Calculation method and system for volume scattering characteristics of alumina cluster particles

Abstract

The invention belongs to but is not limited to the technical field of volume scattering characteristic calculation, and particularly relates to a method and a system for calculating volume scattering characteristics of alumina cluster particles, which are used for calculating statistical average scattering characteristics of single alumina cluster particles with different basic particle numbers; calculating the number of the alumina cluster particles under different particle numbers according to the logarithmic normal distribution of the number of the alumina cluster particles to obtain scattering characteristics of the alumina cluster particles under different particle numbers; and obtaining the volume scattering characteristic of the aluminum oxide cluster particles through the scattering characteristic of the single cluster and the particle number distribution of the cluster particles. According to the method for calculating the scattering property of the aluminum oxide cluster particles, the scattering property of the aluminum oxide cluster particles in unit volume can be obtained through detailed particle counting and averaging treatment of optical properties. The innovative method can promote the development of material science, optics and related fields.

Description

Technical Field

[0001] The present invention belongs to but is not limited to the technical field of volume scattering property calculation, and in particular relates to a method and system for calculating the volume scattering property of aluminum oxide cluster particles. Background Art

[0002] The solid fuel of the aircraft contains about 15% to 22% aluminum powder, so most of the solid particles in the tail flame of the aircraft are aluminum oxide particles. In the current research on the scattering characteristics of aluminum oxide particles in the tail flame of the aircraft, early researchers often used Mie theory to calculate the scattering characteristics of aluminum oxide particles, but the aluminum oxide particles in the tail flame cannot be equivalent to a single sphere. According to recent studies, it is known that under the complex thermodynamic environment of high temperature and high pressure, the aluminum oxide particles in the tail flame often condense into clusters of different sizes. According to the ratio of aluminum oxide surface tension and shear force, in general, when the number of basic particles in the tail flame aluminum oxide cluster particles exceeds 30, these cluster particles will break. Therefore, in the study, the optical properties of aluminum oxide cluster particles with a number of basic particles of 1 to 30 are usually calculated, and then based on the statistical average optical properties of these cluster particles, the scattering properties of aluminum oxide clusters in the small volume element of the transmission medium can be further calculated, thereby realizing the analysis and research of the volume scattering properties and radiation properties of aluminum oxide cluster particles in the transmission medium.

[0003] Traditional methods often suffer from poor calculation results and reproducibility when dealing with large quantities of alumina particles due to the diversity of particle size and shape and the complexity of particle interactions. In addition, existing technologies often require complex instrumentation and time-consuming sample preparation, making it difficult to obtain data quickly and efficiently.

[0004] Technical problems of existing methods in industrial applications:

[0005] 1. Insufficient handling of the diversity of particle shapes and sizes:

[0006] Problem description: The traditional Mie theory calculation method assumes that the particles are a single sphere, but the aluminum oxide particles in the actual tail flame often exist in irregular clusters. This diversity of irregular shapes and sizes cannot be accurately described by a single spherical assumption.

[0007] Impact: This causes a large deviation between the calculated results and the actual situation, affecting the accurate prediction and analysis of the scattering characteristics of aluminum oxide particles in the tail flame.

[0008] 2. Complexity of volume scattering characteristics in transmission media:

[0009] Problem description: Alumina particles tend to aggregate into clusters in the special high-temperature and high-pressure environment of aircraft tail flames, and the volume scattering characteristics in the transmission medium are complex. Existing methods often require a lot of simplified assumptions when dealing with the transmission problem of light in such a complex medium, while ignoring many actual physical phenomena. Impact: The accuracy and reliability of the calculation results are reduced, and it is difficult to effectively reflect the volume scattering characteristics in the transmission medium.

[0010] 3. Large error:

[0011] Problem description: Due to the complexity of particle shape, size and phase, as well as various simplified assumptions and approximations in the calculation method, the existing methods often have large errors when compared with experimental data.

