Multisized Inert Particle Loading for Solid Rocket Axial Combustion Instability Suppression

Abstract

In the present investigation, various factors and trends, related to the usage of two or more sets of inert particles comprised of the same material (nominally aluminum) but at different diameters for the suppression of axial shock wave development, are numerically predicted for a composite-propellant cylindrical-grain solid rocket motor. The limit pressure wave magnitudes at a later reference time in a given pulsed firing simulation run are collected for a series of runs at different particle sizes and loading distributions and mapped onto corresponding attenuation trend charts. The inert particles’ presence in the central core flow is demonstrated to be an effective means of instability symptom suppression, in correlating with past experimental successes in the usage of particles. However, the predicted results of this study suggest that one needs to be careful when selecting more than one size of particle for a given motor application.

Experimental and theoretical study of iron and mild steel combustion in oxygen flows

“…It is seen that stainless steel requires about 1.5 more energy than iron to ignite. This is because of the much higher temperature required to melt the protective oxide layer (Cr 2 O 3 , T m = 2708 K) [though the thermal diffusivity of stainless steel is several times lower than that of iron at room temperature, the difference is much smaller at higher temperatures relevant to ignition, and the effect of the factor (T m − T 0 ) 2 in Eq. (4) overrides that of the χ-factor].…”

“…The research has been focused primarily on the propulsion technologies which use metallic particles as high-energy additives in propellants to increase the specific impulses and combustion stability of solid rocket motors. 1, 2 The refractory nature of combustion products, on the other hand, has been exploited to synthesize a wide range of materials, including (nano) powders, intermetallics, composites, and functionally graded materials. [3][4][5][6][7] Many important results have been obtained in these directions which are still subjects of ongoing intensive experimental and theoretical studies.…”

Optimum Disposition of Metal Particles in the Propellant Grain

“…Increasing the energy efficiency of propulsion is an important task of designing solid rocket motors (SRM), one of the component parts of which is the creation of a propellant with the high specific impulse [1]. Composite solid propellants are currently widely used in SRM, which contain aluminium, magnesium, and other metals as fuel additives to increase the specific impulse and combustion stability [2].…”