Article
Thermodynamics
Hamed Shariatmadar, Pavlos G. Aleiferis, R. P. Lindstedt
Summary: This study presents experimental data on the size distribution of soot particles and investigates the variation of particle size distribution in turbulent flames under different conditions.
COMBUSTION AND FLAME
(2022)
Article
Chemistry, Physical
Mengzhen Cheng, Haiou Wang, Hua Xiao, Kun Luo, Jianren Fan
Summary: This study investigates the pollutant emissions in ammonia premixed laminar flames and proposes heat release rate surrogates for ammonia combustion using one-dimensional simulations. The findings reveal the emission characteristics of ammonia combustion under different conditions, providing valuable insights for emission control and flame identification of ammonia combustion.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
H. Shariatmadar, R. P. Lindstedt
Summary: This study investigates the impact of flow on the development of particle size distributions (PSDs) in premixed turbulent flames. The results show that using propene as the fuel leads to a two order of magnitude increase in smaller particles compared to using ethene fuel, with median and mean mobility diameters below 10 nm.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Energy & Fuels
Yeonse Kang, Kee Man Lee, Jeong Park
Summary: Experimental and numerical studies showed that the UCSD reaction mechanism could accurately trace the characteristics of SNG-air premixed flames, and that the flame stability map is dependent on methane mole fractions and global strain rate. Increasing global strain rate gradually tilts the lean and rich extinction boundaries, leading to the formation of a flammable region island and eventually only one flammable condition.
Article
Energy & Fuels
Zhixuan Zhang, Xu Han, Mingda Wang, Zhengjie Wu, Xiang Sun, Shaohua Wu
Summary: A new and robust numerical approach, called the hybrid sectional moment projection method, is proposed for solving the population balance equations in laminar premixed flames. This approach combines the fixed sectional method and moment projection method, and adopts a number of quadrature nodes within each section to describe complex particle interactions. Testing and simulation results show that the new approach outperforms the conventional fixed sectional method in terms of numerical accuracy and computational efficiency.
Article
Chemistry, Applied
Zinong Zuo, Bo Hu, Xiuchao Bao, Shibo Zhang, Lingan Kong, Lang Deng, Yibo Xu, Zhennan Zhu, Suozhu Pan
Summary: The study found that increasing initial pressure leads to increased flame instabilities in the alkane-air mixtures due to enhanced hydrodynamic instability. Additionally, under a certain initial pressure, thermal-diffusive instability becomes the main influencing factor on flame instability with an increasing equivalence ratio.
FUEL PROCESSING TECHNOLOGY
(2022)
Article
Energy & Fuels
Mengxiang Zhou, Fuwu Yan, Xianglin Zhong, Lei Xu, Yu Wang
Summary: Oxygenated biofuels like bioethanol and biodiesel are commonly used as clean fuel additives to reduce greenhouse gas and soot emissions. Experimental and numerical studies have shown that the effect of ethanol on soot formation varies depending on combustion conditions, with oxygen-related reactions playing a crucial role in explaining the opposing effects of ethanol addition in different flame configurations.
Article
Energy & Fuels
William L. H. Hallett, Evan Wiens, Marina K. Busigin, Dana Berdusco, Rosalyn Skiffington
Summary: This study investigates the quasi-steady overfeed combustion and gasification of binary mixtures of fuel particles of different sizes and shapes in a fixed bed through experiments and numerical modeling. The results show that physically appropriate definitions of average quantities, such as average sphericity and average particle size, can be used to model bed combustion of a particle mixture.
Article
Engineering, Mechanical
Samuel Wiseman, Andrea Gruber, James R. Dawson
Summary: Ammonia is a promising hydrogen and energy carrier but faces challenges in gas turbines due to its low flame speed and limited flammability range. This paper presents the first measurements of flame transfer functions (FTFs) for NH3/H-2/N-2-air flames and compares them to CH4-air flames. The FTFs for NH3/H-2/N-2 blends have a lower gain at low frequencies but a greater cutoff frequency due to a shorter flame length. The confinement diameter strongly influences the peak gain values for both CH4 and NH3/H-2/N-2 flames.
JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME
(2023)
Article
Engineering, Chemical
Haim Kalman
Summary: This study determines the flowability and physical properties of particulate materials through experiments, and reveals their relationships with factors such as particle size and composition.
Article
Thermodynamics
Jianqin Huang, Shen Li, Weiwei Cai, Yong Qian, Edouard Berrocal, Marcus Alden, Zhongshan Li
Summary: The combustion behavior of iron particles was quantitatively characterized using high-speed digital in-line holography, showing that the ejection speed of iron particles increases with the oxygen concentration, leading to non-uniform spatial distribution and reduced particle number density.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Wu Jin, Chaoqun Ren, Jianzhong Li, Jinhua Wang, Yisheng Yan
Summary: This work systematically investigated the effects of hydrogen addition and CO2 concentration on turbulent combustion characteristics of CH4/H-2 oxyfuel flames. The study utilized PLIF measurement of OH radical to derive turbulent flame speed and flame front structure, and found that thermal-diffusive instability played a key role in the behavior of hydrogen enriched turbulent flames. Additionally, Proper orthogonal decomposition (POD) was applied for multi-scale analysis of flame front structure.
