2020/06/23 by Ryan Darragh, Darragh, Ryan, Colin Towery +5
Chemical Engineering · Engineering · #Advanced Combustion Engine Technologies #Combustion and flame dynamics #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Particle Dynamics in Fluid Flows
paper · pdf · doi:10.48550/arxiv.2006.13749
openalex publication_date 2020/06/23 · openalex created_date 2022/07/17 · openalex updated_date 2026/07/28
Turbulent mixing is a physical process of fundamental importance in\nhigh-speed premixed flames. This mixing results in enhanced transport of\ntemperature and chemical scalars, leading to potentially large changes in flame\nstructure and dynamics. To understand turbulent mixing in non-reacting flows, a\nnumber of classical theories have been proposed to describe the scaling and\nstatistics of dispersing fluid particle pairs, including predictions of the\neffective, or turbulent, eddy diffusivity. Here we examine the validity of\nthese classical theories through the study of fluid particle pair dispersion\nand eddy diffusivity in highly turbulent premixed methane-air flames at a\nKarlovitz number of approximately 140. Using data from a direct numerical\nsimulation and a higher-order Lagrangian tracking algorithm, particle pair\ncentroids are seeded at different initial temperatures and separations, and\nthen integrated forward in time. We show that scaling relations and results\ndeveloped for pair dispersion in non-reacting flows remain relevant in this\nhigh-intensity premixed flame, and we identify the impacts of heat release on\ndispersion and eddy diffusivity.\n