Experimental study of the combined effects of CO2 and obstacles on the explosive behavior of syngas

This article experimentally investigates the explosion behaviors of syngas, focusing on the combined effects of obstacles and CO2 on flame front evolution, flame front velocity (FFV), overpressure, and maximum overpressure (Pmax). Results demonstrate that CO2 prolongs the flame propagation time, with increasing concentration delaying the onset time of the tulip flame (ttulip). A secondary tulip phenomenon is observed at alpha(H2) = 30 % and alpha(CO2) = 20 %. For pipes with obstacles, increasing CO2 concentration reduces the impact of the obstacles on flame propagation, slows the flame front velocity, and causes the flame front to exhibit different shapes after passing through the obstacle. As alpha(H2) increases, the overpressure also rises substantially, with Pmax increasing up to 3.74 times compared to the scenario without obstacles. When alpha(CO2) reaches 15 %-20 %, the Pmax without obstacles surpasses that with obstacles, suggesting that at higher alpha(CO2), the obstacles have a minimal impact on the gas explosion, with alpha(CO2) becoming the dominant factor.