Construction method of atmospheric radiation transfer model containing alumina cluster particles

Abstract

The invention relates to a construction method of an atmospheric radiation transfer model containing alumina cluster particles, belongs to the technical field of atmospheric science, and solves the technical problem of radiation calculation errors caused by neglecting the alumina cluster particles discharged to the whole atmospheric layer by an aircraft in the construction process of the atmospheric radiation transfer model in the prior art. The method comprises the following steps: calculating the mass load of alumina cluster particles discharged by an aircraft, and obtaining the number density and effective radius of low-layer, middle-layer and high-layer alumina cluster particles; simulating alumina cluster particles, configuring a phase state and a doping type of the alumina cluster particles, and modeling while considering a heterogeneous alumina cluster particle model of phase state and doping characteristics; obtaining the effective refractive index of alumina cluster particles; the optical property of a single alumina cluster particle; calculating the average radiation characteristic of alumina cluster particles; and coupling the spatial distribution of the alumina cluster particles and the average radiation characteristics of the alumina cluster particles to an existing atmospheric radiation transfer model.

Description

Technical Field

[0001] This invention belongs to the field of atmospheric science and technology, specifically relating to a method for constructing an atmospheric radiative transfer model containing alumina cluster particles. Background Technology

[0002] With the continuous development of emerging space technologies and the accelerated commercialization of orbital spaceflight, the global space industry is experiencing rapid growth, and the impact of related space activities on the Earth's atmospheric system is becoming increasingly apparent. A 2024 NASA report, "Impact of Spaceflight on Earth's Atmosphere: Climate, Ozone, and the Upper Atmosphere," points out that emissions from rocket launches and spacecraft reentry will increase exponentially in the coming decades, transforming from previously overlooked small emissions into significant anthropogenic emissions comparable to meteorites or dust. Alumina cluster particles are important emissions from solid rocket and spacecraft reentry processes. These particles will be widely distributed in the atmosphere, from the Earth's surface to the upper atmosphere, becoming important anthropogenic aerosol particles. However, the latest Intergovernmental Panel on Climate Change (IPCC) Sixth Report (AR6) primarily focuses on traditional anthropogenic and natural sources, such as sulfates and black carbon from fossil fuel combustion, as well as natural aerosols like dust and sea salt. Alumina cluster particles emitted from aerospace activities have not yet been included in the global aerosol inventory system. Ignoring alumina clusters in the atmosphere leads to biases in the estimation of aerosol particle scattering and absorption radiation in studies such as atmospheric radiation, climate simulation, and target detection.

[0003] Previous researchers have confirmed the impact of stratospheric alumina cluster particles on the atmospheric environment. Alumina cluster particles accelerate the decomposition of stratospheric ozone through catalytic reactions. A 2025 paper by Laura E. Revell et al., "Near-future rocket launches could slow ozone recovery," indicates that alumina cluster particles emitted by rocket launches slow the rate of ozone layer recovery, potentially reducing the global ozone column by as much as 0.29% annually. Furthermore, alumina cluster particles alter the stratospheric radiation balance by scattering and absorbing solar radiation and thermal radiation from Earth. Papers by Yueyuan Xu et al., "Effects of aluminum / carbon impurities and morphology on optical characteristics and radiative forcing of alumina clusters emitted by solid rockets in the stratosphere," and Martin N. Ross et al., "Radiative forcing caused by rocket engine emissions," focus on the stratospheric radiative forcing caused by alumina cluster particles. Their research suggests that the accumulation of alumina cluster particles in the stratosphere may trigger imbalances in both local and global radiation budgets. However, as rockets ascend from the Earth's surface into the high atmosphere and spacecraft fall back into the atmosphere from high altitudes, the emitted alumina cluster particles will continue to be released and distributed at different altitudes throughout the entire atmosphere. However, there is currently a lack of quantitative description of their spatial distribution in the atmosphere, which makes it impossible to quantitatively incorporate alumina cluster particles into existing atmospheric radiation transfer models, resulting in deviations in atmospheric radiation transfer simulations.

[0004] The radiation characteristics of alumina cluster particles are closely related to their physicochemical properties. In the past, scholars often simplified alumina cluster particle models, leading to errors in related simulations and evaluations. For example, Rialland et al.'s paper, "Infrared signature modelling of a rocket jetplume - comparison with flight measurements," simulated the infrared radiation characteristics of the Black Brant sounding rocket exhaust plume and found a significant difference between the simulated and actual measured values ​​of the exhaust plume infrared radiation near the nozzle. They attributed this difference to inaccurate descriptions of the physicochemical characteristics of alumina in the simulation. Similarly, Binauld et al.'s paper, "Numerical simulation of radiation in high altitude solid propellant rocketplumes," simulated the ultraviolet radiation characteristics of the Antares II launch vehicle exhaust plume and found that at 350 nm, the simulated exhaust plume radiation intensity was only half that of the experimental data. They also attributed this difference to the inability to obtain accurate physicochemical characteristics of alumina cluster particles. Martin N. Ross et al.'s paper, "Radiative forcing caused by rocket engine emissions," indicated that inaccuracies in the alumina model led to significant uncertainties in the calculated results of its radiative forcing. In summary, they all assumed that alumina was a uniformly distributed single sphere, ignoring its complex physicochemical characteristics. In reality, firstly, the particle size of alumina is non-uniformly distributed, and the particles aggregate to form clusters at high temperatures; secondly, when these alumina clusters enter the atmosphere, their temperature drops rapidly, causing a phase transition and resulting in multiphase alumina clusters; finally, various chemical components are mixed in during the formation of alumina clusters, generating doped alumina clusters. These discrepancies, due to limitations such as the relatively low transmission frequency of previous spacecraft, limited detection methods, and the complexity of high-altitude atmospheric data acquisition technology, have led to a lack of accurate modeling of alumina clusters, resulting in errors in calculations related to their optical radiation characteristics. Summary of the Invention

