Study of High-Enthalpy Electrothermal Energetic Plasma Source Concept

The electrothermal (ET) energetic plasma source (ETEPS) is a different concept in which the ablation mechanism is forced inside of the open-ended capillary that has energetic liner, a propellant. The generation of the ET plasma results from Joule heating and radiant heat transport to the liner. The discharge initiates erosive burn of the propellant, and the mixed plasma-propellant gasification produces high-enthalpy energetic flow. In the ablation-dominated source, the eroded materials from the solid propellant liner are mixed inside the source before they flow out as a result of the large pressure gradient. The energetic ET source also has another concept in which no ablation occurs and the plasma is generated from the injection of energetic gasses or liquids into the confined open-ended capillary. The ablation-free source generates the plasma from the dissociation of the gaseous/liquid components, which in turn releases the chemical energy of these propellants and mixes the energy with the electrical energy of the plasma. This concept is different from ET chemical (ETC) sources; it generates the propellant or energetic flow without requiring a combustion chamber. It also provides mixing at the ionic level not available in current configurations of ETC launchers, igniters, or thrusters. The ET plasma code ETFLOW-EN was developed to computationally simulate the plasma generation and flow in energetic ET capillary discharges to predict the behavior of the energetic source with the use of lined solid propellants. Operation with liquid/gaseous energetic forms in a nonablative capillary is also a character of this concept and is part of the ETFLOW code. The results of using different forms of energetic materials in solid, liquid, and gaseous mixtures have shown the applicability of ETEPS to produce high-enthalpy energetic plasma flows with sufficient parameters suitable for ETC launch applications. Plasma and flow parameters at the capillary exit were investigated at different mixing ratios.