Explosive Events Research Articles

Numerical Simulation Study of Electromagnetic Pulse in Low-Altitude Nuclear Explosion Source Regions

A nuclear electromagnetic pulse (NEMP) is the fourth effect of a nuclear explosion, characterized by a strong electromagnetic field that can instantly damage electronic devices. To investigate the spatial field value distribution characteristics of the source region of low-altitude NEMPs, this study employed a finite-difference time-domain (FDTD) method based on a rotating ellipsoidal hyperbolic coordinate system. Due to intense field variations near the explosion center, non-uniform grids were employed for both spatial and temporal steps, and an OpenMP parallel algorithm was utilized to enhance computational efficiency. Analysis focused on the following two scenarios: varying angles at a constant distance and varying distances at a constant angle, considering both transverse magnetic (TM) and transverse electric (TE) waves. The results indicate that the spatial field value distribution characteristics differ between the two wave types. For TM waves, the electric and magnetic fields share the same polarity, but their waveform polarities are opposite above and below the explosion center. A TE wave is exactly the opposite. Compared with a TM wave, a TE wave has stronger peak electromagnetic fields but narrower pulse widths and lower overall energy. This research provides significant support for the development of nuclear explosion detection technology and offers theoretical foundations for the protection of surrounding environmental facilities.

Evaluation of the therapeutic effects of nebulized inhalation of hydrogen-rich water on primary blast lung injury in C57BL/6 mice.

Primary blast lung injury is a common and severe consequence of explosion events, characterized by immediate and delayed effects such as apnea and rapid shallow breathing. The overpressure generated by blasts leads to alveolar and capillary damage, resulting in ventilation-perfusion mismatch and increased intrapulmonary shunting. This reduces the effective gas exchange area, causing hypoxemia and hypercapnia. Hydrogen (H2), a small-molecular-weight, nonpolar diatomic molecule, has shown potential in treating various diseases due to its antioxidant and anti-inflammatory properties. This study evaluates the therapeutic effects of nebulized hydrogen-rich water on primary blast lung injury in C57BL/6 mice and explores the underlying mechanisms. C57BL/6 mice (n= 150), aged 6-8weeks, were randomly divided into 2 groups: the blast injury control group (n= 75) and the nebulized hydrogen-rich water treatment group (n= 75). Mice were exposed to a blast overpressure of 266±9.156 kPA and treated with either nebulized hydrogen-rich water or sterile injection water immediately postinjury. Observations were made at 6, 12, 24, and 48hours postinjury. Lung function was assessed using whole-body plethysmography, and arterial blood gases were analyzed. Lung tissue was examined histologically and biochemically for markers of inflammation and oxidative stress. The survival rates at different time points postinjury in the nebulized hydrogen-rich water treatment group were significantly higher than those in the blast injury control group (6hours postinjury: 89.3% vs 78.6%; 12hours postinjury: 81.3% vs 72%; 24hours postinjury: 81.3% vs 61.3%, P < .01). Lung function tests revealed significant improvements in tidal volume (12hours postinjury: 0.11±0.018 vs 0.08±0.016, 24hours postinjury: 0.16±0.013 vs 0.12±0.013, 48hours postinjury: 0.18±0.02 vs 0.13±0.014), respiratory rate (6hours postinjury: 235.07±12.82 vs 268.29±13.73; 12hours postinjury: 265.47±10.06 vs 342.16±16.34; 24hours postinjury: 248.20±9.28 vs 352.80±15.99; 48hours postinjury: 226.12±15.81 vs 318.18±15.81), and minute ventilation (12hours postinjury: 22.05±3.46 vs 15.93±3.68; 24hours postinjury: 27.30±2.15 vs 21.62±2.48; 48hours postinjury: 37.48±3.93 vs 28.32±2.98) in the nebulized hydrogen-rich water treatment group (P < .01). Arterial blood gas analysis indicated better oxygenation and reduced hypercapnia in the nebulized hydrogen-rich water treatment group (P < .05). Histologic examination showed reduced lung edema and hemorrhage in the nebulized hydrogen-rich water treatment group. Levels of inflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor α) and oxidative stress markers (ie, malondialdehyde) were significantly lower, whereas antioxidant enzyme (total superoxide dismutase) activity was higher in the nebulized hydrogen-rich water treatment group compared with the blast injury control group (P < .01). Arterial blood gas analysis indicated better oxygenation and reduced hypercapnia in the nebulized hydrogen-rich water treatment group (P < .05). Histologic examination showed reduced lung edema and hemorrhage in the nebulized hydrogen-rich water treatment group. Levels of inflammatory cytokines (interleukin-1β, interleukin-6, and tumor necrosis factor α) and oxidative stress markers (ie, malondialdehyde) were significantly lower, whereas antioxidant enzyme (total superoxide dismutase) activity was higher in the nebulized hydrogen-rich water treatment group compared with the blast injury control group (P < .01). Hydrogen-rich water treatment significantly improves survival rates and lung function and reduces inflammation and oxidative stress in mice with primary blast lung injury. These findings suggest that hydrogen's antioxidant and anti-inflammatory properties play a crucial role in mitigating lung damage and improving respiratory function postinjury. Further long-term studies and imaging analyses are needed to confirm these findings and elucidate the molecular mechanisms involved. This study provides a theoretical basis for the clinical application of hydrogen-rich water in treating blast-induced lung injuries.

