Roman Keller

Numerical Investigation of Flow and Combustion in a Single Element GCH4/GOx Rocket Combustor

The flow and combustion in a GCH4/GOX single-element rocket combustor is analysed by several groups using different numerical models and tools. The tools and simulation setups vary with respect to modeling fidelity and computational expense. A short overview of the tools and the individual simulation setups is given. The focus of the paper is the comparison of the results obtained by the different groups as well as with experimental data. This encompasses the study of specific features of the combustor flow among the different simulations, as well as the validation with typical rocket engine design and performance parameters, such as wall heat flux and combsution pressure, gained from hot firing tests.

Parallelization and Performance Analysis of an Implicit Compressible Combustion Code for Aerospace Applications

The compressible, implicit combustion code TASCOM3D is used with and without the spray module SPRAYSIM for different aerospace applications. A number of such cases and analysis of the performance of the code on massively parallel systems will be given. These include supersonic combustion simulations of a complete scramjet model, a model rocket combustor fueled with gaseous oxygen and hydrogen as well as two multiphase simulations. The evaporation of kerosene in a preheated, pressurized channel and the spray combustion in a LOX/GH2 rocket combustor require an additional numerical tool to account for the liquid phase. Droplet propagation and evaporation is computed by the research code SPRAYSIM. Furthermore investigations with respect to the performance of the employed numerical codes are addressed. With respect to TASCOM3D the influence of block sizing on the performance is investigated intensively both in terms of weak and strong scaling. The strong scaling performance of SPRAYSIM is investigated for both multiphase simulations. It will be shown that both codes show a nearly ideal behavior.

Towards Affordable LES of Rocket Combustion Engines

Due to the large disparity of length and time scales in rocket combustors corresponding LES are highly time consuming. Steps towards simulating rocket combustion engines with affordable LES with the compressible, implicit combustion code TASCOM3D are presented. DES-family (DES, DDES, iDDES) models are compared and evaluated on two simple test cases: the turbulent isotropic homogeneous turbulence and the planer channel flow. iDDES shows promising results to be used in future rocket combustion engine simulations and can make LES affordable in these kind of combustion simulations.

Numerical Simulations of Rocket Combustion Chambers on Massively Parallel Systems

The compressible, implicit combustion code TASCOM3D is used for the simulation of rocket combustion chambers. Coupled Euler-Lagrange simulations for a subcritical operated model rocket combustor at 5 bar pressure are performed. A quarter of the rectangular combustor is discretized for three-dimensional RANS simulations. Three spray simulations with different initial droplet size distributions are performed. Simulation results exhibit only limited dependency on the initial droplet size distribution. Finally, performance of TASCOM3D on HERMIT and HORNET is compared. A different scaling behavior on both machines with respect to local block size variations is observed.

Numerical Investigation of Flow and Combustion in a Single-Element GCH4/GOx Rocket Combustor: Chemistry Modeling and Turbulence-Combustion Interaction

The flow and combustion in a GCH4/GOX single-element rocket combustor is analysed by several groups using different numerical models and tools. The tools and simulation setups vary with respect to modeling fidelity and computational expense. A short overview of the tools and the individual simulation setups is given. The focus of the paper is the comparison of the results obtained by the different groups as well as with experimental data. This encompasses the study of specific features of the combustor flow among the different simulations, as well as the validation with typical rocket engine design and performance parameters, such as wall heat flux and combsution pressure, gained from hot firing tests.

Numerical Investigation of Reacting Flow in a Methane Rocket Combustor: Turbulence Modeling

A comparison of the numerical predictions of several groups modeling the reacting flow inside a gaseous methane/gaseous oxygen single-element rocket combustion chamber is conducted. The focus is pl...

Numerical Simulations of Rocket Combustion Chambers with Supercritical Injection

A thermodynamically consistent model has been implemented into the compressible, implicit combustion code TASCOM3D for the simulation of rocket combustion chambers with supercritical injection. The Soave-Redlich-Kwong equation of state is used, since it offers a good compromise between accuracy and numerical efficiency. Nonreactive and reactive high pressure test cases were simulated for the validation of the implemented model. Generally, a good agreement could be obtained for all test cases.

Numerical Simulations of a Single Injector Gaseous Methane Rocket Combustion Chamber

Numerical simulations of a single injector gaseous methane/oxygen rocket combustion chamber from the Technische Universitat Munchen at 20 bar pressure are performed using steady RANS techniques on axisymmetric and three-dimensional grids. In a first step the combustion chamber with a square cross-section is simulated using a two-dimensional grid with the assumptions of axisymmetry. This setup is used for a comprehensive parameter study. In a next step a three-dimensional simulation using the findings from the parameter study is performed. It is shown that the q-ω and SST turbulence model produce comparable results and that the turbulent Schmidt and Prandtl numbers have a significant quantitative influence. The presented flow field results indicate that three-dimensional effects are important, questioning the validity of axisymmetry for this chamber. Both the two-dimensional simulations, despite the axisymmetry assumption, and the three-dimensional simulation show good agreement with the experimental values for the wall heat flux and the wall pressure.