Article
Energy & Fuels
Yong Yang, Zhenmin Luo, Xuhan Ding, Fan Zhang, Chuanxu Luo, Hongren Zhang, Chi-Min Shu
Summary: This study investigated the explosion hazards of oil-immersed coal dust in co-existing mine areas through experimental research. The results show that the maximum explosion pressure of oil-immersed coal dust first decreases and then increases as the coal dust particle size increases. For samples with oil-immersed concentrations between 2% and 10%, the explosion characteristic parameters were higher than those of the raw coal counterpart. The influence mechanism of coal dust concentration on maximum explosion pressure is that the number of coal dust particles affects the distance between particles and heat transfer efficiency, while the influence mechanism of particle size is that it affects the diffusion of oxygen in particles and the rate of combustible volatiles released by particles.
Article
Energy & Fuels
Qiao Wang, Xinjiao Luo, Quan Li, Shengchao Rui, Changjian Wang, Aifeng Zhang
Summary: Experiments conducted in an obstructed rectangular tube revealed that the blockage ratio of the obstacle has a significant impact on the peak overpressure induced by the obstacle, but a negligible effect on the peak overpressure resulting from vent rupture. Lower blockage ratios mainly increase peak overpressure through enhanced turbulence and burning rate, while higher blockage ratios result in peak overpressure from the combined effect of flame acceleration and external explosion.
Article
Engineering, Environmental
Nuhindro Priagung Widodo, Septian Hadi Putra, Ahmad Ihsan, Rudy Sayoga Gautama, Jianwei Cheng, Fadli Zaka Waly, Dimas Agung Permadi
Summary: The coal dust explosion tests were conducted in a 20-L explosion chamber using subbituminous coal from Indonesia with coal dust sizes of 53-44 μm (average particle size of 48.5 μm). Different energies of ignitor (4.2 kJ, 6.3 kJ, and 8.4 kJ) were used to study the effect on the Minimum Explosion Concentration (MEC) of the coal dust. The results showed that the MEC for ignitor energies of 4.2 kJ, 6.3 kJ, and 8.4 kJ were 120 g/m3, 100 g/m3, and 70 g/m3, respectively. Compared to previous studies on bituminous coal, this study found a higher MEC in subbituminous coal.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Thermodynamics
Shangyong Zhou, Jiancun Gao, Zhenmin Luo, Shoutao Hu, Le Wang, Tao Wang
Summary: The study found that the magnetic domains of ferromagnetic materials enhance the ability to inhibit chain-initiated reactions and oxidation reactions, leading to better explosion suppression performance. The DC magnetic field can promote the gas explosion reaction, but when iron velvet is magnetized, it strengthens the ability to suppress explosions rather than increasing collision probability.
Article
Engineering, Environmental
Guochun Li, Chuanyu Pan, Yangpeng Liu, Xiaolong Zhu, Xiaomin Ni, Xiangdi Zhao, Guoxin Chen, Xishi Wang
Summary: The characteristics of water mist spray and the installation locations of the nozzles have significant effects on explosion mitigation, and K2CO3 additive can enhance the explosion mitigation effect of water mist, but its effect is weaker compared to changes in water mist characteristics.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Engineering, Civil
Y. S. Jia, C. Zhang, Q. Zhang, H. M. Liang
Summary: The concentration and droplet size of ethanol aerosol, as well as the turbulence distribution, were observed in a 20 L vessel under pneumatic pressure of 1 MPa-2 MPa. The study analyzed the correlation between the actual concentration, droplet size, turbulent intensity, and pneumatic pressure. The effect of concentration, droplet size, and turbulence on the explosion parameters of ethanol aerosol was examined. The study revealed that ethanol aerosol had lower actual concentration than the designed concentration, with a ratio of 65%-90% at pneumatic pressures from 1.0 MPa to 2.0 MPa. The concentration increased with time initially, reached a steady state, and then decreased gradually. The droplet size and turbulence intensity showed distinct changes over time. The effect of pneumatic pressure on the maximum rate of explosion pressure rise differed from its effect on the peak explosion pressure. Ethanol vapor/air had higher explosion hazard than ethanol aerosol with the same concentration.
