Scattering properties of alumina particle clusters with different radius of monomers in aerocraft plume

- Diffusion limited aggregation algorithm is improved to generate the alumina particle cluster with different radius of monomers in the plume.
- Based on multi-sphere T matrix method, the effect of the number and radius of monomers on the scattering properties of the alumina particle clusters with different radius of monomers is discussed.
- The scattering properties of two types of alumina particle clusters are compared, one's radius follows lognormal probability distribution, another radius equals the mean of lognormal probability distribution.

In this paper, diffusion limited aggregation (DLA) algorithm is improved to generate the alumina particle cluster with different radius of monomers in the plume. Scattering properties of these alumina clusters are solved by the multiple sphere T matrix method (MSTM). The effect of the number and radius of monomers on the scattering properties of clusters of alumina particles is discussed. The scattering properties of two types of alumina particle clusters are compared, one has different radius of monomers that follows lognormal probability distribution, another has the same radius of monomers that equals the mean of lognormal probability distribution. The result show that the scattering phase functions and linear polarization degrees of these two types of alumina particle clusters are of great differences. For the alumina clusters with different radius of monomers, the forward scatterings are bigger and the linear polarization degree has multiple peaks. Moreover, the vary of their scattering properties do not have strong correlative with the change of number of monomers. For larger booster motors, 25-38% of the plume being condensed alumina. The alumina can scatter radiation from other sources present in the plume and effect on radiation transfer characteristics of plume. In addition, the shape, size distribution and refractive index of the particles in the plume are estimated by linear polarization degree. Therefore, accurate scattering properties calculation is very important to decrease the deviation in the related research.