Article
Chemistry, Physical
Min Li, Dandan Liu, Ting Shen, Jinhua Sun, Huahua Xiao
Summary: Numerical simulations were conducted to investigate flame acceleration and deflagration-to-detonation transition (DDT) in hydrogen-air mixture with various obstacle layouts and blockage ratios. The results demonstrate that both obstacle layout and blockage ratio play significant roles in flame acceleration and DDT occurrence. The study provides insights into the effects of different layouts and blockage ratios on flame propagation and detonation initiation.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Review
Chemistry, Physical
Mohammad Hosein Shamsadin Saeid, Javad Khadem, Sobhan Emami
Summary: This numerical study investigates the effect of obstacle spacing and mixture concentration on the deflagration-to-detonation transition (DDT) in hydrogen-air mixtures, revealing that DDT only occurs in inhomogeneous mixtures in a lean condition. Three different regimes of DDT were observed in near-stoichiometric inhomogeneous mixtures depending on obstacle spacing.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Jiabao Wang, Xinyu Zhao, J. P. Dimi-Ngolo, Longkun Gao, Jianfeng Pan, Yuejin Zhu
Summary: Using fluidic obstacles can mitigate the thrust loss caused by solid obstacles in the deflagration to detonation transition (DDT) process. A detailed simulation investigates the impact of multiple groups of fluidic obstacles on flame acceleration and DDT process under different initial velocities and gas types. The findings indicate that the initial jet velocity hinders flame acceleration due to the propagation of the reflected shock wave formed by jet impingement being opposite to the flame acceleration direction. However, as the flame accelerates, the vortex structure and enhanced turbulence promote flame acceleration, and increasing the initial jet velocity or using reactive jet gases can shorten the detonation initiation time and distance.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Zhaorong Liu, Xiaoxi Li, Min Li, Huahua Xiao
Summary: Experiments and numerical simulations were conducted to study the effects of obstacle shape and arrangement on flame acceleration and deflagration-to-detonation transition (DDT) in a obstructed channel filled with a stoichiometric hydrogen-oxygen mixture. The results show that triangular obstacles with a low blockage ratio accelerate the flame faster and result in an earlier DDT occurrence compared to rectangular obstacles with a high blockage ratio.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Engineering, Aerospace
Xinyu Zhao, Jiabao Wang, Longkun Gao, Xujiang Wang, Yuejin Zhu
Summary: This study investigates the effects of different solid obstacle distribution patterns on flame acceleration and deflagration-to-detonation transition in an inhomogeneous concentration field, and identifies three types of detonation initiation mechanisms. The study also finds that flame evolution experiences four velocity augmentation regions before detonation initiation.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Min Li, Huahua Xiao
Summary: This study investigated flame acceleration and deflagration-to-detonation transition (DDT) in a channel with staggered cylindrical obstacles and a stoichiometric hydrogen-air mixture. The results showed that the mechanisms of flame acceleration and transition to detonation were consistent, and were affected by the spacing of the obstacles. The flame propagation speed and DDT run-up distance and time were found to be highly dependent on the obstacle spacing.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Aerospace
Pavel Krivosheyev, Alexey Novitski, Oleg Penyazkov
Summary: Developing stable operation methods for the new generation of rocket engines based on detonation principles is crucial for safety. This study investigates the flame acceleration and detonation onset processes, identifying four characteristic flame propagation stages. The experimental findings are compared with existing theoretical models and the burning velocity of a diluted acetylene-oxygen mixture is determined.
Article
Thermodynamics
Xiaoyi Lu, Carolyn R. Kaplan, Elaine S. Oran
Summary: This paper presents a numerical study of flame acceleration and deflagration-to-detonation transition (DDT) of hydrogen-air mixtures in a channel with obstacles, where the mixture composition has a spatial gradient perpendicular to the wave propagation direction. The simulation results show that the ease with which an inhomogeneous mixture can detonate is bounded by the detonation limits of the most and least detonable homogeneous mixture.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Yves Ballossier, Florent Virot, Josue Melguizo-Gavilanes
Summary: Simultaneous schlieren visualization was used to perform deflagration-to-detonation-transition (DDT) experiments in a fully optically accessible smooth narrow channel. The effect of dilution on flame acceleration (FA) and detonation onset (DO) was assessed using stoichiometric H2-O2 mixtures with various N2 dilution levels. The experimental evidence demonstrates the role played by walls and corners in the formation of ignition centers/hot spots on DDT.