Article
Thermodynamics
Shreshtha Kumar Gupta, Vaibhav Kumar Arghode
Summary: Internal recirculation of product gases and mixing with fresh reactants can reduce pollutant emissions if certain conditions are met. This study uses chemical kinetic simulations to investigate the characteristics and combustion efficiency of hot and diluted mixtures, and the resulting CO and NOx emissions.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Junhao Yan, Suya Gao, Wenchuan Liu, Tairan Chen, Timothy H. Lee, Chia-Fon Lee
Summary: The study aimed to investigate the effects of fuel properties on flash boiling sprays using multihole injectors. It was found that adding ethanol or hexane to isooctane enhanced flash boiling by increasing vapor pressure. Sprays with ethanol blends exhibited more severe flash boiling than those with hexane blends at certain ratios, with differences in liquid penetration and dispersion. Droplet size decreased with increasing hexane content, while noticeable reductions were observed with 10% ethanol content. However, higher ethanol blend ratios did not further decrease droplet size due to vaporization inhibition.
Article
Chemistry, Physical
Chengbin Song, Haiou Wang, Mengzhen Cheng, Tingquan Tian, Kun Luo, Jianren Fan
Summary: This study investigates the combustion characteristics of ammonia and develops surrogate models for predicting the heat release rate (HRR). The NH2+NO elementary reaction is found to be an important contributor to HRR, and the [NH2][NO] surrogate is proposed as a promising predictor. The findings have significant implications for understanding ammonia combustion and its practical applications.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Thermodynamics
Angiras Menon, Jacob W. Martin, Gustavo Leon, Dingyu Hou, Laura Pascazio, Xiaoqing You, Markus Kraft
Summary: The impact of localized sr-radicals on soot formation was explored based on their electronic structure and relative concentrations in flame conditions. It was found that different temperatures favor different structures on rim-based pentagonal rings. Localized sr-radicals were more concentrated at lower temperatures but became negligible at higher temperatures.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Dingyu Hou, Qingzhao Chu, Dongping Chen, Laura Pascazio, Markus Kraft, Xiaoqing You
Summary: This study investigated the sintering process of two homogeneous polycyclic aromatic hydrocarbon (PAH) clusters with diameters in the range of 3-6 nm using molecular dynamics simulations. Results showed the dependency of sintering rate on temperature and crosslinking level of PAH clusters.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Laura Pascazio, Jacob W. Martin, Angiras Menon, Dingyu Hou, Xiaoqing You, Markus Kraft
Summary: A new crosslinking reaction between two pentagonal rings around pericondensed aromatic molecules is proposed, leading to the formation of a stable aromatic molecule that may play a role in soot nucleation.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Thermodynamics
Mengda Wang, Junyu Mei, Xiaoqing You
Summary: This study investigated the effect of potassium chloride (KCl) addition on soot formation during ethylene pyrolysis using various characterization techniques. The results showed that with the addition of KCl, the nucleation of soot particles was not affected while the size growth of soot particles was inhibited, leading to smaller and more compact particles. Charge characteristics analysis also revealed that the multi-charged particles were neutralized by KCl, resulting in slower coagulation rates and smaller particles.
COMBUSTION AND FLAME
(2021)
Article
Engineering, Chemical
Girish Sharma, Mengda Wang, Michel Attoui, Xiaoqing You, Pratim Biswas
Summary: This study evaluated the performance of an ultrafine butanol based CPC for measuring alkyl ammonium halide ions and flame-generated particles, finding optimal operating conditions for detection efficiency. The flame generated particles of TiO2 and soot were activated more readily than alkyl ammonium halide salts, especially in smaller sizes, and negatively charged particles had higher activation efficiencies with butanol vapors.
AEROSOL SCIENCE AND TECHNOLOGY
(2021)
Article
Thermodynamics
Junyu Mei, Yuxin Zhou, Xiaoqing You, Chung K. Law
Summary: The study found that a small amount of oxygen can promote soot formation at lower temperatures of 1473 and 1573 K, but at 1673 K, total soot yield increases with higher fuel-rich conditions. Additionally, soot morphology is primarily influenced by temperature, leading to larger primary particles and less fractal aggregates at lower temperatures.
