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Large eddy simulations of stratified charge engines

Objective



The objective of LES Engines is to develop a novel combusting flow computer simulation technique to support the development of fuel-efficient and clean automobile engines. This will contribute to improvement of the environment and competitiveness of the European Union. Such improved Computational Fluid Dynamics (CFD) techniques are required to master the complex challenges imposed by the new generation of engines characterized by a very strong charge stratification created mostly by fuel injection. The development of these engines is a priority both for European automotive manufacturers competitiveness and European citizens quality of life.

Today, most of the CFD engine codes are based on statistically-averaged models of turbulence and combustion which are well known to have limited potential to reproduce the engine behavior when large structures have a direct impact on mixing or combustion, and to predict the engine cyclic variability. The semi-deterministic approach based on Large Eddy Simulations (LES) is viewed as potentially able to overcome these limitations. The objective of LES Engines is to make the Large Eddy Simulation methodology available for new spark-ignition (SI) reciprocating engine development.
The development of engine LES methodology is a complex scientific problem, with ultimate application in industry. Therefore, academic, R&D, and industrial partners, all known to be leaders in their respective fields, are collaborating in the LES Engines project. The development of the engine LES methodology will rely on: the use of state-of-the-art numerical (Direct Numerical Simulations) and experimental (laser based optical techniques) diagnostics to produce data bases for basic model development and validation purposes; the use of research and industrial CFD codes to as test vehicles for the methodology, and on extensive validation for situations ranging from simple academic flows to actual modern four-valve engines.
For the partners, the expected achievements of LES Engines should be:
*An LES methodology (Subgrid Scale Models and numerical schemes) tailored for SI engine reacting flows and validated by relevant experiments. *An evaluation of LES accuracy and particular characteristics and requirements for proper use, for applications ranging from simple experiments to actual stratified engines
*Practical experience on the use of LES in academic and industrial contexts. *Generation of DNS data bases for turbulence, mixing, droplet dispersion and evaporation and combustion for engine-relevant conditions
*Experimental data bases on flow fields, mixing fields, droplet dispersion and combustion, for the aforementioned situations.

It is expected that at the end of this project a LES methodology of quantified accuracy for engine combustion simulation will emerge and be available for incorporation into industrial CFD codes used by the automotive partner companies.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

GROUPEMENT EUROPÉEN DE RECHERCHES TECHNOLOGIQUES SUR LES HYDROCARBURES
Address
Avenue Napoléon Bonaparte 232
92500 Rueil Malmaison
France

Participants (4)

AB Volvo Technological Development
Sweden
Address

405 08 Göteborg
IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
United Kingdom
Address
Exhibition Road
SW7 2BX London
INSTITUT NATIONAL POLYTECHNIQUE DE TOULOUSE
France
Address
Allee Du Professeur Camille Soula, 4
31400 Toulouse
N/A
Germany
Address
Mercedesstrasse 137
70546 Stuttgart