COMBUSTION AND FLAME
(2023)
Article
Chemistry, Physical
Qi Jing, Jinxiang Huang, Qingming Liu, Dan Wang, Xu Chen, Zhisong Wang, Changqi Liu
Summary: The study revealed that the DDT process in ammonia/oxygen mixtures consists of four stages, with the flame front and the leading shock wave propagating at different speeds for stoichiometric ammonia/oxygen mixtures until they propagate together at a steady speed. With an increase in equivalence ratio, the detonation velocities and peak overpressures of ammonia also increase.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Chemistry, Physical
Dandan Liu, Zhaorong Liu, Huahua Xiao
Summary: Understanding flame acceleration and deflagration-to-detonation transition is crucial for combustion applications. Numerical simulations were conducted to study these processes in narrow channels, revealing the importance of boundary layer effects and heat flux density during detonation.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Aerospace
Xiongbin Jia, Ningbo Zhao, Shizheng Liu, Xiang Chen, Wanli Zhu, Hongtao Zheng
Summary: Numerical simulation was conducted to characterize the detonation initiation and propagation of low-volatility liquid fuel/air mixtures in an obstructed tube. The study found differences in detonation behavior between liquid fuel and gaseous fuel, mainly due to atomization and evaporation of the liquid fuel causing a delay in initiation time. Additionally, the research indicated that droplet size has a significant impact on detonation transition time and distance.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Thermodynamics
Shinichi Maeda, Masahiro Irokawa, Daiki Taneichi, Tetsuro Obara
Summary: The effect of small roughness elements on flame acceleration and deflagration-to-detonation transition (DDT) was experimentally investigated. The results showed that roughness greatly enhanced flame acceleration and DDT. The study also directly observed the interference between the flow-field affected by the roughness and the propagating flame surface, providing clear evidence for the increase of chemical reactions and turbulence on the flame front.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
Jiabao Wang, Xinyu Zhao, Longkun Gao, Xujiang Wang, Yuejin Zhu
Summary: This study explores the effect of solid obstacle distribution on the deflagration to detonation transition (DDT) in a homogeneous hydrogen-air mixture. The results show that there are two types of detonation initiation processes, and the flame acceleration experiences two periodic acceleration-deceleration processes. The symmetric distribution of obstacles leads to the shortest initiation distance and time. Furthermore, a higher unilateral blockage ratio results in more unfavorable DDT.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Environmental
Kai Zheng, Qianhang Jia, Zimao Ma, Zhixiang Xing, Yongmei Hao, Minggao Yu
Summary: This study experimentally and numerically investigates the effect of obstacle gradient on methane/air explosion characteristics in obstructed ducts. The results show that the obstacle gradient significantly affects the flame evolution structure, propagation speed, and overpressure, and the numerical simulation can accurately predict the flame evolution behavior.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Chemistry, Physical
Dandan Liu, Zhaorong Liu, Huahua Xiao
Summary: Understanding flame acceleration and deflagration-to-detonation transition is crucial for combustion applications. Numerical simulations were conducted to study these processes in narrow channels, revealing the importance of boundary layer effects and heat flux density during detonation.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Ting Shen, Min Li, Huahua Xiao
Summary: Numerical simulations were conducted to study the dynamics of premixed flames in a closed tube. The results showed that the flame evolved from a planar flame to a series of distorted tulip flames, and the formation of the flame was closely related to the generation of pressure waves.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Materials Science, Multidisciplinary
Mi Li, Lin Jiang, Hua-Hua Xiao, Jin-Hua Sun
Summary: This study experimentally investigated the burning characteristics of 2-D horizontal discrete flame spread and established prediction models for ignition time and global mass loss rate. Through the analysis of heat transfer models and numerical correlations, the mechanism of horizontal discrete flame spread was revealed and can be applied in predicting and assessing real fire incidents.
FIRE AND MATERIALS
(2023)
Article
Engineering, Multidisciplinary
Siyuan Cheng, Yuhang Hu, Lihua Jiang, Hongbin Dang, Yibin Ding, Qiangling Duan, Huahua Xiao, Jinhua Sun, Qingsong Wang
Summary: In this study, the thermal stability of the semi-solid lithium slurry battery material system was investigated for the first time. The results showed a lower heat generation compared to traditional lithium-ion battery, while maintaining similar electrochemical performance. The mechanism of cycle heat generation was explained through the HPPC test. The study provides a preliminary evaluation on the safety and cycling stability of the semi-solid lithium slurry battery.
