Article
Chemistry, Physical
H. S. Zhen, H. Liu, Z. L. Wei, Z. H. Liu, X. Y. Liu, Z. H. Huang
Summary: This study experimentally examines the interaction between acoustic field and flame. The results show that under acoustic forcing, the flow dynamics, flame front patterns, and heat transfer characteristics are altered. The flame front exhibits convective bubbling, wrinkling, and shrinking under acoustic excitation. Acoustic modulation can promote heat transfer for flame impingement applications. The acoustic field lowers the high-temperature region of the flame, resulting in higher local heat transfer. A 10% increase in total heat transfer rate is achieved with the optimal nozzle-to-plate distance and forcing frequency of 50 Hz.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Energy & Fuels
R. Rabello de Castro, P. Brequigny, J. P. Dufitumukiza, C. Mounaim-Rousselle
Summary: Syngas, a gaseous biofuel, requires operation mode adaptation when used for stationary electricity generation in Internal Combustion engines. Research indicates that combustion parameters of different syngas compositions from various gasifiers affect flame speeds, with Updraft and Downdraft compositions showing higher speeds. Kinetic modeling results show good overall agreement with experimental data, with CRECK mechanism deviating by only 5-10%.
Article
Thermodynamics
Berk Can Duva, Lauren Elizabeth Chance, Elisa Toulson
Summary: The study investigated the effect of lower radius limits on extrapolation results of stretch models for spherically expanding flames, identifying a critical lower radius limit (R-L,R-critical) that converges laminar flame speed and burned gas Markstein length values. The critical lower radius limit strongly depends on the burned gas Markstein number (Ma(b)), with a correlation shown as |Ma(b)| = 0.8424*R-L,R-critical. This approach was used to correct laminar flame speeds and burned gas Markstein lengths for methane, hydrogen, propane, and iso-octane flames, resulting in comparisons with previously published experimental data.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2021)
Article
Chemistry, Physical
Berk Can Duva, Elisa Toulson
Summary: The fundamental combustion characteristics of H-2/air flames with the addition of actual H-2/air combustion residuals were examined experimentally and numerically. The results showed that the flame speed and adiabatic flame temperature decreased linearly with increasing diluent level, while the change in burned gas Markstein length was more complex.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Energy & Fuels
Natarajan Rajesh, M. Akash, Chockalingam Prathap
Summary: This study investigates the dilution effects of steam, carbon dioxide, and nitrogen on the unstretched laminar burning velocity and burned gas Markstein length of premixed mixtures. The addition of 50% diluents significantly suppressed flame propagation, with CO2 showing the highest impact due to the simultaneous reduction in flame temperature and kinetic effect. Experimental and simulated results provide valuable insights into the behavior of different diluents in combustion processes.
Article
Thermodynamics
Yunde Su, Seung Hyun Kim
Summary: The stretch effects in LES of a turbulent lean propane-air premixed Bunsen flame in the wrinkled flamelet regime are investigated. A simple approach to model the subgrid-scale flame stretch is proposed, which suggests using the volume-filtered strain rate on the unburned side of the filtered flame brush to approximate the surface-filtered strain rate. The study highlights the importance of mitigating the artificial heat release effects and examines the relative importance of curvature stretch and strain effects.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Thermodynamics
Sampath Adusumilli, Jerry Seitzman
Summary: Laminar flame speeds of ethylene were measured and compared to predictions based on chemical kinetic mechanisms. Results showed larger prediction discrepancies with CO2 dilution in the oxidizer, indicating a possible underestimation of third-body efficiency for three-body association reactions.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Andisheh Khanehzar, Francisco Cepeda, Seth B. Dworkin
Summary: The study investigates the effects of adding different percentages of hydrogen and nitrogen to the fuel in ethylene/air diffusion flames on soot formation and flame characteristics. Results show that blending hydrogen and nitrogen into the fuel decreases soot volume fraction and radiation. The dilution effect of hydrogen has the most significant influence on soot formation/oxidation reaction rates among the various effects.
