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Effects of phase change material(PCM)-based nanocomposite additives on thermal decomposition and burning characteristic of high energy propellants containing RDX

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Defence Technology（防务技术） 2022年第4期18卷 557-566页

作者： En-fa Fu Na Sun zheng-gang xiao Key Laboratory of Special Energy Materials Ministry of Education School of Chemical Engineering Nanjing University of Science and Technology

A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy *** effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS *** to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is *** the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is *** burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared *** main burning gaseous products are N2,CO_(2),CO,H2O,CH4,*** the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning *** progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy *** study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.

关键词： Phase change material Propellants Nanocomposite Thermal decomposition Burning

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Investigation on thermal characteristics and desensitization mechanism of improved step ladder-structured nitrocellulose

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Defence Technology（防务技术） 2023年第2期20卷 93-102页

作者： Cheng-kai Pu Yu Luan Ming-jun Yi zheng-gang xiao Key Laboratory of Special Energy Materials Ministry of EducationSchool of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing210094People's Republic of China

Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas ***,its high mechanical sensitivity caused many accidents during its storage and usage in *** this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were *** products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization *** with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC *** H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,*** results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of *** LNC provides an alternative to be used as a binder in insensitive propellants formulation.

关键词： Nitrocellulose Decomposition Desensitization Ladder structure Thermal characteristic Polyethylene glycol

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Dynamic hydraulic jump and retrograde sedimentation in an open channel induced by sediment supply: experimental study and SPH simulation

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Journal of Mountain Science 2019年第8期16卷 1913-1927页

作者： zheng xiao-gang CHEN Ri-dong LUO Min KAZEMI Ehsan LIU Xing-nian State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China Zienkiewicz Centre for Computational Engineering College of EngineeringSwansea UniversitySA1 8ENUK Department of Civil and Structural Engineering University of SheffieldSheffield S1 3JDUnited Kingdom

Mountainous torrents often carry large amounts of loose materials into the rivers, thus causing strong sediment transport. Experimentally it was found for the first time that when the intensive sediment motion occurs downstream over a gentle slope, the siltation of the riverbed is induced and the sediment particles can move upstream rapidly in the form of a retrograde sand wave, resulting in a higher water level along the river. To further study the complex mechanisms of this problem, a sediment mass model in the framework of the Smoothed Particle Hydrodynamics(SPH) method was presented to simulate the riverbed evolution, sediment particle motion, and the generation and development of dynamic hydraulic jump under the condition of sufficient sediment supply over a steep slope with varying angles. Because the sediment is not a continuous medium, the marker particle tracking approach was proposed to represent a piece of sediment with a marked sediment particle. The twophase SPH model realizes the interaction between the sediment and fluid by moving the bed boundary particles up and down, so it can reasonably treat the fluid-sediment interfaces with high CPU efficiency. The critical triggering condition of sediment motion, the propagation of the hydraulic jump and the initial siltation position were all systematically studied. The experimental and numerical results revealed the extra disastrous sediment effect in a mountainous flood. The findings will be useful references to the disaster prevention and mitigation in mountainous rivers.

关键词： Dynamic hydraulic jump Retrograde sedimentation Sediment supply Mountainous river Smoothed Particle Hydrodynamics Marked sediment particle

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HYDRODYNAMIC ANALYSIS AND SIMULATION OF A SWIMMING BIONIC ROBOT TUNA

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Journal of Hydrodynamics 2007年第4期19卷 412-420页

作者： CHEN Hong ZHU Chang-an YIN Xie-zhen XING xiao-zheng CHENG gang College of Mechatronics and Control Engineering Shenzhen University Shenzhen 518060 China School of Engineering Science University of Science and Technology of China Hefei 230027 China

A dynamic model for undulatory locomotion was proposed to study the swimming mechanism of a developed bionic robot tuna. On the basis of inviscid hydrodynamics and rigid-body dynamics, the momentum and propulsive force required for propelling the swimming robot tuna＇s flexible body was calculated. By solving the established dynamic equations and efficiency formula, the swimming velocity and propulsive efficiency of the bionic robot tuna were obtained. The relationship between the kinematic parameters of the robot tuna＇s body curve and the hydrodynamic performances was established and discussed after hydrodynamic simulations. The results presented in this article can be used to increase the swimming speed, propulsive thrust, and the efficiency of underwater vehicles effectively.

