COMBUSTION AND FLAME
·
2023
·
IF 4.4
Xiaodong Wang,Lili Ye,Xiaoyuan Zhang,Zhihe Zhang,Jiuzhong Yang,Long Zhao
Acetaldehyde, ethylene oxide , and vinyl alcohol are three C 2 H 4 O isomers that are ubiquitous in combustion over a wide temperature range. A comprehensive reaction kinetics study has been performed for reactions that occur on the same C 2 H 4 O potential energy surface , mainly including the unimolecular reactions of three C 2 H 4 O isomers and the recombination reaction of CH 3 with HCO. Temperature- and pressure-dependent rate coefficients were updated or newly predicted by performing quantum chemical calculations coupled with RRKM/master equation simulations. The dominance of C C bond fission is reconfirmed for acetaldehyde decomposition at higher temperatures. The negligible contribution of CH 4 + CO channel from usual tight intramolecular H-shift transition state provides indirect evidence for previously reported roaming mechanism that was proposed to explain the observation of CH 4 + CO in acetaldehyde pyrolysis . For ethylene oxide pyrolysis , current experiment and kinetic prediction have a good consistency in branching ratios between the formation of acetaldehyde and vinyl alcohol products. The radicals of CH 3 + HCO can also be directly generated from ethylene oxide through a well-skipping reaction mechanism especially at higher temperatures. For CH 3 + HCO recombination, we highlight the importance of CH 3 CO + H channel that was often overlooked previously. Kinetic simulations show that the incorporation of updated rate coefficients and newly identified channels results in a measurable influence on C2 chemistry , indicating the possibility and necessity of further improvement of core mechanism in combustion kinetic models .
研究领域:
物理化学
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燃烧化学
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反应动力学
·
量子化学计算
·
分子反应机制
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2018
·Vol. 37
·期 1
·565-573
·
IF 5.336
Xiaoyuan Zhang,Yuyang Li,Chuangchuang Cao,Jiabiao Zou,Yan Zhang,Wei Li,Tianyu Li,Jiuzhong Yang,Philippe Dagaut
The kinetics of propanal oxidation was studied in a jet-stirred reactor (JSR) at atmospheric pressure. The investigated temperature range is from 450 to 800 K at two different equivalence ratios (0.35 and 4.0). Thanks to the synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS), critical intermediates were identified, including methylperoxy, methyl hydroperoxide , ethylperoxy, ethyl hydroperoxide, α-lactone, β-propiolactone and ketohydroperoxides. A kinetic model for propanal oxidation was also developed and validated against the present experimental results, as well as those available from the literature. Main chain-branching pathways under the investigated conditions were analyzed based on present experimental data and kinetic model . The O 2 addition reaction to the propanoyl radical and subsequent oxidation reactions play an important role in determining the oxidation rate of propanal under fuel-lean conditions, especially in the low-temperature oxidation region. Under fuel-rich conditions, the decomposition of the propanoyl radical is predominant and C 2 H 5 relevant reactions consequently determine the kinetics of oxidation of propanal.
研究领域:
物理化学
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燃烧化学
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反应动力学
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分析化学
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能源化学
✓ 已验证
DOI
高影响因子
FUEL
·
2014
·
IF 3.406
Wenqing Li,Liying Wang,Yu Qiao,Jian-Ying Lin,Meijun Wang,Liping Chang
Understanding the effect of the atmosphere on the release of alkali and alkaline-earth metals (AAEM) during oxy-fuel combustion is important for the development of oxy-fuel combustion technologies with reduced problems with particulate formation and corrosion. To this end, we examined the release behavior of AAEM during oxy-fuel combustion in different gas environments. A drop-tube reactor and ion chromatography were used to investigate the release rates of AAEM. Our results show that the release rates of Na and K were higher than those of Ca and Mg in all types of gas environments. Experimental conditions that favor combustion, namely, higher temperature, higher oxygen content, and longer residence time, markedly increased the release rates of Na and K, whereas changes in the release rates of Ca and Mg were much smaller. The presence of SO 2 in the atmosphere suppressed the release of AAEM via formation of sulfates, whereas the presence of H 2 O promoted it. A synergistic effect of H 2 O and SO 2 on the release of AAEM during oxy-fuel combustion was observed.
