Markus Lempke - Profile on Academia.edu (original) (raw)

Papers by Markus Lempke

Numerical Simulations of Rocket Combustion Chambers on Massively Parallel Systems

High Performance Computing in Science and Engineering ´15, 2016

International Journal for Numerical Methods in Fluids, 2015

This article may be used for non-commercial purposes in accordance with Wiley Terms and Condition... more This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Unsteady High-Order Simulation of a Liquid Oxygen/Gaseous Hydrogen Rocket Combustor

Journal of Propulsion and Power, 2015

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

High Performance Computing in Science and Engineering ‘14, 2014

Steady and Unsteady RANS Simulations of Cryogenic Rocket Combustors

49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2011

Delayed Detached Eddy Simulation of a Rotationally Symmetric Supersonic Jet

High Performance Computing in Science and Engineering ‘13, 2013

High Performance Computing on Vector Systems 2011, 2011

Numerical Investigation of the HyShot Supersonic Combustion Configuration

44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 2008

Numerische Untersuchung des HyShot-Experiments

Numerical Simulation of Subcritical Model Rocket Combustors with Single Shear Coaxial Injectors

Progress in Propulsion Physics, 2013

In order to account for the interaction between turbulence and chemistry, a multivariate assumed ... more In order to account for the interaction between turbulence and chemistry, a multivariate assumed PDF (Probability Density Function) approach is used to simulate a model rocket combustor with ¦nite-rate chemistry. The reported test case is the PennState preburner combustor with a single shear coaxial injector. Experimental data for the wall heat §ux is available for this con¦guration. Unsteady RANS (Reynolds-averaged NavierStokes) simulation results with and without the assumed PDF approach are analyzed and compared with the experimental data. Both calculations show a good agreement with the experimental wall heat §ux data. Signi¦cant changes due to the utilization of the assumed PDF approach can be observed in the radicals, e. g., the OH mass fraction distribution, while the e¨ect on the wall heat §ux is insigni¦cant.

International Journal for Numerical Methods in Fluids, Jun 17, 2015

In this paper a mixed Euler-Lagrange approach is used for a 3D simulation of a LOX/H2 model rocke... more In this paper a mixed Euler-Lagrange approach is used for a 3D simulation of a LOX/H2 model rocket combustor with a single shear coaxial injector. The specific test case presented is the MASCOTTE combustor at 10 bar pressure in the so called A-10 configuration. The simulation of the gas phase is conducted with the scientific code TASCOM3D which works in an Eulerian mode while the liquid fuel droplets are treated by the scientific code SPRAYSIM in a Lagrangian framework. The two codes and the coupling mechanisms are explained and results of a preliminary simulation will be presented. At the end an outlook is given focusing on how to obtain an even more accurate representation of the experiment in subsequent simulations. Finally some comments on the computational costs of the calculations and the performance of the two codes on the NEC SX-9 are given.

In the present paper different types of scramjet (supersonic combustion ramjet) combustors are in... more In the present paper different types of scramjet (supersonic combustion ramjet) combustors are investigated. Thereby the main difference between the combustors is the way of injecting the fuel into the combustion chamber. The first investigated concept of fuel injection is the injection by strut injectors. Here the injection of fuel is realized by a lobed strut that is located in the middle of the combustion chamber. The second concept for fuel supply is the wall injection of hydrogen. Here the fuel is injected by several holes in the wall of the combustor. Both concepts of fuel injection have different advantages and disadvantages which are explained in detail. Although different performance parameters for both scramjet combustors are introduced this paper will not compare the different techniques among each other. Because of the high Reynolds numbers in scramjet combustors, the need to resolve the boundary layers and the necessity of detailed chemistry, the simulation of scramjets is extremely CPU time demanding.

Diagnostics of Xe Ion in an Anode-layer Type Hall Thruster Using Laser-Induced Fluorescence

Transactions of The Japan Society for Aeronautical and Space Sciences, Space Technology Japan, 2009

ABSTRACT The discharge oscillation in an anode-layer type Hall thruster is one of the most seriou... more ABSTRACT The discharge oscillation in an anode-layer type Hall thruster is one of the most serious problems to be overcome. In general, a hollow anode is used in order to stabilize the operation. Recent numerical simulation results show the stable operation depends on the ionization rate in the hollow anode. In order to verify the simulation result, it is needed to measure the plasma profile in the hollow anode. In this paper, as a first step, the number density and the velocity distribution of single-charged xenon ions in an anode-layer type Hall thruster were investigated by means of Laser-Induced Fluorescence (LIF) for the 5d2F7/2-->6p2D05/2 excitation transition at 834.7 nm detecting the non-resonant line to the 6s2P3/2 state at 541.9 nm. As a result, we obtained the relative ion number density and the velocity distributions. The ion velocity distribution function shows both ionization and acceleration occur in the acceleration channel, while only ionization occurs in the hollow anode.