Article
Thermodynamics
Qiang Wang, Xuan Liang, Aquan Lu, Ben Wang, Osamu Fujita, Suk Ho Chung, Longhua Hu
Summary: The blowout behavior of inclined nonpremixed turbulent jet flames is investigated by varying the jet inclined angle. Experimental quantification of the blowout limit and numerical simulations are performed to analyze the flow field difference for different inclined angles. Physical modeling and analysis are conducted to understand the effect of inclined angle on blowout behavior. The findings provide new insights into the blowout limit of nonpremixed inclined turbulent jet flames and propose a model to characterize this behavior.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Mathematics, Applied
Arijit Bhattacharya, Somnath De, Sirshendu Mondal, Achintya Mukhopadhyay, Swarnendu Sen
Summary: Lean premixed combustors are prone to flame instability, which can have serious consequences. This study explores the use of a nonlinear dynamical tool, the recurrence network, to predict lean blowout. The results show that recurrence network parameters exhibit similar trends for different degrees of premixing, but the sensitivities and absolute trends differ between highly premixed and partially premixed configurations.
Article
Thermodynamics
Linyuan Huang, Changchun Liu, Tiandiao Deng, Hua Jiang, Pengzhi Wu
Summary: Central airflow has been investigated for its effects on the combustion stability and shape of swirl flames in this study. Results show that central airflow can alter flame shape and height, but may also cause flame blowout at high equivalence ratios.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Thermodynamics
Chengdong Kong, Yu Wang, Xiaojiang Wu, Zhongxiao Zhang
Summary: This study investigated the characteristics of rotating gliding arc (RGA) assisted swirling methane combustion near the lean blowout limit using high-speed videography. Four flame modes were observed: self-sustained flame, RGA-sustained stable flame, RGA-induced oscillating flame, and RGA anchored flame modes. The oscillating flame mode occurred with specific air flow rates and equivalence ratios, and it was found to be influenced by RGA discharge characteristics, transformer input voltage, and combustion chamber wall temperature. A three-staged mechanism was proposed to explain this RGA-induced low-frequency oscillating flame phenomenon. In conclusion, this study expands our knowledge of oscillating combustion behaviors and GA assisted combustion.
COMBUSTION AND FLAME
(2023)
Article
Engineering, Aerospace
Lei Sun, Yong Huang, Xiwei Wang, Zekun Zheng, Ruixiang Wang, Xiang Feng
Summary: The paper presents an innovative hybrid method based on the FV concept for quick prediction of the LBO limit of aircraft engines, which can improve prediction accuracy and achieve better accuracy compared to existing methods.
CHINESE JOURNAL OF AERONAUTICS
(2021)
Article
Chemistry, Physical
Xudong Song, Runmin Wu, Ying Zhou, Jiaofei Wang, Juntao Wei, Jinyun Li, Guangsuo Yu
Summary: The thickness of the burner rim and incidence angles can affect the stability of the inverse diffusion flame. When the burner rim thickness exceeds a certain value, the flame transitions directly from the attachment state to the blow-out state. Different incident angles result in various shear angles and affect the flame structure, with lower incidence angles leading to increased tangential velocity and more stable flames.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Jianlong Wan, Haibo Zhao
Summary: This study experimentally investigates the dynamics of laminar premixed flames at fuel ultra-rich condition, revealing normal, anomalous, and low speed blow-off phenomena, as well as the oscillation and stability limit behavior of the flames with the change in Reynolds number.
Article
Energy & Fuels
Yaojie Tu, Hao Liu, Yuqi Zhu, Thibault F. Guiberti, William L. Roberts
Summary: This study proposes an inverse-diffusion flame burner configuration to enhance the combustion stability of MILD regime. Experimental results show that increasing burner load and equivalence ratio can improve combustion stability, and MILD combustion can reduce NO emission by nearly 50%.
