Computational diagnostics for reacting flows with global pathway analysis aided by chemical explosive mode analysis

Due to the development of computational capability for reacting flows nowadays, more and more detailed and large-sized information and data are generated by reacting flow simulations. To extract meaningful information from these data sets, computational diagnostic methods are critical, especially when detailed chemistry with thousands of reactions are involved. In this study, in light of the methods of chemical explosive mode analysis (CEMA) and global pathway analysis (GPA), we proposed a hybrid CEMA-GPA method, the CEMA-aided GPA (CGPA) method, to not only understand the combustion modes and the contributing reactions and species, but also achieve a global representation of the chemical kinetics that contribute the most to the local explosiveness. Based on this newly-developed CGPA, a one dimensional (1D) premixed flame is firstly simulated and analyzed, showing that CGPA is able to capture the diffusion assisted ignition mode in this flame. More importantly, the global reaction pathways at different positions are identified and the reactions and radical production associated with the global pathways are extracted to understand the flame structure and chemical kinetics. A three dimensional (3D) piloted turbulent jet flame (Sandia Flame D) is then simulated and analyzed with CGPA.