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1.
A differential/integral method to estimate the kinetic parameters (apparent activation energy Ea and pre-exponential factor A) for thermal decomposition reaction of energetic materials based on Kooij formula are applied to study the nonisothermal decomposition reaction kinetics of hexanitrohexaazaisowurtzitane (HNIW) by analyzing nonisothermal DSC curve data. The apparent activation energy (Ea) obtained by the integral isoconversional non-isothermal method based on Kooij formula is used to check the constancy and validity of apparent activation energy by the differential/integral method based on Kooij formula. The most probable mechanism function of thermal decomposition reaction of HNIW is determined by a logical choice method. The equations for calculating the critical temperatures of thermal explosion (T_b) and adiabatic time-to- explosion (t_Tlad) based on Kooij formula are used to calculate the values of Tb and t_Tlad to evaluate the thermal safety and heat-resistant ability of HNIW. All the original data needed for analyzing the kinetic parameters are from nonisothermal DSC curves. The results show that the kinetic model function in differential form and the values of E_a and A of decomposition reaction of HNIW are 3(1 - α)[-ln(1 - α)]2/3, 152.73 kJ mol 1 and 10~11.97 S 1, respectively, and the values of self-accelerating decomposition temperature (T_SADT), Tb and t_Tlad are 486.55 K, 493.11 K and 52.01 s, respectively.  相似文献   

2.
The object of the research are explosive properties of the pyrotechnic composite consist of fine grade magnesium-aluminium powder(PAM)and highly dispersed polytetrafluorethylene(PTFE).The composite reveals high resistance to all mechanical and thermal impulses and is extremely sensitive to hot sparks and open fire.The burning rate of the composition changes from 1 cm·s-1 to 100 m·s-1 along with decreasing its density.Charges of the composition with density below 1 g·cm-3 burn so violently,that the phenomena is similar to explosion.Charges with density above 1.1 g·cm-3 burn relatively rapidly and stably.The main part of the paper concerns the pressure impulses in the air generated during high-rate burning of the composition of bulk density.The nature of the generated pressure impulse is not that of a typical shock wave.A rise of pressure over the distance from the point of explosion to the maximum value lasts 50-100 milliseconds,while for shock waves this factor is less than a microsecond for equivalent charges.The methods of initiation of the composition influence the shape and parameters of the pressure impulse.The explanation of the nature of great changes of the composition burning rate has been proposed.The effect described in the paper was used for evaluation of explosive pressure resistance of industrial doors and windows.  相似文献   

3.
A space-dispersed double-wall jet combustion system was developed by adopting the wall-guiding spray method and the stratification theory.The experimental test was carried out to optimize the structural parameters of the diesel-engine combustion system,including chamber structure,swirl ratio of cylinder head,included angle of jet orifice,number and diameter of jet orifice,fuel injection pressure and timing.The effect of double-wall jet combustion system on combustion and engine performance was tested to obtain the best performance indexes,and the double-wall jet combustion system was compared to the prototype.The results show that NOx is reduced from 712 PPm to 487 PPm at 2 100 r/min,and from 593 PPm to 369 PPm at 3 000 r/min,which are reduced by 31.6% and 37.7%,respectively.The smoke intensity was reduced form 3.67 BSU to 2.1 BSU,and the oil consumption was reduced from 240.5 g/(kW·h) to 225.4 g/(kW·h),which was decreased by 6.3% at low speed.The pressure in the cylinder was obviously reduced from 115 bar to 108 bar,which was reduced by 6%.  相似文献   

4.
The design, modeling, and simulation of a micro electlical switch for fuze are presented. It consists of spring mass system with zigzag slot in mass, latching and electlical cnnecfion mechanism and movement-lhnit mechanism. The switch keeps off-state until it is subjected to an acceleration when fuze is launched normally. The acceleration is simulated as half-shoe pulse with specific amplitude and duration. The dynamics model of the switch is studied. Based on zigzag slot in mass, the methods used for recogllizing acceleration load are estahhshed and analyzed according to the dynamics theory. Two typical half-shoe accelerations are loaded on the switch in simulation. The simulation resuhs are in accordance with those of tfieoretical analysis. The inertial response characteristics of the switch can ensure that the fuze power supply and circuit are connected safely and reliably.  相似文献   