Article
Thermodynamics
Shangqing Tao, Jun Fang, Hassan Raza Shah, Lizhong Yang
Summary: This study experimentally investigated the structures, dynamics, and extinction behaviors of buoyancy-induced ultra-low-stretch diffusion flames with N(2)/CO(2) dilution in a CH(4) stream. The results showed that the characteristics and extinction process of the flame varied under different dilution and fuel mixture injection speed conditions. The dilution effect of N(2)/CO(2) reduced the flame temperature and soot formation. The extinction of the flame was influenced by stability instability and heat losses.
COMBUSTION AND FLAME
(2022)
Article
Chemistry, Physical
Rongxue Shang, Zixuan Zhuang, Yue Yang, Gang Li
Summary: This study systematically investigates the laminar flame speeds of H-2/CH4/air mixtures with CO2 and N-2 dilution through experimental and numerical methods. The results show that the combustion transition from methane dominated to hydrogen inhibited occurs with increasing H-2 fractions, and CO2 has a stronger dilution effect on flame speeds compared to N-2. The experimental data is well-predicted by a semiempirical correlation.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Thermodynamics
Natarajan Rajesh, Shu Zheng, Chockalingam Prathap
Summary: The objective of this study was to measure the unstretched laminar burning velocity (LBV) and burned gas Markstein length (Lb) of oxy-n-dodecane mixtures using the spherically outwardly propagating flame (SPF) method. Mixtures with different compositions were analyzed under varying conditions, and the LBV was simulated using different mechanisms. The predicted results showed good agreement with the experimental measurements.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Liqiao Jiang, Yuxuan Wu, Guangzhao Zhou, Xing Li
Summary: This experimental study investigates the effects of CO2 dilution on intrinsic instabilities of non-adiabatic n-butane/air cellular flames. The results show that CO2 dilution significantly enhances flame instability, and the enhanced effect is positively correlated with CO2 dilution ratio.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Thermodynamics
Haoyang Li, Jinyuan Hao, Zhiming Du, Tianwei Zhang
Summary: In this study, the laminar flame speed (S-L) of pyrolysis gas from red pine wood was investigated. The results showed that the laminar flame speed of the gas increased with the increase of pyrolysis temperature. The effect of hydrocarbon gases on the laminar flame speed was linear in a certain concentration range, while the effect of H-2, CO, and CO2 followed a quadratic polynomial distribution.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Luming Fan, Bo Tian, Cheng Tung Chong, Mohammad Nazri Mohd Jaafar, Kenji Tanno, Dante McGrath, Pedro M. de Oliveira, Bernd Rogg, Simone Hochgreb
Summary: In this study, the impact of fuel droplets on stretched laminar flame speeds was investigated by adding small acetone droplets to methane/air mixtures. It was found that the presence of droplets altered the relationship between flame speed and strain rate, especially under rich conditions. Unlike fully vaporized flames, a two-stage reaction flame structure was observed with droplets, indicating a change in flame behavior.
COMBUSTION AND FLAME
(2021)
Article
Energy & Fuels
Ya Li, Wu Xu, Yong Jiang, K. M. Liew
Summary: Recent investigation suggest that CO2, N2, and He have varying effects on the laminar burning velocity (LBV) and cellular instability of 2-MTHF-air flames. The most chaotic state occurred at approximately phi = 1.3 under all test conditions. CO2 and He showed similar abilities to delay the onset of cellular instability, while N2 showed a weaker ability to do so.
