ADVANTAGES AND DRAWBACKS OF BORON-FUELED PROPULSION

The theoretical energetic advantages and the practical problems and characteristics associated with three modes of ramjet-type propulsion systems are discussed. It is shown that the use of boron may result in a remarkable theoretical energetic gain compared with hydrocarbon fuels, especially in volume limited systems, However, the poor combustion characteristics of boron and the high ignition temperature required (1900 K), impose special constraints on the combustor system in order to obtain high efficiencies. Solid fuels and propellants containing a high percentage of boron tend to exhibit irregular combustion, which may cause thrust modulation, while agglomeration of boron particles may result in incomplete combustion due to the insufficient residence time in the combustor.