Thermochemical Evaluation of Proposed Electrothermal-Chemical Propellants.

Due to the addition of electrical energy, the customary thermodynamic method of screening candidate fuels needs to be modified for application to electrothermal -chemical ETC systems. Instead of computing the gravimetric impetus, it is mom useful to study the volumetric energy, which is defined as Idgamma - 1 I impetus, d density, and y the ratio of the specific heats at constant pressure and constant volume. While computing the gravimetric impetus or chemical energy is nowadays a straightforward matter, estimating densities is not. A rough estimate can be obtained by assuming that volumes are additive. In addition, for a given set of ingredients, the composition with the maximum chemical energy turns out to change mildly with the amount of added electricity. Also, the density itself changes with composition. A correct computation of the maximum energy must take both effects into account. In this report, thermochemical requirements for potential ETC propellants which are required to meet weapon performance levels am identified. In addition, a procedure to the performance potential of candidate ETC propellants is proposed. This procedure is then applied to several candidate propellants. Electrothermal- chemical, ETC, Working fluids, Propellants, Thermochemical, Impetus, thermodynamics.