Performance calculations for solid propellant ramrockets

The paper investigates the influence of propellant composition, fuel, oxidizer, and binder content on ducted rocket performance as well as the influence of primary chamber fuel to oxidizer ratio and secondary chamber fuel to air ratio. Also the influence of some geometric and flight parameters like air inlet angle, inlet cross-section and flight Mach number can be treated. Primary and secondary combustion chamber reaction products composition and temperatures are computed, too. A simple model of a solid propellant ramrocket based on chemical equilibrium thermodynamics is developed by dividing the ducted rocket is into seven sections. These are characteristic for flight conditions like flight Mach number, flight velocity and atmospheric conditions, exit conditions of the air inlets, gas generator nozzle exit conditions, secondary combustion chamber conditions and the corresponding secondary combustion chamber nozzle throat and exit conditions. The results show the appearance of large amounts of C(gr) and hydrogen together with metal oxides and metal carbides in the exhaust gas of the primary combustor. The results also show that there is a second maximum in the dependence of primary chamber combustion temperature on fuel to air ratio. The flight range was up to 40 percent higher for propellants which contained high energy ingredients like boron and cubane as compared to a non-metallized propellant based on HTPB for a sea level mission.