Effects of mesh size on wrinkle behavior of H-air premixed flame inside of a vessel; Numerical simulations by using XiFoam

Thwe Thwe, A.  ; Terada, Atsuhiko  ; Hino, Ryutaro; Kadowaki, Satoshi

For the risk reduction on hydrogen combustion and explosion due to hydrogen generated by radiolysis of water inside of high-level radioactive waste vessels, understanding the phenomena and characteristics of hydrogen combustion is necessary, and CFD approaches are of important role. In this numerical simulation, XiFoam solver was modified by adding a new laminar flame speed model deduced from experiment by Katsumi et al. (Nagaoka University of Technology). It reproduced the propagation of H-air premixed flame and we clarified the effects of mesh size (2 mm to 0.625 mm) on wrinkle behavior. The results showed that the mesh size should be equal to or less than 1.0mm to observe the wrinkle behavior of flame in which the flame temperature and radius for each mesh size were almost same at 0.003s to 0.006s, and then the former increased and the later became large due to intrinsic instabilities. The wrinkle flame shape from the simulation was similar to that from the experiment when the mesh size became small.