Rheological Matching of Gel Propellants

SIGNIFICANT effort has been undertaken by several research groups worldwide over the past decades to study various aspects of gel propellants. The principal objective of these basic studies is to realize a flexible energy-management propulsion system, which assures insensitive munitions compliance. In addition, their increased energy density, when metal particles are introduced in the gel matrix, in comparison to neat-liquid propellants presents a significant potential advantage. The non-Newtonian complex rheological character of these propellants and the resulting system-level implications make their use in operational rocket engines very challenging. Nevertheless, their potentially full pulse-width-modulation capabilities, combined with the ability for divert and attitude control system application, make them attractive for future rocket propulsion systems in both tactical and space applications. Key aspects of gel-propulsion technology, propellant preparation, rheology, atomization, and combustion are presented in an extensive review by Natan and Rahimi. A general rheological classification of gel propellants and simulants has been proposed in a recent study on the shear rheology of gel propellants.