Abstract
Direct numerical simulations of three-dimensional spatially-developing turbulent Bunsen flames were performed at three different turbulence intensities. The simulations were performed using a reduced methane-air chemical mechanism which was specifically tailored for the lean premixed conditions simulated here. A planar-jet turbulent Bunsen flame configuration was used in which turbulent preheated methane-air mixture at 0.7 equivalence ratio issued through a central jet and was surrounded by a hot laminar coflow of burned products. The turbulence characteristics at the jet inflow were selected such that combustion occured in the thin reaction zones (TRZ) regime. At the lowest turbulence intensity, the conditions fall on the boundary between the TRZ regime and the corrugated flamelet regime, and progressively moved further into the TRZ regime by increasing the turbulent intensity. The data from the three simulations was analyzed to understand the effect of turbulent stirring on the flame structure and thickness. Statistical analysis of the data showed that the thermal preheat layer of the flame was thickened due to the action of turbulence, but the reaction zone was not significantly affected. A global and local analysis of the burning velocity of the flame was performed to compare the different flames. Detailed statistical averages of the flame speed were also obtained to study the spatial dependence of displacement speed and its correlation to strain rate and curvature.
| Original language | English |
|---|---|
| Pages (from-to) | 3294-3306 |
| Number of pages | 13 |
| Journal | Combustion and Flame |
| Volume | 162 |
| Issue number | 9 |
| DOIs | |
| State | Published - Aug 17 2015 |
Funding
Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725 . The work at SNL was supported by the Division of Chemical Sciences, Geosciences and Biosciences, the Office of Basic Energy Sciences (BES), the U.S. Department of Energy (DOE) and also by the U.S. DOE, BES, SciDAC Computational Chemistry program . SNL is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the U.S. DOE under contract DE-AC04-94-AL85000. The work at UNIST was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2015R1A2A2A01007378 ).
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-AC04-94-AL85000, DE-AC05-00OR22725 |
| Office of Science | |
| Basic Energy Sciences | |
| Chemical Sciences, Geosciences, and Biosciences Division | |
| Ministry of Science, ICT and Future Planning | 2015R1A2A2A01007378 |
| National Research Foundation of Korea |
Keywords
- Direct numerical simulation
- Flame speed
- Lean premixed
- Natural gas
- Thin reaction zones
- Turbulent combustion