The characteristics of synags/air mixture explosion in half-open and closed ducts with various hydrogen fractions at the stoichiometric were comparatively studied by a self-made laboratory experimental facility. The results show that there is a significant difference in the premixed flame propagation structure of syngas explosion in open and closed pipelines. In the closed duct
the classic tulip flame is observed from all hydrogen fractions
and the distorted tulip flame can be observed at the hydrogen fraction of 70% and 90%
respectively. In the half-open duct
the classic tulip flame forms at hydrogen fraction of 10%
30%
and 50%
respectively
and the distorted tulip flame can be observed at the hydrogen fraction of 10% and 30%
respectively. Both in half-open and closed duct
the flame propagation speed and maximum pressure increases with the hydrogen fraction increase. When the hydrogen fraction is low (f < 50%)
the flame propagation speed and maximum pressure increase rapidly as hydrogen fraction increases
and at higher hydrogen fraction (f ≥ 50%)
the flame propagation speed and maximum pressure increase slowly with increasing hydrogen fraction.