Laboratory-Scale Turbulent Premixed Flames
Using our adaptive low Mach number combustion code, we have begun to simulate low-emission premixed turbulent flame experiments in LBNL's EETD laboratories. The goal of the experiments is to aid in the understanding of premixed flames under a variety of turbulent stabilization scenarios, and in particular to assess the effects of turbulence on the combustion process in lean premixed flames. Current flame diagnostics include photographs and particle image velocitimetry (PIV) for instantaneous realizations of the highly wrinkled turbulent flame surfaces. Note that without a full map of the reacting flow field, laboratory researchers are left to infer the behavior of the three-dimensional flame surface using only two-dimensional images. Also, there is essentially no information readily available for determining fuel consumption charateristics, or the behavior of flame radicals, etc.
Without invoking phenomenological or heuristic models for subgrid-scale behavior, CCSE's low Mach number model incorporates the detailed chemistry and transport of up to 20 species in this premixed methane flame. The modelled domain includes the entire relevant flow field (tens of centimeters from the nozzle outflow). Additionally, since little is known about the details of the high-speed cold flow within the nozzle itself, we simulate that flow as well using a geometry-capable adaptive model for compressible gas. Results from the auxiliary compressible calculation are coupled into the low Mach simulation through numerical boundary conditions at the inlet plane.
Follow the links below to pages describing various applications of the adaptive low Mach projection method to turbulent premixed combustion.
The adaptive low Mach number simulation code, an extension of CCSE code IAMR for incompressible flows, is not presently available for release. For more information about the adaptive methodology for low Mach number combustion modeling applications, or about these calculations, contact Marc Day or John Bell of CCSE.