Experimental study on the results of natural gas explosions in tunnels and the effect of damage on parallel pipelines

• A parallel pipeline explosion experimental system is constructed in a tunnel space. • The dynamic responses of gas cloud explosions on parallel pipelines are explored. • A correlation is set between peak overpressure, peak time, and the gas cloud volume. In this study, we examine the progression of natural gas explosions within confined tunnel spaces, employing both experimental and numerical methodologies. The primary focus is elucidating the explosion pressure development and the dynamic response to the adjacent pipelines. This paper describes a confined space natural gas leakage explosion experiment under the condition of three pipelines in parallel. The explosion overpressure curve can be segmented into four phases: ignition delay, primary explosion, secondary explosion, and oscillation decay. The Φ219 and Φ813 pipelines are in a safe state under the influence of the explosion shock wave. Next, the pressure change trends at each monitoring point are simulated by establishing a three-dimensional finite element model that includes the tunnel pipeline gas system. The pressure changes are characterized by an initial increase followed by a decrease, confirming the experimental results. Furthermore, the volume of the exploding gas cloud shows a quadratic polynomial and approximately linear relationship with the peak overpressure and peak time, respectively. The findings of this study offer valuable insights and references for ensuring the secure operation of parallel pipelines within tunnel environments.