[0012] Impact: It is not conducive to high-precision industrial applications, making it difficult to promote and apply existing methods.

[0013] 4. Lack of targeted algorithms:

[0014] Problem description: Most of the existing calculation methods and algorithms are simplified, and there is a lack of algorithms for the scattering characteristics of alumina cluster particles whose number of elementary particles follows a log-normal distribution.

[0015] Impact: The calculation accuracy is limited, and the advantages of specific particle characteristics cannot be fully utilized, affecting the actual effect.

[0016] Necessity of solving the above problems:

[0017] In order to improve the accuracy and efficiency of the analysis of the scattering characteristics of alumina particles in the tail flame, it is necessary to develop new computational methods and optimization algorithms that can better handle the diversity and complex interactions of particles, improve computational reproducibility, reduce experimental costs and complexity, and meet the needs of fast, efficient and accurate industrial applications. Summary of the invention

[0018] In view of the problems existing in the prior art, the present invention provides a method and system for calculating the volume scattering characteristics of aluminum oxide cluster particles in a light transmission medium.

[0019] The present invention is implemented in this way: a method for calculating the volume scattering characteristics of aluminum oxide cluster particles comprises the following steps:

[0020] Step 1, calculating the statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles;

[0021] Step 2, calculating the number of aluminum oxide cluster particles under different particle numbers according to the logarithmic normal distribution of the particle number of aluminum oxide cluster particles, and obtaining the scattering characteristics of the aluminum oxide cluster particles under different particle numbers;

[0022] Step three, obtaining the volume scattering characteristics of the aluminum oxide cluster particles through the scattering characteristics of a single cluster and the particle number distribution of the cluster particles.

[0023] Furthermore, in step one, the statistical average scattering characteristics of the alumina cluster particles are calculated based on the multi-sphere T-matrix (MSTM) algorithm. During the calculation process, the incident wavelength, the complex refractive index of the alumina particles, and the basic particle radius of the cluster particles need to be input.

[0024] Furthermore, the logarithmic normal distribution expression of the number of alumina cluster particles in step 2 is as follows:

[0025]

[0026] Among them, N 0 is the number of alumina cluster particles contained in unit volume, n is the number of basic particles of alumina cluster particles, n is 1 to 30, n g is the geometric mean of the number of elementary particles of alumina cluster particles, σ g The geometric standard deviation of the number of elementary particles of alumina cluster particles is, dN is the number of alumina cluster particles under different elementary particle numbers dn, N(n) = N 0 ·P(n).

[0027] Further, the calculation of the number of alumina cluster particles N 0 Methods include:

[0028] (1) The volume V of each alumina cluster particle is calculated by treating the basic particles in the alumina cluster particles as spheres, and then the mass m of a single cluster is calculated based on the density of the alumina particles in the alumina cluster particles. The volume and mass of each alumina cluster particle are expressed by the following formula:

[0029]

[0030] m=ρ·V

[0031] Wherein, r is the radius of the monomer in the alumina cluster particle, n is the number of basic particles of the alumina cluster particle, n is 1 to 30, V is the volume of a single alumina cluster particle, ρ is the density of the alumina particle, and m is the mass of a single alumina cluster particle;

[0032] (2) According to the log-normal distribution of the basic number of alumina cluster particles, the statistical average mass m of alumina cluster particles per unit volume is calculated. g , according to the total mass m 0 and the statistical average mass m g The number of particles N per unit volume can be calculated by 0 ; expressed by the following formula:

[0033]

[0034] m 0 =N 0 ·m g

[0035] Furthermore, the number of elementary particles n based on the alumina cluster particles obeys the log-normal distribution, and its probability density function is:

[0036]

[0037] Where n is the number of basic particles of the alumina cluster particles, n is 1 to 30, n g is the geometric mean of the number of elementary particles of alumina cluster particles, σ g Geometric standard deviation of the number of elementary particles of alumina cluster particles.

