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Direct numerical simulation of formation and propagation of turbulent spherical premixed syngas/air flames

English title Direct numerical simulation of formation and propagation of turbulent spherical premixed syngas/air flames
Applicant Frouzakis Christos
Number 149500
Funding scheme Project funding (Div. I-III)
Research institution Institut für Energietechnik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Mechanical Engineering
Start/End 01.02.2014 - 31.07.2017
Approved amount 208'819.00
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All Disciplines (2)

Discipline
Mechanical Engineering
Fluid Dynamics

Keywords (4)

Direct Numerical Simulation; Spark ignition; Turbulent premixed flames; Spherical flame

Lay Summary (German)

Lead
Für die Entwicklung von neuen sauberen Technologien zur Energieerzeugung sind effizientere Verbrennungs-Strategien notwendig, um den steigenden Energiebedarf zu decken und die Schadstoffbelastung zu reduzieren. Die Entwicklung von neuen Systemen, wie der Niedertemperatur-Verbrennung bei Automobilen oder der mager Vormisch-Verbrennung bei Turbinen, hängt dabei stark von der Verfügbarkeit von Modellen ab, welche die Interaktion zwischen Strömung und Verbrennung genau erfassen können.
Lay summary
Für die Simulation von Selbst- und Erzwungener Zündung zur Untersuchung der Flammentwicklung wird ein extrem genauer und hoch skalierbarer numerischer Code eingesetzt. Der Fokus liegt dabei auf Syngas, einem Kraftstoff bestehend aus Wasserstoff und Kohlenstoffmonoxid, der aus Kohle, organischen Abfällen und Biomasse synthetisiert werden kann. Die Ergebnisse der Simulationen geben Aufschluss über wichtige Verbrennungseigenschaften, wie der turbulenten Flammgeschwindigkeit, der lokalen Flammentwicklung und der Flammfläche also Funktion der lokalen chemischen Zusammensetzung und des lokalen Strömungsfeldes. Die neu dazu gewonnenen Daten werden zusätzlich beitragen die Beschränkungen von bestehenden Verbrennungsmodellen zu identifizieren und die Entwicklung von neuen Modellen für die Auslegung von realen technischen Anlagen zu fördern.
Direct link to Lay Summary Last update: 13.01.2014

Lay Summary (English)

Lead
Advanced combustion strategies and new clean energy technologies are needed to cover the increasing energy demands and pollutant emissions requirements. The development of systems operating in novel combustion regimes, such as low-temperature combustion for automobiles and lean premixed combustion for turbine power plants, depends heavily on the availability of predictive models that can accurately describe the tightly-coupled flow and combustion interactions in the regimes of interest.
Lay summary

A highly-accurate and scalable numerical code will be used to perform large-scale simulations of forced and compression ignition to investigate the initiation, early flame evolution and the long-term propagation of premixed flames. Syngas, a reformed fuel consisting of hydrogen and carbon monoxide which can be obtained from coal, organic waste and biomass and is particularly attractive for power generation will be used. The simulations will provide high-quality data for many important combustion characteristics, including the turbulent burning velocity, local flame propagation speed and flame surface area as a function of composition and local flow properties. The results will also help to identify the limitations of existing engineering models and foster the development of new models that can be used for design purposes.


Direct link to Lay Summary Last update: 13.01.2014

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Laminar syngas–air premixed flames in a closed rectangular domain: DNS of flame propagation and flame/wall interactions
Jafargholi Mahmoud, Giannakopoulos George K., Frouzakis Christos E., Boulouchos Konstantinos (2018), Laminar syngas–air premixed flames in a closed rectangular domain: DNS of flame propagation and flame/wall interactions, in Combustion and Flame, 188, 453-468.

Collaboration

Group / person Country
Types of collaboration
Prof. Ananias Tomboulides, U. Western Macedonia Greece (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
2nd International Workshop on Near-Wall Reactive Flows Talk given at a conference Premixed flame propagation in confined geometries and flame-wall interactions: a DNS study 01.06.2017 Darmstadt, Germany Jafargholi Mahmoud; Boulouchos Konstantinos; Frouzakis Christos;
International Congress on Engine Combustion Processes Talk given at a conference Direct Numerical Simulations for Internal Combustion Premixed Gas Engines: First Steps, Challenges and Prospects 16.03.2017 Ludwigsburg, Germany Boulouchos Konstantinos; Jafargholi Mahmoud; Frouzakis Christos;
International Energy Agency/ERCOFTAC joint workshop on Gas engine combustion fundamentals Talk given at a conference DNS of flame propagation in confined geometries and flame-wall interaction 13.06.2016 Zurich, Switzerland Boulouchos Konstantinos; Jafargholi Mahmoud; Frouzakis Christos;


Associated projects

Number Title Start Funding scheme
135514 Direct numerical simulation of flow, heat transfer, and autoignition in engine-like geometries 01.07.2011 Project funding (Div. I-III)

Abstract

Premixed flames propagating in turbulent flow fields are challenged not only by their intrinsic instabilities but also interact with vortical structures extending over a broad range of length scales. The intricate coupling of different physical and chemical processes results in complex dynamics making difficult their understanding at a fundamental level that would enable their accurate modeling. At the same time, turbulent premixed flames are of interest in a broad range of applications including the design of internal combustion engines, the storage and distribution of flammable gases, and, in much larger scale, in Type Ia supernova explosions.The fundamental challenges and practical interest is the turbulent premixed combustion the target of intensive theoretical, experimental (physical as well as numerical) and computational investigations. Driven by advances in numerical algorithms and the availability of computational resources, direct numerical simulation (DNS) has become an essential tool in combustion research and is viewed as supplementary or even equivalent to physical experiments. In the proposed project, we intend to perform direct numerical simulations (DNS) to study (a) the processes resulting in the successful ignition from localized ignition kernels in premixed mixtures of synthetic gas (or syngas, a fuel mixture of carbon monoxide and hydrogen) and air in turbulent flow fields with non-zero mean velocity, (b) the early growth of the flame initiated at the ignition kernel, and (c) the long-term development of the propagating flame front as it interacts with turbulent eddies of different size. The associated phenomena are important factors influencing the overall performance and the cycle-to-cycle variation in spark-ignited internal combustion engines. Their direct numerical simulation with detailed chemistry and multi-component transport will enhance their fundamental understanding. The choice for the fuel is motivated by different factors. On one hand, in addition to hydrodynamic instabilies, syngas premixed flames are susceptible to instabilities resulting from the imbalance in mass and thermal transport (thermo-diffusive instabilities), the combined effect of which has not been investigated numerically for spherical flames propagating in turbulent flows. These combined effects have not received much attention in the DNS of turbulent spherical premixed flame literature. In addition, the basic understanding of synthesis gas and hydrogen combustion has relevance to many situations, the most near-term application being the coal-based integrated gasification combined cycle (IGCC) technology which makes possible cleaner electric power production with reduced carbon dioxide emissions (``clean coal" energy, \cite{syngas}). Finally, the carbon monoxide/hydrogen submechanism is a core sub-model of the detailed mechanism of all hydrocarbon fuels and the DNS data can be interrogated to identify the rate-determining steps.The high accuracy and scalability of our spectral element code offers the capability to efficiently suppress numerical noise and allow the collection of high-quality data for the turbulent burning velocity, the flame surface density, flame brush thickness and the stretch factor as a function of the turbulence intensity and length scale which are also essential for the development of better models or parameter tuning of existing models for turbulent premixed combustion.
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