Condensed Products of Combustion of Boron-Based Solid Propellants

Condensed combustion products of model propellants based on aluminum boride in the combustion chamber of the gas generator of a ducted rocket engine have been studied. The mass fraction of the condensed combustion products, their chemical composition, and their particle size distribution have been determined. It has been demonstrated that the condensed combustion products mainly contain boron compounds with carbon, nitrogen, and oxygen, and it is in this form that boron enters the secondary combustion chamber of the ducted rocket engine. The mass fraction of elemental boron in the condensed combustion products does not exceed 15% and decreases with increasing pressure. It has been found that, regardless of the types and contents of the major components of the model propellants, there are no large (more than 100 μm in size) particle conglomerates at the outlet of the gas-generator nozzle. A comparison of the experimental data with the results of thermodynamic calculations indicates that the calculation methods should be corrected for the nonequilibrium of the combustion products.