Supplemental Operational Guidance for Minimizing Potential Inhalation Doses to Workers and Volunteers at Community Reception Centers and Public Shelters.

In the event of a nuclear explosion in an urban environment, contaminated persons may be directed to Community Reception Centers (CRC) and/or public shelters. This paper is a companion document to a previous paper that addresses the inhalation hazard to workers at a CRC from resuspension of fallout from the evacuees. To limit the inhalation hazard evacuees must be screened to prevent severely contaminated persons from entering a CRC. The suggested screening level is 10,000 dpm cm-2 and rapid methods of screening arriving evacuees are presented. Practical advice is provided on methods that can be used to limit contamination within a CRC. These methods include alterations to heating and cooling systems and the implementation of monitoring strategies to guard against unexpected increases in airborne activity levels.

Valorization of corn stover in a single experimental unit: The synergistic effects of steam explosion and semi-continuous subcritical water processing.

Lignocellulosic waste, like corn stover (CS), is widely produced and serves as a key feedstock for biofuels and biochemicals. Semi-continuous subcritical water hydrolysis (SWH) is an eco-friendly method that breaks down cellulose and hemicellulose bonds. To boost fermentable sugar (FS) yields, steam explosion (SE) pretreatment was tested on CS, achieving a cellulose content of 74.06% at 200°C for 10min. Hydrolysis of untreated (UCS) and pretreated (PCS) CS was conducted at temperatures of 230°C and 260°C, with solvent/biomass ratios (R-20, R-40). Maximum FS yields were 11.67g/100g for UCS and 19.28g/100g for PCS. Although SE increased FS yields, it also led to more inhibitors due to the higher sugar production. Overall, integrating SE with SWH improved FS yields.

Spectroscopic Modeling of Luminous Transients Powered by H-rich and He-rich Circumstellar Interaction

Abstract In this study, we perform detailed spectroscopic modeling to analyze the interaction of circumstellar material (CSM) with ejecta in both hydrogen-rich and hydrogen-poor superluminous supernovae (SLSNe), by systematically varying properties such as the CSM density, composition, and geometry to explore their effects on spectral lines and light-curve evolution. Using advanced radiative transfer simulations with the new, open-source SuperLite code to generate synthetic spectra, we identify key spectroscopic indicators of CSM characteristics. Our findings demonstrate that spectral lines of hydrogen and helium exhibit significant variations due to differences in CSM mass and composition. In hydrogen-rich Type II SLSNe, we observe pronounced hydrogen emission lines that correlate strongly with a dense, extended CSM, suggesting massive, eruptive mass-loss histories. Conversely, in hydrogen-poor SLSNe, we recover mostly featureless spectra at early times, with weak hydrogen lines appearing only in the very early phases of the explosion, highlighting the quick ionization of traces of hydrogen present in the CSM. We analyze the properties of the resulting emission lines, particularly H α and H β , for our models using sophisticated statistical methods. This analysis reveals how variations in the SN progenitor and CSM properties can lead to distinct spectroscopic evolutions over time. These temporal changes provide crucial insights into the underlying physics driving the explosion and the subsequent interaction with the CSM. By linking these spectroscopic observations to the initial properties of the progenitor and its surrounding material, our study offers a useful tool for probing the pre-explosion histories of these explosive events.

