ACTA ASTRONAUTICA
·
2013
·
IF 0.701
Jian-zhong Liu,Jian-fei Xi,Wei-juan Yang,You-rui Hu,Yan-wei Zhang,Yang Wang,Jun-hu Zhou
Boron is an attractive fuel for propellants and explosives because of its high energy density . However, boron particles are difficult to combust because of inhibiting oxide layers that cover the particles. The use of magnesium as additives has been shown to promote boron oxidation . In this study, laser ignition facility and thermobalance were used to investigate the effect of magnesium on the burning characteristics of boron particles. The influences of magnesium addition on sample combustion flame , boron ignition delay time, boron combustion efficiency and initial temperature of boron oxidation. Results show that all Mg/B samples exhibit the same type of flame structure, i.e., a bright plume surrounded by green radiation which is interpreted as BO 2 emission. The combustion flame intensity of a sample increases with the increasing magnesium content of boron particles. An increase in magnesium content results in a decrease and a subsequent increase in boron ignition delay time. (Mg/B) 0.2 has a minimum ignition delay time of ~48 ms. Boron combustion efficiency increases with increasing magnesium addition. (Mg/B) 0.5 shows a maximum boron combustion efficiency of ~64.2%. Magnesium addition decreases the initial temperature of boron oxidation.
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiang Lv,Yi Gao,Yueshuai Cui,Chen Wang,Gangchui Zhang,Fang Wang,Peijin Liu,Wen Ao
The ignition and combustion properties of n -Al/CuO/kerosene nanofluid fuels are examined, with a focus on the formulation effects of the n -Al/CuO nano-thermite. The DSC data shows the addition of CuO facilitates the exothermic process of n -Al particles, which then promote the n -Al/CuO/kerosene droplets to evaporate. There are two exothermic peaks on the DSC curve of n -Al/CuO (5 %) at 249.3 ℃ and 463.8 ℃, respectively. The burning of n -Al/CuO/kerosene droplets consists of four stages: ignition, d 2 -law combustion, vapor flame extinguishment, and agglomerate burning. During the agglomerate burning stage, n -Al/CuO (5 %)/kerosene shows the minimum ignition delay at 0.057 s and the highest emission spectral intensity. Droplet combustion conforms well to the d 2 -law, and the maximum combustion rate is found for n -Al/CuO (20 %)/kerosene, at 1.287 mm 2 s −1 . The particle size of combustion residues is uniform, and the overall appearance smoothens as the CuO content increases. A new nanofluid fuel with better ignition and combustion properties than traditional nanofluid fuels is proposed.
研究领域:
能源科学
·
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
Energetic Materials Frontiers
·
2023
·
IF 0
Yu-shu Xiong,Yong-qi Wang,Chong Wan,Wen-zhen Zhang,Zhao Qin,Su-hang Chen,Kang-zhen Xu
To overcome the agglomeration and insufficient combustion of nano-boron (n-B) powders, this study successfully prepared two novel types of boron-based nanocomposites using the acoustic resonance technology, namely high-substitute nitrochitosan/nano-boron (NCh-B) with ratios of 1:3, 1:5, 1:7 and 1:9, and nitrochitosan/nano-boron powder/nano-titanium (NCh-B-Ti) with Ti contents of 5 wt%, 10 wt%, 15 wt% and 20 wt%. The structural morphologies, laser ignition and combustion properties of the composites were systematically investigated. The results suggest that the addition of NCh can significantly improve the dispersion of n-B. NCh-B exhibited a higher combustion performance than n-B, as evidenced by their ignition delay and flame areas. When the laser power density was 81 W, NCh-B 5 -Ti 15% exhibited a combustion time and an ignition delay of 240 ms and 5.5 ms respectively, which were higher and lower than those of NCh-B 5 (199 ms and 17 ms, respectively). Furthermore, NCh-B 5 -Ti 15% displayed a lower ignition delay than both n-B powders (12 ms) and NCh-B (11 ms), as well as brighter flames and a larger combustion area. Therefore, the addition of n-Ti can promote the combustion of n-B powders, with the combustion products of NCh-B-Ti including H 3 BO 3 , B 2 O 3 , TiB 2 , and TiO. This study provides a new method for improving the ignition performance and combustion efficiency of n-B powders.
