2. The mechanism research system of the non-volatile combustible liquid aerosol according to claim 1, characterized in that: The aerosol atomization device realizes the secondary atomization of the liquid through the first pulsation and the second pulsation of high-pressure gas to form an aerosol; the first pulsation action carries out the continuous liquid out of the liquid storage chamber and forms an annular liquid film in the gas-liquid delivery pipe section; the second pulsation action disperses the annular liquid film from multiple angles through the porous hollow sphere and the spherical spray chamber to form uniform aerosol droplets.

3. The mechanism research system of the hardly volatile combustible liquid aerosol according to claim 1, characterized in that: The transient aerosol turbulence measurement system realizes the matching calculation of flow field particles through the particle matching probability method, and solves the key technologies of high-speed flow field, operation efficiency, and calculation accuracy; the system also includes: A multi-plane turbulence measurement module for measuring the changes in the aerosol turbulence field at different positions; A data visualization module for generating transient aerosol turbulence cloud maps and analyzing the turbulence integral scale and pulsation characteristics.

4. The mechanism research system for the hardly volatile combustible liquid aerosol according to claim 1, characterized in that: The transient concentration and particle size measurement system measures the particle size distribution and concentration of aerosol droplets in real time; the data processing module can compare and verify the measurement results with a known standard system to ensure the accuracy and reliability of the data; generate a dynamic curve of the aerosol particle size and concentration changing with time, and provide data support for the aerosol diffusion and change characteristic model.

5. The mechanism research system for the non-volatile combustible liquid aerosol according to claim 1, characterized in that: The aerosol combustion and explosion experiment device includes: A cast iron explosion tank body for providing a stable experimental environment and ensuring the accuracy of explosion parameters; An ignition system including a high-voltage electrode and an ignition controller for precisely controlling the ignition energy and ignition time; An explosion parameter measurement module for recording parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate, and flame propagation rate.

6. A method for studying the mechanism of non-volatile flammable liquid aerosol based on the system according to any one of claims 1-5, characterized in that: Including the following steps: S1: Aerosol atomization: Use the aerosol atomization device to pneumatically atomize the non-volatile combustible liquid to form an aerosol, control the gas-liquid ratio and spray pressure, and obtain aerosol samples with different particle size distributions and concentrations; S2: Turbulence intensity measurement: Use the transient aerosol turbulence measurement system to measure the turbulence intensity during the aerosol formation process, and record the turbulence integral scale and pulsation characteristics; S3: Particle size and concentration measurement: Use a transient concentration and particle size measurement system to measure the particle size distribution and concentration of the aerosol, and generate a dynamic curve of the aerosol droplet size and concentration changing with time; S4: Combustion and explosion experiment: Conduct an ignition experiment in an aerosol combustion and explosion experimental device to measure parameters such as the explosion limit, minimum ignition energy, explosion pressure, pressure rise rate, and flame propagation rate of the aerosol; S5: Data analysis: Based on the experimental data, combined with the theories of multiphase flow and explosion mechanics, establish a model of aerosol formation and explosion mechanism, and reveal the influence mechanism of aerosol particle size, concentration, and turbulence on the explosion limit, ignition energy, and explosion intensity.

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