Analysis of UV radiation of solid rocket plume containing multiphase alumina clusters

Alumina particles, ejected from rocket nozzles, undergo dynamic crystallization, resulting in multiphase clusters in the rocket plume. These multiphase alumina (MA) clusters exhibit significantly different optical properties compared to stable-phase alumina studied in previous research, inevitably affecting the radiative characteristics of the plume. However, research in this area remains sparse. To address this, a plume radiation model incorporating multiphase alumina was proposed to analyze the UV radiation characteristics of the solid rocket plume containing multiphase alumina clusters. The line-by-line integration method was used to solve the absorption coefficient of OH molecules, and super position T-matrix method and the statistical average optical algorithm were utilized to obtain the optical properties of alumina clusters. The results indicate that, if the presence of multiphase alumina clusters is ignored, the radiance of plumes will be underestimated by 41.3 % in our study. The thermal radiation and scattering of alumina clusters can increase the UV radiation of plume, and the magnitude of such enhancement is affected by the phase state of alumina. Although our study used simplified cluster models due to the lack of precise data for each alumina cluster in the plume, it emphasizes the importance of alumina’s phase state in plume radiation studies. The findings offer a new theoretical foundation for aircraft detection and identification.