[0005] To address the problem of radiation calculation errors caused by neglecting alumina cluster particles emitted by aircraft into the entire atmosphere during the construction of atmospheric radiation transfer models in existing technologies, this invention proposes a method for constructing an atmospheric radiation transfer model containing alumina cluster particles.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A method for constructing an atmospheric radiative transfer model containing alumina cluster particles includes the following steps:

[0008] Step 1: Quantifying the spatial distribution of alumina cluster particles

[0009] Based on the propulsion dose consumed per launch, the annual launch frequency, and the emission index, the mass load of alumina cluster particles emitted by the spacecraft's exhaust plume is calculated. Based on the annual reentry volume, the proportion of aluminum material in the reentry vehicle, the mass fraction of oxidized aluminum in the reentry vehicle, and the conversion index, the mass load of alumina cluster particles emitted by the reentry vehicle is calculated. The atmosphere is divided into lower, middle, and upper layers, and the mass load of alumina cluster particles in the lower, middle, and upper layers of the atmosphere is calculated. The number density of alumina cluster particles in the lower, middle, and upper layers of the atmosphere is obtained.

[0010] Step 2: Obtain the average radiation characteristics of alumina cluster particles.

[0011] Simulate alumina cluster particles, configure the phase type and doping type of alumina cluster particles, and model a non-homogeneous alumina cluster particle model that considers both phase and doping characteristics; obtain the effective refractive index of alumina cluster particles; the optical properties of individual alumina cluster particles; and calculate the average radiation properties of alumina cluster particles.

[0012] Step 3: Construct an atmospheric radiative transfer model containing alumina cluster particles.

[0013] By coupling the spatial distribution and average radiative properties of alumina cluster particles into existing atmospheric radiative transfer models, an atmospheric radiative transfer model containing alumina cluster particles is obtained.

[0014] The method for constructing the atmospheric radiative transfer model of alumina-containing cluster particles described above, wherein step 1 further includes:

[0015] The first step is to calculate the mass load of alumina cluster particles emitted from the aircraft's exhaust plume and reentry.

[0016] Based on the propulsion dose P consumed by the spacecraft in each launch m Calculate the mass load M of alumina cluster particles emitted from the aircraft's exhaust plume, based on the aircraft's annual launch frequency Y and emission index ε. 尾焰 Based on the annual number of re-entering spacecraft M re The proportion of aluminum in the reentry vehicle F Al The mass fraction of oxidized aluminum in the reentry vehicle, F tran The conversion index ζ is used to calculate the mass loading M of alumina cluster particles emitted during spacecraft reentry. 再入 The calculation formula is as follows:

[0017]

[0018] In equation (1), P m M re The units for ε and ζ are kg. ε represents the emission index, which is the mass of alumina cluster particles released per kilogram of propellant combustion. ζ is the conversion index, which represents the mass of alumina cluster particles converted from per kilogram of aluminum after oxidation.

[0019] The second step is to calculate the mass load of alumina cluster particles in each layer of the atmosphere.

[0020] The lower layer is from the ground to the tropopause, the middle layer is from the tropopause to the mesotope, and the upper layer is above the mesotope.

[0021] Mass loading M of lower-layer alumina cluster particles 低层 The mass loading M of the alumina cluster particles in the middle layer 中层 The mass loading M of high-level alumina cluster particles 高层 The calculation formula is as follows:

[0022]

[0023] In equation (2), These represent the percentage of propellant burned in the lower, middle, and upper atmospheres, respectively. These represent the mass percentages of aluminum material oxidized in the lower, middle, and upper layers of the aircraft, respectively; τ 低层 τ 中层 τ 高层 These represent the time that alumina cluster particles remain in the lower, middle, and upper layers, respectively, in years.

[0024] The third step is to obtain the number density of alumina cluster particles in each layer of the atmosphere.

[0025] Number density N of alumina cluster particles in each layer L The calculation formula is as follows:

[0026]

[0027] In equation (3), ρ represents the density of alumina cluster particles, L represents the atmospheric level, L = lower, middle or upper atmosphere, and V L The volume of the L-level atmosphere is represented by Ns, the number of monomers in a single alumina cluster particle is represented by n, and the number of samples of alumina cluster particles is represented by r. i R represents the radius of the i-th individual particle in a single cluster, and the effective radius of the alumina cluster particle is R.

[0028] In the method for constructing the atmospheric radiative transfer model of the above-mentioned alumina-containing cluster particles, in step 1, the first step is defined as follows: ε = 0.06 kg, ζ = 1.24 kg, F Al =30%, F tran =32%.

[0029] In step 1, second step, the lower layer is 0-10km, the middle layer is greater than 10km-85km, and the upper layer is greater than 85km. The proportions of propellant combustion in the lower, middle, and upper layers are respectively: L 低层 =0.34, L 中层 =0.649, L 高层 =0.22; the mass percentages of aluminum material oxidized in the lower, middle, and upper atmospheres during spacecraft reentry were respectively The residence times of alumina cluster particles in the lower, middle, and upper layers are τ, respectively. 低层 =1 year, τ 中层 =4 years, τ 高层 = 0.02 years.

[0030] In step 1, third step, the density of the alumina cluster particles is ρ = 3.8 g / cm³. 3 The sample size n of alumina cluster particles is greater than or equal to 1000.