研究领域:
材料科学
·
燃烧学
✓ 已验证
DOI
COMBUSTION AND FLAME
·
2022
·
IF 5.767
Wanjun Zhao,Qingjie Jiao,Pengwan Chen,Shi Yan,Yanli Zhu,Bi Zhang,Xin Zeng,Dazhi Liu,Yapeng Ou,Fang Wang
Zn has been incorporated into Mg via centrifugal atomization in this work. The prepared Mg-Zn alloys have been characterized via SEM/EDS and XRD . The thermal behavior and combustion of Mg-Zn alloys have been tested by TG/DSC and laser ignition. Then, Mg-Zn alloys have been applied in pyrotechnics with PTFE as the oxidizer , followed by measuring the reactivity and ignition delay . Mg-5%Zn and Mg-10%Zn alloys consisting of α-Mg and eutectic phase (α-Mg and MgZn 2 ) in a high degree of sphericity with evenly distributed Zn were obtained. Thermal behavior characterization indicates that the oxidation of Mg-Zn alloys initiates ∼50 °C earlier than Mg along with a higher oxidation rate, which could be attributed to the lower melting point of MgZn 2 and Zn. In addition, the oxidation rate of Mg-Zn alloys is also higher than Mg that is the result of significantly lower apparent activation energy of Mg-Zn alloys than Mg. Due to the great discrepancy of melting and evaporation point between Mg, MgZn 2 , and Zn, a visible microexplosion phenomenon has been observed during the combustion process of Mg-Zn alloys. Then, Mg-Zn alloys have been applied as the fuel to replace Mg in Mg/PTFE pyrotechnics. The ignition delay of Mg-Zn/PTEE composites is shorter than that of Mg/PTFE, which is due to the easier oxidization initiation of Mg-Zn alloys compared to Mg. Besides, the lower melting and evaporation points of MgZn 2 and Zn than Mg can accelerate the combustion of Mg-Zn alloys, leading to the improved peak pressure and reaction rate of Mg-Zn/PTEE. Thus, the lower apparent activation energy of Mg-Zn alloys and the lower melting point of MgZn 2 and Zn could promote the energetic kinetics of Mg-Zn alloys synergistically. Above all, the prepared Mg-Zn alloys in this study are ambitious candidates in pyrotechnics for controllable ignition and reactivity kinetics.
研究领域:
材料科学
·
燃烧学
·
烟火技术
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Lei Shi,Ping Xu,Rui Wang,Weixin Tang,Tao Ding,Rongpei Jiang,Changhua Zhang
Ignition delay times of JP-10 in air and the vitiation effect of NO 2 on JP-10 autoignition at high temperatures were investigated behind reflected shock waves. The experiments were carried out at pressures of 2 and 10 atm, temperatures between 900 and 1460 K, fuel lean and stoichiometric conditions with and without 1.0 % NO 2 . The experimental results show that the ignition delay times of JP-10/air decrease with the increase of pressure or the decrease of equivalence ratio. The effect of adding 1.0 % NO 2 is pressure dependence. At 10 atm, the addition of NO 2 promotes the ignition of fuel, which shortens the ignition delay time. At 2 atm, the addition of 1.0 % NO 2 inhibits the ignition of JP-10, which prolongs the ignition delay time. A chemical kinetic mechanism of JP-10/NO 2 consisting of 290 species and 1768 reactions was developed by extending from a C0-C5 alkane and a cyclopentene sub-mechanism. The proposed mechanism has been well validated by ignition delay times, laminar flame speeds and species concentration profiles from literature. To further investigate the autoignition of JP-10 and the vitiation effect of NO 2 , kinetics analyses including reaction pathways and sensitivity coefficients were performed by the developed mechanism. The main consumption pathways of JP-10 in air are H-abstraction reactions from JP-10 by HO 2 radicals. With 1.0 % NO 2 vitiation, the addition of NO 2 has a strong effect on JP-10 consumption via the H-abstraction pathway JP-10 + NO 2 = C 10 H 15 + HONO, which further affects the autoignition of JP-10.
