A numerical model of a multicomponent gas-aerosol medium designed for studying the transmission function in the visual and IR ranges has been proposed. Taking into account the molecular absorption by the gas component and also the light scattering and absorption by the aerosol, the radiation extinction is determined. To calculate the optical characteristics of a dispersed component, the Mie theory is applied. Methane is selected as the main gas component of the medium. The separate and combined contributions of molecular absorption and aerosol extinction to the transmission of optical radiation by a gas-aerosol medium are analyzed.
The analysis of the calculation results of extinction coefficient, scattering coefficient, and absorption coefficient of aerosol, as well as transmission function under the joint and separate impact of components of mixture containing trioxide dialuminum was carried out. The spectral features of the optical characteristics of the medium at various parameters of particle size distribution function were illustrated.
Calculated absorption spectra of the mixture of gases (H<sub>2</sub>O, CO, CO<sub>2</sub>, NO, NO<sub>2</sub>, and SO<sub>2</sub>) and aerosol (soot and Al<sub>2</sub>O<sub>3</sub>), contained in the exhausts of aircraft and rocket engines are demonstrated. Based on the model of gas-aerosol medium, a numerical study of the spectral dependence of the absorptance for different ratios of gas and aerosol components was carried out. The influence of microphysical and optical properties of the components of the mixture on the spectral features of absorption of gas-aerosol medium was established.
In this work, a numerical study of the transmission function, extinction coefficient, scattering coefficient, and absorption coefficient of the aerosol generated by the jet engine emissions was performed. Analyzing the calculation results of the IR optical characteristics of anthropogenic emissions containing the dialuminum trioxide was carried out. The spectral features of the optical characteristics of the medium caused by the average size, concentration and complex refractive index of the particles were illustrated.