FIRE SAFETY JOURNAL
(2023)
Article
Engineering, Environmental
Qi Jing, Dan Wang, Qingming Liu, Yang Shen, Zhisong Wang, Xu Chen, Yingpeng Zhong
Summary: The study shows that the explosion intensity parameters vary significantly under different conditions, with CH4/air explosion exhibiting higher intensity than cornstarch/air explosion. Adding methane can enhance the explosive intensity of cornstarch, but this effect decreases after a certain concentration is reached.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Engineering, Environmental
Minggao Yu, Yuanpeng Fu, Ligang Zheng, Rongkun Pan, Xi Wang, Wen Yang, Hongwang Jin
Summary: An experimental study was conducted to suppress methane-air explosions in a 5 L vessel connected to discharge duct of different scales and sodium bicarbonate concentrations. Results show that the ducted-vessel experienced more flame fragmentation compared to the simply vented vessel. The flame structure becomes more irregular with a larger vent coefficient and the appropriate SBC concentration can transform the mechanism for pressure rise in the vessel.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Engineering, Chemical
Wenying Wu, Weixing Huang, Aizhu Wei, Martin Schmidt, Ulrich Krause, Dejian Wu
Summary: The minimum explosion concentration (MEC) of three agriculture dusts and two coal dusts was studied to investigate the role of gaseous inhibitors. Both active and passive methods were used, and the thermal analysis tests were conducted to study the pyrolysis and combustion characteristics. An alternative explosion criterion based on combustion duration time was used to determine MEC, and the results were compared with the standardized overpressure method.
Article
Engineering, Environmental
Hongsheng Ma, Zhiyu Liu, Yang Li, Jiaqing Zhang, Yubiao Huang, Changjian Wang
Summary: The effects of ignition energy, oil volume, and ignition position on the overpressure buildup and fireball behavior caused by transformer oil explosions are investigated in this study. Experimental results show that the shape of the fireball is significantly affected by the ignition position and both the maximum fireball radius and area increase with the increase of oil volume. The study also observes a double-peak overpressure structure, with the first peak generated by the explosive explosion and the second peak induced by the coupling between initial fireball combustion waves and reflected shock waves.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Chemistry, Physical
Quan Li, Shengchao Rui, Xinjiao Luo, Changjian Wang
Summary: This study investigated the effects of hydrogen concentration, ignition location, and obstacles on vented hydrogen-air explosions. Results showed that obstacles changed the flame propagation inside the container and increased the flame area, promoting the reaction. Existing engineering models over-predicted the maximum reduced explosion pressure for high-reactivity mixtures.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Il Woong Park, Jia Yu, Sang Min Song, Yeon-Gun Lee
Summary: Although hydrogen is a promising material for global energy transportation, its leakage or generation in enclosed spaces can cause explosion hazards, including nuclear power plants. To manage these risks, it is important to understand the characteristics of hydrogen dispersion in air and its stratification behavior. This study investigated the distribution of hydrogen in an enclosed vessel under steam-condensing conditions using helium as a substitute. The experiments included steady-state and transient tests to observe the impact of helium injection and subsequent redistribution.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2023)
Article
Engineering, Chemical
Matteo Pietraccini, Pierre-Alexandre Glaude, Anthony Dufour, Olivier Dufaud
Summary: Explosions of gas-dust hybrid mixtures in specific industrial contexts have long been recognized. However, this study emphasizes the importance of the pyrolysis reaction in the explosion of organic powders. The results provide valuable insights for the design of explosion protection measures.
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
(2023)
Article
Chemistry, Analytical
Bin Yuan, Zhiming Zhou, Bin Jiang, Ghulam Mustafa Kamal, Xu Zhang, Conggang Li, Xin Zhou, Maili Liu
Summary: CORDY is a novel approach for NMR spectroscopy that utilizes concentration order to separate and quantify components in complex samples, by utilizing prior information of chemical shift distribution and line shape characteristics to shrink the solution space, it generates a pseudo-two-dimensional spectrum. The combination of CORDY and DOSY (CORDY-DOSY) has been found to be more efficient in resolving molecules with similar concentrations or self-diffusion coefficients.
