Dynamics Modulation of Combustion of SHS Reaction via Electromagnetic Stimulation

Energetic materials are a type of material that has chemical energy stored in them, and they can be released through external stimulation. As one of the energetic materials, solid propellants have many attractive properties such as high energy density, safety to transport and handle. In this work, we are trying to modulate combustion of solid propellants using microwave energy. Compared with laser energy that mainly concentrates on the surface of the propellants. Microwave can penetrate propellants' surfaces and achieve volumetric heating if the propellant is microwave sensitive. However, microwave stimulation can also heat the ionized gas species generated during combustion and cause discharge [1]. This can affect the initial combustion reaction that we are targeting. To overcome this disadvantage, the self-propagating high-temperature synthesis (SHS) system is used in this experiment. By mixing a light metal and a transition metal, SHS system can react exothermically without gas generation [2]. The propellant was prepared by ball milling the molar ratio of 2Al/1.2Zr/1C and direct printing the composites. The reaction was started by joule heating, and a monopole antenna was used to enhance the reaction during propagation by applying microwave power at 2.45 GHz. A color camera and an infrared camera were synced and recorded the reaction process. The preliminary results show that the composites are microwave sensitive, and the propellant can absorb microwave energy. And the propagation speed can be increased up to 200% with maximum microwave power intensity applied. We hope to build a pathway of combustion modulation vis microwave enhancement through this experiment.