Location
MC 5501
Speaker
Cecile Devaud, Mechanical and Mechatronics Engineering, University of Waterloo
Title
Conditional Moment Closure methods for turbulent flames
Abstract
This presentation will be focused on the numerical aspects behind the simulations of turbulent combustion phenomena and specific physical models with their associated numerical methods. Combustion processes have been around for a long time; however, turbulent combustion simulations remain challenging with many unresolved issues that need to be carefully examined. With increasing demands for sustainable energy, additional problems are encountered related to new fuel blends and their impact on flame stability, ignition/extinction and atmospheric emissions. There is strong coupling between the turbulent fluctuations initially stemming from the turbulent flow and mixing environment and the chemical reactions. This creates non-linear terms in the flow, enthalpy and chemical species transport equations. Their determination is not trivial and leads to what is called the “closure” problem. Several turbulent combustion models exist with pros and cons for each. Methods relying on conditional moment closure will be reviewed. These models include at least one additional variable space to better capture the level of turbulent fluctuations in the determination of the mean chemical source term in the species transport equations. This conditioning approach may be implemented differently leading to different numerical treatments. Within this framework, numerical techniques will be reviewed in the context of applications in Computational Fluid Dynamics (CFD). This will be followed by some recent developments and illustrations from our research group.