[0031] The method for constructing the atmospheric radiative transfer model of the above-mentioned alumina-containing cluster particles, wherein step 2 further includes:

[0032] Step 201, Simulating alumina cluster particles

[0033] An improved diffusion-induced condensation model (DLA) was used to simulate alumina cluster particles.

[0034] Step 202: Configure the phase type of alumina cluster particles.

[0035] The phase types of alumina cluster particles are configured as follows: α phase, γ phase and multiphase, wherein the multiphase includes α phase, γ phase and liquid phase.

[0036] Step 203: Configure the doping type of alumina cluster particles.

[0037] The impurities doped into the alumina cluster particles are one or more of the following: iron, carbon black, aluminum, silver, silicon, air, copper, and magnesium.

[0038] Step 204: Model a non-homogeneous alumina cluster particle model that simultaneously considers phase state and doping characteristics.

[0039] The first step is to model an alumina cluster particle model that considers phase states.

[0040] The α-phase and γ-phase alumina cluster particles are uniformly distributed; the multiphase alumina cluster particles consist of three spheres from the outside to the inside, corresponding to the α-phase, γ-phase, and liquid phase, respectively. A phase-considered alumina cluster particle model is constructed based on the phase type of the configured alumina cluster particles.

[0041] The second step is to model the alumina cluster particles that are doped.

[0042] Alumina cluster particle doping modes are classified into alumina shell type, alumina core type, and a uniform mixture of alumina and impurities type.

[0043] Alumina shell type, meaning alumina encapsulates impurities; alumina core type, meaning impurities encapsulate alumina; and uniformly mixed type, meaning alumina clusters and impurities are uniformly mixed.

[0044] The third step is to model the alumina cluster particles that simultaneously consider both phase state and doping.

[0045] By coupling the alumina cluster particle model that considers phase state with the alumina cluster particle model that considers doping, a non-homogeneous alumina cluster particle model that considers both phase state and doping is obtained.

[0046] Step 205: Obtain the effective refractive index of alumina cluster particles.

[0047] The first step is to collect the refractive indices of α-phase, γ-phase, and liquid-phase alumina cluster particles and impurities;

[0048] The second step involves calculating the effective refractive index of the heterogeneous alumina cluster particles based on the effective medium theory.

[0049] Step 206: Obtain the optical properties of individual alumina cluster particles.

[0050] By coupling a non-homogeneous alumina cluster particle model that simultaneously considers phase state and doping characteristics, the effective refractive index of alumina cluster particles, and the superposition T-matrix method (STMM), the optical properties of a single alumina cluster particle are obtained.

[0051] Step 207: Calculate the average optical properties and average radiation properties of the alumina cluster particles.

[0052] The first step is to take the arithmetic mean of the optical properties of n alumina cluster particles to obtain the average optical properties, including the average scattering phase function. Average extinction efficiency factor Average scattering efficiency factor Average absorption efficiency factor

[0053] The second step is to base the analysis on the average optical properties of alumina cluster particles and the number density N of alumina cluster particles. LThe average radiation characteristics of alumina cluster particles were calculated using the effective radius R.

[0054] The method for constructing the atmospheric radiative transfer model of the above-mentioned alumina-containing cluster particles, wherein step 201 further includes:

[0055] The fractal structure construction and morphological description of alumina cluster particles are as follows:

[0056]

[0057] In equation (6), k f It is the pre-fractal factor, Ns is the number of monomers in the alumina cluster particles, and R g D represents the radius of rotation. f The fractal dimension is represented by 'a', which represents the average radius of the monomers in the alumina cluster particles, and 'l' represents the fractal dimension. j r is the distance from monomer j to the center point of the alumina cluster particle. i It is the radius of the i-th individual unit.

[0058] The individual radii of alumina cluster particles follow a log-normal distribution, and its distribution function P(r) is as follows:

[0059]

[0060] In equation (7), σ g R represents the geometric standard deviation. g It is the average radius of a single particle in the cluster.

[0061] In the above method for constructing the atmospheric radiative transfer model of alumina-containing cluster particles, in step 201, the geometric standard deviation σ g =1.5nm, average radius r of cluster particle individual g =100nm.

[0062] The method for constructing the atmospheric radiative transfer model of the above-mentioned alumina-containing cluster particles, step 204, further includes:

[0063] Based on the dynamic decay equation of the crystallization front of alumina cluster particles

[0064]

[0065] In the above formula, a * =0.64×10 -6 m / (sec×K 1.8 ), T m =2289K,T s =2273 represent the melting point and crystallization front temperature of the alumina particles, respectively; relative crystallization front radius. Where r is the particle radius, rliquid Let r be the radius of the liquid state inside the particle. s Let be the radius of the solid portion of the particle. The volume fraction P of the α phase is... α It depends on the following equation:

[0066]

[0067] In the above formula, a α and b α It is an empirical coefficient, a α =1.5×10 12 1 / sec,b α =58368K.

[0068] Assume f α ,f γ and f liquid Let f represent the volume fractions of the α-phase, γ-phase, and liquid phase contained in the alumina cluster particles, respectively. α +f γ +f liquid =1, and according to formulas (8) and (9), the following equation is obtained:

[0069]

[0070] Volume V of each phase i This can be represented by the following equation:

[0071]

[0072] Alumina cluster particles transform from a high-temperature liquid phase to a solid phase, which is either an α-phase or a γ-phase. According to formula (8), the volume of the solid phase is:

[0073]

[0074] Therefore, the formula for calculating the solid phase radius of alumina cluster particles is as follows:

[0075]

[0076] Combining formulas (8) and (13), we get:

[0077]

[0078] Solve the equations to obtain the volume percentage of each phase in the multiphase alumina cluster particles.