ENZYMATIC HYDROLYSIS OF STEAM EXPLODED STRAW WITH THE ADDITION OF ACETIC ACID

The effect of steam explosion on the enzymatic hydrolysis of straw was investigated in the presence of 5, 10, 15 and 20% wt. addition of acetic acid. Analysis was performed at temperatures of 160, 170, 180, 190, 200 and 210°C. The concentration of monosaccharides obtained after enzymatic hydrolysis was considered the main indicator of the increased availability of cellulose due to their release into the solution. The results indicate that the addition of acetic acid increases the concentration of monosaccharides, but only at lower temperatures. The temperature of 180°C corresponded to the most effective pretreatment by steam explosion in the presence of acetic acid with the highest concentration of 10%, which corresponds to the conversion of polysaccharides to monosaccharides of 74.78%. At high temperatures above 200°C, the addition of acetic acid results in a decrease in the concentration of monosaccharides due to the high severity factor in the range of 3.94 – 4.24.

Consequences of a major eruption of Shiveluch volcano (Kamchatka, April 11–13, 2023) for forest vegetation (preliminary report)

The strong eruption of Shiveluch volcano in April 2023 led to radical changes in the natural environment of a vast territory. Analysis of changes in the aff ected area using satellite images and during fi eld work in the summers of 2023 and 2024 revealed the features, depth and scale of the impact on forest vegetation. Multimeter layer of high-temperature pyroclastic deposits covered an area of more than 60 sq. km on the southern and southeastern slopes of the volcano. The main buried areas include a vast deposit fi eld measuring 38 sq. km, lying in the altitude range of 400–800 m and a series of pyroclastic fl ow tongues with a total area of 12.5 sq. km, descending to an altitude of 140–350 m, with a maximum length of 22 km from the eruption center. Before the eruption, there were coniferous (Larix cajanderi) and deciduous (Betula ermanii) forests, dwarf alder (Alnus fruticosa) covers, mountain meadows and volcanic badlands (legacy of previous eruptions). Woody vegetation, including valuable coniferous forests, was buried and destroyed over an area of approximately 24 km2. Burial of forests by thick (up to tens of meters) high-temperature strata occurred over an area of more than 20 km2. The pyroclastic surge and the peripheral parts of the pyroclastic fl ows turned forests and dwarf alder forests into dead stands over an area of several square kilometers. The cause of its death was powerful and rapid thermal damage by hot gas-sand vortices. Immediately after the eruption, surface watercourses begin to wash away pyroclastic deposits, transporting them, and burying forest areas with washed-out materials. As a result, the forest dies. Vegetation adjacent to pyroclastic deposit fi elds is aff ected by frequent and intense dust transports that occur in open areas above the tree line. The 2023 eruption was the largest explosive event in Kamchatka and the Kuril Islands in recent decades, and caused large- scale destruction of forests.

Investigating the Effects of Remapping Method in Explosion

Using real explosives to detect explosion effects is a difficult and impractical method due to its danger and cost. Performing numerical analyses based on previously conducted experimental studies allows for the diversification of studies on this subject. Since the elaboration of numerical analyses causes an increase in the amount of processing, it requires the devices that need to perform these operations to be very advanced. It is an important optimization that the solutions are shorter and closer to reality, and this can be done with the remapping method. With this method, the explosion loads obtained from 1D analysis can be integrated into 2D and 3D analyses with certain methods, and the duration of these analyses is reduced and their accuracy is increased. Within the scope of this study, the methods and approaches for the application of this method are explained. As a result of this study, it will help those who want to perform explosion simulations to obtain more accurate results in a shorter time with less processing power, and it will pave the way for many scientific studies to be carried out.

