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N. Pizzirani, T. Lauer:
"Computational optimization of the efficiency of a large gas engine";
Talk: AVL AST International User Conference 2011, Graz (invited); 2011-06-28 - 2011-06-30; in: "AVL AST International User Conference 2011", AVL List GmbH (ed.); (2011), 9 pages.

The combustion process of a large gas engine operating at very lean conditions is simulated in the present study. The CFD software FIRE® was used for the analysis of the flame front propagation. The modified and extended coherent flame models (MCFM and ECFM) were examined and the tuning approach is shown. Then the influence of the combustion chamber geometry on flame front propagation is exposed. Design of experiment (DoE) and optimization approaches based on a BOOST® one-dimensional single cylinder engine model were introduced. Predictive models for the nitrogen oxide (NO) formation (according to Pattas and Häfner) and for the knock prediction (acc. to Douaud and Eyzat) were used. A parameterized heat release curve was used to define the optimum shape necessary to increase the thermal efficiency within the limits of NO-Emissions and knock probability.
A late ignition and short combustion duration could be shown as the best solution.

gas engine, combustion, efficiency, NO-formation, knocking