[0079] The method for constructing the atmospheric radiative transfer model of the above-mentioned alumina-containing cluster particles, wherein step 205 further includes:

[0080] The effective refractive index of alumina cluster particles was calculated using the Maxwell-Garnett method, and the formula is as follows:

[0081]

[0082] Where x is the number of matter types embedded in the principal particle, ε h F is the dielectric constant of alumina cluster particles. i and ε i They are respectively the i-th th Volume fraction and dielectric constant of the mixture, ε ef and m ef These are the macroscopic effective dielectric constant and effective refractive index of non-uniform particles.

[0083] The method for constructing the atmospheric radiative transfer model of alumina-containing cluster particles described above, wherein step 207 further includes:

[0084] Average radiation characteristics include scattering phase function Extinction coefficient Scattering coefficient absorption coefficient The calculation formula is as follows:

[0085]

[0086] In the above method for constructing the atmospheric radiative transfer model of alumina-containing cluster particles, step 3 refers to the method of construction as follows:

[0087] Based on the spatial distribution and average radiative properties of alumina cluster particles, an atmospheric radiative transfer model containing alumina cluster particles is constructed by coupling these properties to an existing atmospheric radiative transfer model. The coupling mechanism is as follows: For monochromatic radiance I(Ω; λ), the atmospheric radiative transfer equation is given along the Ω direction through the atmospheric path s containing alumina cluster particles:

[0088]

[0089] Among them, κ ext Let J(λ,Ω) be the extinction coefficient, and J(λ,Ω) be the radiation source function, including local thermal radiation J. em (Ω,λ), direct transmission single-scattered solar irradiance J ss (Ω,λ) and diffuse scattering along the line of sight J ms (Ω,λ). Local thermal radiation J em (Ω,λ) is the product of Planck's blackbody function B(T,λ) and emissivity, the latter being the ratio of absorption coefficient to extinction coefficient (assuming the medium is a blackbody, whose emissivity equals the medium's absorptivity). The second term is the direct-transmission single-scattered solar irradiance J. ss (Ω,λ) represents the solar irradiance F in the upper atmosphere. sun(λ). The last term is the diffuse scattering along the line of sight J. ms (Ω,λ) is the integral of diffuse scattering incident from all directions into the path. The specific definition is as follows:

[0090]

[0091] in It is the absorption coefficient of gas molecules. The existing atmospheric radiative transfer model is Modtran (Moderate Resolution Atmospheric TRANsmission).

[0092] The beneficial effects of this invention are:

[0093] A method for constructing an atmospheric radiative transfer model containing alumina cluster particles is presented. Based on the spatial lifetime of alumina cluster particles, the atmosphere is divided into three layers. The method for calculating the mass loading and number density of alumina cluster particles in each layer is provided, enabling a quantitative description of the spatial distribution of alumina cluster particles. This allows for effective coupling of alumina cluster particles with existing atmospheric radiative transfer models, correcting calculation biases caused by the neglect of aerosol particle absorption and scattering radiation introduced by alumina cluster particles in the atmosphere. The model simultaneously considers the phase state and doping characteristics of heterogeneous alumina cluster particles, more realistically reflecting the physicochemical characteristics of alumina cluster particles in the actual atmosphere, thereby improving the accuracy of calculations related to the optical radiation properties of alumina cluster particles. By coupling the spatial distribution of alumina cluster particles and the heterogeneous alumina cluster particle model considering phase state and doping with existing atmospheric radiative transfer models, an atmospheric radiative transfer model containing alumina cluster particles is constructed, improving the accuracy of atmospheric radiative transfer simulation. Attached Figure Description

[0094] Figure 1 This is a flowchart illustrating the construction of an atmospheric radiative transfer model containing alumina cluster particles according to Embodiment 1 of the present invention.

[0095] Figure 2 This is a flowchart of obtaining the average radiation characteristics of alumina cluster particles according to Embodiment 1 of the present invention;

[0096] Figure 3 This is a schematic diagram of alumina cluster particles obtained through simulation in Embodiment 1 of the present invention;

[0097] Figure 4 This is a schematic diagram of the phase types of alumina cluster particles in Embodiment 1 of the present invention;

[0098] Figure 5 This is a schematic diagram of the alumina cluster particle doping mode in Embodiment 1 of the present invention. Detailed Implementation

[0099] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0100] Example 1

[0101] A method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles, such as... Figure 1 As shown, it includes the following steps:

[0102] Step 1: Quantify the spatial distribution of alumina cluster particles.

[0103] The spatial distribution of alumina cluster particles refers to the determination of the number density of alumina cluster particles in each atmospheric layer by dividing the atmosphere laterally from the ground to the top of the atmosphere; that is, the number of alumina cluster particles per cubic meter of atmosphere in each layer. The method for obtaining this information is as follows:

[0104] The first step is to calculate the emission mass load M of alumina cluster particles in the aircraft exhaust plume. 尾焰 The mass load M of alumina cluster particles emitted by the reentry vehicle 再入 The unit is kg, and the formula is as follows:

[0105]

[0106] Among them, P m The value represents the propellant dose consumed per launch of the spacecraft, in kg; Y represents the annual launch frequency of the spacecraft; ε = 0.06 kg represents the emission index, i.e., the mass of alumina cluster particles released per kilogram of propellant combustion is 0.06 kg; M re Annual reentry volume of spacecraft, in kg, F Al =30% is the percentage of aluminum material in the reentry vehicle, F tran =32% indicates the mass fraction of aluminum oxidized in the reentry vehicle, and ζ =1.24kg conversion index, which means that the mass of aluminum converted into alumina cluster particles is 1.24kg per kilogram of aluminum.

