CAREER: Structure and Dynamics of Highly Turbulent Premixed Combustion

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

Highly turbulent premixed flames are found in a range of engineering and natural systems, including engines, gas turbines, and even supernova explosions. Much of the current knowledge in this area has been obtained from numerical simulations of idealized configurations using relatively simple chemical models. To address the need for greater realism, this project will use advanced computational tools and more sophisticated chemical modeling to study the characteristics and behaviors of highly turbulent premixed flames in practically relevant configurations. Ultimately, physical insights resulting from this project will enable more accurate simulations of advanced energy systems. Complementary to the research goals of this project, a new summer workshop on computational fluid dynamics will be established for under-represented minority students. The goal of this workshop is to give the next generation of scientists and engineers, from all backgrounds, experience in modeling real-world energy systems. These students will improve their understanding of the engineering design process as well as become aware of the environmental and engineering issues related to the continued use of combustion for energy generation. This research will make use of adaptive mesh refinement (AMR) for overcoming the computational cost of simulating more complex practical configurations, including those where secondary flows, shear, swirl, and walls are important. Using AMR, new direct numerical simulations will be performed, and the resulting datasets will be examined using Lagrangian and scale-dependent diagnostics to address three fundamental questions: (i) How does high intensity turbulence affect premixed flame structure, dynamics, and chemical pathways? (ii) How are turbulence structure and kinetic energy dynamics affected by premixed flames? (iii) How do flame properties depend on configuration and operating conditions? The configurations examined will include bluff-body stabilized flames, interacting jet and Bunsen flames, and swirling multi-nozzle combustors. Each of the simulations will be performed in close collaboration with experimentalists, allowing validation of all results. In addition to refining theories and models of highly turbulent combustion, the proposed project will impact the broader combustion community by publicly sharing data and statistics from each of the simulations, as well as all analysis codes and diagnostic tools. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.