Characteristics of flame-turbulence interactions in freely propagating turbulent premixed flames under decaying and forced isotropic turbulence conditions
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| Title: | Characteristics of flame-turbulence interactions in freely propagating turbulent premixed flames under decaying and forced isotropic turbulence conditions |
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| Authors: | Smith, Robert |
| Committee Members: | Ranjan, Reetesh; Sreenivas, Kidambi; Margraves, Charles; College of Engineering and Computer Science |
| Summary: | Turbulent premixed flames observed in energy conversion and propulsion applications are characterized by highly nonlinear, unsteady, and multi-scale processes. Previous numerical studies of freely propagating flames have utilized either forced or decaying background isotropic turbulence to provide detailed insights into the features of flame-turbulence interactions; however, none have made direct comparisons of cases where the turbulence decays or is sustained using a forcing strategy. This study compares the features of turbulent premixed flames via direct numerical simulations, where we consider both decaying and forced turbulence scenarios. Four turbulent premixed flames are simulated, corresponding to the thin reaction zone and broken/distributed reaction zone regimes. The comparative analysis focuses on the instantaneous reacting flow field, mean flame structure in both physical and state space, and the transport and dynamics of enstrophy. The results provide quantitative insights into how sustained versus decaying turbulence influences flame topology, small-scale vorticity generation, and reaction-zone structure. |
| URL: | https://scholar.utc.edu/theses/1044 |
| Database: | OpenDissertations |
| Abstract: | Turbulent premixed flames observed in energy conversion and propulsion applications are characterized by highly nonlinear, unsteady, and multi-scale processes. Previous numerical studies of freely propagating flames have utilized either forced or decaying background isotropic turbulence to provide detailed insights into the features of flame-turbulence interactions; however, none have made direct comparisons of cases where the turbulence decays or is sustained using a forcing strategy. This study compares the features of turbulent premixed flames via direct numerical simulations, where we consider both decaying and forced turbulence scenarios. Four turbulent premixed flames are simulated, corresponding to the thin reaction zone and broken/distributed reaction zone regimes. The comparative analysis focuses on the instantaneous reacting flow field, mean flame structure in both physical and state space, and the transport and dynamics of enstrophy. The results provide quantitative insights into how sustained versus decaying turbulence influences flame topology, small-scale vorticity generation, and reaction-zone structure. |
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