Large Eddy Simulation of a swirling premixed flame
in a laboratory-scale annular combustor. Left side
of image shows the instantaneous velocity field,
the right side shows the time-averaged velocity field.
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Large Eddy Simulation of a swirling premixed flame in a laboratory-scale annular combustor. Left side of image shows the instantaneous velocity field, the right side shows the time-averaged velocity field. |
Application of the Large Eddy Simulation (LES) technique provides the formal ability to treat the full range of multidimensional time and length scales that exist in turbulent reacting flows in a computationally feasible manner. The large energetic-scales are resolved directly. The small “subgrid-scales” are modeled. This allows simulation of the complex multiple-time multiple-length scale coupling between processes in a time-accurate manner. It also facilitates the simultaneous analysis of all dynamic processes in a given geometric configuration if an appropriated level of physics is represented by the models, and if correspondingly appropriate grid resolutions are applied. Treating the full range of scales is a critical requirement since turbulent interactions are inherently coupled through a cascade of nonlinear interactions. This presentation will provide a perspective on LES and its application to turbulent combustion. In particular, the combination of LES, high-performance massively-parallel computing, and advanced experimental capabilities in combustion science offer unprecedented opportunities for synergistic, high-fidelity investigations of combustion phenomena. Information from state-of-the-art laser-based experiments on well-defined benchmark flames, combined with detailed simulations that match the experimental conditions, present new opportunities to understand the central physics of turbulence-chemistry interactions and for the development of accurate predictive models. Understanding these fundamental physical processes, and developing advanced simulation capabilities that efficiently and accurately describe them, are crucial requirements for the development of next generation combustion systems. Results will be shown to demonstrate the progression toward more complex systems, with emphasis placed on the fundamental issues of turbulence-chemistry interactions and the value of carefully designed experiments for model validation.