Lagrangian Simulation of Diffusion Flames

Abstract

Abstract Abstract-We develop a new Lagrangian numerical technique to investigate the interaction between fluid mechanics and chemical reaction in diffusion flames through volumetric expansion and baroclinic vorticity production. We base our numerical method on the mixture-fraction variable formulation and the Burke-Schumann limit of an infinitely thin flame sheet, In this way. we do not attempt to resolve the flame structure in detail, but instead are in a position to simulate combustion in more complex flow fields. The method employs Lagrangian blobs that carry gradients of the mixture-fraction variable. Other blobs act as sources to account for thermal expansion, while vortex blobs are introduced to represent the baroclinic vorticity production. These blobs deform as a result of diffusion, strain, and thermal expansion. In its Lagrangian nature, our approach to diffusion flames corresponds to the technique recently developed by Ghoniem for premixed flames. In the incompressible flow limit, we demonstrat...