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Direct numerical simulation of flow, heat transfer, and autoignition in engine-like geometries

Titel Englisch Direct numerical simulation of flow, heat transfer, and autoignition in engine-like geometries
Gesuchsteller/in Frouzakis Christos
Nummer 135514
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Institut für Energietechnik ETH Zürich
Hochschule ETH Zürich - ETHZ
Hauptdisziplin Maschineningenieurwesen
Beginn/Ende 01.07.2011 - 30.06.2014
Bewilligter Betrag 167'482.00
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Alle Disziplinen (2)

Disziplin
Maschineningenieurwesen
Fluiddynamik

Keywords (4)

internal combustion engine; direct numerical simulation; turbulent boundary layer; autoignition

Lay Summary (Englisch)

Lead
Lay summary
   Internal combustion engine flows are turbulent, unsteady and exhibit high cycle-to-cycle variations. Turbulence generation mechanisms are multiple and their effects overlap in time and space, rendering the simple turbulence models currently used in industry inappropriate for the in-depth understanding of underlying mechanisms as well as for predictive purposes. Even currently emerging LES-models for engine flows are subject to uncertainties with respect to sub-grid scale models, particularly for processes in the proximity of walls, which are prominent in engine combustion chambers.
   Experimentally, optical methods have provided valuable insight into turbulent engine flows during the last 30 years. Despite recent progress, inherent limitations with respect to the efficient scanning of the whole domain with sufficient spatial resolution down to the smallest flow scales and in the proximity of walls still persist. Features of the high frequency part of the turbulence kinetic energy and dissipation spectrum and the associated interactions with the larger scales can therefore be uncovered only to a limited extent through measurements, and with heavy experimental effort.
  This project aims at performing very large scale direct numerical simulations, first of non-reacting and then of a few autoigniting cases with gaseous mixtures, in engine-like geometries employing a highly scalable and effiecient parallel, spectral element low Mach number code. We intend to investigate the following processes:
• Evolution of turbulent flow parameters as a function of the initial conditions after intake valve closing (including swirl and tumble) and combustion chamber geometry (compression ratio, clearance height, bowl-in-piston depth and diameter) in gaseous, non-reactive cases

• Evolution of the unsteady hydrodynamic and thermal boundary layer structure during compression and expansion for the above mentioned parameter variation

• Autoignition and combustion of gaseous mixtures employing sufficiently detailed chemistry and to study the multiple interactions between flow and thermo chemistry including near-wall phenomena.

   The results of these simulations can be used for multiple purposes. Firstly, they will shed light into the complex interactions between flow and thermochemistry in unsteady engine flows at time and space scales. Secondly, they can be used to validate, or identify the shortcomings of models used in conventional RANS or LES approaches for describing turbulent engine flows. Finally, they can be used to guide future experiments for mutual (cross-) validation.

Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
Direct numerical simulation of the compression stroke under engine relevant conditions: Local wall heat flux distribution
Schmitt Martin, Frouzakis Christos E., Wright Yuri M., Tomboulides Ananias, Boulouchos Konstantinos (2016), Direct numerical simulation of the compression stroke under engine relevant conditions: Local wall heat flux distribution, in International Journal of Heat and Mass Transfer, 92, 718-731.
Role of the intake generated thermal stratification on the temperature distribution at top dead center of the compression stroke
Schmitt M., Boulouchos K. (2016), Role of the intake generated thermal stratification on the temperature distribution at top dead center of the compression stroke, in International Journal of Engine Research, 17(8), 836-845.
Comparison of Direct and Large Eddy Simulations of the Turbulent Flow in a Valve/Piston Assembly
Montorfano Andrea, Piscaglia Federico, Schmitt Martin, Wright Yuri M., Frouzakis Christos E., Tomboulides Ananias G., Boulouchos Konstantinos, Onorati Angelo (2015), Comparison of Direct and Large Eddy Simulations of the Turbulent Flow in a Valve/Piston Assembly, in Flow, Turbulence and Combustion, 95(2-3), 461-480.
Direct numerical simulation of the compression stroke under engine-relevant conditions: Evolution of the velocity and thermal boundary layers
Schmitt Martin, Frouzakis Christos E., Wright Yuri M., Tomboulides Ananias G., Boulouchos Konstantinos (2015), Direct numerical simulation of the compression stroke under engine-relevant conditions: Evolution of the velocity and thermal boundary layers, in International Journal of Heat and Mass Transfer, 91, 948-960.
Direct numerical simulation of the effect of compression on the flow, temperature and composition under engine-like conditions
Schmitt Martin, Frouzakis Christos E., Tomboulides Ananias G., Wright Yuri M., Boulouchos Konstantinos (2015), Direct numerical simulation of the effect of compression on the flow, temperature and composition under engine-like conditions, in Proceedings of the Combustion Institute, 35(3), 3069-3077.
Investigation of wall heat transfer and thermal stratification under engine-relevant conditions using DNS
Schmitt M., Frouzakis C. E., Wright Y. M., Tomboulides A. G., Boulouchos K. (2015), Investigation of wall heat transfer and thermal stratification under engine-relevant conditions using DNS, in International Journal of Engine Research, 17(1), 63-75.
Direct numerical simulation of multiple cycles in a valve/piston assembly
Schmitt Martin, Frouzakis Christos E., Tomboulides Ananias G., Wright Yuri M., Boulouchos Konstantinos (2014), Direct numerical simulation of multiple cycles in a valve/piston assembly, in Physics of Fluids, 26(3), 035105-035105.
Investigation of cycle-to-cycle variations in an engine-like geometry
Schmitt M., Frouzakis C. E., Wright Y. M., Tomboulides A. G., Boulouchos K. (2014), Investigation of cycle-to-cycle variations in an engine-like geometry, in Physics of Fluids, 26(12), 125104-125104.

