Study On Measurement Method Of Spectral Absorption Coefficient And Scattering Phase Function Of Particle Suspension

The parameters of the radiation properties of the particle suspensions are the basic calculation parameters for the solution of the radiative transfer equation.Obtaining highly accurate parameters of the radiation properties of particle suspensions is important for analyzing the distribution of light in the medium.Some methods have been developed to solve the radiative properties of particles based on electromagnetic scattering theory such as Mie theory,T-matrix,generalized Mie theory GMM.The electromagnetic scattering theory requires the particles to be homogeneous spherical particles or multilayer spherical particles,which is a high limitation.In nature and industrial production,the shape,structure and size of the particles are often not spherical or sphere-like with a uniform texture,and these factors will affect the radiation properties of the particles.It is due to the complexity and uncertainty of particle shape and internal structure that the methods of theoretical research are difficult to provide accurate data for practical engineering problems.In terms of experimental measurement methods for radiation property parameters of particle suspensions,the effect of particle-to-particle scattering and the refraction of the cuvette glass container will cause large errors in the experimental measurements of radiation properties of particle suspensions.Therefore,the experimental measurement method of the radiation property parameters of particle suspensions needs to be further investigated.Improved experimental measurement methods for the radiometric properties of particle suspensions will help improve the accuracy of the measurements.Only by obtaining highly accurate parameters of the radiation properties of granular suspensions can we better develop the application of granular suspensions in several fields.This paper presents an improved method for the measurement of spectral absorption coefficients and scattering phase functions of particle suspensions.Establishing an experimental system by analyzing the factors affecting measurement accuracy.Standard particle of silica with known complex refractive index and particle size distribution is selected as the experimental sample,and the experimental value of scattered light is obtained by experimental measurement.The experimental value of scattered light is obtained by experimental measurement,normalized and compared with the theoretical value of Mie to obtain the scattered light correction coefficient.The scattering phase functions of other particles are corrected with this correction factor and verified against the Mie theoretical values.In the 400nm-900 nm spectral range,development of a mathematical calculation model capable of eliminating the effects of multiple refraction and reflection at the cuvette glass interface.Standard particle samples with known refractive index and particle size distribution were measured by a three-layer dielectric tracking system.Experimental data such as the experimentally measured normal hemisphere transmittance are substituted into the mathematical calculation model to obtain the spectral absorption coefficients of the particles,and are compared with the conventional integrating sphere measurement method as well as the Mie theory for verification.The results show that the improved method of scattering phase function measurement for particle suspensions can significantly improve the measurement accuracy of the scattering phase function and is in high agreement with the theoretical value of Mie.When the particle size parameter is greater than 10,the correction factor can be regarded as a constant.The use of a standard particle with a diameter of 2.53 ?m as a reference system can be used to correct the scattering phase function of any unknown particle(size parameter >10).It is worth noting that using similar sized particles as a reference system provides more reliable results.The spectral absorption coefficients obtained by the improved method of measuring the spectral absorption coefficients of particle suspensions are in good agreement with the theoretical values of Mie.Significant improvement in the accuracy of the spectral absorption coefficients obtained compared to traditional integrating sphere measurement methods.The method is applicable to the measurement of spectral absorption coefficients of particle suspensions of different types,concentrations and particle sizes.The research has important practical engineering implications for the study of the radiation properties of granular suspensions...