Insights From Direct Numerical Simulation Of Multi-Stage Ignition And Flame Propagation In Intense Shear-Driven Turbulence

Direct numerical simulation (DNS) of turbulent combustion on petascale supercomputers has transformed our ability to interrogate fine-grained gas-phase ‘turbulence-chemistry’ interactions in simple laboratory configurations. In particular, three-dimensional DNS, performed at moderate Reynolds numbers, at ambient and elevated pressure and with complex chemistry has provided an unprecedented level of detail used to isolate and understand mechanistic causality between turbulence, mixing and reaction in combustion regimes dominated by finite-rate chemical kinetics. The DNS data has provided new physical insights and statistical results to assist in the development and validation of engineering CFD models. In this presentation, the role of shear-driven turbulence on spontaneous ignition, flame stabilization and propagation problems relevant to diesel engines, and stationary and aero-gas turbine engines will be presented. In particular, the role of low-temperature cool flames on the dynamics of n-dodecane ignition at diesel conditions, and turbulent mixing effects in high-Karlovitz piloted premixed methane/air jet flames will be elucidated. Finally, I will describe recent advances in alternative asynchronous task-based programming models applied to CFD simulations to facilitate more comprehensive data-intensive workflows on exascale machines in the 2020 horizon.

About the speaker...
Jacqueline H. Chen is a Distinguished Member of Technical Staff at the Combustion Research Facility at Sandia National Laboratories. She has contributed broadly to research in petascale direct numerical simulations (DNS) of turbulent combustion focusing on fundamental turbulence-chemistry interactions. These benchmark simulations provide fundamental insight into combustion processes and are used by the combustion modeling community to develop and validate turbulent combustion models for engineering CFD simulations. In collaboration with computer scientists and applied mathematicians, she was the founding Director of the Center for Exascale Simulation of Combustion in Turbulence (ExaCT). She led an interdisciplinary team to co-design DNS algorithms, domain-specific programming environments, scientific data management and in situ uncertainty quantification and analytics, and architectural simulation and modeling with combustion proxy applications. She is also the PI of a DOE Exascale Simulation Project on Combustion. She received the DOE INCITE Award in 2005-2017, the DOE ALCC Award in 2012, and the 34th International Combustion Symposium Distinguished Paper Award 2012. She is a member of the DOE Advanced Scientific Computing Research Advisory Committee (ASCAC) and Subcommittees on Exascale Computing, and Big Data and Exascale. She was the editor of Flow, Turbulence, and Combustion, the co-editor of the Proceedings of the Combustion Institute, volumes 29 and 30, the Co-Chair of the Local Organizing Committee for the 35th Intl Combustion Symposium, and a member of the Board of Directors of the Combustion Institute.