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Nuclear Science and Engineering, 71(3), p.330 - 342, 1979/00
Times Cited Count:6no abstracts in English
Thwe Thwe, A.; Terada, Atsuhiko; Hino, Ryutaro; Kadowaki, Satoshi
no journal, ,
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.
Thwe Thwe, A.; Terada, Atsuhiko; Hino, Ryutaro; Nagaishi, Ryuji; Kadowaki, Satoshi
no journal, ,
For long-term safe storage of fuel debris from hydrogen (H) explosion, the development of simulation codes for H behaviors is important. In this simulation, propagation of H-air premixed flames was reproduced by using a public open source code OpenFOAM. Not only default solver but also modified one based on a new laminar flame speed model derived from the experiments at Nagaoka University of Technology were applied. Three-dimensional 1/8 of cubic shaped vessels with two sizes of 0.21m and 0.13m in length were modeled with mesh sizes of 0.625mm and 0.5mm, respectively. H-air mixture with a unity equivalence ratio, temperature 298K and pressure 101,325Pa was used. The flames propagated spherically and the propagation phenomena had good agreement with the experimental results within 0.005s. The wrinkle flame shape appeared in the smaller model was more likely with that observed in the experiments. This is because mesh size has influence on the wrinkle shape formation in the simulations.