5.
A method is presented to control the vibration of high-speed cannonball transport mechanism due to the reduction of its weight, which adhere a nonlinear Zn-27Al-1Cu damping alloy layer and a constraint layer partly to the part of mechanism driven by impact. Based on the equivalent viscous damping theory and using curve fitting to describe the rule of the dissipation factor of damping alloy changing with stress, the nonlinear constitutive relation of Zn-27Al-1Cu damping alloy is given. The nonlinear spring damping contact model is adopted to describe the contact force of the clearance joint.Based on the nonlinear finite element contact theory, the outer impact contact force between the mechanism and its working environment is analyzed, and a coupled dynamic model of structural impact and mechanism motion with clearance joint is put forward. A dynamic model is established for the cannonball transport mechanism partly adhering Zn-27Al-lCu damping alloy layer and constraint layer under complex impact conditions. At last, the feasibility of the method presented is proved by numerical simulation.  相似文献   

6.
The relationship between the crystal lattice free volume,ΔV,and impact sensitivity,E_(dr),of ten nitramines has been analyzed. It was found that this relationship is not uniquely determined,i. e. it is not given only by their own ΔV values but fundamentally by the type and intensity of the intermolecular forces in the nitramine crystals. Also,relationships between the E_(dr)values,on the one hand,and bulk modulus,K,and shear modulus,G,on the other,have been the subject of discussion not only for pure cyclic nitramines but also for their PBXs,bonded by a poly-fluoro binder. The closest linear correlation exists between the E_(dr)values and dimensionless K·G~(-1) ratio which indicates the plasticity range. A similar relationship is valid also for the ΔV values. Relationships of the E_(dr) and / or ΔV values with the shear modulus or to the K·G~(-1) ratio reflect an unusual behavior of ε-HNIW to which the published morphological instability of this particular HNIW version might also be related.  相似文献   

7.
The generation and development of microcracks of SiCp/Al materials in the machining process were researched, and the forming causes and mechanism of the cut surface morphology for ap=0.2 mm or ap=0.4 mm and at 2 m/min~10 m/min were systematically analyzed. The supporting and "floor"roles of aluminum are wake at a shallower cutting depth and a lower speed, the SiC particles are shed under the role of cutting force, and the microcrack size of cut surface is larger. With the increase in the cutting depth and the cutting speed, the cutting temperature increases, the supporting and "floor" roles of aluminum are enhanced, the shedding and fracture of the reinforcement particles are flexible under the action of the cutting force, the fracture of cutting transforms from brittle to ductile, and the expansion of microcrack on the entire surface tends to balance with a smaller size. A curve between the cutting force and the cutting speed was plotted, a microcrack form of the cut surface was given, and some theoretical basis is provided for the mechanical processing and the surface quality.  相似文献   

8.
Interface debonding between particle and matrix in composite propellant influences its macroscopic mechanical properties greatly. For this, the laws of interface cohesive damage and failure were analyzed. Then, its microscopic computational model was established. The interface mechanical response was modeled by the bilinear cohesive zone model. The effects of interface properties and particle sizes on the macroscopic mechanical behavior were investigated. Numerical simulation of debonding damage evolution of composite propellant under finite deformation was carried out. The debonding damage nucleation, propagation mechanism and non-uniform distribution of microscopic stress-strain fields were discussed. The results show that the finite element simulation method based on microstructure model can effectively predict the trend of macroscopic mechanical behavior and particle/matrix debonding evolution process. It can be used for damage simulation and failure assessment of composite propellants.  相似文献   

9.
In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put for ward and discussed for the preparation of explosive micro-particles. The satisfactory micro-particles of explosives can be obtained easily by its particular mechanism of creating micro-particles, and operating conditions at normal temperature. This method is good for further study and development.  相似文献   

10.
The geometry and the potential curve of thermal decomposition for 1, l'dimethyl-5, 5'-azotetraol (1-DMAT) are calculated by ab initio quantum chemistry method. The structural characteristics and decomposition mechanism are carefully studied, It is found that the terrazzo ring satisfies 4n + 2 rule and it is a conjugated π-system for 1-DMAT. The azotetrazol has aromatic characteristic and its thermal decomposition can proceed in two steps: ring opening and separation N2. The activation energies of the two steps are 243.5 kJ/mol and 64.01 kJ/mol, respectively. The ring opening is the rate-controlling step.  相似文献   