Article
Engineering, Chemical
Qian Zhang, Isabelle Jones, Mingming Zhu, Zhezi Zhang, Jian Gao, Dongke Zhang
Summary: This study investigates the catalytic hydrodesulfurization of a spent tire pyrolysis oil distillate using a Ni-Mo catalyst. The results show that increasing temperature, pressure, or H-2 concentration enhances sulfur removal efficiency, and the sulfiding of the catalyst plays a critical role in the hydrodesulfurization process.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Industrial
Chen Zheng, Yushu An, Zhanxi Wang, Xiansheng Qin, Benoit Eynard, Matthieu Bricogne, Julien Le Duigou, Yicha Zhang
Summary: Robotic manufacturing systems are an effective solution for modern manufacturing enterprises to address customer demands and market competition. However, these systems may not fully satisfy user requirements due to differences between user and design perspectives. A user-customised design approach is needed to alleviate the burden on designers. The authors propose a knowledge-based engineering method to aid users in customising the architectures of robotic manufacturing systems.
INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH
(2023)
Review
Environmental Sciences
Shui Cheung Edgar Leung, Pradeep Shukla, Dechao Chen, Ehsan Eftekhari, Hongjie An, Firuz Zare, Negareh Ghasemi, Dongke Zhang, Nam-Trung Nguyen, Qin Li
Summary: This review article focuses on the degradation methods for perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Various technologies, such as bioremediation, electrocoagulation, foam fractionation, sonolysis, photocatalysis, mechanochemical, and electrochemical degradation, have been developed and studied in recent years to address the PFAS crisis. However, challenges remain in terms of large-scale operation complexity and the release of toxic byproducts.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Environmental
Chiemeka Onyeka Okoye, Mingming Zhu, Isabelle Jones, Juan Zhang, Zhezi Zhang, Dongke Zhang
Summary: This study prepared carbon black using a drop tube furnace to promote the use of recycled waste materials as an industrial feedstock. The yield and properties of the carbon black were found to be affected by reaction temperature, oxygen concentration, and residence time. Characterization showed that the carbon black produced from recycled waste materials had comparable properties to commercial products, indicating its potential for use in circular economy strategies.
Article
Thermodynamics
Hendrix Yulis Setyawan, Mingming Zhu
Summary: The ignition, combustion characteristics, and cenosphere formation of single droplets combustion of four vacuum residues (VRs) with different asphaltene contents were experimentally studied. The ignition and combustion behavior of the VRs were recorded and analyzed, and the effect of droplet size, gas temperature, and asphaltene content on various parameters was investigated. The combustion process of VRs was divided into five stages, including pre-ignition, steady combustion, splashing combustion, disruptive combustion, and solid residue ignition and combustion. The presence of asphaltene affected the combustion behavior, leading to the formation of a visible and sooty flame and the increased size of the droplets. The ignition delay time was mainly influenced by the initial droplet size and gas temperature, while the asphaltene content had minimal impact. The thermal decomposition of asphaltene produced cenosphere particles with varying sizes and blowholes, which were more pronounced in VRs with higher asphaltene content.
COMBUSTION SCIENCE AND TECHNOLOGY
(2023)
Article
Thermodynamics
Xiaofei Long, Jianbo Li, Hongjian Wang, Yintang Liang, Xiaofeng Lu, Dongke Zhang
Summary: Formation of ash deposits during Zhundong lignite combustion in a circulating fluidized bed boiler was characterized. The deposits were found to be thick, composed of inner and outer layers, and had different thermal conductivities. The deposits significantly impacted heat transfer and fuel economics.
Article
Energy & Fuels
Yintang Liang, Jianbo Li, Xiaofei Long, Xiaofeng Lu, Dongke Zhang
Summary: In this study, the effect of ash deposition during the combustion of high-sodium Zhundong lignite in a circulating fluidized bed was simulated and experimentally observed. The results showed that the thickness of the deposit and the increase in surface temperature were in agreement with the experimental observations. Factors such as particle size, chemistry, and flue gas temperature were found to affect ash deposition.