关键词： undulatory locomotion swimming propulsive force efficiency body curve hydrodynamic simulations

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Deconsolidation and combustion performance of thermally consolidated propellants deterred by multi-layers coating

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Defence Technology（防务技术） 2014年第2期10卷 101-105页

作者： zheng-gang xiao San-jiu YING Fu-ming XU School of Chemical Engineering Nanjing University of Science and Technology

Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate(TEGDN)(TEGDN propellants) to high density *** obtained consolidated propellants are deterred and coated with the slow burning multi-layer *** maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/*** mechanic,deconsolidation and combustion performances are tested by the materials test machine,interrupted burning set-up and closed vessel,*** static compression strength of consolidated propellants deterred by multi-layer coating increases significantly to 18 MPa,indicating that they can be applied in most circumstances of charge *** the samples are easy to deconsolidate in the interrupted burning ***,the closed bomb burning curves of the samples indicate a two-stage combustion phenomenon under the condition of certain thickness of coated *** the outer deterred multi-layer coating of consolidated samples is finished burning,the inner consolidated propellants continue to bum and breakup into aggregates and *** high burning progressivity can be carefully obtained by the smart control of deconsolidation process and duration of consolidated *** preliminary results of consolidated propellants show that a rapid deconsolidation process at higher deconsolidation pressure is presented in the dynamic vivacity curves of closed bomb *** density and higher macro progressivity of consolidated propellants can be obtained by the techniques in this paper.

关键词：燃烧性能推进剂多层涂布拆分材料试验机热固多层涂层乙二醇酯

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含氟功能助剂对发射药燃烧性能的影响

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含能材料 2015年第8期23卷 796-801页

作者：田翠华肖正刚南京理工大学化工学院江苏南京210094

为提高发射药表面防盐湿、耐高温性能的同时调控其燃烧性能,采用TiO2纳米粒子与含氟单体反应合成了TiO2-含氟丙烯酸酯功能助剂。功能助剂和太根双基推进剂药片共混制备了发射药颗粒,对其进行了密闭爆发器实验。研究了含氟功能助剂的含... 详细信息

为提高发射药表面防盐湿、耐高温性能的同时调控其燃烧性能,采用TiO2纳米粒子与含氟单体反应合成了TiO2-含氟丙烯酸酯功能助剂。功能助剂和太根双基推进剂药片共混制备了发射药颗粒,对其进行了密闭爆发器实验。研究了含氟功能助剂的含量、含氟量及粒径对发射药定容燃烧性能的影响。结果表明：随着十二氟功能助剂含量的降低,发射药燃速呈增大趋势。十二氟功能助剂使发射药燃速提高0.1-0.3 cm·s^-1,三氟功能助剂使发射药燃速降低0.4-1.0 cm·s^-1。在本实验条件下,粒径对改善发射药燃速效果不明显。为更好地调控发射药起始燃烧速度,需要综合考虑含氟功能助剂链段中含氟量与TiO2含量二者比例以及发射药聚集体的物理形态。

关键词：含氟功能助剂燃烧性能发射药表面富集密闭爆发器实验

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Ag-TiO_2空心复合微球制备及其光催化性能

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功能材料 2015年第2期46卷 2115-2119页

作者：孙娜赵祥肖正刚南京理工大学化工学院南京210094

为了提高空心TiO2的光催化活性和拓展其对可见光的响应,以聚苯乙烯为模板合成TiO2空心微球,再通过KBH4还原AgNO3,制备了TiO2空心壳层表面载有Ag单质粒子的复合微球。利用SEM、TEM、XRD和EDS对Ag-TiO2空心微球的形貌结构和组成进行表征,... 详细信息