COMBUSTION AND FLAME
(2021)
Article
Engineering, Environmental
Guoliang Li, Sen Shao, Shuxiao Wang, Xiaoqing You, Junhua Li, Qingru Wu, Liwen Xu, Minneng Wen, Yu Wang, Kaiyun Liu
Summary: Flame synthesis technology was used to enhance thermal and hydrothermal resistance of Cu/Ce based catalysts for Hg-0 oxidation, resulting in smaller lattice size, more stable carrier structure, and more oxygen vacancies. The highly thermostable rutile form of TiO2 in the catalyst contributed to its excellent oxidation activity.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Energy & Fuels
Yage Gao, Xiaoqing You
Summary: The kinetics of hydrogen addition reactions of unsaturated fatty acid methyl esters were investigated by computing reaction rate constants at different theoretical levels, considering high-pressure limits and pressure-dependence, resulting in recommended rate constants for the development of combustion models.
Article
Engineering, Chemical
Dingyu Hou, Laura Pascazio, Jacob Martin, Yuxin Zhou, Markus Kraft, Xiaoqing You
Summary: This study investigated the coagulation process of two PAH clusters with diameter similar to 2 nm using reactive molecular dynamics simulations. The results showed that the coagulation efficiency decreases with increasing temperature, mainly due to the increased kinetic energy of atoms within the clusters at higher temperatures. Additionally, the introduction of surface sigma-radical site fraction could moderately improve the coagulation efficiency, suggesting a low efficiency of incipient soot nanoparticles with surface sigma-radicals in high temperature flame regions.
JOURNAL OF AEROSOL SCIENCE
(2022)
Article
Chemistry, Physical
Yuxin Zhou, Qingzhao Chu, Dingyu Hou, Dongping Chen, Xiaoqing You
Summary: In this paper, the condensation efficiency of polycyclic aromatic hydrocarbon (PAH) molecules on a quasi soot surface is studied using molecular dynamics simulations. The results show that the condensation efficiency increases with molecular mass but decreases with temperature. The presence of aliphatic chains on soot particle surfaces can lower the condensation efficiency significantly at higher temperatures. A condensation efficiency model is proposed and validated with experimental data.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Thermodynamics
Yuxin Zhou, Mengda Wang, Qingyan He, Xiaoqing You
Summary: By studying the soot maturity in a series of laminar premixed ethylene flames, it is found that soot particles grow bigger and become more mature in flames with higher maximum flame temperature (1809 and 1869 K), while soot maturity remains almost unchanged in flames with lower maximum flame temperature (1630 and 1724 K). The growth of soot particles is mainly controlled by particle coagulation or PAH condensation, rather than surface reactions. Higher equivalence ratio leads to faster soot size growth, but the particles from flames with lower equivalence ratio are more mature than those from flames with higher equivalence ratio.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
Yuxin Zhou, Dingyu Hou, Xiaoqing You
Summary: The study examines soot particle size distributions in iron doped premixed ethylene flames using scanning mobility particle sizer measurements. It is found that iron addition promotes the growth in soot particle size, mainly due to enhanced particle coagulation. Molecular dynamics simulations investigating the coagulation of polycyclic aromatic hydrocarbon (PAH) clusters reveal that iron addition increases coagulation efficiency, but has no significant effect on collision frequency. The simulation results also show that iron addition promotes coronene cluster growth, leading to larger soot particle size in iron-doped flames.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Thermodynamics
Mengda Wang, Xiaoqing You
Summary: This work investigates the adsorption behavior of pyrene on the surface of 2-nm iron oxide nanoparticles in the temperature range of 600-2500 K using ReaxFF molecular dynamics simulations. The simulation results show that pyrene can form a core-shell structure by either physical or chemical adsorption on the iron oxide nanoparticle surface, consistent with experimental observations. At lower temperatures (600-1200 K), pyrene dimers are formed before physically adsorbing on the nanoparticle surface, while at higher temperatures (2000-2500 K), pyrene undergoes H abstraction by the oxygen atom of iron oxide and forms a C-Fe bond. In the intermediate temperature range (1200-2000 K), both physical and chemical adsorptions can occur.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
Xiaoqing You, Ying Li, Huangrui Mo, Yuxin Gui
Summary: In this study, the Lennard-Jones parameters of benzene and polycyclic aromatic hydrocarbons interacting with bath gases were theoretically studied using three different computing methods. The results showed that while the SA method is reliable and the sigma-epsilon method is efficient, the eta-xi method is both reliable and efficient, capturing the anisotropic effects of molecular structure on L-J parameters better than empirical methods.
FARADAY DISCUSSIONS
(2022)
Article
Chemistry, Physical
Huangrui Mo, Xiaoqing You, Kai Hong Luo, Struan H. Robertson
Summary: This study focuses on determining the effective Lennard-Jones parameters between a polyatomic molecule and a bath gas molecule from interatomic interactions. An iterative search algorithm is developed to find orientation-dependent collision diameters and well depths on intermolecular potential energy surfaces. An orientation-averaging rule based on characteristic variables is proposed to derive the effective parameters. Three-dimensional parametric surfaces are constructed to quantitatively depict molecular anisotropy.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
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)
