Fathoming the Processes inside Rocket Combustion Chambers

Universität Stuttgart (Germany)

Principal Investigator: Peter Gerlinger, Institut für Verbrennungstechnik der Luft- und Raumfahrt

Introduction

At the Institute of Combustion Technology for Aerospace Engineering (IVLR) of the University of Stuttgart a team of scientists numerically investigates reacting flows at conditions typical for modern space transportation systems. The goal of the project is the better understanding of the ongoing processes in the combustion chambers and an improvement of the thermal load predictions. The research is integrated into the program SFB/TRR-40 (Technological Foundations for the Design of Thermally and Mechanically Highly Loaded Components of Future Space Transportation Systems) funded by the DFG (Deutsche Forschungsgemeinschaft).

Cryogenic Rocket Combustion

Fig. 1: Iso-contours of temperature (3300 K) reveal the three-dimensional character and the large differences in the scales of the flame structures in this model rocket combustor with a single shear-coaxial injector.
Copyright: IVLR, University of Stuttgart

Rocket propulsion systems like the European Vulcain II engine have been successfully used to deliver payloads, such as telecommunication and earth observation satellites, into space for several decades. Yet, the complex processes in rocket combustion chambers are still not fully understood. These devices have to sustain massive thermal and mechanical loads due to the high temperatures and pressures of the combustion processes. Furthermore these propulsion systems are very sensitive to thermo-acoustic instabilities which may be strong and cause to the destruction of the combustion chamber. For further improvements or reusability of the combustion chamber, as done by SpaceX with their Falcon 9 rocket and Merlin engine, a better understanding of the processes is indispensable. By the use of modern supercomputers it is possible to gain detailed insights into the complex phenomena like multi-phase flow (liquid oxygen), turbulence and chemical reactions, as well as their interaction.

Fig. 2: Temperature slices and oxygen iso-contours showing the three-dimensional character of the flow field due to the multi-injector-interaction in a methane model rocket combustor with seven shear-coaxial injectors.
Copyright: IVLR, University of Stuttgart

Research topics at the IVLR include combustion instabilities, new fuel compositions (e.g. methane), thermal load prediction improvements of the combustion chamber structure, modelling of turbulence-chemistry interaction, multi-injector interaction and trans- or supercritical real-gas flows (liquid-like oxygen).

Fig. 3: Temperature distribution near the injector for the model rocket combustor of Fig. 1 which shows strong three-dimensional effects and a strong convolution of the flame.
Copyright: IVLR, University of Stuttgart

For their investigations the IVLR scientists employ, develop and improve sophisticated turbulence and combustion models that are accurate but computationally time consuming and therefore require the utilization of modern high performance computers such as the petascale system Hazel Hen of the HLRS Stuttgart.

Scientific Contact

apl. Prof. Dr.-Ing. Peter Gerlinger
Universität Stuttgart
Institut für Verbrennungstechnik der Luft- und Raumfahrt
Pfaffenwaldring 38-40, D-70569 Stuttgart
e-mail: peter.gerlinger@dlr.de

Febuary 2018