Effects of Steam Explosion on Curcumin Extraction from Fresh Turmeric Chips.

The purpose of this research is to study the effect of the steam explosion (SE) process on curcumin extraction from fresh turmeric chips. Fresh turmeric chips abruptly disintegrated during the steam explosion process. The investigation into the turmeric particles following the steam explosion process in the SEM micrographs revealed that the formation of surface cracks and cavities led to an increase in the surface area of turmeric particles. Curcumin extracted from turmeric particles after the steam explosion process yielded 3.24% (w/w), which was comparable to the yield of 3.98% (w/w) from finely ground turmeric particles, while the steam explosion used 74% less energy than the grinding process. Therefore, the steam explosion process is an efficient process compared to untreated and conventional mechanical grinding methods. On average, the turmeric particles decreased in size when the dissipated energy per mass increased. The curcumin yield from the steam explosion exhibited a linear positive correlation with the dissipated energy per mass. FTIR, TG/DTG, and DSC analyses on the turmeric particles after the steam explosion process showed that the compounds exhibited no change in chemical structure, higher thermal decomposition properties, and higher purity, respectively. The results of this research can be applied to find optimal conditions for extracting curcumin and predicting the yield of curcumin. Additionally, they can be applied to evaluate the process condition in commercial applications.

A numerical investigation into the behaviour of cable-stayed bridges under deck explosions

This paper explores the behaviour of cable-stayed bridges (CSBs) when subjected to intentional explosion events. An example CSB was proposed and analysed using a three-dimensional (3D) finite-element (FE) model; a nonlinear time-history analysis taking into account the geometric and material nonlinearities was conducted. Six blast scenarios were considered; the explosion took place on the bridge deck. Response quantities, such as forces in cables, movements of deck and pylons, states of stress in main girders, and reactions on bearings and pylon foundations were examined. The critical blast scenario for each of these quantities was identified. Some design measures for mitigating cable failure were proposed and examined. The results of analyses showed that considering several blast scenarios for the design and evaluation of CSBs is mandatory. Non-symmetric (relative to the bridge longitudinal axis) blast loading scenarios are generally more critical than symmetric ones. Increasing the area of some long cables in the main span, and increasing spacing of the cables nearby the pylon together with strengthening the main girder nearby the pylon could be useful measures to reduce failure potential. This study may help better understand the response of CSBs to extreme events.

Dynamic Analysis of Plates Subjected to Explosive Loading: Comparison Between SDOF and FEM Models

With the global increase in explosive events, arising from armed conflicts and/or accidental occurrences, a thorough analysis of the dynamic behavior of structures under this type of load becomes important. The explosive phenomenon causes an overpressure (positive) wave with a subsequent underpressure (negative) phase, which is often disregarded. Moreover, recent studies have highlighted that this negative phase can generate displacements and stresses as relevant as the ones from the positive phase only. This work investigates simply supported plates subjected to explosive loading considering the membrane effect (laterally immovable condition) which introduces nonlinearities in the model. Due to the problem’s mathematical complexity, these nonlinear dynamic analyses are usually performed using complicated finite element models. In this way, a software called DYNAblast was developed using a simpler approach based on a Single Degree of Freedom (SDOF) analytical model which incorporates the von Karman plate theory. Dynamic analyses were carried out in DYNAblast to understand the influence of the positive and negative phases of the blast loads, as well as the contribution of the membrane energy of the plate. Numerical models implemented in ABAQUS software were used for the validation of DYNAblast results, with excellent agreement.

