Study On Primary Combustion Of Boron-based Fuel-rich Propellant

In-depth researches on primary combustion of boron-based fuel-rich propellant containing 30% boron were completed on the base of experiments and theoretical analysis, establishing a basis for application on item of missiles.(1) The combustion mechanism of boron-based fuel-rich propellant was studied. The condensed combustion mechanism was studied by analyzed of surface appearance with SEM and pyrocellulose actions of compounds such as HTPB, AP, AP/HTPB, B/HTPB, B/AP, B/AP/HTPB with thermal analysis of DSC and TG; The gaseous phase was studied by analyzed of the flame structure with photo technique and the combustion wave temperature profiles with micro-thermocouple. The steady combustion model was established on the basis of BDP combustion model. The formula of combustion velocity was obtained.(2) The influences of some factors to combustion properties of boron-based fuel-rich propellant were studied. The influences of formulation of propellant to combustion properties were analyzed using the results of combustion velocity and pressure exponent by strand burner. The boron-based fuel-rich propellant was obtained, which pressure exponent is 0.42, and combustion velocity is 6.75mm/s at l.OMPa.(3) Agglomerations of boron in process of combustion of propellant were studied. The process of agglomerate of boron was researched by SEM analysis. The result showed that, the spherical agglomerations of boron was formed by aggregation of (BO)_n,which was obtained by the actions between B and B₂O₃.(4) The influences of some factors to eject efficiency of primary combustion of boron-based fuel-rich propellant were studied. The influences of combustion velocity, primary combustion temperature, radius of boron aggregations, pressure, ratio of Ab to Ap and structure of eject to eject efficiency were analyzed by gas generator. The eject efficiency can improve to 97% as the content of B is 30%.(5) Pilot research on after burning of propellant was studied. The influences of flux and temperature of inlet air to after burning efficiency was studied.The after burning efficiency can reach to 80.2% when the content of boron was 28% by adopting appropriate formulation of propellant.