The explosion wave overpressure and the flame propagation velocity of the gas explosion in a bifurcating duct are experimentally measured and theoretically analyzed. The results show that the effect...

Mine ventilation provides fresh air to underground workers. The dampers can provide a qualified fresh air to each demand workplace by adjusting the air volume, which can ensure workers’ health. However, the powerful impact damage caused by gas explosions in the roadway can lead to deformation and damage to the dampers and even cause the breakdown of the ventilation system. At the same time, the impact effects of gas explosions may cause worker fatalities. For this reason, the dynamic response of gas explosions to dampers and their effects need to be studied. Based on the analysis of the damper construction and the damage characteristics of the gas explosion, ANSYS/LS-DYNA software is used to establish a mathematical-physical model of the damper with ventilation-regulating windows of six different sizes. The reliability of the model is verified by comparing the simulated pressure values with the values calculated by the Sadowski equation. The dynamic response characteristics of the dampers under the gas explosion impact are simulated and the displacement, equivalent stress and effective plastic strain of the dampers are measured. Finally, a theoretical analysis is carried out. The study results show that the displacement of the damper increases gradually from the edge to the center and the deformation is symmetrical in the absence of the ventilation-regulating window. The deformation region below the ventilation-regulating window is more obvious when the ventilation-regulating window is installed. The maximum stress of the damper first appears at the four corners of the damper, the stress of the unit at this position increases with the increase of the side length of the ventilation-regulating window. The stress of the unit in the lower left corner of the ventilation-regulating window first increases and then decreases with the increase of the side length of the ventilation-regulating window, and all the stresses of the units first increase and then decrease, and finally, the stresses basically approach a stable value. From the instantaneous ignition to the completion of the final reaction, the plastic strain gradually increases, but the area of the plastic strain region gradually decreases. The damage and deformation of the damper are basically consistent with the situation of the damper in the explosion accident. The research results can provide some theoretical basis and data support for the damper structure selection, damper location selection and setting of ventilation-regulating window.

In order to investigate the damage influence of the leakage explosion in urban gas pipeline on the surrounding environment, the numerical models of buried PE (polyethylene) pipes under urban pavement were established by using ANSYS/LS‐DYNA in this study. The reliability of the numerical models was verified on the basis of the explosion experiments. According to the amount of gas leakage, the TNT explosive equivalent was determined. The gas leakage explosion process of buried PE pipes was studied, and the pressure and stress changes of pipes and pavements under different explosive equivalents and buried depths were analyzed; at last, the deformation law of pipes and pavements were discussed. The results show that the PE pipes are fractured during the leakage explosion and a spherical explosion cavity is formed in the soil. The pavement above the explosion point bulges upward and forms a circle. The maximum pressure of pipe near the explosion point increases linearly with the increase of explosive equivalent, and a proportional relation is observed between the fracture width of pipe and the explosive equivalent. The degree and duration of pavement deformation increase significantly with the increase of explosive equivalents. The dynamic response of the pipes is rarely affected by the buried depth, and the change of maximum effective stress is no more than 7%. However, the buried depth is of great influence on the damage degree of pavement. When the buried depth increases from 0.9 m to 1.5 m, the pavement deformation can be reduced effectively. The variation rule of pavement deformation is similar to the change rule of maximum overpressure and effective plastic stress; they change in the form of concave functions with the increase of buried depth. The results can provide theoretical basis for municipal pipeline construction design and urban safety planning and provide references for the risk assessment of gas explosion in buried pipelines.

Sound wave fire suppression, an emerging firefighting technology, demonstrates unique potential by regulating the physicochemical processes of flames. This paper systematically reviews the research progress in acoustic fire extinguishing technology. Through a literature review and systematic comparison of existing methodologies, it reveals the core mechanisms of flame suppression: low-frequency sound waves (40–80 Hz) disrupt combustion stability via airflow disturbance, while high-frequency waves (>1 kHz) may rely on thermal effects or resonance mechanisms, with sound pressure and waveform significantly affecting extinguishing efficiency. Experimental results demonstrate that acoustic cavity focusing technology extends the effective fire suppression distance to 1.8 m while improving cooling efficiency by 10–20%. Integration with drone platforms and adaptive feedback systems enhances fire extinguishing energy efficiency by over 30%. When combined with water mist, this approach reduces suppression time to 30 s while mitigating sound pressure hazards. However, the critical parameters distinguishing sound-induced “flame enhancement” from “suppression” remain undefined, with insufficient research on adaptability to solid fuels and complex environments (microgravity, confined spaces), and a lack of high-temperature-resistant acoustic materials and multi-physics coupling models. Current fire suppression technologies predominantly rely on airflow disturbance-driven indirect mechanisms, whose stability remains questionable under extreme scenarios. Future advancements require breakthroughs in acoustic metamaterials, the integration of intelligent algorithms, and the collaborative optimization of multi-technology systems to facilitate the transition of acoustic wave-based fire suppression from laboratory settings to real-world industrial firefighting applications. Additionally, this study proposes an optimized solution that integrates acoustic waves with complementary fire suppression approaches, aiming to enhance overall firefighting effectiveness. Concurrently, an interdisciplinary research framework must be established to address the dual challenges of mechanistic elucidation and practical implementation.