In order to fully understand the explosion risk of electrostatic spraying powder, corresponding preventive measures are put forward. The explosion characteristics, ignition sensitivity, and flame propagation of three typical electrostatic spraying powders were tested using a 20 L spherical explosion test device, a G-G furnace test device, and a Hartmann tube test device, and the explosion process and mechanism of electrostatic spraying powders were discussed. The results show that the maximum explosion pressure and the maximum explosion pressure rise rate increase first and then decrease with the increase in mass concentration. The maximum explosion pressure and the maximum explosion pressure rise rate of acrylic powder coating are the largest, which are 0.75 and 85.4 MPa/s, respectively. The shortest burning time is 97.5 ms, and the highest explosion danger level is 23.46 MPa·m/s. The flame propagation of electrostatic spraying powder develops slowly; the flame front spreads linearly and the average flame velocity increases first and then decreases. The explosive development process of powder coating particles is concentrated in the three-phase system of solid particles, molten particles, and pyrolytic gasification combustible gas, which goes through the kinetic process of particle heating melting, cross-linking curing, pyrolytic gasification, combustion, and extinction.

Aiming at the shortcomings of the current rock-breaking technology, a new type of high-energy expansion agent for energetic materials based on combustion-to-detonation was developed. By characterizing the basic physical and chemical properties of the high-energy expansion agent (HEEA) such as morphology, particle size distribution, and pyrolysis characteristics, the work performance of different types of high-energy expansion agents was analyzed in combination with the energy characteristics. The results showed that the relationship between the expansion work done by the gas to the outside world was W_HEEA-I > W_HEEA-II > W_HEEA-III under the same quality of HEEA combustion. The damage effect of high-temperature and high-pressure gas cracking specimens generated by deflagration of HEEA was obvious, having the rule that the disturbance damage of rock caused by low heat and high gas specific volume was smaller, and the damage degree of rock caused by high heat and low gas specific volume was larger. The mechanism of HEEA combustion and detonation in confined space is revealed, which provides a theoretical basis for the application of HEEA-cracked rock.

This study investigated the inhibitory effect and mechanism of modified ultrafine ABC powder on the explosion of a methane (CH₄)/coal dust mixed system. Through experiments, it was found that the addition of ABC powder significantly weakened the deflagration characteristics of the CH₄/coal dust mixture system. During decomposition, heat was absorbed to generate ammonia and phosphoric acid. Inert gases such as CO₂ and water vapor produced during decomposition could dilute the oxygen concentration. Phosphate ions produced during the decomposition of ammonium phosphate would bind with free radicals during combustion, reducing their reactivity. The explosion reaction was suppressed through a dual mechanism of physical cooling and chemical consumption of free radicals. The experimental results showed that the weight loss rate of modified ABC powder was 49% at 800 °C, while the weight loss rate of unmodified ABC powder was 78%. The modified ABC powder had better thermal stability and could absorb more heat at high temperatures, further suppressing explosive reactions. This study provides a new modification scheme for explosion suppressants for coal mine safety, which has important theoretical and practical application value.

This study investigates the microscale suppression mechanisms of four powder explosion suppressants on coal dust/methane (CH₄) mixed system explosions. Combining experimental and numerical simulation methods, we explore the gas-phase reaction processes and the role of free radicals in the explosion suppression. Results show that all suppressants reduce the maximum explosion pressure and pressure rise rate, with MPP being the most effective, reducing pressure by 38%. Suppressants inhibit explosions through physical (heat absorption) and chemical (free-radical consumption) mechanisms. Phosphorus-containing intermediates from NH₄H₂PO₄ and MPP react with free radicals, while NaHCO₃ and MCA decompose to produce inert gases and consume O• and H• radicals. This work provides a theoretical foundation for optimizing explosion suppressants in mining safety applications.

The explosion characteristics and explosion mechanism of petroleum volatile gas were studied by 20 L spherical explosion experiment and gas explosion flame propagation experiment. The results show that with the increase of the equivalent ratio, the peak explosion pressure and the maximum explosion pressure rise first and then decline. When the equivalent ratio is 1.2, the explosion pressure reaches the maximum. Under different equivalent ratio conditions, the flame propagation trend shows “N” type, and the propagation speed is the fastest when the equivalent ratio is 1.0. During the test of petroleum volatile gas explosion in a closed container, the effect of heat loss on the test results should not be ignored.