While certain propellant gels exhibit similar spraying behavior to liquid propellants in many areas, others can show completely different spraying patterns.
Gelled propellants are produced from liquid propellants with the addition of gelling agents. They are solid at rest, for example in a tank, and become flowable under the influence of shear stress, as can be generated in suitable injectors. This special property makes it possible for gel propellants to combine the advantages of liquid propellants, such as compact combustion chambers and controllability, with those of solid propellants, such as easier storage and the possibility of adding solid substances. Extensive research is being carried out to develop efficient drives with such advantages. Rheological and physical properties of gel propellants such as viscosity and surface tension are determined in the physical-chemical laboratory. Due to their special properties, fuel preparation (spraying or injection) in the combustion chamber can differ significantly from that of conventional liquid fuels. While certain fuel gels exhibit similar spraying behavior to liquid propellants over a wide range, others can show completely different spraying patterns.
The conversion of gelled propellants is investigated within modular model combustion chambers on the M11 research test facility. The data obtained here makes it possible to determine suitable combustion chamber processes and assess the performance of such propulsions.