为了提高空心TiO2的光催化活性和拓展其对可见光的响应,以聚苯乙烯为模板合成TiO2空心微球,再通过KBH4还原AgNO3,制备了TiO2空心壳层表面载有Ag单质粒子的复合微球。利用SEM、TEM、XRD和EDS对Ag-TiO2空心微球的形貌结构和组成进行表征,并以有机染料罗丹明B(RhB)为目标降解物,研究该复合微球的光催化性能。在紫外光下,载银量为2%的Ag-TiO2复合微球2h内对RhB的降解率比同条件下空心TiO2提高23.8%;在可见光下,载银量为2%的Ag-TiO2复合微球在6h内对RhB的降解率比同条件下空心TiO2提高28.2%。结果表明,壳层表面载有适量Ag单质粒子的空心TiO2复合微球,其光催化活性和对可见光的响应显著高于纯空心TiO2微球。

关键词：空心TiO 银负载光催化罗丹明B

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深钝感球扁药混合装药的势平衡理论模拟

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弹道学报 2006年第1期18卷 80-82页

作者：肖正刚应三九徐复铭南京理工大学化工学院南京210094

应用势平衡理论及深钝感球扁药混合装药膛内实际燃烧规律,建立了某火炮球扁药混合装药的内弹道解法,以坡膛处测得的压力时间曲线为标准,利用势平衡理论内弹道方程进行了数值模拟,结果表明模拟计算曲线与火炮实测曲线基本一致.数值模拟... 详细信息

应用势平衡理论及深钝感球扁药混合装药膛内实际燃烧规律,建立了某火炮球扁药混合装药的内弹道解法,以坡膛处测得的压力时间曲线为标准,利用势平衡理论内弹道方程进行了数值模拟,结果表明模拟计算曲线与火炮实测曲线基本一致.数值模拟的结果表明内弹道势平衡理论在本研究中提出的高装填密度装药系统中的应用是可行的,扩展了内弹道势平衡理论的应用范围.

关键词：发射药装药高装填密度势平衡理论弹道解法

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压实工艺对太根压实药柱定容燃烧性能的影响

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弹道学报 2009年第4期21卷 92-94页

作者：肖正刚应三九徐复铭南京理工大学化工学院南京210094

将太根小粒药进行解体预处理后,利用升温直接模压法、丙酮热蒸汽软化法等压实成不同密度的药柱,然后对其进行表面组合钝感处理.利用密闭爆发器试验测试该压实药柱的定容燃烧性能,研究其静态能量释放规律及这3种压实工艺对其定容燃烧性... 详细信息

将太根小粒药进行解体预处理后,利用升温直接模压法、丙酮热蒸汽软化法等压实成不同密度的药柱,然后对其进行表面组合钝感处理.利用密闭爆发器试验测试该压实药柱的定容燃烧性能,研究其静态能量释放规律及这3种压实工艺对其定容燃烧性能的影响.采用升温直接模压法和丙酮热蒸汽软化法制得的压实药柱的燃烧性能与散装药类似,而对压实药柱进行合适的表面组合钝感处理后,能较好地抑制起始燃烧阶段的燃气生成速率,采用的预解体技术能实现压实药柱的瞬间解体,解体一致性较好.

关键词：发射药压实装药钝感密闭爆发器

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超临界CO_2制备微孔球扁药的研究

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兵工学报 2012年第5期33卷 534-539页

作者：陈西如应三九肖正刚南京理工大学化工学院江苏南京210094

为改善球扁药的燃烧性能,根据燃面渐增原理,设计出了一种具有微孔结构的球扁药,并采用超临界流体技术升温发泡工艺制备出该结构的球扁药,分析了发泡过程中的泡孔的成核和长大机理;研究了CO2含量和粒子对泡孔形貌的影响。扫描电镜(SEM)... 详细信息

为改善球扁药的燃烧性能,根据燃面渐增原理,设计出了一种具有微孔结构的球扁药,并采用超临界流体技术升温发泡工艺制备出该结构的球扁药,分析了发泡过程中的泡孔的成核和长大机理;研究了CO2含量和粒子对泡孔形貌的影响。扫描电镜(SEM)结果显示,微孔球扁药内部泡孔是独立的闭孔泡,粒子可以改变泡孔的形貌,随着CO2在球扁药中含量的降低,平均泡孔直径变小。密闭爆发器试验表明,该微孔发射药具有良好的燃烧渐增性能。因此,利用超临界流体技术可以制备出不同泡孔形貌和燃烧性能的微孔球扁药。

关键词：应用化学超临界CO2 微孔球扁药溶解度燃烧渐增性

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