Effect of a sudden change in cross-sectional area of the solid rocket motor duct on coagulation of condensed particles

Results of numerical simulations are reported for two-phase flows with allowance for coagulation and fragmentation of particles of polydisperse condensate in the combustor duct of the solid rocket motor (SRM) with a sudden change in cross-sectional area typical of solid-propellant charges of a complex shape. It is shown that a sudden change in cross-sectional area can lead to a significant (multiple) coagulation-induced increase in the mean particle size. The calculation results are validated by a test series on a model SRM with the use of a laser system for diagnosing particle dispersion.