Article
Thermodynamics
Zhaorong Liu, Xiaoxi Li, Min Li, Huahua Xiao
Summary: Experiments and numerical simulations were conducted to study the effects of obstacle shape and arrangement on flame acceleration and deflagration-to-detonation transition (DDT) in a obstructed channel filled with a stoichiometric hydrogen-oxygen mixture. The results show that triangular obstacles with a low blockage ratio accelerate the flame faster and result in an earlier DDT occurrence compared to rectangular obstacles with a high blockage ratio.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Huahua Xiao, Xiaoxi Li
Summary: This study conducted experiments and numerical simulations on flame acceleration and deflagration-to-detonation transition in a channel obstructed by continuous triangular obstacles. The results showed that the triangular obstacles can significantly promote flame acceleration and provide conditions for DDT to occur. The success of DDT formation depends on successive local detonation ignitions and the height of the narrow space between the bulk flame and obstacle vertex.
COMBUSTION THEORY AND MODELLING
(2023)
Article
Chemistry, Physical
Min Li, Huahua Xiao
Summary: This study investigated flame acceleration and deflagration-to-detonation transition (DDT) in a channel with staggered cylindrical obstacles and a stoichiometric hydrogen-air mixture. The results showed that the mechanisms of flame acceleration and transition to detonation were consistent, and were affected by the spacing of the obstacles. The flame propagation speed and DDT run-up distance and time were found to be highly dependent on the obstacle spacing.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Zixian Chen, Zhiyang Liu, Lei Liu, Huahua Xiao
Summary: This paper presents an experimental and theoretical study on the blue whirl, a newly-discovered fire phenomenon that has attracted attention due to its unique flame structure and potential advantages in fuel-spill cleanup. The study investigates how the blue whirl is generated over a water surface in an apparatus and examines the effects of heat release rate, gap size, and external axial velocity on the circulation and flame width of the blue whirl. The results provide insights into the characteristics and formation of the blue whirl, and can contribute to quantifying and modeling this phenomenon.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Analytical
Peiyu Duan, Qingkui Peng, Songlin Zhang, Qiangling Duan, Huahua Xiao, Kaiqiang Jin, Jinhua Sun
Summary: Au/SnO2@rGO porous ternary nanocomposites with controllable micromorphology were synthesized by a facile one-pot hydrothermal method. The prepared nanocomposites showed larger specific surface area and faster response/recovery time, resulting in high-performance hydrogen sensing.
SENSORS AND ACTUATORS B-CHEMICAL
(2023)
Article
Thermodynamics
Chenyuan Cai, Min Li, Jizhou Dong, Huahua Xiao
Summary: Adding hydrogen into the natural gas pipeline network and utilizing CH4-H-2 binary fuel are efficient ways for hydrogen storage and utilization. This study experimentally and numerically investigated the flame acceleration in stoichiometric mixtures of CH4/H-2/air with different hydrogen blend ratios. The results show that a higher hydrogen blend ratio leads to faster flame acceleration and the process is influenced by fuel mixture properties, flame surface area, pressure waves, and heat loss.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
Yuhang Hu, Siyuan Cheng, Pengjie Liu, Jiaqing Zhang, Qiangling Duan, Huahua Xiao, Jinhua Sun, Qingsong Wang
Summary: Semi-solid lithium-ion flow battery (SSLFB) is a promising candidate for large-scale energy storage, but the slurry component poses a significant fire hazard due to its highly flammable electrolyte content. This study investigated the combustion characteristics of different electrolytes and slurries to evaluate the fire risk of SSLFB. The results showed that LiTFSI-based electrolyte had lower peak heat release rate (pHRR) and peak mass loss rate (pMLR) compared to LiPF6-based electrolyte, indicating reduced fire hazard. The order of fire risk for slurries containing different electrode materials was determined as S-LTO > S-LFP > S-NCM > S-Graphite based on pHRR and pMLR. The findings provide valuable insights for fire hazard assessment and safety improvement of the SSLFB system.