Article
Thermodynamics
Shangpeng Li, Qiang Yao, Chung K. Law
Summary: The study focused on the stabilization of the flame base in the bottom Ekman boundary layer of fire whirl under strong circulation, relevant for fire safety and the understanding of blue whirl generation mechanism. The theoretical solutions of liftoff position and critical blowout limit agreed well with the numerical results, indicating two solutions for r(f) under relatively large Damkohler number, with one stable and the other unstable. Explicit solution of the blowout limit showed a proportional relationship with the stoichiometric planar flame speed, with the transversal radial velocity gradient also investigated for its effect on flame stabilization.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2021)
Article
Engineering, Aerospace
Meng Han, Quanhong Xu, Xiao Han, Yuzhen Lin
Summary: By conducting experiments and simulations, this study investigated the flame dynamics near LBO conditions in a stratified swirl burner, revealing changes in flame structure and the presence of a characteristic frequency of 405 Hz, demonstrating the mechanism of flame-vortex interactions.
PROPULSION AND POWER RESEARCH
(2021)
Article
Energy & Fuels
Aravind Muraleedharan, Jithin Edacheri Veetil, Akram Mohammad, Sudarshan Kumar, Ratna Kishore Velamati
Summary: The characteristics of microjet hydrogen diffusion flames stabilized near extinction were investigated numerically, with the impact of burner wall material, thickness, and thermal radiation on flame properties such as height and temperature examined. Results showed that quartz burners stabilized flames at lower fuel velocities compared to steel or aluminum burners, with low conductive burners having higher flame temperatures and lengths correlating with increased thermal conductivity. Although thermal radiation had minimal effects on flame temperature and height, it significantly influenced flame structure for low conductive burner materials.
Article
Thermodynamics
Sajjad Rahimi, Kiumars Mazaheri, Alireza Alipoor, Amirreza Mohammadpour
Summary: This numerical study investigates the impact of adding 20% and 40% hydrogen in different slots of a turbulent methane-air flame. Injection configurations include the inner slot, outer slot, and both slots. The results show that adding hydrogen in the inner slot and both slots increases combustion intensity and robust flame attachment, while adding hydrogen in the outer slot has minimal effects. In terms of pollutant emissions, the addition of hydrogen decreases CO and increases NOx emission in all configurations.
Article
Thermodynamics
Qianpeng Zhao, Jinhu Yang, Cunxi Liu, Fuqiang Liu, Shaolin Wang, Yong Mu, Gang Xu, Junqiang Zhu
Summary: Lean combustion in gas turbine combustors reduces NOx emissions, but poses a risk of blowout in aero-engines at low power conditions. This study experimentally investigated the LBO process of spray flame and found that LBO performance deteriorated with increasing altitude. The flame changed from a double V-shape to a single V-shape and the spectral analysis showed changes in peak frequencies before flame extinction, which can be considered as a precursor for blowout.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Energy & Fuels
Faizan Habib Vance, Yuriy Shoshin, Philip de Goey, Jeroen van Oijen
Summary: This study investigated the stabilization and blow-off of ultra-lean hydrogen flames behind a cylindrical bluff body using experiments and numerical simulations. Results showed that the flame displacement speed can be scaled with a relevant tubular flame displacement speed, and flames with neck formations are quenched due to excessive local stretching. Extinct flames with closed flame fronts were found to be stabilized inside a recirculation zone.
Article
Thermodynamics
Yiran Feng, Wenyuan Qi, Yifan Zhou, Yuyin Zhang, Liqiao Jiang, Haolin Yang
Summary: A new fuel/air mixing mode, called the multi-staged tubular flame (MSTF) burner, was proposed and applied to solve the problems in conventional tubular flame burners. Comparisons between MSTF and conventional burners were conducted through experiments and simulations, which showed that MSTF burner has better flame stability and wider extinction limits.
COMBUSTION SCIENCE AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Yingna Du, Chen Huang, Wei Jiang, Qiangwei Yan, Yongfei Li, Gang Chen
Summary: In this study, anionic surfactants modified hydrotalcite was used as a flow improver for crude oil under low-temperature conditions. The modified hydrotalcite showed a significant viscosity reduction effect on crude oil. The mechanism of the modified hydrotalcite on viscosity and pour point of crude oil was explored through characterization and analysis of the modified hydrotalcite and oil samples.
Article
Energy & Fuels
Mohammad Saeid Rostami, Mohammad Mehdi Khodaei
Summary: In this study, a hybrid structure, MIL-53(Al)@MWCNT, was synthesized by combining MIL-53(Al) particles and -COOH functionalized multi-walled carbon nanotube (MWCNT). The hybrid structure was then embedded in a polyethersulfone (PES) polymer matrix to prepare a mixed matrix membrane (MMM) for CO2/CH4 and CO2/N2 separation. The addition of MWCNTs prevented MIL-53(Al) aggregation, improved membrane mechanical properties, and enhanced gas separation efficiency.
