DOI: 10.1615/ICHMT.2012.ProcSevIntSympTurbHeatTransfPal
ISBN Print: 978-1-56700-302-4
ISSN: 2377-2816
Local structure of swirling premixed flame in a microscale combustor
SINOPSIS
To investigate local structure of swirling premixed flame, direct numerical simulation of hydrogenair swirling premixed flame in a micro combustor is conducted by considering a detailed kinetic mechanism. Two swirl number cases of 0.6 and 1.2 are investigated. Large-scale helical vortical structures are generated near the inlet of combustion chamber, and a lot of fine-scale vortices emerge downstream. Flame structure is entrained by the vortical structure and thin layer of unburnt mixture is generated in the inner recirculation zone. Flame structures depend largely on the swirl number. For the case of S = 0.6, H atom tends to be retained in the inner recirculation zone and shows high concentration. This behavior is different from that in the outer region. Temperature continues to increase even farther downstream consuming H and O atom and generating OH gradually. For the case of S = 1.2, H atom exists in a thick layer around the inlet and temperature in this region is also high. Furthermore, OH concentration tends to be high near the inlet. Moreover, interactions between flame and eddy structure and pressure fluctuations in the combustor are discussed.