Study On Ultraviolet Radiation Transmission Characteristics Of Aircraft Plume Based On Monte Carlo Method

With the rapid development of hypersonic vehicles,the early warning and detection of the aircraft's plume has become the focus of various military powers.In this paper,the ultraviolet radiation transmission characteristics of the hypersonic vehicle in the ascending stage are studied based on the Monte Carlo method.In this paper,about the Monte Carlo random number generator,a new type of linear combination generator is proposed on the basis of a generalized feedback register generato r and a parabolic map generator.After a series of statistical tests such as parameters,uniformity,and independence;the test results show that the combination generator has better statistical properties than two independent generators.Then,in the Monte Carlo solution of transport equations,the problem of photon number truncation is discussed in terms of optical thickness,asymmetry factor and single-scattering albedo.It is concluded that the optical thickness of the medium is the main factor,and according to the different optical thickness of the medium,the photon number in the Monte Carlo solution is divided into intervals.This article focuses on the research work on both the UV radiation of aircraft plume and the ultraviolet atmospheric transport.When calculating the c haracteristics of the UV radiation of aircraft plume,two main UV radiation sources,the thermal radiatio n of particles and the CO chemical fluorescence radiation,are firstly described.Then the proportion of the two radiation sources and the particle size distribution of aluminum oxide are discussed using the spherical harmonic discrete coordinate method.Finally,the radiance curve of the aircraft plume in the radial and different observation angles is given.When calculating the characteristics of atmospheric transmission,the multi-layered Monte Carlo method was first validated with Modtran software for atmospheric transmission.Then a multi-layered Monte Carlo simulation is performed based on the ozone data of Kunming,Lhasa,and Antarctica Zhongshan Station.Compared with the low latitude area,the high latitude area has the lowest atmospheric ultraviolet transmittance at 20-25 km.Finally,using multi-layered Monte Carlo method,the variation of the rad iant intensity of the aircraft plume with the transmission distance at different observation angles of different heights is solved.In summary,the calculation results in this paper provide a reference for the early warning and detection of hypersonic targets.