Comparative study on explosion characteristics of hydrogen and gasoline vapor in a semi-confined pipe based on Large Eddy Simulation

•LES simulation has been applied to study the explosion characteristics of hydrogen and gasoline vapor occurring in a semi-confined pipe with and without obstacles.•The growth rates of hydrogen explosion parameters relative to gasoline vapor explosion parameters of the pipe without obstacle were significantly higher than those of barrier conditions.•The growth rate of the explosion parameters of gasoline vapor explosion condition was significantly higher than those of hydrogen explosion in the pipe with obstacles. In this work, Large Eddy Simulation has been applied to investigate the explosion characteristics of hydrogen and gasoline vapor in a pipe with and without obstacles. It is found that the explosion parameters caucused by the hydrogen explosion are significantly more violent than those of gasoline vapor explosion, both for the conditions with and without obstacles. However, the growth rates of hydrogen explosion parameters relative to gasoline vapor explosion parameters of the pipe without obstacles are significantly higher than those of the conditions without obstacles. With obstacles in the pipe, the growth rates of the explosion parameters of gasoline vapor explosion conditions are significantly higher than those of hydrogen explosion. Additionally, it is found that for gasoline vapor explosion, when the flame propagated through the obstacles, the obstacles would hinder the flame propagation for a very short time, causing the flame speed to rise rapidly, while for hydrogen explosion in the same condition, no similar phenomenon can be observed. Moreover, it could be seen that with obstacles in the pipe, the rise of explosion overpressure is more synchronized with the coupling of the combustion reaction, and the synchronization is less obvious for the pipe without obstacles.