Article
Engineering, Electrical & Electronic
Yan Zhang, Jiayi Zhang, Huahua Xiao, Derrick Wing Kwan Ng, Bo Ai
Summary: In this article, the authors study the sum spectral efficiency of a multi-user communication system aided by reconfigurable intelligent surfaces (RISs). They consider a realistic scenario with the impact of channel aging due to user mobility and the spatial correlation among the reflecting elements of the RIS. They propose a joint pragmatic model to encompass the impact of channel estimation error and channel aging and formulate the transmit beamforming and phase shift design as a nonconvex optimization problem. They propose an efficient suboptimal algorithm to address the design problem.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Peng Zhang, Jiayi Zhang, Huahua Xiao, Hongyang Du, Dusit Niyato, Bo Ai
Summary: Reconfigurable Intelligent Surface (RIS) can enhance the performance of 6G communication systems by providing additional Line of Sight (LoS) paths. However, the deployment of RIS increases the complexity of beam tracking, making conventional schemes impractical. In this study, a time-varying RIS-aided millimeter wave (mmWave) system is proposed, which uses a robust complex-valued extended Kalman filter method to solve the beam alignment problem. Simulation results show that the proposed algorithm can improve the performance of beam tracking by 37% compared to conventional methods.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Environmental
Chunxiang Zhao, Xing Li, Xiaohan Wang, Min Li, Huahua Xiao
Summary: This paper experimentally studied the characteristics of H-2/CH4 jet flames at varied heat release rates (HRRs) with H-2 volume fraction (fv) ranging from 0% to 90%. The results showed that the flame height is affected by the increase in mixture molecular diffusivity, radicals pool, air entrainment, flame temperature, and jet velocity of fuel flow. A flame height model for H-2/CH4 flames was obtained through comparisons of different correlations.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Energy & Fuels
Huizhen Li, Huahua Xiao
Summary: This paper presents an experimental study of the explosion characteristics of NH3/DME blends. The results show that the peak explosion pressure, maximum pressure rise rate, and deflagration index vary nonmonotonically with the equivalence ratio, and reach peak values at certain ratios. DME addition has a positive effect on explosion intensity.
Article
Thermodynamics
Yifan Yang, Haodong Zhang, Linye Li, Mingming Gu, Xi Xia, Fei Qi
Summary: This paper investigates the formation of a blue whirl by controlling tangential and radial airflows. By using a unique fire whirl apparatus, the blue whirl can be formed directly upon ignition without going through the transient phase. The study also discovers new flame regimes and explores the mechanism behind the formation and transition of the blue whirl.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Xiaobin Qi, Songyan Gao, Zhiping Zhu, Qinggang Lyu, Haixia Zhang
Summary: This study experimentally investigated the propagation characteristics of reverse combustion under oxygen-limited and enriched conditions. The contribution of volatiles gas-phase oxidation and char surface oxidation to reverse combustion was evaluated. The results showed that oxygen enrichment expanded the operating range of oxygen flow rate for reverse combustion and enhanced the low-temperature oxidation of the solid fuel. The findings provide a better understanding of the driving mechanism of reverse combustion and have important implications for efficient thermal conversion of solid fuels.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Bingjie Chen, Peng Liu, Bingzhi Liu, Zhandong Wang, Xiang Gao, William L. Roberts
Summary: In this study, the low temperature oxidation of 1,2,4-trimethylbenzene was investigated using experiments and numerical simulations. The results showed the presence of toxic oxygenated aromatic compounds and proposed potential formation pathways. The numerical simulations accurately predicted the mole fractions of most compounds, but some compounds were missing.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Meng Sui, Zhiheng Zhu, Fashe Li, Hua Wang
Summary: The effect of adding ferrocene as a combustion catalyst to Jatropha biodiesel on its pyrolysis and combustion performance is investigated. The results show that adding ferrocene reduces activation energy and harmful emissions while improving combustion efficiency.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Manaf Sheyyab, Mohammed Abdulrahman, Subharaj Hossain, Patrick T. Lynch, Eric K. Mayhew, Kenneth Brezinsky
Summary: Fuel surrogates, simplified representations of complex fuels, accurately model speciation results and reaction kinetics, reproduce the ignition quality and chemical functional group compositions of their parent fuels.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Yan Wang, Shumeng Xie, Hannes Bottler, Yiqing Wang, Xinyi Chen, Arne Scholtissek, Christian Hasse, Zheng Chen