研究领域:
燃烧学
·
化学动力学
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2019
·
IF 4.12
Baozhong Zhu,Fan Li,Yunlan Sun,Yuxin Wu,Wei Shi,Weikang Han,Qichang Wang,Qi Wang
Micron-sized aluminum powder exhibits difficulties in ignition and burnout in steam. To overcome these problems, we added various sodium fluoride contents to micron-sized aluminum powder in steam at 800, 900, and 1000 °C to assess their effects on ignition and combustion performances. The ignition delay times, ignition temperatures , and combustion characteristics of all samples were measured primarily using two high-temperature tube resistance electric furnace systems. The experiments showed that adding sodium fluoride to micron-sized aluminum powder decreases its ignition delay time and temperature. Moreover, the ignition delay time and temperature of aluminum powder with addition of sodium fluoride decreases considerably when the temperature increases. For this study, the components and morphology of solid combustion products were obtained using X-ray diffraction and scanning electron microscopy. The combustion efficiency was measured volumetrically using a specially designed apparatus. The obtained combustion efficiency was found to increase with the amount of sodium fluoride added and increase in the temperature. The relationship among the parameters related to combustion characteristics and product characterization was examined in detail to reveal the combustion mechanism.
研究领域:
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2018
·Vol. 12
·期 3
·358-366
·
IF 2.643
E Xiu-Tian-Feng,Zhang Lei,Wang Fang,Zhang Xiangwen,Zou Ji-Jun
High energy density fuels are critical for hypersonic aerospace propulsion but suffer from difficulties of ignition delay and incomplete combustion. This research reports aluminum nanoparticles (Al NPs) assisted ignition and combustion of high energy density JP-10 fuel. Al NPs with a size of 16 nm were fabricated through a mild and simple method by decomposing AlH 3 ·Et 2 O with the addition of a surfactant ligand. The uniform size distribution, nanoscaled size and surface ligand make Al NPs stably suspend in JP-10, with 80% NPs being dispersed in the liquid fuel after six months. A shock tube test shows that the presence of 1 wt-% Al NPs can significantly shorten ignition delay time at temperature of 1500 to 1750 K, promote the combustion, and enhance energy release of JP-10. This work demonstrates the potential of Al NPs as ignition and combustion additive for high energy density fuel in hypersonic applications.
研究领域:
航空航天工程
·
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Zujun Zheng,Yiwei Li,Lei Shi,Dongdong Chen,Changhua Zhang,Jingbo Wang,Ping Li
Indene is an important intermediate in the ring growth process of polycyclic aromatic hydrocarbons (PAHs) which are soot precursors in the fuel combustion . Ignition delay times of indene/3.3% O 2 /Ar and indene/air mixtures were measured behind reflected shock waves over temperatures of 1098–1618 K, pressures of 2.5–10.0 atm, and equivalence ratios of 0.5, 1.0 and 2.0. An Arrhenius-type formula can describe all the measured indene/3.3% O 2 /Ar ignition delay data. But three Arrhenius-type formulas were used to describe the measured indene/air ignition delay data for three pressures because the activation energy varies with different ignition pressures. Indene ignition characteristics in different dilution conditions were compared and discussed. Current results show that the indene ignition delay follows τ ∝ Φ + n diluted in Ar with fuel-lean mixture igniting the fastest and τ ∝ Φ −n at real fuel-air condition with fuel-rich mixture igniting the fastest. For indene/air, when the pressure increases, the effect of equivalence ratio on ignition becomes stronger and the sensitivity of ignition to the variation of temperature becomes weaker. Furthermore, an indene combustion mechanism was developed. The predictions of the developed mechanism are in good agreement with the measured data. Reaction pathway and sensitivity analyses were carried out to determine reaction pathways during the ignition process and dominate reactions which affect ignition delay times. Current experimental results are useful for understanding the ignition properties of indene and studying the formations of larger PAHs and soot. To our knowledge, experimental ignition delay times and a detailed combustion mechanism for indene are firstly reported in this work.
研究领域:
燃料化学
·
燃烧动力学
✓ 已验证
DOI
高影响因子
ENERGY
·
2022
·
IF 8.857
Yanwu Ji,Yunlan Sun,Baozhong Zhu,Jianzhong Liu,Yuxin Wu
Aluminum (Al) powder as an additive can enhance the specific impulse of propellants. However, it is hard to completely burn due to its aggregates in the combustion of propellants. To improve the combustion of Al powder, calcium fluoride (CaF 2 ) was added to micron-sized Al powder to form the Al/CaF 2 mixture, whose thermal behaviors, ignition and combustion performance, and combustion products were investigated. Micron-sized Al powder with CaF 2 addition can decrease its ignition delay time and increase its self-sustaining combustion time. The corresponding values can be decreased by more than 65% and increased by more than 16%, respectively. Compared with micron-sized Al powder, an obvious gas-phase combustion occurs in the Al/CaF 2 mixture. The agglomeration mechanism of Al combustion in the Al/CaF 2 mixture were analyzed. On the one hand, the uneven distribution of oxidant leads to a pressure difference during combustion to accelerate Al agglomeration; on the other hand, the melting-agglomeration-combustion process occurs because the melting temperature and the ignition temperature of Al have a big difference. In addition, an improved Al combustion mechanism was established.
