BEHAVIOR OF A WORKING FLUID IN AN ELECTROTHERMAL LAUNCHER CHAMBER

Electrothermal propulsion higher limits of projectile velocity. It pro vides many advantages over conventional propulsion. As for a conventio nal gun, the knowledge of thermochemical data and propellant behaviour is necessary to optimize the system. The reaction products issued fro m the decomposition of methanol during an electrothermal process were characterized in order to understand the chemical process. Therefore, a plasma generator is specially added to a closed vessel suitable for high pressures. The combustion products of methanol were identified an d quantified by the analysis of the gases with a chromatograph coupled with a mass spectrometer. The released chemical energy is calculated from the analysis results. A defined electrical energy injected into t he plasma is found by which the amount of methanol is completely decom posed. This energy is estimated by an empirical method. The theoretica l calculations of temperature fit well with the observed phenomena. Re sults indicate that the plastic materials used in the closed vessel ha ve an important influence on the combustion. Moreover, the chemical en ergy released during reaction is not the decisive parameter for the op timization of the launcher's performances during the electrothermal pr ocess. A relation between the chemical energy released during reaction and the plasma injection energy is established for methanol.