Summary: This study investigates how flow affects the ignition and transition process of a cool flame. The results show that the ignition energy determines the highest temperature and the strain rate influences the flame propagation and the transition from cool flame to hot flame.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Tanusree Chatterjee, Mengyuan Wang, Goutham Kukkadapu, Chih-Jen Sung, William J. Pitz
Summary: Cycloalkanes, including cyclohexane, are important hydrocarbons in transportation fuels. However, limited oxidation data at low-to-intermediate temperatures and inadequate predictive ability of kinetic models have hindered the understanding and improvement of cyclohexane oxidation. This study provides experimental and modeling results to develop a more accurate kinetic model for cyclohexane oxidation.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Tao Wu, Erik Hagen, Haiyang Wang, Dylan J. Kline, Michael R. Zachariah, Carole Rossi
Summary: It was found that incorporating CuO into Al/I2O5 can significantly reduce the ignition time and enhance the combustion performance. The optimum composition of 80/20 wt% of I2O5/CuO shows a 30 times shorter ignition time and produces a peak pressure and pressurization rate 4 and 26 times greater than traditional Al/I2O5. A series of characterizations helped unravel the cause of improvement and propose a reaction mechanism for this ternary Al/I2O5/CuO system. This study proposes a facile, inexpensive, and efficient way to enhance the combustion performance of Al/I2O5 biocidal nanoenergetic materials.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Mahmoud Gadalla, Shervin Karimkashi, Islam Kabil, Ossi Kaario, Tianfeng Lu, Ville Vuorinen
Summary: In this study, the flame initiation process in dual-fuel spray assisted combustion is explored through scale-resolved simulations, providing numerical evidence on the initiation of premixed flames. It is found that there is a transient mixed-mode combustion phase after ignition, followed by a primarily deflagrative combustion mode. The interactions between turbulence and premixed flame front are characterized in the corrugated regime.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Neeraj Kumar Pradhan, Arindrajit Chowdhury, Debasis Chakraborty, Neeraj Kumbhakarna
Summary: In this study, a modified model for predicting the burn rate of composite solid propellants is proposed. The model has been validated against experimental and theoretical results, and it outperforms existing models in all cases considered. The model is highly robust and provides results quickly, making it highly efficient in terms of time, effort, and computational resources.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Lili Ye, Zhihe Zhang, Fan Wang, Xiaodong Wang, Yiming Lu, Lei Zhang
Summary: This study investigated the pyrolysis mechanism of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) explosive using ab initio and kinetic modeling simulations. The results showed that N-NO2 bond fission and C-H beta-scission are important channels in the decomposition of HMX.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Andrei N. Lipatnikov, Hsuchew Lee, Peng Dai, Minping Wan, Vladimir A. Sabelnikov
Summary: This study investigates the importance of thermodiffusive and hydrodynamic instabilities of laminar flames in turbulent flows through numerical simulations. The analysis suggests that laminar flame instabilities play a minor role at sufficiently high Karlovitz numbers.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Shijie Xu, Yue Qiu, Leilei Xu, Jianqing Huang, Shen Li, Elna J. K. Nilsson, Zhongshan Li, Weiwei Cai, Marcus Alden, Xue-Song Bai
Summary: Metal powder is a promising carbon-free and recyclable energy carrier. In this study, a computational model for the combustion and phase change of micron-sized iron particles was proposed and validated. The model successfully captures the melting, surface reactions, cooling, and solidification processes. The study also reveals a two-stage solidification phenomenon and identifies a diffusion-controlled mechanism during the melting process. The reaction between iron and CH4/O2/N2 flame products is found to play a significant role in the iron combustion process.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Khalid Aljohani, Abd El-Sabor Mohamed, Haitao Lu, Henry J. Curran, S. Mani Sarathy, Aamir Farooq
Summary: This study investigates the impact of exhaust gas recirculation (EGR) and NOx on the ignition delay time of oxygenated gasoline. A gasoline surrogate model is developed and the experimental data are useful for predicting fuel ignition behavior in internal combustion engines. The results show that EGR inhibits gasoline reactivity, while NOx has a promoting effect at high temperatures. This research is important for understanding the combustion behavior of gasoline in engines.
COMBUSTION AND FLAME
(2024)
Article
Thermodynamics
Chengcheng Ao, Jia Yan, Tong Yan, Lidong Zhang, Pan Wang
Summary: This study investigates the inhibitory effect of ammonia blended with hydrocarbon fuels on soot formation. The results show that there is a chemical interaction between ammonia and polycyclic aromatic hydrocarbons (PAHs), blocking the formation of larger PAHs.
COMBUSTION AND FLAME
(2024)