Theoretical prediction of hydrogen cloud explosion overpressure considering self-accelerating flame propagation

Abstract

On the basis of revealing the effects of equivalence ratio on flame morphology, radius and maximum explosion overpressure, this work was aimed at establishing a theoretical model to predict hydrogen cloud explosion overpressure by considering self-accelerating flame propagation. The results indicated that the decreasing order of flame propagation velocity is Φ=2.0, Φ=1.0 and Φ=0.8. For Le＜1.0 and Le＞1.0, the cellular structures could be formed on the flame surface, which would increase flame surface area and result in self-accelerating flame propagation. When the equivalence ratio was fixed, the positive maximum explosion overpressure and absolute value of negative maximum explosion overpressure continue to decrease as the distance between pressure senor and ignition source increases. As the equivalence ratio changes, there are some differences for positive maximum explosion overpressure and absolute value of negative maximum explosion overpressure at the fixed distance. The absolute value of negative maximum explosion overpressure was relatively higher than positive maximum explosion overpressure. Before rupture of thin film, the explosion overpressure evolution at various monitoring points could be reproduced using the theoretical model considering self-accelerating flame propagation.