Optimisation of a LOX/Ethanol rocket engine ignition

Abstract: For more than half a century, humanity has achieved the feat of extracting itself from the earth's atmosphere and sailing into space, broadening the spectrum of knowledge and curiosity. Although space market seemed mastered and stable the arrival of new private players has reorganized the sector through new technological choices. Flexibility, production rapidity, versatility and cost reduction of launchers are more than ever at the heart of new strategies, notably with the arrival of Ariane 62 and 64. In addition, a new market is emerging for the launch of nanosatellites. This market being very promising, numerous private and public actors join the mini-launchers competition (such as the Electron rocket of Rocket Lab). In order to be present on the market of mini launchers, the French National Center for Space Studies (CNES) has initiated the PERSEUS project. The project aims to develop a complete reusable mini-launch vehicle operational by 2026 with the help of students, associations, and industrials. The project is divided into macro-projects that study each key elements of the final launcher. One of them, ASTEROS sub-project, consists in realizing a biliquid launcher propelled by the MINERVA engine (Oxygen / Ethanol) that should attains an altitude of 5km. The ignition of the MINERVA engine is a critical part of the project. Many parameters must be considered to guarantee optimum thrust, a safe ignition and an operation without damage. The aim of this thesis is to achieve these objectives. To do so, one must predict the tanks pressures, the percentages of openings of the control valves as well as the good opening times of the injection valves. Engine ignition implies several physical phenomena that must be clearly understood and clearly modeled. To do so, a first understanding of the implied phenomena will be carried out, followed by a first simple numerical model implemented on Excel, in order to get a global overview of the parameters sought. The first parameters obtained (pressures and openings of the control valves) will decide the first engine test configurations. Thanks to these test results a more complex model implemented on AMESim, will be adjusted. The new model will allow to predict the optimized steady state parameters (tanks pressures and valve openings) more accurately as well as examine the transient behavior of the valve openings. This new model, implemented on AMESim, which is a simulation software used for the modeling and analysis of multi domain system, is more precise and allows to study dynamic behaviors of systems. Numerical modelling supported by test campaigns will be carried out in this project to optimize the ignition of the MINERVA engine. Once parameters have been chosen, a complete ignition sequence will be detailed and coded on the Labview software which controls the engine valves.