Direct Numerical Simulation of an Unpremixed Jet Flame.
Abstract
Direct numerical simulations have been used to study the effects of large coherent structures in two-dimensional, unpremixed, chemically reacting mixing layers under both temporally evolving and spatially developing assumptions. In the temporally evolving mixing layer calculations, a temperature dependent chemical reaction was incorporated into a computer code that uses pseudospectral numerical methods. The nonequilibrium effects leading to the local quenching of a diffusion flame were investigated. Results indicate that the primary important parameter to be considered for flame extinction is the local instantaneous scalar dissipation rate conditioned at the scalar stoichiometric value. At locations where this value is increased beyond a critical value, the local temperature decreases and the instantaneous reaction rate drops to zero, leading to local quenching of the flame. Purposes of simulating spatially developing flows, a two-dimensional, hybrid pseudospectral-finite difference code was constructed. The resulting code was tested with simulations of the pretransitional region of laboratory mixing layers. Examination of some of the statistical quantities obtained from the results of these simulations are in qualitative agreement with recent experimental data obtained at the California Institute of Technology and Stanford University. The asymmetric nature of the mixing processes has been numerically simulated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1986
- Accession Number
- ADA173143
Entities
People
- P. Givi
- R. W. Metcalfe
- W.-h. Jou