[0107] The second step involves dividing the atmosphere into three layers based on the time alumina cluster particles spend at different altitudes: the lower layer (from the ground to the tropopause, with an altitude of 0–10 km), the middle layer (from the tropopause to the mesotope, with an altitude of 10 km–85 km), and the upper layer (above the mesotope, with an altitude greater than 85 km).

[0108] The mass load of each layer of alumina cluster particles is calculated as follows:

[0109]

[0110] Among them, M 低层 M 中层 M 高层These represent the mass loadings of alumina cluster particles in the lower, middle, and upper layers, respectively; L 低层 =0.34, L 中层 =0.649 and L 高层 =0.22 represent the proportion of propellant combustion in the lower, middle, and upper atmospheres, respectively; These represent the percentage of aluminum material oxidized in the lower, middle, and upper atmospheres of the spacecraft during reentry; τ 低层 =1、τ 中层 =4 and τ 高层 =0.02 represents the time that alumina cluster particles remain in the lower, middle, and upper layers, respectively, in years.

[0111] The third step is to obtain the number density N of alumina cluster particles in each layer. L The formula is as follows:

[0112]

[0113] The density of the alumina cluster particles is ρ = 3.8 g / cm³. 3 L = lower, middle, or upper atmosphere indicates the atmospheric level; V L L represents the volume of the atmosphere, Ns represents the number of monomers in a single alumina cluster particle, n represents the sample size of alumina cluster particles, n is greater than or equal to 1000, and r i R represents the radius of the i-th individual particle in a single cluster, and R represents the effective radius of the alumina cluster particle.

[0114] Step 2: Obtain the average radiation characteristics of alumina cluster particles.

[0115] An improved diffusion-induced condensation model (DLA) was used to simulate alumina cluster particles;

[0116] Configure the phase type and doping type of alumina cluster particles;

[0117] Modeling a non-homogeneous alumina cluster particle model that considers both phase state and doping characteristics;

[0118] The effective refractive index of alumina cluster particles is obtained based on the MG algorithm of the effective medium theory.

[0119] The superimposed T-test algorithm STMM was used to calculate the optical properties of individual alumina cluster particles;

[0120] To obtain the average radiation characteristics of alumina cluster particles;

[0121] Step 3: Based on the spatial distribution and average radiation characteristics of alumina cluster particles, construct an atmospheric radiative transfer model containing alumina cluster particles.

[0122] The construction method refers to:

[0123] The spatial distribution and average radiative properties of alumina cluster particles are coupled into an existing atmospheric radiative transfer model to construct an atmospheric radiative transfer model containing alumina cluster particles. The coupling mechanism is as follows: For monochromatic radiance I(Ω; λ), the atmospheric radiative transfer equation is given along the Ω direction through the atmospheric path s containing alumina cluster particles:

[0124]

[0125] Among them, κ ext Let J(λ,Ω) be the extinction coefficient, and J(λ,Ω) be the radiation source function, including local thermal radiation J. em (Ω,λ), direct transmission single-scattered solar irradiance J ss (Ω,λ) and diffuse scattering along the line of sight J ms (Ω,λ). Local thermal radiation J em (Ω,λ) is the product of Planck's blackbody function B(T,λ) and emissivity at temperature T, the latter being the ratio of the absorption coefficient to the extinction coefficient (assuming the medium is a blackbody, whose emissivity equals the medium's absorptivity). The second term is the direct-transmission single-scattered solar irradiance J. ss (Ω,λ), F sun (λ) is the solar irradiance of the upper atmosphere, τ sun (λ) is the transmittance. The last term is the diffuse scattering along the line of sight, J. ms (Ω,λ) is the integral of diffuse scattering incident from all directions into the path. The specific definition is as follows:

[0126]

[0127] in, and These are the absorption coefficient and scattering coefficient of the alumina cluster particles, respectively. It is the absorption coefficient of gas molecules. Existing atmospheric radiative transfer models include, but are not limited to, Modtran (Moderate resolution atmospheric radiative transfer).

[0128] Figure 2 yes Figure 1 The expansion of step 2, such as Figure 2 As shown, the steps for obtaining the average radiation characteristics of alumina cluster particles include:

[0129] Step 201: Simulate alumina cluster particles.

[0130] Alumina cluster particles were simulated using an improved diffusion-aggregation algorithm (DLA). The fractal structure and morphological description of the alumina cluster particles are as follows:

[0131]

[0132] In the formula, k f It is the pre-fractal factor, Ns is the number of single particles in the cluster, and R g D represents the radius of rotation. f The fractal dimension is represented by 'a', which indicates the average radius of a single particle within the cluster. j r is the distance from the individual particle j to the center point of the cluster particle. i It is the radius of the i-th monomer. The monomer radii of alumina cluster particles follow a log-normal distribution, and its distribution function P(r) is as follows:

[0133]

[0134] In the formula, σ g =1.5nm represents the geometric standard deviation, r g =100nm is the average radius of a single cluster particle. The alumina cluster particles obtained from the simulation are as follows: Figure 3 As shown.

[0135] Step 202: Configure the phase type of alumina cluster particles.

[0136] The phase types of alumina cluster particles refer to: α phase, γ phase, and multiphase state, where the multiphase state simultaneously includes the α phase, γ phase, and liquid phase, such as... Figure 4 As shown.

[0137] Step 203: Configure the doping type of alumina cluster particles.