[0038] Furthermore, the volume scattering characteristics of the particles in step 3 are obtained by summing up the single scattering characteristics, including the volume extinction coefficient < b ext >, volume scattering coefficient<b sca >, volume absorption coefficient <b abs >, volume single scattering albedo <ω>, volume asymmetry factor <g> and volume phase function <F 11 (θ)>;

[0039]

[0040]

[0041] Among them, N n is the number of clusters under the number of basic particles n of alumina cluster particles, C ext,n is the extinction cross section of alumina cluster particles with n elementary particles, C sca,n is the scattering cross section of alumina cluster particles with n elementary particles, C abs,n is the absorption cross section of alumina cluster particles with n elementary particles, ω n is the single scattering albedo of the alumina cluster particles with n elementary particles, g n is the asymmetry factor of the alumina cluster particles with n elementary particles, F 11 (θ) n is the phase function of alumina cluster particles with n elementary particles.

[0042] Another object of the present invention is to provide a method for calculating the volume scattering characteristics of aluminum oxide cluster particles and a system for calculating the volume scattering characteristics of aluminum oxide cluster particles, comprising:

[0043] The statistical average scattering characteristic calculation module is used to calculate the statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles;

[0044] A scattering characteristic calculation module is used to calculate the number of aluminum oxide cluster particles under different particle numbers according to the logarithmic normal distribution of the number of aluminum oxide cluster particles, and obtain the scattering characteristics of the aluminum oxide cluster particles under different particle numbers;

[0045] The volume scattering characteristic calculation module is used to obtain the volume scattering characteristics of the aluminum oxide cluster particles through the scattering characteristics of a single cluster and the particle number distribution of the cluster particles.

[0046] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0047] First, the present invention proposes an algorithm for calculating the volume scattering characteristics of alumina cluster particles in a small volume element of a transmission medium. The statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles are calculated using a multi-sphere T-matrix (MSTM) algorithm. Then, the number of alumina cluster particles under different numbers of particles is obtained based on the log-normal distribution of the number of alumina cluster particles. Thus, the scattering characteristics of alumina cluster particles under different numbers of particles are obtained. Then, the volume scattering characteristics are obtained through the optical properties of a single cluster and the particle number distribution of cluster particles.

[0048] Among them, the step of calculating the statistical average scattering characteristics in a unit volume is the core of this method. It calculates the scattering, absorption and reflection characteristics of aluminum oxide clusters with different numbers of elementary particles by statistical averaging. This calculation not only enhances the practical application value of the theoretical model, but also makes the experimental results close to the actual application scenario. Furthermore, based on these volume scattering characteristics, the optical properties of the entire tail flame can be inferred, thereby providing certain ideas for the study of the optical properties of the aircraft tail flame. The proposal and application of this method is expected to bring important theoretical and practical significance in the field of aerospace.

[0049] The algorithm provided by the present invention can calculate the volume scattering and radiation transmission characteristics of a medium containing clustered particles, laying the foundation for further research; it can solve the problem that it is difficult to measure the number and quality of clustered particles in complex environments, providing a certain data basis for subsequent research; by adopting a log-normal distribution model, it helps to better explain experimental data, and guide practical applications through theoretical models, providing important technical support and reference for the industry.

[0050] The method of the present invention not only takes into account the distribution and agglomeration behavior of aluminum oxide particles in a complex environment, but also provides certain ideas for related research and practical applications through statistical analysis and mathematical models.

[0051] The present invention proposes a method for calculating the scattering properties of alumina cluster particles. Through careful particle counting and averaging of optical properties, the scattering properties of alumina cluster particles per unit volume can be obtained. This innovative method will promote the development of materials science, optics and related fields, and provide solid technical support for further research and application of alumina cluster particles.

[0052] Second, the parameters, algorithms, mathematical models, etc. of the technical solution of the present invention solve the technical problems of the prior art and represent significant technical progress.

