Explosion characteristics of aluminum powder in different mixed gas environments

Pressure Characteristics and Secondary Ignition Effects of Gas Produced in RDE Using Lignite and Anthracite/CH4 Fuel

This study aims to address the energy efficiency release and environmental impact of coal dust in rotating detonation engines (RDEs) by monitoring the detonation characteristics of lignite and anthracite in methane gas-solid mixtures using high-precision sensor technology. Experimental results indicate that the peak detonation pressure of anthracite is 1.4% higher than that of lignite, and its detonation wave propagation speed is at least 5.5% faster, suggesting that anthracite exhibits more stable and efficient fuel energy release characteristics during detonation. Additionally, the sensor technology enabled detailed recording of pressure fluctuations and gas composition changes during the detonation process, providing accurate data for assessing and controlling emissions of harmful gases such as carbon monoxide and carbon dioxide. These data are crucial for designing more efficient and environmentally friendly coal dust detonation systems, enhancing mine safety and environmental protection. The outcomes of this research not only advance technological progress in the field of energy science but also address efficiency and environmental issues in industrial applications, offering significant support for achieving safer and more sustainable energy production methods.

Investigation on the Inhibition of Aluminum Dust Explosion by Sodium Bicarbonate and Its Solid Product Sodium Carbonate

To characterize the inhibiting effects of sodium bicarbonate (NaHCO₃) on aluminum dust, the inhibiting capacities of NaHCO₃ and its solid product sodium carbonate (Na₂CO₃) on the explosions of 10 and 20 μm aluminum dusts were studied using a standard 20 L spherical chamber. Explosion parameters were analyzed based on the induction period and explosion stage to evaluate the inhibiting effects. The results show that the induction period of 10 μm aluminum dust explosion is 18.2 ms, which is shorter than that of 20 μm aluminum dust. Two aluminum dust explosions can be completely inhibited during the induction period when inert ratios of NaHCO₃ are 350 and 150%, respectively, but that is not observed after adding the corresponding amount of Na₂CO₃. When the inert ratio ranges from 0 to 150%, the physical effect of NaHCO₃ on 10 μm aluminum is poor and the chemical effect is the essential process. But as the inert ratio increased from 200% to 350%, the physical effect of NaHCO₃ is higher than the chemical effect, suggesting that the physical effect is the key factor. With the increase of NaHCO₃, the physical effect increases gradually. However, the chemical effect changes little. The physical effects of NaHCO₃ including heat absorption and isolation play an essential role in the inhibiting process, which has a significant impact on the pyrolysis process and explosion parameters. The results of the present work provide guidance for the prevention and control of aluminum dust explosions.

Investigation on the Explosion Characteristics of an Aluminum Dust-Diethyl Ether-Air Mixture

In this work, the explosion characteristics of an aluminum (Al)-diethyl ether (DEE)-air mixture were investigated in a 20 L spherical vessel. The effect factors of the explosion characteristics considered were fuel concentration, component proportion, and ignition energy. With the increasing concentration of the mixed fuel (Al/DEE = 1:1), the maximum pressure (P _max), the maximum rate of pressure rise ((dP/dt)_max), and the flame propagation speed (ν_F) exhibit an inversely "U-shaped" curve. The maximum P _max, (dP/dt)_max, and ν_F values are 901.2 kPa, 148.3 MPa/s, and 15.3 m/s, respectively, corresponding to an optimum concentration of 600 g/m³. The P _max, the (dP/dt)_max, and the ν_F increase with the addition of DEE when the proportion of DEE is below 55% but have a decrease tendency when the proportion of DEE is over 55%. As the explosions of Al and DEE were mutually promoting, the studied explosion characteristics of the Al-DEE-air mixture are obviously higher than those of pure Al or DEE in air. The minimum ignition energy (MIE) of the Al-DEE-air mixture is 1.9 mJ, between the MIE of Al and DEE. With the increase of ignition energy, P _max, (dP/dt)_max, and ν_F all increase, while the minimum explosion concentration presents a linear decreasing trend. This work could provide significant scientific evidence for evaluating the explosion risk of the Al-DEE-air mixture.