High-speed combustion

Since 2014, we have undertaken extensive studies of the multi-scale interactions between turbulence and premixed flames, particularly focused on highly turbulent conditions. Using a conditional Fourier analysis and data from direct numerical simulations (DNS) of premixed flames, we provided the first quantitative evidence of net kinetic energy backscatter in turbulent premixed combustion. In particular, an analysis of spectral kinetic energy transfer indicated that, contrary to the net down-scale transfer of energy found in the unburnt reactants, advective processes lead to a net transfer of energy from small to large scales in the flame brush close to the products. Since this study, we have continued to examine multi-scale turbulence-flame interactions and the spectral structure of turbulence in premixed flames using structure function, differential filtering, and wavelet analyses. Taken together, these studies represent an in-depth and coordinated effort to understand the multi-scale nature of turbulence and premixed flames, and our group has subsequently become one of the leaders in this area of study.

To better understand the effects of turbulence on chemical reactions in the flame, we have developed and used a Lagrangian analysis to track changes in chemical species concentrations and thermodynamic variables as they occur in fluid parcels traveling through a premixed flame. We found that temperature and chemical species evolutions along fluid trajectories were non-monotonic due to the effects of molecular transport, that fluid parcel residence times during combustion were substantially shorter as the turbulence intensity increased, and that the turbulent flame speed could be predicted using only Lagrangian information. These results have implications for our understanding of turbulent flame structure, chemical reaction pathways, flame speed predictions, and the formation of reactant pockets in highly turbulent flames. We have now extended this analysis to the study of autoignition and combustion modes in highly compressible reactive turbulence.

Michael Meehan
Michael Meehan
PhD Student

Mike is a graduate student using computation fluid dynamics to understand fundamental physics in turbulent combustion problems.

Ryan Darragh
Ryan Darragh
Computational Physicist
Colin Towery
Colin Towery
Postdoctoral Research Associate

Colin is a former research associate in the Paul M. Rady Department of Mechanical Engineering at the University of Colorado Boulder and also a former student in the Turbulence and Energy Systems Laboratory, earned his PhD in May 2018.

Sam Whitman
Sam Whitman
PhD student
Jennifer Miklaszewski
Jennifer Miklaszewski
PhD student

Short bio here.

Peter Hamlington
Peter Hamlington
Associate Professor

Peter is an associate professor in the Paul M. Rady Department of Mechanical Engineering at the University of Colorado Boulder and the principal investigator of the Turbulence and Energy Systems Laboratory.

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