[0053] Existing technical problems solved:

[0054] 1. Insufficient Diversity Processing

[0055] Solution: The multi-sphere T-matrix algorithm is used to calculate the statistical average scattering characteristics of cluster particles, which takes into account the scattering characteristics of multi-sphere systems under different numbers and arrangements of elementary particles and accurately describes cluster particles of irregular shapes and sizes.

[0056] The accuracy of the calculation results is improved, and the scattering characteristics of aluminum oxide particles in the tail flame can be more realistically reflected.

[0057] 2. Volume scattering properties in complex media

[0058] Solution: The log-normal distribution model is used to describe the elementary particle number distribution of alumina cluster particles. Combined with the multi-sphere T-matrix algorithm, the volume scattering characteristics in the transmission medium are systematically calculated.

[0059] The accuracy and reliability of calculations have been improved to better reflect actual physical phenomena.

[0060] 3. Poor accuracy

[0061] Solution: The accuracy of the method is ensured by using statistical methods (such as lognormal distribution) and standardized calculation procedures.

[0062] The reliability and accuracy of the results are improved and are suitable for promotion in industrial applications.

[0063] Significant technological advancements:

[0064] 1. The calculation accuracy and efficiency are significantly improved: By combining the multi-sphere T-matrix algorithm and the log-normal distribution model, the volume scattering characteristics in the transmission medium are systematically calculated, and the calculation results are closer to the actual situation.

[0065] 2. Enhanced accuracy and consistency of the method: The use of standardized calculation processes and statistical methods improves the accuracy and consistency of the results, making it suitable for promotion in industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a flow chart of a method for calculating the volume scattering characteristics of aluminum oxide cluster particles provided in an embodiment of the present invention.

[0067] Figure 2 It is a detailed flow chart of a method for determining the volume scattering characteristics of aluminum oxide cluster particles provided in an embodiment of the present invention.

[0068] Figure 3 It is a probability density diagram of aluminum oxide cluster particles provided in an embodiment of the present invention.

[0069] Figure 4 It is a volume diagram of aluminum oxide cluster particles provided in an embodiment of the present invention.

[0070] Figure 5 It is a quality diagram of the aluminum oxide cluster particles provided in an embodiment of the present invention.

[0071] Figure 6 It is a number density diagram of aluminum oxide cluster particles per unit volume provided in an embodiment of the present invention.

[0072] Figure 7 It is a structural diagram of a calculation system for volume scattering characteristics of aluminum oxide cluster particles provided in an embodiment of the present invention.

[0073] Figure 8 It is the volume scattering phase function of 0180 degrees provided in the embodiment of the present invention. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0075] like Figure 1 As shown, an embodiment of the present invention provides a method for calculating the volume scattering characteristics of aluminum oxide cluster particles, comprising the following steps:

[0076] Step 1, calculating the statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles;

[0077] Step 2, calculating the number of aluminum oxide cluster particles under different particle numbers according to the logarithmic normal distribution of the particle number of aluminum oxide cluster particles, and obtaining the scattering characteristics of the aluminum oxide cluster particles under different particle numbers;

[0078] Step three, obtaining the volume scattering characteristics of the aluminum oxide cluster particles through the scattering characteristics of a single cluster and the particle number distribution of the cluster particles.

[0079] like Figure 2As shown, the following are specific implementation steps of the method for calculating the volume scattering characteristics of aluminum oxide cluster particles provided in an embodiment of the present invention:

[0080] Alumina cluster particle model with constant elementary particle radius and log-normal distribution of number;

[0081] According to the scanning electron microscopy of alumina particles, the alumina particles in the tail flame often condense into clusters, and the number of elementary particles n of alumina cluster particles obeys the log-normal distribution, and its probability density function is:

[0082]

[0083] Where n is the number of elementary particles of the alumina cluster particles, n is 1 to 30, and the geometric mean of the number of elementary particles of the alumina cluster particles is n g is 10, the geometric standard deviation σ g is 1.5. In addition, it is assumed that the radius of the elementary particles in the alumina cluster particles is the same, and r is taken as 100nm. The probability density of the alumina cluster particles is as follows: Figure 3 shown.