Computational analysis of submerged submarine bow hull dynamics subjected to torpedo blunt impact and warhead detonation events

In the maritime sector, ensuring the survivability of ships and submarines against diverse threats such as torpedo impacts, Underwater Explosion (UNDEX) events, and environmental factors is paramount. Comprehensive analysis of hull dynamics under various impact scenarios is essential. Numerical simulations of these impacts utilize different material models, ship grounding tests, impact modes, UNDEX simulations, and failure mechanisms. In the current study, the blunt impact of a torpedo on the submarine bow and the surface detonation effects of the torpedo warhead (at different distances from the hull) on the submarine bow structure were analyzed within an underwater enclosure. The torpedo design was based on the MK-48, with Ti6Al4V alloy used for the torpedo hull and HY-80 steel for the submarine hull. The impact simulations were conducted using ANSYS Explicit Dynamics® computational software. For the blunt impact scenario, a torpedo speed of 55 knots (102 km/h) was used. For the UNDEX studies, the warhead at the front end of the torpedo was modeled using PBX-9501 (a commonly used high explosive in warheads). The novelty of the current work was the employment of a water enclosure in the model to simulate the underwater impacts. The analysis focused on hull deformation, equivalent plastic and elastic strains, equivalent stress and damage profiles for the different impact scenarios. To effectively capture fluid–structure interactions, the study also examined pressure variations within the Eulerian domain. Among the scenarios analyzed, the near-field detonation of the warhead emerged as the most destructive, resulting in severe structural damage to the bow hull. In contrast, the blunt impact of the torpedo induced moderate plastic deformation, while the far-field detonation resulted in minimal damage.

Artificial Intelligence and Machine Learning Tools for Improving Early Warning Systems of Volcanic Eruptions: The Case of Stromboli.

Explosive volcanic blasts can occur suddenly and without any clear precursors. Many volcanoes have erupted in the last years with no evident change in the eruptive parameters and with dramatic consequences for the population living nearby the volcano and the tourists visiting the active areas. In recent years, a big effort has been made to develop Early Warning systems to issue timely alerts to the population. At Stromboli volcano, the development of sensitive instruments to measure the deformation (tilt) of the ground has revealed that the volcano edifice is inflating tens of minutes before the explosion following a recurrent exponential ramp-like pattern. This scale-invariant of ground deformation has allowed the development of a quasi-deterministic Early Warning system which is operative since 2019. In this article we show how Artificial Intelligence and Machine Learning can be successfully applied to improve the efficiency and the sensitivity of Early Warning systems, provided the availability of a comprehensive experimental data set on past explosive events. The approach presented here for the Stromboli case demonstrates promising results also in forecasting the intensity of explosive events, offering valuable insights and new perspectives into the potential risks associated with volcanic activities.

The Peak Frequency and Luminosity of Synchrotron Emitting Shocks: From Nonrelativistic to Ultrarelativistic Explosions

Synchrotron emission is ubiquitous in explosive astrophysical events—it is a natural byproduct of shocks formed when matter expelled by the explosion collides with ambient material. This emission is well observed in various classes of transients, and is often interpreted within a canonical “equipartition” framework that allows physical properties of the shock to be inferred from the frequency and luminosity at which the observed spectral energy distribution (SED) peaks. This framework has been remarkably successful in explaining observations of radio supernovae. It has also been used for transrelativistic explosions, where the shock velocities approach the speed of light. However, the conventional framework does not incorporate relativistic effects. Neither does it account for thermal electrons, which have been shown to be important for high-velocity shocks. In this paper we describe a revised framework that accounts for these two effects, and is applicable to nonrelativistic, transrelativistic, and ultrarelativistic explosions. We show that accounting for these effects can dramatically change the inferred parameters of high-velocity shocks, and, in particular, that the shock velocity, ambient density, and total energy are overestimated by the conventional nonrelativistic framework. We delineate the phase-space where such modifications are important in terms of observationally measurable parameters. We also find a novel upper limit on the peak synchrotron luminosity of shock-powered transients, which is remarkably consistent with existing observations. Finally, we discuss a prediction of the model—that the SED will qualitatively change as a function of shock velocity—and show that this is broadly consistent with data for representative events (e.g., SN1998bw, AT2018cow, CSS161010, AT2020xnd).