Article
Agricultural Engineering
Jianbo Li, Xiaofei Long, Hongyan Zhu, Zhuo Liu, Xiaofeng Lu, Dongke Zhang
Summary: In this paper, the fusibility of biomass ashes with different chemical and mineral compositions was studied using HT-XRD technique. It was found that ash fusion temperatures (AFTs) increased in the order of walnut shell (WS) < wheat straw (WHS) < peanut shell (PES) < pine sawdust (PS). The chemical compositions of the ashes played a role in these differences. HT-XRD analysis revealed the presence and disappearance of K-bearing minerals in WS ash, the release of KCl and formation of K silicates or aluminosilicate in WHS ash, and the identification of SiO2, MgO, CaAl2Si2O8, and CaAl2SiO6 in PES ash. The macro- and micro-morphological analysis confirmed the sintering behavior of the different ashes at various temperatures.
BIOMASS & BIOENERGY
(2023)
Article
Thermodynamics
Shanshan Zhu, Qiang Xu, Ruoyue Tang, Jian Gao, Zhandong Wang, Jiaying Pan, Dongke Zhang
Summary: The oxidation of ammonia in the presence of dimethyl ether was studied in a jet-stirred reactor at atmospheric pressure. The effects of DME addition on the NH3-NH2 pathway and the formation of nitrogen oxides were investigated. Experimental analysis using a synchrotron vacuum ultraviolet photoionization mass spectrometer and a gas chromatograph was conducted to analyze reaction intermediates and products. A kinetic model for NH3/DME oxidation was developed, and it was found that DME significantly promotes the formation of NH2 and nitrogen oxides under different temperature conditions.
COMBUSTION AND FLAME
(2023)
Article
Agricultural Engineering
Sabar Pangihutan Simanungkalit, Isabelle Jones, Chiemeka Onyeka Okoye, Zhezi Zhang, Mingming Zhu, Dongke Zhang
Summary: The possibility of direct methanol synthesis from biomass pyrolysis syngas using Cu/ZnO/Al2O3 catalysts was investigated. Methanol yield was influenced by temperature, pressure, and time on-stream. The presence of CO2 in the syngas resulted in decreased catalyst performance, while CH4 did not affect performance. This research provides insights into the challenges of producing methanol from unconventional syngas and motivates future work to develop a robust catalyst for H2-deficient and CO2-rich syngas.
BIOMASS & BIOENERGY
(2023)
Article
Chemistry, Multidisciplinary
Huanran Wang, Xianchun Li, Junzhi Wu, Dongke Zhang
Summary: This study systematically investigated the NO reduction over highly dispersed zerovalent iron supported on graphene. In situ FTIR spectroscopy and DFT calculations were used to examine the reaction mechanism. The results showed that NO is reduced to active surface oxygen species and then further reduced by carbon in graphene. The presence of CO helps in the regeneration of iron sites and facilitates NO reduction.
Article
Engineering, Chemical
Xiaofei Long, Jianbo Li, Xiaofeng Lu, Kai Zhang, Dongke Zhang
Summary: This study systematically investigated the effects of NaCl, Na2CO3, and Na2SO4 on the agglomeration of quartz particles and bed defluidisation in a high-temperature bubbling fluidised bed. Various characterisation techniques were used to analyse the bed particles and agglomerates. The results showed that bed defluidisation occurred at 800-900 degrees C with NaCl or Na2CO3 feeding at NaCl(Na2CO3)/SiO2 ratios <1.32%, while no bed defluidisation occurred with Na2SO4. The release rate of Na salts was also determined to understand the transition behaviour of fluidisation.
Article
Chemistry, Physical
Penglei Wang, Shiying Fan, Xinyong Li, Jun Duan, Dongke Zhang
Summary: The impact of the piezoelectric effect on the photocatalytic production of hydrogen peroxide (H2O2) over graphitic carbon nitride (CN) was investigated by modulating its molecular structure. The results showed that the photocatalytic activity of CN, CN-P, CN-OF was enhanced by approximately 1.40, 1.46, and 1.51 times due to the piezoelectric effect, respectively, while CN-CA exhibited a 6-fold decrease in activity. Various techniques were employed to explore the active sites, piezoelectric polarization, and charge separation, revealing that the piezoelectric effect's influence on photocatalytic H2O2 production over CN is determined by multiple factors.