[0084] First, calculate the statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles.

[0085] The statistical average scattering characteristics of alumina cluster particles are calculated based on the multi-sphere T-matrix (MSTM) algorithm. The incident wavelength used in the calculation process is 280nm, the complex refractive index of the alumina particles is 1.87+i0.11, and the basic particle radius of the cluster particles is 100nm.

[0086] Second, the number of alumina cluster particles under different particle numbers is calculated according to the logarithmic normal distribution of the particle number of alumina cluster particles, and the scattering characteristics of the alumina cluster particles under different particle numbers are obtained.

[0087] (1) Calculate the number N of alumina cluster particles in a small volume element of the transmission medium 0 :

[0088] 1) The volume V of each alumina cluster particle is calculated by treating the basic particles in the alumina cluster particles as spheres, and then the mass m of a single cluster is calculated based on the density of the alumina particles in the alumina cluster particles; the volume and mass of each alumina cluster particle are expressed by the following formula:

[0089]

[0090] m=ρ·V

[0091] Where r is the radius of the monomer in the alumina cluster particle, r is 100 nm, n is the number of basic particles of the alumina cluster particle, n is 1 to 30, V is the volume of a single alumina cluster particle, ρ is the density of the alumina particle, ρ is 3.97 g / cm 3 , m is the mass of a single alumina cluster particle; the volume and mass of the alumina cluster particles are Figure 4 and Figure 5 shown.

[0092] 2) According to the log-normal distribution of the basic number of alumina cluster particles, the statistical average mass m of alumina cluster particles per unit volume is calculated. g , the total mass per unit volume m is known 0 1g / cm 3 , according to the total mass m 0 and the statistical average mass m g The number of particles N per unit volume can be calculated by 0 ; expressed by the following formula:

[0093]

[0094] m 0 =N 0 ·m g

[0095] (2) Calculate the number of alumina cluster particles corresponding to each number of elementary particles;

[0096] The logarithmic normal distribution expression of the number of alumina cluster particles is as follows:

[0097]

[0098] Among them, N 0 1g / cm 3 The number of alumina cluster particles contained in 0 is 5.592×10 12 / cm 3 , n is the number of elementary particles of alumina cluster particles, n is 1 to 30, and the geometric mean of the number of elementary particles of alumina cluster particles is n g is 10, the geometric standard deviation of the number of elementary particles of alumina cluster particles σ g = 1.5, N(n) means the number of alumina cluster particles (dN) under different numbers of elementary particles (dn) in a unit volume, N(n) = N 0 ·P(n). The number density of alumina cluster particles per unit volume is Figure 6 shown.

[0099] Third, the volume scattering characteristics of alumina cluster particles are obtained through the scattering characteristics of single clusters and the particle number distribution of cluster particles.

[0100] The volume scattering properties of the particle are obtained by summing up the single scattering properties, including the volume extinction coefficient < b ext >, volume scattering coefficient<b sca >, volume absorption coefficient <b abs >, volume single scattering albedo <ω>, volume asymmetry factor <g> and volume phase function <F 11 (θ)>;

[0101]

[0102] Among them, N n is the number of clusters under the number of basic particles n of alumina cluster particles, C ext,n is the extinction cross section of alumina cluster particles with n elementary particles, C sca,n is the scattering cross section of alumina cluster particles with n elementary particles, C abs,n is the absorption cross section of alumina cluster particles with n elementary particles, ω n is the single scattering albedo of the alumina cluster particles with n elementary particles, g n is the asymmetry factor of the alumina cluster particles with n elementary particles, F 11 (θ) n is the phase function of alumina cluster particles with n elementary particles.

