Chair of Fluid Dynamics

The team develops and tests methods for the simulation and optimization of reactive flows and flames in installations such as heavy-duty gas turbines, nanoparticle synthesis reactors, piston engines or biomass- and pulverised coal furnaces. Our methods allow for shortened development times to further reduce costs. Our research helps to develop cost-effective, flexible and safe systems which emit fewer pollutants.

The complex processes in synthesis reactors and combustors require a detailed numerical characterisation of reaction and transport processes. Their simulation provides insights into areas, which are inaccessible to experiments, enables the investigation and comprehension of isolated subprocesses, and their interactions, and helps to bridge the gap between lab and industrial scale. For this purpose we develop and implement numerical models and methods which are necessary to describe and simulate turbulent combustion of multiphase flows as well as reaction kinetics.

Our work is financed by the state of North Rhine-Westphalia, the German Research Foundation (DFG), the Federal Ministry of Economics and Technology (BMWi), the Alliance for industrial research (AiF), national and international supercomputing centres as well as multiple private companies.

At the University of Duisburg-Essen, our group is closely linked with other groups at CeNIDE (Center for Nano-Integration Duisburg-Essen), CER.UDE (Center for Energy Research) and CCSS (Center for Computational Sciences and Simulation). As a menber of the IVG, we provide detailed simulation results and utilize data from the experiments of the other groups, which are essential for us.

The study at the chair imparts competences in the fields of flow simulation, in the description of reacting flows and in turbulence modeling.

NEWS

29.09.2022 Publication in Proceedings of the Combustion Institute

A first LES study on the co-firing of coal and ammonia is performed in this publication. A new reaction mechanism is developed for this purpose. Simulative results are compared with experimental data and good agreement is achieved. Link

22.09.22 Team Excursion

​The most hardy members of the group gathered for a canoeing trip in the rain, of the river of Wupper.

09.09.2022 Publication in Flow, Turbulence and Combustion

A joint numerical and experimental investigation of cyclical variations in spark ignited engines was performed in this publication. A fired multicycle LES using clean numerical methods was performed. Similar observations were made from experiment and simulation. Link

1.9.2022 The CFD Team

Great teamwork is the only way we create the breakthroughs that define our careers

                                                                                                                                     – Pat Riley

24.08.2022 39th International Symposium on Combustion

From 24th to 29th of July 2022, a team represented the Chair of Fluid Dynamics at this year's 39th International Symposium on Combustion in Vancouver. Some interesting work was presented and new contacts were made with passionate colleagues. We are proud and grateful to have been a part of this event!

11.05.2022 Publication in the journal "Powder Technology"

LES of nanoparticle synthesis in the SpraySyn burner: a comparison against experiments - The paper by Johannes Sellmann is now available in the Journal "Powder Technology": https://doi.org/10.1016/j.powtec.2022.117466

25.4.2022 Publication in the Journal of Computational Physics

Innovative new approach for modeling high Schmidt number and high Prandtl number flows developed. The technique can be used to  simulate nano-particle reactors or the liquid cooling of electric motors and power electronics. The paper by Michael Leer is now available in the Journal of Computational Physics. (https://doi.org/10.1016/j.jcp.2022.111216 )

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https://authors.elsevier.com/c/1f7PQ508HsZDb

29.03.2022 Publication accepted in Computers and Fluids

Established and recent closures for subgrid momentum and scalar fluxes in LES were analyzed a-posteriori in a turbulent premixed burner experiment. LES of the Cambridge burner experiment using FGM tabulation were performed and the performance was compared with respect to the influence of the subgrid model. It was found that the recently developed KKK2 and sensor-enhanced Smagorinsky model outperformed the rest. This work was conducted in cooperation with the University of Federal Armed Forces in Munich.

10.01.2022 Accepted for publication at Optics Express

In this work, the application of an evolutionary reconstruction technique to background-oriented schlieren tomography is presented for the first time (https://doi.org/10.1364/OE.450036).

24.11.2021 Publication accepted in Combustion and Flame

In this collaborative work with Newcastle University, the results of the quasi-DNS of a stratified flame are presented.

15.09.2021 Publication accepted in the Journal of Physical Chemistry

A collaboration within the DFG-FOR2284 project. In this study, quantum chemical calculations and isodesmic reaction approach are presented for the determination of temperature-dependent standard enthalpy of formation, entropy, and heat capacity of Si-C-H-O radicals and molecules determined by combinatorial considerations group additivity values (GAVs). For the first time, the uncertainties of the group values are calculated.

27.07.2021 Publication accepted in Combustion Theory and Modelling

In this collaborative work with Newcastle University, the validity of the famous flame efficiency function models for stratified flames are tested. 


11.06.2021 Publication accepted in Flow Turbulence and Combustion

In a joint study with the Stanford University an investigation torwards the suitability of the information entropy as a quality measure was performed. Canonical cases of fluiddynamics and chaos-theory were analyzed and a dependence between the simulation quality and information entropy has been observed. Well and poorly resolved simulations were performed, and have been compared with DNS data. While several established quality measures failed to assess the simulation quality correctly, the entropy was able to distinguish between the poor and well resolved calculations. Link

26.02.2021 Publication accepted in Energy & Fuels

A hydrogen-piloted pulverized coal flame is investigated using a flamelet/progress variable approach via massively parallel LES. A method is presented that accounts for suction probing effects on the scalar field measurements and significantly improves the agreement between experiment and simulation. This work is a collaboration with the TU Darmstadt and the University of Stuttgart. Link

15.02.2021 Publication accepted in Energy & Fuels

A collaborative work in the framework of DFG-FOR2284 project. The thermal decomposition of ethylsilane (H3SiC2H5, EtSiH3) is investigated behind reflected shock waves and the gas composition is analyzed. A kinetics mechanism accounting for the gas-phase chemistry of EtSiH3 is developed, which consists of 24 Si-containing species, 31 reactions of Si-containing species, and a set of new thermochemical data. The experimental data is reproduced very well by simulations based on the mechanism of this work and is in very good agreement with literature values. It is shown that EtSiH3 is a promising precursor for the synthesis of SiC nanoparticles. Link

18.01.2021 Publication accepted in Energy & Fuels

A comprehensive Euler-Lagrange framework for pulverized coal combustion using detailed multi-step heterogeneous kinetics is presented. 3D carrier-phase DNS have been performed for a turbulent mixing layer. The data is compared to simpler pyrolysis models. A new devolatilization model approach suitable for fitting bimodal volatile release rates is proposed. This work is a collaboration of the University of Stuttgart, TU Darmstadt and University of Duisburg-Essen. Link

06.01.2021 Publication accepted in Computer and Fluids

The behaviour of bounded passive scalars with respect to different subgrid-models in a-posterori LES is investigated in a joint study together with the Bundeswehr University Munich. DNS and LES calculations using known and new subgrid-models have been performed for a turbulent free jet. The influence of cross-combination of different models as well as the choice of numerical discretization for the subgrid-fluxes on the boundedness of the transported scalars is analyzed.

22.12.2020 Publication in Optics Express

A novel application of tomographic imaging using multi-simultaneous measurements (TIMes) for flame emission reconstructions. Link