研究领域:
燃烧化学
·
能源工程
·
环境化学
·
材料腐蚀
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颗粒物形成
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2022
·Vol. 39
·期 1
·315-324
·
IF 6.535
Qianjin Lin,Wanxiong Liao,Jia Cheng,Chun Zou,Bin Yang,Wenxiang Xia
Few studies on the low-temperature combustion behavior of MIPK, being a promising fuel additive , have been conducted. In this work, ignition delay times (IDTs) of MIPK were measured in the temperatures ranging between 780–910 K and pressures of 20 and 25 bar using a rapid compression machine (RCM). Oxy-fuel combustion combined with biofuel could remove CO 2 from the atmosphere. The IDTs of MIPK were measured in the temperatures ranging between 1125–1600 K under the O 2 /CO 2 atmosphere at the pressures of 1 and 10 bar using a shock tube . A low to high-temperature MIPK kinetic model (HUST-MIPK model) was proposed, in which the low-temperature sub-model consists of 19 low-temperature reaction classes and was constructed by analogy-based method, the high-temperature sub-model was adapted from the works of Cheng et al.. The predictions of HUST-MIPK model are in good agreement with the present low-temperature IDTs, high-temperature O 2 /CO 2 atmosphere IDTs, and the literature experimental data. The negative temperature coefficient (NTC) behavior was not observed in the temperature range from 790 to 910 K in the present RCM experiments, but was observed for methyl propyl ketone (MPK) and diethyl ketone (DEK) under similar conditions. The low-temperature chemistry of three pentanone isomers (MIPK, MPK, and DEK) was compared using the flux and sensitivity analysis. The comparison of the experimental high-temperature IDTs between O 2 /CO 2 and O 2 /Ar atmospheres indicates the IDTs of MIPK under O 2 /CO 2 atmosphere are longer than those under O 2 /Ar atmosphere at 1 bar, and the effects of CO 2 are almost independent of the pressure. The physical and chemical effects of CO 2 on the ignition were studied in detail.
研究领域:
燃烧化学
·
燃料化学
·
反应动力学
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能源工程
·
大气环境影响
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Jizhen Zhu,Sixu Wang,Mohsin Raza,Yuan Feng,Jing Li,Yebing Mao,Liang Yu,Yong Qian,Xingcai Lu
Methanol is an attractive oxygenate increasingly used as primary fuel for dual-fuel combustion technology yielding beneficial thermal-efficiency and emissions in modern engines. As such, it is significant to fundamentally understand the autoignition behavior of methanol/diesel mixtures. This study measured the ignition delay times (IDTs) of methanol/diesel blends with different mixing ratios (30%, 50%, 70% methanol by mol.) on a heated shock tube and a heated rapid compression machine at temperatures of 650−1450 K, pressures of 6−20 bar, and equivalence ratios of 0.5, 1.0 and 2.0. The typical two-stage ignition characteristics with the negative temperature coefficient response were observed for dual-fuel mixtures. In general, both the total and first-stage IDTs decrease with the increment of pressure and equivalence ratio as well as diesel proportion in mixtures. The simulation results performed with a published detailed mechanism in conjunction with a tri-component diesel surrogate demonstrate generally good agreement with the experimental data at all test conditions. Moreover, a crossover of IDTs occurs at a higher temperature (~1500 K) for varying equivalence ratios, and experiment and simulation both exhibit a non-linear mixing effect of methanol addition on diesel ignition. Interestingly, simulation results clearly suggest a crossover (~940 K) for mixtures with varying methanol content at an intermediate-temperature, where the IDT of the mixture with a lower methanol ratio becomes longer as the temperature is higher than that of the crossover. Furthermore, brute-force sensitivity analyses assisted with reaction path analysis were conducted to gain deeper insights into the autoignition chemistry of dual-fuel mixtures, especially for the chemical interaction between both fuels during the low-temperature oxidation process . It is found that methanol hardly generates •OH, whereas •OH is mainly produced by the low-temperature reaction pathways of diesel. Thus, •OH is the bridge for both fuels during the ignition process. At the high methanol ratio, the H-abstraction of diesel is mainly via •HO 2 while CH 3 OH consumes a large percentage of •OH. Consequently, the competition between methanol and diesel for •OH radicals inhibits the overall reactivity of reaction network. In addition, the original data reported here lay a foundation for the development and validation of more accurate and robust dual-fuel kinetic schemes.
研究领域:
燃烧化学
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燃料科学
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化学动力学
·
内燃机工程
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替代燃料技术
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Hong Wang,Bingzhi Liu,Qiang Xu,Shijun Dong,Zhandong Wang,Long Zhu
Cyclopentanone (CPN) is a widely available biofuel with excellent combustion properties, but detailed speciation profiles during its pyrolysis have rarely been studied. This work examines the pyrolysis of CPN in a jet-stirred reactor (JSR) at atmospheric pressure, with residence time of 2 s and a temperature range from 830 K to 1100 K. Dozens of pyrolysis intermediates and products were measured using synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) and gas chromatography (GC). Among them, several new species were observed, including water, carbon dioxide , formaldehyde, indene , 1,2-dihydroindene, naphthalene , 1,2-dihydronaphthalene, 1-methylnaphthalene, acenaphthylene , biphenyl , and fluorene . A detailed kinetic model was developed based on the literature, and in general, it predicted the experimental results for most species well. Kinetic analyses indicated that the consumption of CPN was controlled by the bimolecular reactions with H atom. The formation of water, carbon dioxide and formaldehyde could be explained by the reaction pathways of OH radical. The pyrolysis of CPN yielded a significant number of alkenes and alkynes at higher temperatures; the bimolecular addition reactions of these species with resonantly stabilized radicals are important to the formation of polycyclic aromatic hydrocarbons (PAHs). Based on those, this work provides valuable insights into CPN pyrolysis chemistry and it promotes the development of a comprehensive CPN combustion model.
