CN-122021437-A - Vacuum plume infrared radiation rapid calculation method

CN122021437ACN 122021437 ACN122021437 ACN 122021437ACN-122021437-A

Abstract

The invention belongs to the technical field of physics and infrared radiation simulation, and particularly relates to a vacuum plume infrared radiation rapid calculation method which comprises the following steps of S1, generating a discrete lattice covering a calculation domain according to an input calculation domain geometric parameter, S2, carrying out weighted average on initial parameters of components at a nozzle to obtain equivalent mixed gas parameters at the nozzle, S3, solving based on an incoming flow-plume collision model to obtain equivalent particle source positions under the influence of the incoming flow, S4, utilizing a vacuum plume engineering calculation model and combining a numerical integration algorithm to carry out solving to obtain microscopic flow field parameter distribution of the component gases on the discrete lattice, S5, obtaining the overall flow field distribution of the vacuum plume of the whole calculation domain, S6, adopting an apparent ray method to solve the problems that the calculation flow of the conventional vacuum plume flow field is complex and time-consuming, and cannot cover the whole flow from the generation of the plume flow field to the infrared radiation transmission.

Inventors

NIU QINGLIN
YUAN YOUHONG
GAO WENQIANG
REN DONGDONG
WANG HONGLI
ZHANG PENGJUN

Assignees

中北大学

Dates

Publication Date: 20260512
Application Date: 20260131

Claims (9)

1. A vacuum plume infrared radiation rapid calculation method is characterized by comprising the following steps: s1, generating a discrete lattice covering a calculation domain by adopting a variable-spacing method according to an input calculation domain geometric parameter; S2, carrying out weighted average on initial parameters of all components at the nozzle to obtain equivalent mixed gas parameters at the nozzle; S3, solving each point in the discrete lattice based on an incoming flow-plume collision model to obtain an equivalent particle source position under the influence of the incoming flow; S4, based on the equivalent mixed gas parameters and the equivalent particle source positions, solving by utilizing a vacuum plume engineering calculation model and combining a numerical integration algorithm to obtain microscopic flow field parameter distribution of each component gas on the discrete lattice; S5, carrying out weighted average on microcosmic flow field parameters of each component gas corresponding to each point on the discrete lattice based on the number density to obtain macroscopic overall flow field parameters of the point, thereby obtaining the overall flow field distribution of the vacuum plume of the whole calculation domain; and S6, calculating radiation physical parameters by adopting a statistical narrow band model based on the vacuum plume overall flow field distribution, and solving a radiation transmission equation by adopting an apparent ray method to obtain the spectrum radiation intensity in the observation direction.
2. The method of claim 1, wherein in step S1, the variable pitch method is an arithmetic series variable pitch method for generating non-uniformly distributed discrete point coordinates along the length and width directions respectively in a rectangular calculation domain.
3. The method for rapidly calculating vacuum plume infrared radiation according to claim 1, wherein in the step S2, the weighted average comprises weighting the gas constants of the components based on the mole fractions of the components to obtain equivalent gas constants in the equivalent mixed gas parameters, and summing the mass flow rates of the components to obtain the total point source intensity of the nozzle.
4. The method of claim 1, wherein in step S4, the numerical integration algorithm is Gaussian-Legendre integration algorithm.
5. The method of claim 1, wherein in step S5, the macroscopic total flow field parameters include pressure, density, velocity, and mole fractions of each component.
6. The method of claim 1, wherein in step S5, the weighted average based on the number density is calculated by weighted average of the micro-feature values of the macro-scale flow field parameters of each component gas corresponding to any point on the discrete lattice according to the number density of each component.
7. The method for rapidly calculating vacuum plume infrared radiation according to claim 1, wherein in step S6, the statistical narrow band model is Malkmus model for calculating average transmittance in a narrow band, the average transmittance is calculated by average spectral line half-width and average absorption coefficient in a band, and the average spectral line half-width and average absorption coefficient in a band are determined by the macroscopic overall flow field parameter.
8. The method of claim 6, wherein the average spectral line half-width is determined by empirical relationship based on total pressure, temperature and mole fraction of critical gas components of the flow field.
9. The method for rapidly calculating infrared radiation of vacuum plume according to claim 1, wherein in step S6, the apparent ray method comprises the following specific steps: (a) A two-dimensional axisymmetric flow field constructed based on the distribution of the vacuum plume overall flow field is rotationally expanded around a symmetry axis to form a three-dimensional cylindrical flow field; (b) Setting a group of rays parallel to the observation direction to pass through the three-dimensional cylindrical flow field, and dividing a medium area through which each ray passes into a plurality of layers along a path; (c) Parameters in the overall flow field distribution of the vacuum plumes are endowed to each layer of medium by an interpolation method, and the medium in the same layer is assumed to be uniform; (d) And combining the radiation physical parameters, solving a radiation transmission equation in a layering way, and accumulating to obtain the spectrum radiation intensity along each ray.