Three-dimensional peridynamic modeling of damage and penetration in composite plates exposed to localized explosive blasts

Localized failures in composites can lead to catastrophic consequences in some vehicles and systems, such as airplanes and submarines. The paper presents a new three-dimensional (3D) peridynamic model to explore the localized explosive effects on composite plates. The study utilizes the peridynamic method to simulate fractures and deformations in composite plates when exposed to localized explosive blasts. Accurate prediction of composites' performance during explosive blast events is crucial in the design process to avoid the deadly effects of their failures. This study highlights the following novelties: (1) We present, for the first time, a novel 3D mesh-free model to simulate the fracture and damage behavior of composite plates when exposed to explosive blasts; (2) The adopted numerical modeling technique enables highly efficient simulations of fractures and failures in composites when compared with other mesh-based numerical models; (3) We introduce a new mathematical framework to reflect the explosive pressure loads through different composite layers; (4) The study provides an accessible and efficient tool for engineers and researchers to enhance the design of composites in several industries instead relying on limited-access commercial software packages. In addition to the previous novelties, the paper presents a new parametric study that investigates the performance of several composite plates, such as titanium-aramid and aluminum-aramid composites, in explosive blast scenarios. Moreover, the roles of explosive mass and plate thickness in the failure mechanisms of composites are examined.

Ambient PM2.5 Orchestrates M1 Polarization of Alveolar Macrophages via Activating Glutaminase 1-mediated Glutaminolysis in Acute Lung Injury.

The temporary explosive growth events of atmospheric fine particulate matter (PM2.5) pollution during late autumn and winter seasons still frequently occur in China. High-concentration exposure to PM2.5 aggravates lung inflammation, leading to acute lung injury (ALI). Alveolar macrophages (AMs) participate in PM2.5-induced pulmonary inflammation and injury. The polarization of AMs is dependent on metabolic reprogramming. However, the mechanism underlying the PM2.5-induced glutaminase-mediated glutaminolysis in AM polarization are still largely obscure. In his study, we found that PM2.5-treated mice exhibited pulmonary dysfunction and inflammation. The concentraions of glutamate and succinate were increased in PM2.5-treated lungs and AMs compared with the controls, whereas glutamine and α-ketoglutarate (α-KG) levels were decreased, indicating that glutaminolysis in AMs was aberrantly activated as evidenced by increased mRNA and protein levels of GLS1 after PM2.5 exposure. Moreover, we deterimined that the GLS1/nuclear factor kappa-B (NF-κB)/hypoxia-inducible factor-1α (HIF-1α) pathway regulated M1 polarization of AMs upon PM2.5 exposure. Inhibition of glutaminolysis by GLS1 specific inhibitor CB-839 and GLS1 siRNA significantly decreased PM2.5-induced M1 macrophage polarization and attenuated pulmonary damage. Taken together, our findings reveal a novel mechanism by which a metabolic program regulates M1 polarization of AMs and suggest that GLS1-mediated glutaminolysis is a potential therapeutic target for treating PM2.5-induced ALI.

Effect of supercavity and shell casing on underwater energy release characteristics of armor-piercing-explosion supercavitating projectile charge

Abstract The Armor-Piercing Explosive Supercavitating Projectile (APESP) integrates explosion and armor-piercing effects, introducing a novel approach to underwater munitions. The energy release characteristic of the APESP charge underwater may differ from traditional underwater explosions due to the presence of the supercavity and shell casing. In order to investigate the effects of the supercavity and shell casing on this energy release characteristics, a finite element model of APESP charge underwater explosions is established. The deformation of the target is examined to evaluate the effects of the supercavity and shell casing. The mechanisms of these factors are further analysed theoretically. The results indicate that plastic deformation under the explosion of the APESP charge is primarily completed during the shock wave phase. Both the supercavity and shell casing influence the final deformation of the target by affecting the shock wave intensity, and the supercavity having a more significant impact. The pressure of the initial shock wave transmitted to the external medium of the charge is the highest when the charge is encased by a shell casing, and is the lowest when the charge is inside a supercavity. As the shock wave transmits through interfaces, it is amplified at the air-water interface and attenuated at both the shell-water and shell-air interfaces, with the greatest attenuation at the shell-air interface. Additionally, the presence of the shell casing reduces shock wave intensity but extends the duration of its action, thereby increasing the shock wave impulse.