Article
Energy & Fuels
Yunlong Li, Desheng Huang, Xiaomeng Dong, Daoyong Yang
Summary: This study develops theoretical and experimental techniques to determine the phase behavior and physical properties of DME/flue gas/water/heavy oil systems. Eight constant composition expansion (CCE) tests are conducted to obtain new experimental data. A thermodynamic model is used to accurately predict saturation pressure and swelling factors, as well as the phase boundaries of N2/heavy oil systems and DME/CO2/heavy oil systems, with high accuracy.
Article
Energy & Fuels
Morteza Afkhamipour, Ebad Seifi, Arash Esmaeili, Mohammad Shamsi, Tohid N. Borhani
Summary: Non-conventional amines are being researched worldwide to overcome the limitations of traditional amines like MEA and MDEA. Adequate process and thermodynamic models are crucial for understanding the applicability and performance of these amines in CO2 absorption, but studies on process modeling for these amines are limited. This study used rate-based modeling and Deshmukh-Mather method to model CO2 absorption by DETA solution in a packed column, validated the model with experimental data, and conducted a sensitivity analysis of mass transfer correlations. The study also compared the CO2 absorption efficiency of DETA solution with an ionic solvent [bmim]-[PF6] and highlighted the importance of finding optimum operational parameters for maximum absorption efficiency.
Article
Energy & Fuels
Arastoo Abdi, Mohamad Awarke, M. Reza Malayeri, Masoud Riazi
Summary: The utilization of smart water in EOR operations has gained attention, but more research is needed to understand the complex mechanisms involved. This study investigated the interfacial tension between smart water and crude oil, considering factors such as salt, pH, asphaltene type, and aged smart water. The results revealed that the hydration of ions in smart water plays a key role in its efficacy, with acidic and basic asphaltene acting as intrinsic surfactants. The pH also influenced the interfacial tension, and the aged smart water's interaction with crude oil depended on asphaltene type, salt, and salinity.
Article
Energy & Fuels
Dongao Zhu, Kun Zhu, Lixian Xu, Haiyan Huang, Jing He, Wenshuai Zhu, Huaming Li, Wei Jiang
Summary: In this study, cobalt-based metal-organic frameworks (Co-based MOFs) were used as supports and co-catalysts to confine the NHPI catalyst, solving the leaching issue. The NHPI@Co-MOF with carboxyl groups exhibited stronger acidity and facilitated the generation of active oxygen radicals O2•, resulting in enhanced catalytic activity. This research provides valuable insights into the selection of suitable organic linkers and broadens the research horizon of MOF hybrids in efficient oxidative desulfurization (ODS) applications.
Article
Energy & Fuels
Edwin G. Hoyos, Gloria Amo-Duodu, U. Gulsum Kiral, Laura Vargas-Estrada, Raquel Lebrero, Rail Munoz
Summary: This study investigated the impact of carbon-coated zero-valent nanoparticle concentration on photosynthetic biogas upgrading. The addition of nanoparticles significantly increased microalgae productivity and enhanced nitrogen and phosphorus assimilation. The presence of nanoparticles also improved the quality of biomethane produced.
Article
Energy & Fuels
Yao Xiao, Asma Leghari, Linfeng Liu, Fangchao Yu, Ming Gao, Lu Ding, Yu Yang, Xueli Chen, Xiaoyu Yan, Fuchen Wang
Summary: Iron is added as a flocculant in wastewater treatment and the hydrothermal carbonization (HTC) of sludge produces wastewater containing Fe. This study investigates the effect of aqueous phase (AP) recycling on hydrochar properties, iron evolution and environmental assessment during HTC of sludge. The results show that AP recycling process improves the dewatering performance of hydrochar and facilitates the recovery of Fe from the liquid phase.
