Thermodynamic Investigation of Conventional and Alternative Rocket Fuels for Aerospace Propulsion

Abstract

The magnitude of the exhaust velocity is dependent on molecular and chemical properties of the propellant, and the expansion ratio of the engine. The main requirement for all propellant combinations is to maximize the energy release per kilogram; in other words, the lower the mass for a given energy release, the higher is the ultimate velocity of the vehicle. This also implies that the mass flow rate depends on the density, while the exhaust velocity depends on the energy contained in the hot gas. The main performance parameters can be defined as the thrust coefficient related to the nozzle performance, and the characteristic velocity related to the propellant and combustion performance. The first parameter reaches its optimum when the exhaust pressure is equal to the ambient pressure while the second parameter is defined by the choice of propellant combination. The objective of this work is to investigate, numerically and thermodynamically, different combinations of oxidizers with conventional and alternative fuels, for different rocket propulsion and energy generation systems. Based on the state-of-the-art and the analysis results on the most promising fuel-oxidizer combinations for the future of aerospace propulsion and space transportation, in a technically and environmentally sound manner, conclusions are made.