[0103] like Figure 7 As shown, a method for calculating the volume scattering characteristics of aluminum oxide cluster particles and a system for calculating the volume scattering characteristics of aluminum oxide cluster particles provided by an embodiment of the present invention include:

[0104] The statistical average scattering characteristic calculation module is used to calculate the statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles;

[0105] A scattering characteristic calculation module is used to calculate the number of aluminum oxide cluster particles under different particle numbers according to the logarithmic normal distribution of the number of aluminum oxide cluster particles, and obtain the scattering characteristics of the aluminum oxide cluster particles under different particle numbers;

[0106] The volume scattering characteristic calculation module is used to obtain the volume scattering characteristics of the aluminum oxide cluster particles through the scattering characteristics of a single cluster and the particle number distribution of the cluster particles.

[0107] Example 1: Simulation and analysis of infrared characteristics of rocket tail flame

[0108] During the launch of a rocket, its tail flame contains a large number of aluminum oxide particles, and the scattering characteristics of these particles have a significant impact on the spectral radiation characteristics of the tail flame. Traditional methods are difficult to accurately describe the volume scattering characteristics of aluminum oxide cluster particles in the tail flame, which affects the infrared characteristics analysis of the tail flame.

[0109] Tail flame flow field data acquisition

[0110] In the simulation experiment of the infrared characteristics of rocket tail flame, the tail flame flow field data including temperature, pressure, alumina particle morphology, alumina particle number density and various gas components are obtained.

[0111] 2. Determine the parameters

[0112] The complex refractive index of aluminum oxide particles is obtained according to the temperature and detection wavelength.

[0113] 3. Calculate the statistical average scattering properties

[0114] The statistical average scattering properties of single alumina cluster particles with different numbers of elementary particles are calculated using the multi-sphere T-matrix (MSTM) algorithm.

[0115] 4. Particle number distribution calculation

[0116] According to the logarithmic normal distribution of the number of alumina cluster particles, the number of alumina cluster particles under different particle numbers is calculated.

[0117] 5. Calculation of volume scattering characteristics

[0118] The volume scattering characteristics of alumina cluster particles, including volume extinction coefficient, volume scattering coefficient, volume absorption coefficient, etc., are calculated based on the scattering characteristics of a single cluster and the particle number distribution of cluster particles.

[0119] 6. Calculate the infrared radiation characteristics of the tail flame

[0120] Based on the flow field data and volume scattering characteristics, the infrared radiation characteristics of the rocket tail flame are calculated and analyzed to provide relevant basis for rocket detection.

[0121] Through this embodiment, the scattering characteristics of aluminum oxide particles in rocket tail flames can be accurately analyzed, providing a scientific basis for space target detection. At the same time, the accuracy and reliability of tail flame spectral radiation characteristic analysis are improved.

[0122] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for calculating the volume scattering characteristics of aluminum oxide cluster particles, characterized in that: The following steps are involved: Step 1, calculating the statistical average scattering characteristics of a single alumina cluster particle under different numbers of elementary particles; Step 2, calculating the number of aluminum oxide cluster particles under different particle numbers according to the logarithmic normal distribution of the particle number of aluminum oxide cluster particles, and obtaining the scattering characteristics of the aluminum oxide cluster particles under different particle numbers; Step three, obtaining the volume scattering characteristics of the aluminum oxide cluster particles through the scattering characteristics of a single cluster and the particle number distribution of the cluster particles.

2. The method for calculating the volume scattering characteristics of aluminum oxide cluster particles according to claim 1, characterized in that: In the step 1, the statistical average scattering characteristics of the aluminum oxide cluster particles are calculated based on the multi-sphere T matrix MSTM algorithm. During the calculation process, the incident wavelength, the complex refractive index of the aluminum oxide particles, and the basic particle radius of the cluster particles need to be input.

