Investigation of Subgrid-Scale Mixing and Turbulence-Chemistry Interaction in Turbulent Partially Premixed Flames
Abstract
This research project focused on issues met in using large-eddy simulation (LES) to predict turbulent nonpremixed/partially premixed combustion. In LES of such flames the subgrid-scale (SGS) scalar mixing and the resulting subgrid-scale scalar distributions must be faithfully represented. In this research the mixture fraction filtered mass density function (FMDF) of mixture fraction, temperature, and species mass fractions, the conditionally filtered dissipation rates and the conditionally filtered diffusion were studied experimentally using data from Sandia flames. The results show that the subgrid-scale mixture fraction has two limiting mixing regimes, which have strong effects on the flame structure. For the well mixed regimes the scalar diffusion had a simple structure whereas for the poorly mixed regime the diffusion structure was more complex, with the reaction and the spatial structure playing important roles. The results in the present study suggest that it is important for combustion models to predict accurately both distributed reaction zones and flamelets. Specifically, mixing models need to be able to account for the different SGS mixing structures.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 07, 2012
- Accession Number
- ADA567058
Entities
People
- Chenning Tong
Organizations
- Clemson University