Article
Energy & Fuels
He Liang, Tao Wang, Zhenmin Luo, Jianliang Yu, Weizhai Yi, Fangming Cheng, Jingyu Zhao, Xingqing Yan, Jun Deng, Jihao Shi
Summary: This study investigated the influence of inhibitors (carbon dioxide, nitrogen, and heptafluoropropane) on the lower flammability limit of hydrogen and determined the critical inhibitory concentration needed for complete suppression. The impact of inhibitors on explosive characteristics was evaluated, and the inhibitory mechanism was analyzed with chemical kinetics. The results showed that with the increase of inhibitor quantity, the lower flammability limit of hydrogen also increased. The research findings can contribute to the safe utilization of hydrogen energy.
Article
Energy & Fuels
Zonghui Liu, Zhongze Zhang, Yali Zhou, Ziling Wang, Mingyang Du, Zhe Wen, Bing Yan, Qingxiang Ma, Na Liu, Bing Xue
Summary: In this study, high-performance solid catalysts based on phosphotungstic acid (HPW) supported on Zr-SBA-15 were synthesized and evaluated for the one-pot conversion of furfural (FUR) to γ-valerolactone (GVL). The catalysts were characterized using various techniques, and the ratio of HPW and Zr was found to significantly affect the selectivity of GVL. The HPW/Zr-SBA-15 (2-4-15) catalyst exhibited the highest GVL yield (83%) under optimized reaction conditions, and it was determined that a balance between Bronsted acid sites (BAS) and Lewis acid sites (LAS) was crucial for achieving higher catalytic performance. The reaction parameters and catalyst stability were also investigated.
Article
Energy & Fuels
Michael Stoehr, Stephan Ruoff, Bastian Rauch, Wolfgang Meier, Patrick Le Clercq
Summary: As part of the global energy transition, an experimental study was conducted to understand the effects of different fuel properties on droplet vaporization for various conventional and alternative fuels. The study utilized a flow channel to measure the evolution of droplet diameters over time and distance. The results revealed the temperature-dependent effects of physical properties, such as boiling point, liquid density, and enthalpy of vaporization, and showed the complex interactions of preferential vaporization and temperature-dependent influences of physical properties for multi-component fuels.
Article
Energy & Fuels
Yuan Zhuang, Ruikang Wu, Xinyan Wang, Rui Zhai, Changyong Gao
Summary: Through experimental validation and optimization of the chemical kinetic model, it was found that methanol can accelerate the oxidation reaction of ammonia, and methanol can be rapidly oxidized at high concentration. HO2 was found to generate a significant amount of OH radicals, facilitating the oxidation of methanol and ammonia. Rating: 7.5/10.
Article
Energy & Fuels
Radwan M. EL-Zohairy, Ahmed S. Attia, A. S. Huzayyin, Ahmed I. EL-Seesy
Summary: This paper presents a lab-scale experimental study on the impact of diethyl ether (DEE) as an additive to waste cooking oil biodiesel with Jet A-1 on combustion and emission features of a swirl-stabilized premixed flame. The addition of DEE to biodiesel significantly affects the flame temperature distribution and emissions. The W20D20 blend of DEE, biodiesel, and Jet A-1 shows similar flame temperature distribution to Jet A-1 and significantly reduces UHC, CO, and NOx emissions compared to Jet A-1.
Article
Energy & Fuels
Jiang Bian, Ziyuan Zhao, Yang Liu, Ran Cheng, Xuerui Zang, Xuewen Cao
Summary: This study presents a novel method for ammonia separation using supersonic flow and develops a mathematical model to investigate the condensation phenomenon. The results demonstrate that the L-P nucleation model accurately characterizes the nucleation process of ammonia at low temperatures. Numerical simulations also show that increasing pressure and concentration can enhance ammonia condensation efficiency.
Article
Energy & Fuels
Shiyuan Pan, Xiaodan Shi, Beibei Dong, Jan Skvaril, Haoran Zhang, Yongtu Liang, Hailong Li
Summary: Integrating CO2 capture with biomass-fired combined heat and power (bio-CHP) plants is a promising method for achieving negative emissions. This study develops a reliable data-driven model based on the Transformer architecture to predict the flowrate and CO2 concentration of flue gas in real time. The model validation shows high prediction accuracy, and the potential impact of meteorological parameters on model accuracy is assessed. The results demonstrate that the Transformer model outperforms other models and using near-infrared spectral data as input features improves the prediction accuracy.