Simulation of the temperature and flow conditions in a high-pressure autoclave before and during the combustion of rocket propellants

Rocket propellants differ in terms of their application, performance and safety requirements. Their composition, mechanical properties and combustion properties of the propellant are essential for its application. An important performance characteristic is the burning rate, which depends on the fuel geometry, the composition, the pressure in the combustion chamber and the propellants. Therefore, the propellants burning behaviors are studied under controlled conditions in high-pressure autoclaves. At the Fraunhofer Institute for Chemical Technology (ICT) an autoclave with viewing windows is used to investigate burning behaviors. During the experiments, a process gas flows through the combustion chamber to direct the reaction products out of the combustion chamber. The temperature and flow conditions in the combustion chamber are difficult to investigate experimentally. Within this work numerical flow simulations were utilized to gain insights to the development of temperature and flow in the combustion chamber depending on the initial propellant temperature, the pressure and the mass flow of the process gas. The simulations focused on the cases with and without propellant combustion. In Order to investigate the influence of the operating parameters on the temperature of the propellant samples and the cooling of the combustion gases, a statistical experimental design and evaluation were carried out.