Michael E. Mueller

Department of Mechanical and Aerospace Engineering

Princeton University

“Turbulent Combustion Modeling for Large Eddy Simulation: Finding Simplicity in Complexity”

May 2 @ 1:30pm
Montgomery Knight Rm 317

Abstract:

Turbulent combustion modeling is a challenging multi-physics, multi-scale modeling problem.  Both turbulence and combustion are already difficult multi-scale problems, and the combination of the two brings in new interactions across various length and time scales that fundamentally change both the combustion processes and the turbulence.  This seminar will focus on the modeling of unresolved, small-scale details of the combustion processes and the many chemical species involved.

Large Eddy Simulation (LES) models for turbulent combustion generally fall into two distinct classes subject to an inherent trade-off: models that are very general in their description of the underlying combustion processes but computationally intensive versus models that make very constraining assumptions about the underlying combustion processes but are computationally efficient.  In the latter class of models, the combustion processes are typically constrained to low-dimensional manifolds obtained by assuming combustion occurs in a single asymptotic mode: premixed flames, nonpremixed flames, or homogeneous reactions.  For multi-modal combustion, the current state-of-the-art is to apply the “best” asymptotic model locally.  However, recent LES results in a laboratory-scale turbulent flame exhibiting partially premixed combustion demonstrate the inherent shortcomings of this approach not only in selecting the “best” asymptotic model but also in relying solely on asymptotic models.

In the final portion of the seminar, a new, generalized combustion model will be presented that seeks to break the inherent trade-off above.  The model relies on a more detailed manifold description that can capture not only all of the asymptotic modes of combustion in their respective limits but also intermediate regimes.  Key characteristics of the model will be discussed, and algorithmic challenges and opportunities in coupling the model with LES will be highlighted.

About the speaker:

Michael E. Mueller is an Assistant Professor in the Department of Mechanical and Aerospace Engineering at Princeton University, an associated faculty member in the Princeton Institute for Computational Science and Engineering, and an associated faculty member in the Andlinger Center for Energy and the Environment.  He received a BS degree in mechanical engineering from The University of Texas at Austin in 2007, a MS degree in mechanical engineering from Stanford University in 2009, and a PhD degree in mechanical engineering from Stanford University in 2012 before moving to Princeton in 2012.  His expertise is the computational modeling of turbulent reacting flows, where he utilizes a multi-fidelity approach leveraging first-principles calculations for physics discovery for the development of physics-based models for engineering calculations.  Areas of current interest within his research group include multi-modal turbulent combustion, pollutant emissions, and combustion-affected turbulence.  In addition, he is active in areas of applied computational science including the development of new approaches to uncertainty quantification and the development of new numerical algorithms and their implementation on emerging architectures.