Description

Vacuum plume infrared radiation rapid calculation method Technical Field The invention belongs to the technical field of physics and infrared radiation simulation, and particularly relates to a vacuum plume infrared radiation rapid calculation method. Background The attitude control or orbit control engine is often used as a power device of the space-based aircraft. The high-temperature and high-speed fuel gas generated by the operation of the engine is accelerated by the spray pipe and then is sprayed into the high-altitude or vacuum environment at supersonic speed. In particular, for the height above 150 km, the molecular number density of the atmosphere is extremely low, the molecular free path is above 10 1 m, and engine fuel gas forms a feather-like highly underexpanded free jet in the environment. The vacuum plume generally contains diatomic and polyatomic gas components such as CO 2、CO、H2 O, which emit infrared radiation of a specific wave band due to the transition of vibration at high temperature, and becomes a radiation source of great concern for DTCI. At present, the vacuum plume is usually simulated by adopting a direct simulation Monte Carlo method (DSMC), however, the DSMC method is extremely time-consuming in calculation, is unfavorable for the rapid calculation of the vacuum plume, and is difficult to meet the real-time, efficient and massive sample calculation requirements in engineering application. Therefore, developing a method for rapidly estimating the infrared radiation characteristics of the vacuum plume, which can achieve both the calculation efficiency and the estimation accuracy, has become a key technical problem to be solved in the art. Disclosure of Invention The invention provides a vacuum plume infrared radiation rapid calculation method, which aims to solve the problems that the existing vacuum plume flow field calculation flow is complex, time is long, and the whole flow from plume flow field generation to infrared radiation transmission cannot be covered. The invention is realized by adopting the following technical scheme: A vacuum plume infrared radiation rapid calculation method comprises the following steps: s1, generating a discrete lattice covering a calculation domain by adopting a variable-spacing method according to an input calculation domain geometric parameter; S2, carrying out weighted average on initial parameters of all components at the nozzle to obtain equivalent mixed gas parameters at the nozzle; S3, solving each point in the discrete lattice based on an incoming flow-plume collision model to obtain an equivalent particle source position under the influence of the incoming flow; S4, based on the equivalent mixed gas parameters and the equivalent particle source positions, solving by utilizing a vacuum plume engineering calculation model and combining a numerical integration algorithm to obtain microscopic flow field parameter distribution of each component gas on the discrete lattice; S5, carrying out weighted average on microcosmic flow field parameters of each component gas corresponding to each point on the discrete lattice based on the number density to obtain macroscopic overall flow field parameters of the point, thereby obtaining the overall flow field distribution of the vacuum plume of the whole calculation domain; and S6, calculating radiation physical parameters by adopting a statistical narrow band model based on the vacuum plume overall flow field distribution, and solving a radiation transmission equation by adopting an apparent ray method to obtain the spectrum radiation intensity in the observation direction. Further, in step S1, the pitch-varying method is an arithmetic progression pitch-varying method, which is used to generate non-uniformly distributed discrete point coordinates along the length and width directions, respectively, in a rectangular calculation domain. Further, in step S2, the weighted average comprises the steps of weighting the gas constants of the components based on the mole fractions of the components to obtain equivalent gas constants in the equivalent mixed gas parameters, and summing the mass flow rates of the components to obtain the total point source intensity of the nozzle. Further, in step S4, the numerical integration algorithm is a gaussian-legendre integration algorithm. Further, in step S5, the macroscopic overall flow field parameters include pressure, density, velocity, and mole fractions of the components. Further, in step S5, the weighted average based on the number density refers to that for any point on the discrete lattice, any macroscopic overall flow field parameter value of the point is obtained by performing weighted average calculation on the microscopic feature quantity of the parameter of each component gas corresponding to the point according to the number density of each component. Further, in step S6, the statistical narrow band model is Malkmus model, and is used for calculating averag