Advanced Propellants for Space Propulsion A Task within the DLR Interdisciplinary Project "Future Fuels"
Creators: name:  H. CIEZKI 
name:   V. ZHUKOV 
name:   L. WERLING 
name:   C. KIRCHBERGER 
name:   J.V. SCHYNDEL 
name:   E. GOOS 
name:   D. SUSLOV 
name:   M. WILHELM 
name:   D. FREUDENMANN 
name:   C. NAUMANN 
name:   M. FRIESS 
name:   M. KURILOV 
name:   C. JANZER 
name:   B. HEIDENREICH 
name:   T. METHLING 
name:   J. HARDY 
name:   J. MARTIN 
name:   S. RICHTER 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: PROPULSION PHYSICS
FUTURE FUELS

description: Advanced and synthetic fuels and propellants are a decisive building block for the successful implementation of the German energy transition (Energiewende). These carriers allow to store energy in a simple, flexible, efficient and sustainable way. They are also powerful guarantors of future mobility in a vast range: as fuels for road vehicles, trains and ships as well as for aircrafts and rockets. The challenges are manifold, but climate-neutral production and fuel and propellant design for optimized properties are key aspects in current research. In contrast to fossil fuels, designer fuels allow optimization of their chemical and physical properties in a way that no or at least significantly less pollutants, such as soot particles and nitrogen oxides, are formed. Eleven institutes of the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) are researching the development and application of synthetic fuels in DLR\'s interdisciplinary \"Future Fuels\" project. Within the sub-project Advanced Rocket Propellants (TP5) three promising advanced green propellant systems are under investigation with regard to applicability and efficiency in rocket engines. Here, the DLR Institutes of Space Propulsion, of Combustion Technology and of Structures and Design are working together in a close collaboration. The work with three different propellant system candidates aims on different mission scenarios and tasks, whereas performance, low costs, environmentally friendliness, and safe handling characteristics are essential. The objective of this sub-project is to show and elaborate the potential of these propellant systems, to develop and to understand combustor processes and model combustion chambers with ceramic materials with the task to advance the technology development in direction to commercial development and usage and to provide this technology to industry. The work within the four-year collaborative research project Future Fuels started at the beginning of the year 2018 and will last till the end of 2021. The three selected promising propellant system candidates within this sub-project are: The cryogenic bipropellant combination liquid methane / liquid oxygen (LCH4/LOX). This combination is currently deemed to be one of the most promising bipropellant combinations for the development of new generations of launcher propulsion systems. LCH4/LOX offers in comparison to conventional storable propellants (e.g. MMH/NTO) an increase of the specific impulse of approximately 50 s. Liquid mono- and bipropellants consisting of hydrocarbons and nitrous oxide (called HyNOx). These high-performance green propellants are interesting because their specific impulse is comparable to storable bipropellant combinations like MMH/MON. Furthermore, the propellant combinations are non-toxic and promise system advantages like self-pressurized systems, easy ignitability and thus a lower structural (dry) mass. In this project mixtures of N2O/C2H4 and N2O/C2H6 are investigated. They are interesting candidates for the replacement of the highly toxic hydrazine and its derivatives. Green gelled propellants. They combine thrust variation on demand with increased safety and handling charac-teristics. They are of interest for various rocket applications as for example space tugs, landers, divert and attitude control (DACS) systems, but also throttleable upper stages of sounding rockets and micro-launchers. Within the scope of this sub-project, the ignition and combustor process of green gel propellants is investigated. The proposed presentation and the paper will give a detailed overview on the conducted work and obtained results within this project and will serve as introduction to the proposed selected presentations in the pre-arranged Special Session: DLR Future Fuels Project.