Experimental Investigation of Obstruction Effects on C₃H₈/H₂ Hybrid Fuel Explosion Dynamics in Semiconfined Pipelines

This study systematically investigates the effects of porous obstacle blockage ratios on the explosion characteristics of C₃H₈/H₂ mixtures in semiconfined pipelines through experimental methods. High-speed imaging and high-frequency pressure sensors were employed to simultaneously capture flame propagation dynamics and pressure field evolution. The results demonstrate that porous obstacles significantly alter flame propagation mechanisms. At blockage ratios exceeding 75%, flame acceleration becomes pronounced with propagation velocities increasing by 2-3 times, while flame fronts develop distinct turbulent characteristics. The overpressure evolution exhibits a three-stage pattern, reaching peak values at 87% blockage ratio before declining with further increases. Pressure waves display significant reflection and superposition effects near obstacles, with underpressure duration showing positive correlation with blockage ratio. A modified deflagration index model reveals maximum explosion hazard at 87% blockage ratio. These findings provide critical experimental evidence and theoretical support for safety design and explosion suppression in hydrogen-blended fuel pipeline systems.