3. The method for calculating the volume scattering characteristics of aluminum oxide cluster particles according to claim 1, characterized in that: The logarithmic normal distribution expression of the number of alumina cluster particles in step 2 is as follows: Wherein, N0 is the number of alumina cluster particles contained in unit volume, n is the number of basic particles of alumina cluster particles, n is 1 to 30, and n g is the geometric mean of the number of elementary particles of alumina cluster particles, σ g Geometric standard deviation of the number of elementary particles of alumina cluster particles.

4. The method for calculating the volume scattering characteristics of aluminum oxide cluster particles according to claim 1, characterized in that: The method for calculating the number N0 of aluminum oxide cluster particles includes: (1) The volume V of each alumina cluster particle is calculated by treating the basic particles in the alumina cluster particles as spheres, and then the mass m of a single cluster is calculated based on the density of the alumina particles in the alumina cluster particles. The volume and mass of each alumina cluster particle are expressed by the following formula: m=ρ·V Wherein, r is the radius of the monomer in the alumina cluster particle, n is the number of basic particles of the alumina cluster particle, n is 1 to 30, V is the volume of a single alumina cluster particle, ρ is the density of the alumina particle, and m is the mass of a single alumina cluster particle; (2) According to the log-normal distribution of the basic number of alumina cluster particles, the statistical average mass m of alumina cluster particles per unit volume is calculated. g , according to the total mass m0 and the statistical average mass m g The number of particles N0 per unit volume can be obtained by the relationship between the two; it can be expressed by the following formula: m0=N0·m g 5. The method for calculating the volume scattering characteristics of aluminum oxide cluster particles according to claim 4, characterized in that: The number of elementary particles n based on alumina cluster particles follows a log-normal distribution, and its probability density function is: Where n is the number of basic particles of the alumina cluster particles, n is 1 to 30, n g is the geometric mean of the number of elementary particles of alumina cluster particles, σ g Geometric standard deviation of the number of elementary particles of alumina cluster particles.

6. The method for calculating the volume scattering characteristics of aluminum oxide cluster particles according to claim 1, characterized in that: The volume scattering characteristics of the particles in step 3 are obtained by summing up the single scattering characteristics, including the volume extinction coefficient < b ext >, volume scattering coefficient<b sca >, volume absorption coefficient <b abs >, volume single scattering albedo <ω>, volume asymmetry factor <g> and volume phase function <F 11 (θ)>; Among them, N n is the number of clusters under the number of basic particles n of alumina cluster particles, C ext,n is the extinction cross section of alumina cluster particles with n elementary particles, C sca,n is the scattering cross section of alumina cluster particles with n elementary particles, C abs,n is the absorption cross section of alumina cluster particles with n elementary particles, ω n is the single scattering albedo of the alumina cluster particles with n elementary particles, g n is the asymmetry factor of the alumina cluster particles with n elementary particles, F 11 (θ) n is the phase function of alumina cluster particles with n elementary particles.

7. A system for calculating the scattering characteristics of aluminum oxide cluster particles in rocket tail flame based on the method of claim 1, characterized in that: The system includes: Data acquisition module: used to obtain the tail flame flow field data including temperature, pressure, alumina particle morphology, alumina particle number density and various gas components in the rocket tail flame infrared characteristics simulation experiment; Parameter determination module: obtain the complex refractive index of aluminum oxide particles according to temperature and detection wavelength; Scattering characteristic calculation module: Calculate the statistical average scattering characteristics of a single alumina cluster particle based on the multi-sphere T matrix algorithm; Distribution calculation module: according to the logarithmic normal distribution of the number of alumina cluster particles, the number of alumina cluster particles under different particle numbers is calculated; Volume scattering characteristic calculation module: calculates the volume scattering characteristics of aluminum oxide cluster particles through the scattering characteristics of a single cluster and the particle number distribution of cluster particles.

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