研究领域:
燃烧化学
·
能源化学
·
反应动力学
·
分析化学
·
环境化学
✓ 已验证
DOI
高影响因子
Applications in Energy and Combustion Science
·
2022
·
IF 0
Bingzhi Liu,Long Zhu,Qingbo Zhu,Hao Lou,Qiang Xu,Zhandong Wang
Ozone-assisted combustion is an advanced combustion technology that is considered a promising means for the active control of combustion. Ozone addition can enhance combustion processes and extend the experimental parameters to extreme conditions. In this work, ozone-assisted low temperature oxidation of methanol and ethanol in a jet-stirred reactor (JSR) was carried out at atmospheric pressure, with a fuel initial mole fraction of 0.005, an equivalence ratio of 0.28, and in the temperature range of 330–800 K. Significant conversions of methanol and ethanol were observed in the low temperature region when ozone was added. Numerous intermediate species were analyzed and quantified by synchrotron vacuum ultraviolet photoionization mass spectrometry and gas chromatography, which are crucially important for unraveling the low temperature oxidation reaction network. The kinetic model of NUIGMech1.1 is tentatively updated to better explain the measured results, although the improvements of the C 1 –C 2 core mechanisms are difficult. Ozone addition enhances the action of the reaction channel of related radicals. Model analysis shows that the kinetics of Ö/ȮH/HȮ 2 atoms/radicals are crucial for the overall reaction progress, as well as the reaction of HȮ 2 radicals with ozone, which mainly contributes to the formation of ȮH radicals during the initial reaction stage. Inconsistency between measurements and model predictions highlights the considerable uncertainty in the C 1 -C 2 alcohols subchemistry at lower temperatures. The experimental results obtained in this work and model development will motivate further study of the low temperature oxidation chemistry of methanol and ethanol.
研究领域:
化学工程
·
燃烧化学
·
反应动力学
·
能源化学
·
大气压反应器
✓ 已验证
DOI
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Yuxiang Li,Kejuan Meng,Momang Tian,Lei Zhang,Xiaoxia Ma,Kaili Zhang
Metastable intermolecular composites (MICs) typically use Al as fuel and transition metal oxides as oxidizers , while their reactivities are hindered by the inert Al 2 O 3 passivation layer on the surface of Al particles . Recently, transition metal fluorides have emerged as novel fluorine-containing oxidizers for promoting the reactivity of metal fuels through interfacial fluorination of oxide layer . In this work, nanosized CoF 2 and Co 3 O 4 were prepared through pyrolysis of CoF 2 ·4H 2 O precursor using different calcination conditions. To investigate the function of CoF 2 in reaction and the influence of CoF 2 content on reactive performances, a series of MICs composed of n-Al, Co 3 O 4 , and CoF 2 were prepared through ultrasonic dispersion method. Thermal analysis indicated that Al/CoF 2 composite had significantly higher specific heat release (2.30 kJ/g) than that of Al/Co 3 O 4 composite (1.45 kJ/g), and CoF 2 facilitated the occurrence of exothermic reaction at a relatively lower temperature. AlF 3 was found as main reaction products of Al/CoF 2 at 650 °C, and AlF 3 sublimes at the temperature above 850 °C. Although the pressure output and flame intensity of Al/CoF 2 composite is lower than that of Al/Co 3 O 4 composite, hybrid Al/Co 3 O 4 /CoF 2 composites with 20 %–35 % CoF 2 showed significantly enhanced energetic performances compared with sole Al/Co 3 O 4 , suggesting that CoF 2 can function as an effective reaction modifier.
