Workshop report: boron hydrides in very high burning rate (VHBR) applications

Combustion Mechanisms of Very High Burn Rate (VHBR) Propellant. Phase II.

“…Another study [171 reported data which showed that a change in density of 12% could change the bum rate by a factor of 20. to be more sensitive to external stimuli than formulations with other binder systems. This may be due to some sort of incompatibility between the nitrocellulose binder and the boron hydride salt [3].…”

“…While a number of different propellant formulations may exhibit bum rates with magnitudes sufficient to qualify as VHBR propellants [4,8] Since 1981, this class of propellants has been the subject of two Joint Army-Navy-NASA-Air Force (JANNAF) workshops [3,4]. It is the objective of this section to summarize the large quantity of work which has been aimed at the study of VHBR propellant combustion.…”

“…These efforts have included examination of the pyrolysis reactions of entire VHBR propellant formulations, including the binder materials. The discussion following the 1986 JANNAF Workshop [3] provides an excellent overview of the variables influencing combustion rate of VHBR propellants. This section briefly summarizes the results of that discussion.…”

“…There are a number of potential applications for propellants with bum rates of this magnitude. These applications include such advanced ballistic concepts as the traveling charge and monolithic propellants, as well as rocket propellant and ram jet fuels [3].…”

“…VHBR propellants have been defined [3,4] as those which possess "apparent" bum rates which are in the range of approximately 1 to 1,000 m/s. The bounds of this range were selected so that this bum regime falls intermediately between the standard propellant bum regime (0.1 to 50 cm/s) and the detonation regime (2 to 10 krn/s).…”