[0138] The impurities doped with alumina clusters refer to iron, carbon black, aluminum, silver, silicon, air, copper, and magnesium.

[0139] Step 204: Modeling heterogeneous alumina cluster particles that simultaneously consider phase state and doping characteristics. The modeling steps include:

[0140] The first step is to model alumina cluster particles considering different phases. The phase types of alumina cluster particles include: α phase, γ phase, and multiphase. Figure 4 (1), (2), and (3) are monomers of alumina cluster particles in the γ-phase, multiphase, and α-phase states, respectively. Figure 4 (4), (5), and (6) represent alumina cluster particles in the γ-phase, multiphase, and α-phase states, respectively. The multiphase alumina cluster particles consist of three spheres from the outside in, corresponding to the α-phase, γ-phase, and liquid phase, respectively. The calculation steps for the volume percentages of the three phases in the multiphase alumina cluster particles are as follows:

[0141] Based on the dynamic decay equation of the crystallization front of alumina cluster particles

[0142]

[0143] Where a * =0.64×10 -6 m / (sec×K 1.8 ), T m =2289K,T s =2273 represent the melting point and crystallization front temperature of the alumina particles, respectively; relative crystallization front radius. Where r is the particle radius, r liquid Let r be the radius of the liquid state inside the particle. s Let be the radius of the solid portion of the particle. The volume fraction of the α phase (P) is... α It depends on the following equation:

[0144]

[0145] a α and b α It is an empirical coefficient, a α =1.5×10 12 1 / sec,b α =58368K.

[0146] Assume f α ,f γ and f liquid Let f represent the volume fractions of the α phase, γ phase, and liquid phase in the alumina cluster particles, respectively. α +f γ +f liquid =1, and according to formulas (8) and (9), the following equation is obtained:

[0147]

[0148] Volume V of each phase i This can be represented by the following equation:

[0149]

[0150] The alumina cluster particles transform from the high-temperature liquid phase into a solid phase (α / γ phase). According to formula (8), the volume of the solid phase is:

[0151]

[0152] Therefore, the formula for calculating the solid phase radius of alumina cluster particles is as follows:

[0153]

[0154] Combining formulas (8) and (13), we get:

[0155]

[0156] Solve the equations to obtain the volume percentage of each phase in the multiphase alumina cluster particles.

[0157] The second step is to construct a model of alumina cluster particles that takes into account doping. There are three doping modes for alumina cluster particles: the first is the alumina shell type, which refers to alumina encapsulating impurities, such as alumina encapsulating aluminum or air, etc. Figure 5 (a1) and (a2) are schematic diagrams of alumina monomers and corresponding alumina cluster particles encapsulating impurities, respectively; the second type of alumina core refers to impurities encapsulating alumina, such as carbon black, silver, copper, magnesium, and silicon, etc. Figure 5 (b1) and (b2) are schematic diagrams showing alumina monomers and corresponding alumina clusters being encapsulated by impurities, respectively; the third type is a uniform mixture of alumina and impurities, such as... Figure 5 (c1) and (c2) are schematic diagrams showing alumina monomers and corresponding alumina cluster particles uniformly mixed with other impurities.

[0158] The third step is to construct a non-homogeneous alumina cluster particle model that simultaneously considers phase state and doping characteristics.

[0159] The phase characteristics are coupled with the doped alumina cluster particles, meaning that the alumina cluster particles in the doped alumina cluster particles contain phase characteristics.

[0160] Step 205: Obtain the effective refractive index of alumina cluster particles. The method and steps are as follows: (1) Collect the refractive indices of α-phase, γ-phase, and liquid-phase alumina cluster particles and impurities; (2) The effective refractive index of non-homogeneous alumina cluster particles is calculated based on the effective medium theory, which includes but is not limited to Maxwell-Garnett. The method for calculating the effective refractive index using Maxwell-Garnett is as follows:

[0161]

[0162] Where x is the number of matter types embedded in the principal particle, ε h F is the dielectric constant of alumina cluster particles. i and ε i They are respectively the i-th th Volume fraction and dielectric constant of the mixture, ε ef and m ef These are the macroscopic effective dielectric constant and effective refractive index of non-uniform particles.

[0163] Step 206: Couple the model and effective refractive index of the heterogeneous alumina cluster particles with the Superimposed T-matrix Method (STMM) to obtain the optical properties of individual alumina cluster particles, including the extinction efficiency factor Q.ext Scattering efficiency factor Q sca Absorption efficiency factor Q abs Scattering phase function P 11 .

[0164] Step 207: Obtain the average optical properties and average radiation properties of the alumina cluster particles.

[0165] The acquisition steps include:

[0166] The first step is to take the arithmetic mean of the optical properties of n alumina cluster particles to obtain the average optical properties. The average optical properties include the average scattering phase function. Average scattering efficiency factor Average extinction efficiency factor and average absorption efficiency factor

[0167] The second step is to calculate the average radiation characteristics of the alumina cluster particles, which include the scattering phase function. Extinction coefficient Scattering coefficient absorption coefficient The calculation formula is as follows:

[0168]