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
Dept. of Mechanical Engineering, U. of Western Macedonia Griechenland (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
Politechnico di Milano Italien (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation
Argonne National Laboratory Vereinigte Staaten von Amerika (Nordamerika)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
3rd International nek5000 user meeting Vortrag im Rahmen einer Tagung Direct numerical simulation of the compression stroke under engine relevant conditions 21.08.2014 Thessaloniki, Griechenland Wright Yuri Martin; Frouzakis Christos; Schmitt Martin Daniel; Boulouchos Konstantinos;
35th International Symposium on Combustion Vortrag im Rahmen einer Tagung Direct numerical simulation of the effect of compression on the flow, temperature and composition under engine-like conditions 03.08.2014 San Francisco, Vereinigte Staaten von Amerika Boulouchos Konstantinos; Frouzakis Christos; Wright Yuri Martin; Schmitt Martin Daniel;
International Conference on LES for Internal Combustion Engine Flows Vortrag im Rahmen einer Tagung Direct Numerical Simulations in internal combustion engines 29.11.2012 Rueil-Malmaison, France , Frankreich Boulouchos Konstantinos; Frouzakis Christos; Wright Yuri Martin; Schmitt Martin Daniel;
International Conference for High Performance Computing, Networking Storage and Analysis SC12 Vortrag im Rahmen einer Tagung Direct Numerical Simulation of Flow in Engine-Like Geometries 12.11.2012 Salt Lake City, U.S.A, Vereinigte Staaten von Amerika Frouzakis Christos; Schmitt Martin Daniel;
9th International ERCOFTAC Symposium on Engineering Turbullence Modelling and Measurements Vortrag im Rahmen einer Tagung Multiple cycle LES simulations of a direct injection methane engine 06.06.2012 Thessaloniki, Greece, Griechenland Schmitt Martin Daniel; Boulouchos Konstantinos; Frouzakis Christos; Wright Yuri Martin;
Frontiers in Energy Research Einzelvortrag Invited lecture in a course 08.05.2012 ETH Zurich, Schweiz Schmitt Martin Daniel;


Auszeichnungen

Titel Jahr
Outstanding Doctoral thesis 2015, Mechanical and Process Engineering, ETHZ 2015

Verbundene Projekte

Nummer Titel Start Förderungsinstrument
137771 Automated reduction of detailed reaction mechanisms and use in muti-dimensional combustion simulations 01.02.2012 Projektförderung (Abt. I-III)
149500 Direct numerical simulation of formation and propagation of turbulent spherical premixed syngas/air flames 01.02.2014 Projektförderung (Abt. I-III)

Abstract

Internal combustion engine flows are turbulent, unsteady and exhibit high cycle-to-cycle variations. Turbulence generating mechanisms are multiple and their effects overlap in time and space, rendering simple the turbulence models currently used in industry inappropriate for both in-depth understanding of underlying mechanisms and predictive purposes. Even currently emerging LES-models for engine flows are subject to uncertainties with respect to sub-grid scale models, particularly for processes in the proximity of walls, which are prominent in engine combustion chambers.Experimentally, optical methods have provided valuable insight into turbulent engine flows during the last 30 years. Despite recent progress regarding the development of planar or 3-D PIV techniques with high temporal resolution, inherent limitations as to efficient scanning of whole fields with sufficient spatial resolution down to the smallest flow scales and in the proximity of walls still persist. Features of the high frequency part of the turbulence kinetic energy and dissipation spectrum and the associated interactions with the larger scales can therefore be uncovered only to a limited extent through measurements, and with heavy experimental effort.The work proposed here aims at performing very large scale direct numerical simulations, first of non-reacting and then of a few autoigniting cases with gaseous mixtures, in engine-like geometries. The work will employ a highly scalable and effiecient parallel, spectral element low Mach number code that has been developed to a large extent in our group. During the last few years the code has been successfully used in several reactive flow problems, including the very large scale simulations of turbulent autoigniting hydrogen-air jets. At the current stage, the code is capable of peta-scale simulations on the appropriate hardware.We intend to investigate the following processes:•Evolution of turbulent flow parameters as a function of the initial conditions after intake valve closing (including swirl and tumble) and combustion chamber geometry (compression ratio, clearance height, bowl-in-piston depth and diameter) in gaseous, non-reactive cases,•evolution of the unsteady hydrodynamic and thermal boundary layer structure during compression and expansion for the above mentioned parameter variation,•autoignition and combustion of “homogeneous” gaseous mixtures employing sufficiently detailed chemistry and to study the multiple interactions between flow and thermo chemistry including near-wall phenomena.The results of these simulations can be used for multiple purposes. Firstly, they will shed light into the complex interactions between flow and thermochemistry in unsteady engine flows at time and space scales. Secondly, they can be used to validate, or identify the shortcomings of models used in conventional RANS or LES (currently emerging) approaches for describing turbulent engine flows. Finally, they can be used to guide future experiments for mutual (cross-) validation.
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