Are All Solid Propellant Burning Rate Modifiers Catalysts?

Abstract

Solid rocket motors are used for both national defense and launch vehicles. The internal ballistics of the motor depend on the propellant burning rate, which is often modified by burning rate enhancers. Despite the common use, there is not a complete mechanistic understanding of how these modifiers influence the combustion process. In this comment, it is argued that these additives can influence propellant combustion as a catalyst, via thermodynamic means, or a combination. An approach is suggested on how to classify traditional and novel burning rate modifiers as a first step to improving the scientific community's knowledge on the matter.

Accounting for super-, plateau- and mesa-rate burning by lead and copper-based ballistic modifiers in double-base propellants: a computational study

“…1(a). In order to counteract this effect, ballistic modifiers (also known as burn rate catalysts) 4 are added to the propellant system, which alter the burning behaviour of the propellant in three distinct ways. 5 First, in the low-pressure range it enhances combustion, in a process termed super-rate burning, where typically 0.8 < n < 2.0.…”

Macrocycle as a “Container” for Dinitramide Salts

“…However, when tested as a burning-rate modifier, it showed very good positive results towards the inhibition of the burning rate of pyrotechnic compositions, which is typical of high-nitrogen compounds [ 18 , 19 ]. The modifier is employed to adjust and control the burning rate of various energy-rich compositions (gun propellants, СРТТ, pyrotechnic compositions) in order to achieve the required parameters without the need for total re-formulation, which is essential in some cases for pyrotechnic compositions and solid propellants to burn stably [ 20 , 21 ]. Additionally, effective inhibitors can act as flame-extinguishing agents, which are important for fire- fighting in coal mines.…”