研究领域:
材料科学
·
含能材料
·
燃烧化学
·
纳米材料
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Qianjin Lin,Chun Zou,Shibo Liu,Yunpeng Wang,Lixin Lu,Chao Peng
The ignition delay times (IDTs) of 2-pentanone (methyl propyl ketone , MPK) were measured at equivalence ratios of 0.5, 1.0, and 1.5, pressures of 1 bar and 5 bar, and temperatures ranging between 1227 and 1571 K. A MPK low to high-temperature model was constructed on the basis of Pieper model and Fenard model. The improvement of the model is that the rate constants of sixteen MPK decomposition and hydrogen abstraction reactions (R1–R16) obtained by the analogy-based method, were globally optimized by the Bayesian Optimization algorithm using the high-temperature IDTs. The optimized model well predicts the laminar flame speeds (measured by Li et al.) and the IDTs and species profiles in low-temperature (measured by Fenard et al.). There is no overfitting during the optimization process. Therefore, the optimization method and the optimized MPK model are reliable. The comparisons of the optimized model with Pieper model and Fenard model were performed by the reaction pathway analysis and sensitivity analysis for the predictions of the MPK profile, the low and high-temperature IDTs and the laminar flame speeds. Because of the difference in the molecular structure between MPK and 2-butanone, remaining the branching ratio among three MPK decompositions (R1–R3) and the ratio among the rate constants of the MPK hydrogen abstraction reactions by OH, H and CH 3 unchanged is unnecessary in the development of the MPK model using the analogy-based method, while the branching ratio of the hydrogen abstraction reactions at carbon 1, 3, and 5 remains unchanged. The competition among the decomposition and hydrogen abstraction reactions of MPK is intricate and crucial to the low and high-temperature oxidation . It is necessary to globally optimize the rate constants of R1-R16 based on the multidimensional experimental results, such as low and high-temperature IDTs, laminar flame speeds, and species profiles.
研究领域:
燃烧化学
·
化学动力学
·
能源工程
·
反应机理建模
·
优化算法
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Qianjin Lin,Chun Zou,Jianghui Luo,Wenxiang Xia,Wenyu Li,Chao Peng
Ignition delay times (IDTs) for di-isopropyl ketone (DIPK) were measured at pressures of 6 and 10 atm, equivalence ratios ( ϕ ) of 0.5, 1.0, and 2, and over a temperature range of 1100 - 1500 K. In the DIPK sub-model proposed by Barari et al., DIPK⇔IC 3 H 7 +IC 3 H 7 CO (R2) was erroneously written as DIPK⇔IC 3 H 7 + IC 4 H 7 O and the consumption paths of dimethyl ketene (DMK) are missing. A DIPK sub-model was proposed on the basis of Barari model by correcting these errors, reassigning the rate coefficients of the DIPK unimolecular decomposition reactions (R1, R2), H-abstraction reactions by O ˙ H (R3, R4), fuel radical isomerization reaction (R5), and β-scission decomposition reactions (R5-R10) using the analogy method, and adopting the theoretical calculations of the H-abstraction reactions by H ˙ , C ˙ H 3 , and H O ˙ 2 (R11-R16) provided by Allen et al.. The rate coefficients of R1-R10 were globally optimized by the Bayesian optimization algorithm using the experimental IDTs and profiles of DIPK and DMK. The optimized model well predicts not only the IDTs and profiles of DIPK and DMK, but also the laminar flame speeds and the profiles of many intermediates (propyne, propylene , and methyl ketene) and small species (H 2 , CO, CH 4 ) during the pyrolysis of DIPK. The calculation using the method of Chen et al. shows that no optimized reaction violates the collision limit. The sensitivity and rate of production analysis were used to discuss the DIPK unimolecular decompositions, DIPK H-abstraction reactions, DIPK radicals isomerization and β-scission reactions, and the optimization of the DIPK sub-model.
研究领域:
燃烧化学
·
化学动力学
·
能源工程
·
反应机理建模
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2016
·
IF 2.835
Xiangshan Fan,Xibin Wang,Jingshan Wang,Kangkang Yang
The ignition delay times of 2,3-dihydrofuran (23DHF) and 2,5-dihydrofuran (25DHF) were investigated over the temperature range of 1100 to 1635 K with pressure of 1.2, 4, and 10 atm for lean (φ= 0.5), stoichiometric, and rich (φ= 2) fuel/O2/Ar mixtures. 23DHF shows shorter ignition delay times than 25DHF under the above conditions. A modified model (M_Tran model) was presented to improve the prediction of DHF ignition. Kinetic analysis indicated that most 23DHF transforms to cyclopropane carboxaldehyde (CPCA) and further to croton aldehyde (CA) by isomerization while most 25DHF dehydrogenates to furan. Some reactions involving CA and propene show strong sensitivity for 23DHF ignition. Some reactions of furan present strong effect on 25DHF ignition. Ignition delay data between furan, 23DHF, and 25DHF were compared to reveal the effect of number and location of carbon double bonds on the ignition characteristics. The bond dissociation energies of DHF are not as strong as that of furan and are significantly influenced by the locations of carbon double bonds, causing the differences in structure stability. As a result, the ignition trends of furan and DHF in this research are furan < 25DHF < 23DHF.
研究领域:
燃烧化学
·
化学动力学
·
燃料科学
·
高温物理
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）