Estimation of Radiative and Scattering Characteristics of Sodium Aerosols Using Inverse Analysis

点击翻译按钮获取中文摘要

Estimation method is studied for complex index of refraction of aerosol generated by sodium fire. In the present study, non-gray radiative transfer analysis is carried out to simulate the radiative transmission through uniformly distributed dispersed aerosol layer for given values of complex index of refraction considering multiple scattering. The Monte Carlo method is used for the analysis.Using the program, several sets of contour curves of the transmittance of aerosol layer are obtained at several positions on the wall situated opposite to the black body furnace for a wide range of complex index of refraction of the aerosol. The transmittance is obtained for the radiation emitted from a black body furnace. The complex index of refraction of the aerosol is estimated by comparing the value of the transmittance obtained by experiment with the contour curves of transmittance obtained by analysis.The experiment to obtain transmittance of aerosol layer is carried out using magnesium oxide aerosol, whose spectral complex index of refraction is well known. The aerosol is generated by igniting magnesium ribbon, and is fed by air flow to duct with a rectangular cross section. The particle size distribution of the generated aerosol is measured by a microscope with a magnifying power of 3000. The mass concentration of the aerosol is measured by weighting the paper filter set at the end of the duct. Radiative transmittance of the aerosol layer flowing through the duct is measured using a radiation meter set opposite to a black body furnace.From the comparison of the results of the experiment and the contour curves by analysis, the complex index of refraction of magnesium oxide is estimated with good accuracy. From the result, it is concluded that the value of complex index of refraction of aerosol can be estimated by the present method.