Dynamic risk analysis of fire and explosion domino accidents at hydrogen refueling stations using Dynamic Bayesian Network

Hydrogen is a promising energy source and hydrogen refueling stations (HRS) are the main hydrogen supply infrastructures. Unwanted hydrogen leaks and releases at the hydrogen station may cause serious explosion accidents and even induce domino effects due to intensive hazardous equipment in the station. However, scant attention has been accorded to the dynamic risks of fire, explosion, and domino effects at HRS, posing a threat to the safe functioning of HRS and the advancement of the hydrogen energy. This study thus first develops Dynamic Bayesian networks to model the primary fire and explosion accidents as well as domino effects at HRS. By the developed models, the critical factors that lead to accidents and the critical equipment that contributes to the initiation or propagation of domino effects can be identified. Moreover, the failure probability of different equipment exposed to possible accidents can also be obtained, supporting safety management of HRS.

Evolution characteristics of shock wave in microsecond-scale underwater electrical wire explosion

The underwater electrical wire explosion (UEWE) is a physical phenomenon initiated by the rapid injection of electrical energy, triggering an explosive event. UEWE offers advantages in energy conversion efficiency, repeatability, and controllability, making it valuable in various industrial applications. Building upon established zero-dimensional (0D) and one-dimensional (1D) models, this paper proposes an enhanced 0D-1D coupled cold-start model to describe the plasma channel expansion and subsequent shock wave (SW) propagation characteristics. The model comprises two submodules: a 0D magnetohydrodynamics model that describes plasma channel boundary expansion during the explosion, and a 1D hydrodynamics model using an artificial viscosity algorithm to depict SW propagation. The constructed numerical model facilitates investigation of plasma characteristics, SW propagation behavior, and energy conversion efficiency throughout the UEWE process. Additionally, the influences of wire dimensions and discharge frequency on these characteristics were analyzed. The results indicate that SW propagation characteristics are primarily governed by thermal pressure variations within the wire and that different wire dimensions markedly affect SW amplitude, attenuation, and impulse. The efficiency of electrical-to-SW energy conversion remains relatively low; however, thicker and shorter wires can enhance SW amplitude and improve conversion efficiency. Higher discharge frequencies produce greater impact forces and impulses near the explosion site, while also improving energy conversion rates. This study offers a theoretical basis and technical guidance for prospective engineering applications.

Enhancement of calcium alginate and urea in gel-modified dry water inhibition of methane-air explosion

Methane has a wide range of applications in several industries. However, it also exhibits flammable and explosive properties, which pose a potential hazard. This study used calcium alginate to make ordinary dry water powder have a stable network gel structure, and urea was added to enhance further dry water powder’s chemical inhibition. A visual test system verified the explosion suppression effect of gel-modified dry water powder on the methane-air explosion. The results show that the optimal parameters for Ordinary dry water preparation were as follows: mass ratio of SiO2 to H2O = 9:100, stirring speed = 5000 r/min, stirring time = 240 s. The powder concentration for the best explosion suppression effect is 0.52 g/L. 10 mass% Urea-modified dry water, which achieves high explosion suppression efficiency in the methane-air explosion system by cooling and endothermic suppressing the explosion reaction. The spatial distribution of Calcium alginate gel urea modified dry water hinders the propagation of the flame. Urea continuously produces nitride at different temperatures, and nitride competes for O2 and OH· Free radicals, thus destroying the methane-air explosion chain reaction. Calcium alginate gel urea (10 mass%) modified dry water of 0.52 g/L has the best explosion suppression efficiency, which reduces the flame propagation velocity of methane-air explosion system by 42.48 %, the suppression efficiency of flame temperature reaches 40 %, and the suppression effect on explosion relief pressure reaches 16 %. Calcium alginate gel urea modified dry water, a new explosion suppression material, significantly improve the explosion suppression effect of methane-air explosions, which can not only improve the industrial safety of methane-containing processes, extend equipment life, and reduce production costs but also help improve environmental protection and resource utilization efficiency by inhibiting methane explosions. This study helps to promote the development of gas explosion suppression materials and has practical significance for safe energy utilization and industrial methane applications.