Claims

1. A method for constructing an atmospheric radiative transfer model containing alumina cluster particles, characterized in that, Includes the following steps: Step 1, quantifying the spatial distribution of alumina cluster particles: Based on the propulsion dose consumed per launch, the annual launch frequency, and emission index, the mass load of alumina cluster particles emitted by the spacecraft's exhaust plume is calculated. Based on the annual reentry volume, the proportion of aluminum material in the reentry vehicle, the mass fraction of oxidized aluminum in the reentry vehicle, and the conversion index, the mass load of alumina cluster particles emitted by the reentry vehicle is calculated. The atmosphere is divided into lower, middle, and upper layers, and the mass load of alumina cluster particles in the lower, middle, and upper layers of the atmosphere is calculated. The number density of alumina cluster particles in the lower, middle, and upper layers of the atmosphere is obtained. Step 2, obtain the average radiation characteristics of alumina cluster particles: Simulate alumina cluster particles, configure the phase type and doping type of alumina cluster particles, and model a non-homogeneous alumina cluster particle model that considers both phase and doping characteristics; obtain the effective refractive index of alumina cluster particles; Optical properties of individual alumina cluster particles; average radiation properties of alumina cluster particles were calculated. Step 3: Construct an atmospheric radiative transfer model containing alumina cluster particles: By coupling the spatial distribution and average radiative properties of alumina cluster particles into existing atmospheric radiative transfer models, an atmospheric radiative transfer model containing alumina cluster particles is obtained.

2. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 1, characterized in that, Step 1 further includes: The first step is to calculate the mass load of alumina cluster particles emitted from the aircraft's exhaust plume and reentry: Based on the propulsion dose P consumed by the spacecraft in each launch m Calculate the mass load M of alumina cluster particles emitted from the aircraft's exhaust plume, based on the aircraft's annual launch frequency Y and emission index ε. 尾焰 Based on the annual number of re-entering spacecraft M re The proportion of aluminum in the reentry vehicle F Al The mass fraction of oxidized aluminum in the reentry vehicle, F tran The conversion index ζ is used to calculate the mass loading M of alumina cluster particles emitted during spacecraft reentry. 再入 The calculation formula is as follows: NOT 尾焰 JP m Yes (1) M 再入 =M re F Al F tran ζ In equation (1), P m M re The units for ε and ζ are kg. ε represents the emission index, which is the mass of alumina cluster particles released per kilogram of propellant combustion. ζ is the conversion index, which represents the mass of alumina cluster particles converted from per kilogram of aluminum after oxidation. The second step is to calculate the mass loading of alumina cluster particles in each layer of the atmosphere: The lower layer is from the ground to the tropopause, the middle layer is from the tropopause to the mesotope, and the upper layer is above the mesotope. Mass loading M of lower-layer alumina cluster particles 低层 The mass loading M of the alumina cluster particles in the middle layer 中层 The mass loading M of high-level alumina cluster particles 高层 The calculation formula is as follows: In equation (2), These represent the percentage of propellant burned in the lower, middle, and upper atmospheres, respectively. These represent the mass percentages of aluminum material oxidized in the lower, middle, and upper layers of the aircraft, respectively; τ 低层 τ 中层 τ 高层 These represent the residence time of alumina cluster particles in the lower, middle, and upper layers, respectively, in years; The third step is to obtain the number density of alumina cluster particles in each layer of the atmosphere: Number density N of alumina cluster particles in each layer L The calculation formula is as follows: In equation (3), ρ represents the density of alumina cluster particles, L represents the atmospheric level, L = lower, middle or upper atmosphere, and V L The volume of the L-level atmosphere is represented by Ns, the number of monomers in a single alumina cluster particle is represented by n, and the number of samples of alumina cluster particles is represented by r. i R represents the radius of the i-th individual particle in a single cluster, and the effective radius of the alumina cluster particle is R.

3. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 2, characterized in that, In step 1, the first step is defined as follows: ε = 0.06 kg, ζ = 1.24 kg, F Al =30%, F tran =32%; In step 1, second step, the lower layer is 0-10km, the middle layer is greater than 10km-85km, and the upper layer is greater than 85km; the proportions of propellant combustion in the lower, middle, and upper layers are respectively: During spacecraft reentry, the mass percentages of aluminum material oxidized in the lower, middle, and upper atmospheres were respectively... The residence times of alumina cluster particles in the lower, middle, and upper layers are τ, respectively. 低层 =1 year, τ 中层 =4 years, τ 高层 =0.02 years; In step 1, third step, the density of the alumina cluster particles is ρ = 3.8 g / cm³. 3 The sample size n of alumina cluster particles is greater than or equal to 1000.

4. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 1, characterized in that, Step 2 further includes: Step 201, Simulating alumina cluster particles: An improved diffusion-induced condensation model (DLA) was used to simulate alumina cluster particles; Step 202, Configure the phase type of alumina cluster particles: The phase types of alumina cluster particles are configured as follows: α phase, γ phase and multiphase, wherein the multiphase includes α phase, γ phase and liquid phase simultaneously; Step 203, Configure the doping type of alumina cluster particles: The impurities doped into the alumina cluster particles are one or more of the following: iron, carbon black, aluminum, silver, silicon, air, copper, and magnesium. Step 204: Model a non-homogeneous alumina cluster particle model that simultaneously considers phase state and doping characteristics: The first step is to model an alumina cluster particle model that considers phase states: The α-phase and γ-phase alumina cluster particles are uniformly distributed; the multiphase alumina cluster particles are composed of three spheres from the outside to the inside, corresponding to the α-phase, γ-phase and liquid phase respectively; the alumina cluster particle model considering the phase type of the configured alumina cluster particles is modeled. The second step is to model a doped alumina cluster particle model: Alumina cluster particle doping modes are classified into alumina shell type, alumina core type, and alumina and impurity uniform mixture type. Alumina shell type, that is, alumina surrounds impurities; alumina core type, that is, impurities surround alumina; alumina and impurities uniformly mixed type, that is, alumina clusters and impurities are uniformly mixed. The third step is to model the alumina cluster particles that simultaneously consider both phase state and doping: By coupling the alumina cluster particle model that considers phase state with the alumina cluster particle model that considers doping, a non-homogeneous alumina cluster particle model that considers both phase state and doping is obtained. Step 205: Obtain the effective refractive index of the alumina cluster particles: The first step is to collect the refractive indices of α-phase, γ-phase, and liquid-phase alumina cluster particles and impurities; The second step is to calculate the effective refractive index of the non-homogeneous alumina cluster particles based on the effective medium theory. Step 206: Obtain the optical properties of individual alumina cluster particles: The optical properties of a single alumina cluster particle are obtained by coupling a non-homogeneous alumina cluster particle model that simultaneously considers phase state and doping characteristics, the effective refractive index of alumina cluster particles, and the superposition T-matrix method (STMM). Step 207: Calculate the average optical and average radiation properties of the alumina cluster particles: The first step is to take the arithmetic mean of the optical properties of n alumina cluster particles to obtain the average optical properties, including the average scattering phase function. Average extinction efficiency factor Average scattering efficiency factor Average absorption efficiency factor The second step is to base the analysis on the average optical properties of alumina cluster particles and the number density N of alumina cluster particles. L The average radiation characteristics of alumina cluster particles were calculated using the effective radius R.

5. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 4, characterized in that, Step 201 further includes: The fractal structure construction and morphological description of alumina cluster particles are as follows: In equation (6), k f It is the pre-fractal factor, Ns is the number of monomers in the alumina cluster particles, and R g D represents the radius of rotation. f The fractal dimension is represented by 'a', which represents the average radius of the monomers in the alumina cluster particles, and 'l' represents the fractal dimension. j r is the distance from monomer j to the center point of the alumina cluster particle. i It is the radius of the i-th unit; The individual radii of alumina cluster particles follow a log-normal distribution, and its distribution function P(r) is as follows: In equation (7), σ g R represents the geometric standard deviation. g It is the average radius of a single particle in the cluster.

6. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 5, characterized in that, In step 201, the geometric standard deviation σ g =1.5nm, average radius r of cluster particle individual g =100nm.

7. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 4, characterized in that, The first step of step 204 further includes: Based on the dynamic decay equation of the crystallization front of alumina cluster particles In the above formula, a * =0.64×10 -6 m / (sec×K 1.8 ), T m =2289K,T s =2273 represent the melting point and crystallization front temperature of the alumina particles, respectively; the relative crystallization front radius r s * =r liquid / r, where r is the particle radius, r liquid Let r be the radius of the liquid state inside the particle. s Let P be the radius of the solid portion of the particle; where P is the volume fraction of the α phase. α It depends on the following equation: In the above formula, a α and b α It is an empirical coefficient, a α =1.5×10 12 1 / sec,b α =58368K; Assume f α ,f γ and f liquid Let f represent the volume fractions of the α-phase, γ-phase, and liquid phase contained in the alumina cluster particles, respectively. α +f γ +f liquid =1, and according to formulas (8) and (9), the following equation is obtained: Volume V of each phase i This can be represented by the following equation: Alumina cluster particles transform from a high-temperature liquid phase to a solid phase, which is either an α-phase or a γ-phase. According to formula (8), the volume of the solid phase is: Therefore, the formula for calculating the solid phase radius of alumina cluster particles is as follows: Combining formulas (8) and (13), we get: Solve the equations to obtain the volume percentage of each phase in the multiphase alumina cluster particles.

8. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 4, characterized in that, Step 205 further includes: The effective refractive index of alumina cluster particles was calculated using the Maxwell-Garnett method, and the formula is as follows: Where x is the number of matter types embedded in the principal particle, ε h F is the dielectric constant of alumina cluster particles. i and ε i They are respectively the i-th th Volume fraction and dielectric constant of the mixture, ε ef and m ef These are the macroscopic effective dielectric constant and effective refractive index of non-uniform particles.

9. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 4, characterized in that, Step 207 further includes: Average radiation characteristics include scattering phase function Extinction coefficient Scattering coefficient absorption coefficient The calculation formula is as follows:

10. The method for constructing an atmospheric radiative transfer model of alumina-containing cluster particles according to claim 1, characterized in that, In step 3 The construction method refers to: The spatial distribution and average radiative properties of alumina cluster particles are coupled into an existing atmospheric radiative transfer model to construct an atmospheric radiative transfer model containing alumina cluster particles. The coupling mechanism is as follows: the atmospheric radiative transfer equation for monochromatic radiance I(Ω; λ) along the Ω direction through the atmospheric path s containing alumina cluster particles is: Among them, κ ext Let J(λ,Ω) be the extinction coefficient, and J(λ,Ω) be the radiation source function, including local thermal radiation J. em (Ω,λ), direct transmission single-scattered solar irradiance J ss (Ω,λ) and diffuse scattering along the line of sight J ms (Ω,λ); Local thermal radiation J em (Ω,λ) is the product of Planck's blackbody function B(T,λ) and emissivity at temperature T, the latter being the ratio of the absorption coefficient to the extinction coefficient (assuming the medium is a blackbody, whose emissivity equals the medium's absorptivity); the second term is the direct transmission single-scattered solar irradiance J. ss (Ω,λ), F sun (λ) is the solar irradiance of the upper atmosphere, τ sun (λ) is the transmittance; the last term is the diffuse scattering along the line of sight, J. ms (Ω,λ) is the integral of diffuse scattering incident from all directions into the path; specifically defined as follows: in, and These are the absorption coefficient and scattering coefficient of alumina cluster particles, respectively. It is the absorption coefficient of gas molecules; the existing atmospheric radiative transfer model is Modtran (Moderate resolution atmospheric TRANsmission).

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