ANALYTICAL CHEMISTRY
(2021)
Article
Engineering, Chemical
Baiwei Lei, Jianjun Xiao, Mike Kuznetsov, Thomas Jordan
Summary: This study developed a model of methane one-step combustion mechanism and studied the influence of thermal radiation and convection heat transfer on methane explosion through numerical simulations. The results showed that thermal radiation and convection heat transfer significantly affected the methane explosion process.
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
(2022)
Article
Thermodynamics
Xianjia Huang, Zhibiao Li, Tao Huang, Xunjia Zhuo, Chihonn Cheng, Wanki Chow
Summary: This study investigates the parametric effects of fuel distribution and spray angle on the fireball characteristics generated by an aircraft crash through numerical simulations. The comparison with video footage shows that the simulated fireball diameter is closest to the observed results when the fuel spray angle is 15 degrees, regardless of the number of dynamic fuel sprays. Additionally, the simulation suggests that the reliability of predicting the fireball generated by an aircraft crash depends on the generation of a fuel jet in the front of the aircraft's nose.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Construction & Building Technology
W. K. Chow, C. L. Chow
Summary: This article discusses methods for controlling the spread of the novel coronavirus, SARS-CoV-2, and proposes a two-stage containment scheme for isolating patients and identifying asymptomatic individuals. Using a mathematical approach and estimated parameters, the authors believe that this scheme can effectively control the spread of the virus.
INDOOR AND BUILT ENVIRONMENT
(2022)
Letter
Public, Environmental & Occupational Health
Wan Ki Chow, Cheuk Lun Chow
DISASTER MEDICINE AND PUBLIC HEALTH PREPAREDNESS
(2022)
Article
Thermodynamics
Zheming Gao, S. S. Li, Y. Gao, H. Y. Hung, Wan-ki Chow
Summary: This paper reports numerical studies on internal fire whirls generated in a vertical shaft model with a single corner gap. The study combines experimental research on the generation of IFW, burning rate of fuel and temperature with numerical simulations on medium-scale IFW. The results show that Computational Fluid Dynamics can accurately simulate IFW characteristics and phenomena.
BUILDING SIMULATION
(2021)
Article
Engineering, Environmental
Xianjia Huang, He Zhu, Le He, Lan Peng, Chihonn Cheng, Wanki Chow
Summary: A new model was developed based on small-scale experiments to describe the heat release rate of cable tray fires against sidewalls, showing good agreement with experimental data. The new model accurately reflects the fire risk of cable tray fires, improving understanding of fire hazards in such scenarios.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Materials Science, Multidisciplinary
Wei Peng Fan, Ya Wei Wang, Ye Gao, Wan Ki Chow, Joseph Hung Kit Lai, Cheuk Lun Chow, Chi Honn Cheng
Summary: In this article, the velocity distribution and motion of a whirling flame in a room fire with vent were studied using Rankine vortex model. Two whirling flame models with and without decay of rotation velocity were established to analyze the flame's behavior under cross-wind velocity boundary conditions. The study found that lateral winds with linear velocity gradient can affect the position of the whirling flame's axis, but do not change the rotation angular velocity.
FIRE AND MATERIALS
(2022)
Article
Engineering, Multidisciplinary
H. Y. Hung, Z. M. Gao, S. S. Li, Y. Gao, W. K. Chow, C. L. Chow
Summary: Experimental results showed that fire whirls generated by a gasoline pool fire in a vertical shaft exhibited more vigorous swirling motions with increasing height, resulting in upward flame motions due to increased buoyancy. By solving the vorticity transport equation and analyzing measured data, the vertical variation of circular speeds of fire whirls was derived, showing swirling attenuation along the vertical direction.