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2024
·
IF 5.3
Yiyun Hu,Dan Li,Lijun Qin,Wangle Zhang,Ting Gong,Jianguo Li,Hao Feng
Aluminum (Al) powder is widely employed in the aerospace and defense industries, particularly for its use in explosives and as a metal fuel. Enhancing the energy release performances of Al nanopowder is an important task. The surface properties of Al nanoparticles have a significant impact on their energy release characteristics. In this work, atomic layer deposition (ALD) technology is utilized to grow nanometer-thin films of cuprous/cupric oxide (CuOx) on the surface of Al nanopowder as an oxidizer to initiate redox reactions. Structural, morphological, and chemical properties of the Al@CuOx nanocomposites are characterized by various spectroscopic and microscopic techniques. The CuOx coating encapsulates the Al nanoparticles to form Al@CuOx core–shell nanocomposites, wherein the contact between Al and CuOx is significantly promoted; thus, the average fuel-oxidizer diffusion path is reduced. The thickness of the CuOx coating can be conveniently changed with nanometer-scale precision by varying the ALD cycle number, which enables flexible control over the structure of the nanocomposites. Oxidation, ignition, and combustion behaviors of Al@CuOx nanocomposites are investigated by differential scanning calorimetry and laser ignition experiments. Only a few nanometers of the CuOx surface modification layer can effectively enhance the energy release performances of Al powder, which is manifested specifically by significantly reduced ignition delay time, oxidation temperature, and remarkably increased reaction rate.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·
IF 3.205
Fan Li,Baozhong Zhu,Yunlan Sun,Wei Tao
Hydrogen generation by means of the combustion of aluminum powder with sodium borohydride (NaBH 4 ) addition in steam was studied by a pipe furnace at different temperatures. The ignition temperature and the maximum combustion temperature were obtained by an S-type thermocouple . Ignition delay times and combustion efficiencies were measured. The results show that aluminum powder is not ignited at 450 °C, but aluminum powder with NaBH 4 addition is ignited under the same condition. The addition of NaBH 4 significantly decreases the ignition delay time of aluminum powder. Moreover, the ignition delay times of aluminum powder without or with NaBH 4 addition can decrease with increasing the temperature. Combustion products were analyzed by scanning electron microscopy, X-ray diffraction and a portable hydrogen analyzer. The results indicate that NaBH 4 displays a key influence on hydrogen generation. Especially, for aluminum powder with 7 wt% NaBH 4 addition, the obtained maximum volume concentration of hydrogen is about 21,000 ppm at 650 °C.
研究领域:
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Xueqin Liao,Daolun Liang,Fang Wang,Peini Xie,Yukun Chen,Jianzhong Liu
The long ignition delay time, high ignition temperature and agglomeration prevent the aluminum (Al) particles from fully releasing the chemical energy stored within them during combustion. Al-based alloy fuels with high energy density and excellent combustion performance have become a potential candidate for replacement with pure Al. Therefore, understanding the combustion and energy performance of Al-based alloys is beneficial for the development of Al-based energetic materials. Herein, the combustion and energy performance of pure Al and three Al-based alloys were comparatively investigated by means of a thermal analysis system, an ignition and combustion test apparatus, and a variety of physicochemical property characterizations. The results showed that all three Al-based alloys contained at least one intermetallic compound. Al-boron (B) and Al-magnesium (Mg)-B alloys had higher theoretical energy densities than pure Al, while Al-Mg did not. The thermal oxidation properties of all three alloys were significantly better than those of pure Al. Compared with pure Al, the three alloys showed higher burning rate, shorter ignition delays, more vigorous combustion, and higher burnout at room pressure in air. This is still true after adding AP. According to the compositions of the condensed combustion products, the possible chemical reactions during the combustion of the alloys were speculated. Grasping the combustion mechanisms of the alloys is challenging due to the relative lack of thermodynamic data on intermetallic compounds. Finally, a comprehensive comparison of the combustion processes of pure Al and alloys was made. Although the Al-Mg alloy does not have the same theoretical energy density as pure Al, the more outstanding combustion performance and fewer two-phase flow losses may make up for the gap in theoretical energy density.
研究领域:
材料科学
·
燃烧学
·
能源工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）