Article
Management
Martin Lyubomirov Ivanov, Wan Ki Chow, Tsz Kit Yue, Hing Lung Tsang, Wei Peng
Summary: This research aims to check and bridge the gap between the fire safety regulations for newly built tall buildings in Bulgaria and those in fast-growing areas like the Hong Kong Special Administrative Region and Mainland China. By conducting comparative analysis and identifying good practices, the focus is on the development of fire safety designs, facilities, and management. Key issues and recommendations for upgrading fire safety requirements in Bulgarian tall buildings were found, emphasizing the importance of fire safety management. The uniqueness of this research lies in its focus on the implementation of additional and specific fire safety regulations in Bulgaria.
Article
Materials Science, Multidisciplinary
Chi Honn Cheng, Cheuk Lun Chow, Wan Ki Chow
Summary: Compartment fire is an important research area in fire science and fire safety. The zone model is a simple and effective method for studying compartment fire. The differential equations based on a two-layer zone model have no analytical solutions, and numerical methods are required for solving them. However, in some special cases, analytical solutions for certain variables can be obtained. The method proposed in this study shows good agreement with experimental results in predicting smoke layer height.
FIRE AND MATERIALS
(2023)
Article
Construction & Building Technology
Yanhong Xi, Zhihan Zhou, Huanqiang Lian, Jun Mao, Wanki Chow, Fei Tang
Summary: This paper investigates the temperature variation inside a corridor-like enclosure with persistent flame ejection through an opening. The study varies the fire heat release rate and opening sizes under different experimental conditions. An exponential function is built to describe the longitudinal temperature distribution, and the decay rate is found to have a power function relationship with the window aspect ratio. The study proposes a general model for the temperature distribution considering different opening sizes and heat release rates, which is in good agreement with experimental results.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Junmei Li, Zhao Qi, Yanfeng Li, Wan-Ki Chow, Fei Xie, Qiwei Dong
Summary: The study investigated the behavior of walking upstairs in a 10-storey building and found that walking distance and fatigue have a significant impact on the ascent speed. The results suggest that the mean ascent speed used for predicting evacuation time should be combined with the traveling distance or floor levels.
APPLIED SCIENCES-BASEL
(2022)
Article
Mechanics
M. L. Ivanov, W-K Chow
Summary: This study focuses on the blast damage of tall buildings near the explosion site in the 2020 Beirut port's ammonium nitrate explosion. It analyzes the relationship between overpressure and distance by comparing theoretical calculations, blast damage scale, and real post-explosion images. A range of overpressure values were observed, with better match found for buildings at closer distances.
Article
Ecology
Wai Kuen Mok, Wan Ki Chow
Summary: A zonal turbulence model, combining the standard k-epsilon model and its modification, is developed to study the flow field driven by a compartment fire. The model is tested and compared with experimental data, demonstrating promising improvements compared to the base turbulence model, particularly in the recirculating region near the corners of the compartment. This approach of different zones in the plume region is valuable for addressing various scenarios in the initial stage of fire hazard assessments.
Article
Construction & Building Technology
Martin Lyubomirov Ivanov, Wan-Ki Chow
Summary: The duration of evacuation in tall buildings during emergencies is a critical issue, influenced by factors such as stairwell geometry, speed, density, pre-evacuation delay, number of occupants, familiarity with the building, behavior, age, gender, physical abilities, relationships between people, etc. This study conducted two evacuation experiments in a new 107 m tall office building in Bulgaria, under the supervision of professional firefighting personnel, to estimate evacuation times and verify the results through Pathfinder software simulations.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Thermodynamics
Hsin-Hsiu Ho, San-Ping Ho, Chin-Feng Chen, Hui-Pei Chang, Bin Xie, Chi-Honn Cheng, Wan-Ki Chow
Summary: This paper investigates a severe fire incident at a water fun park in Taiwan caused by spraying colored corn flour powder, using a flame acceleration simulator. The simulation results show that igniting the sprayed powder resulted in a dust flash fire without explosion. The environmental parameters used in the simulation agreed with the observed accident, indicating their appropriateness for reproducing explosion scenarios and supporting accident investigations.