11.
郭芳  刘有智  郭强 《含能材料》2018,26(4):339-345
为了解决传统吸附设备存在设备体积庞大,吸附速率较小等问题,采用旋转填料床(RPB)为吸附设备,活性炭为吸附剂处理模拟含间苯二酚废水,考察了超重力因子、液体流量、温度、p H值和初始间苯二酚浓度对间苯二酚去除率的影响,测定了吸附等温平衡线及动力学数据,并在适宜操作条件下与固定床和磁力搅拌器的间苯二酚去除率进行了对比。结果表明:吸附平衡关系主要服从Freundlich模型,吸附热为14.65 k J·mol~(-1)。得到的吸附间苯二酚的适宜操作条件为:液体流量为50 L·h~(-1),超重力因子为41.30,p H值为5,温度为20℃,废水初始浓度为900 mg·L~(-1),吸附时间为2 h。在此条件下,间苯二酚去除率达到96.86%,较相同操作条件下的固定床和磁力搅拌器而言,去除率分别提高了约20%和14%。吸附过程主要符合准二级动力学方程,相同操作条件下,超重力吸附法的吸附速率常数为2.576×10-3g·mg~(-1)·min~(-1),是传统固定床吸附法与磁力搅拌器吸附法的1.626倍和1.413倍。  相似文献   

12.
旋转填料床中活性炭吸附含酚废水研究   总被引:1,自引:1,他引:0       下载免费PDF全文
以旋转填料床(RPB)作为吸附设备,活性炭为吸附剂处理模拟含酚废水,考察了转速、液体流率及初始浓度等因素对苯酚去除率的影响,确定适宜操作条件;分别采用拟一级和拟二级动力学模型研究了吸附动力学,并考察了各因素对吸附速率常数的影响;在相同操作条件下就去除率和速率常数与传统吸附法进行对比。结果表明:超重力因子为44.68、液体流率为35 L·h~(-1)时,处理初始浓度为1000 mg·L~(-1)苯酚废水,吸附2 h后,苯酚去除率最大,为90%左右,相同操作条件下较传统吸附法提高了30%;拟二级动力学模型线性拟合得到的吸附速率常数随着超重力因子以及液体流率的增大而增大,并得到最适宜操作条件下旋转填料床吸附法和传统吸附法的动力学方程分别为t/qt=0.02648+0.77932t和t/qt=0.02869+1.55707t,吸附速率常数较传统吸附法而言,由5.28×10~(-4)提高到9.02×10~(-4)。  相似文献   

13.
TNT-RDX混合废水处理的实验研究——生物-吸附法   总被引:6,自引:1,他引:5  
介绍了在25 ̄35℃的温度下,用厌氧-兼氧-水生生物-吸附组合工艺处理TNT和RDX混合废水的方法,进行了日处理量为60 ̄900L的实验室放大实验。当TNT和RDX混合废水总浓度为4 ̄12mg/L时,经过该工艺处理后可达到国家排放标准。其中厌氧-兼氧能去除废水中80%以上的TNT和RDX,水生生物(水葫芦)对TNT及RDX也有一定的降解效果,最后用活性炭吸附可以实现深度处理。  相似文献   

14.
为研究表面吸附对JO-9159炸药感度的影响,通过Materials Studio软件搭建JO-9159的无定形六组分模型,在COMPASS力场和NPT系综下,对其(001)、(010)和(100)3种晶面的表面吸附进行了周期性分子动力学模拟,基于平衡轨迹对JO-9159的感度进行了研究。结果表明:在295K温度下,吸附后其引发键N-NO_2最大键长(L_(max))较吸附前增大,引发键连双原子作用能(EN-N)和内聚能密度(CED)较吸附前减小,表明吸附后体系感度增大;随着JO-9159炸药表面吸附气体分子数量的增加,L_(max)递增,EN-N递减,CED呈减小趋势,都表明体系感度随着吸附分子数的增加而增大;在195~395K温度内,随着温度的升高,吸附后的JO-9159中N-NO_2的Lmax递增,E_(N-N)呈递减趋势,CED递减,与感度随温度升高而增大的实验事实相一致。  相似文献   

15.
介绍了多组分化学沉积混合药剂的制备原理,通过扫描电镜 (SEM)与X-射线衍射实验对所制备的点火药进行了表面特征和结构分析.在液相介质环境下 ,通过化学反应生成氧化剂包覆可燃剂,同时采用温度-溶度积效应机理,使其它氧化剂沉积包覆在晶粒的表面,形成多组分为一体的火工混合药剂均匀颗粒.  相似文献   

16.
以镍纤维和活性炭为原料,采用湿法造纸与烧结工艺制备了一种微纤维吸附剂(MFS),并将MFS与常规粒状活性炭(GAC)填充床组成双床层,研究了不同初始浓度下双床层固定床对苯蒸气的吸附行为。基于Shilov方程计算了GAC床层和双床层的无效层厚度和吸附容量,并利用Yoon-Nelson方程模拟了GAC床层和双层床的穿透行为。结果表明:GAC床层和双床层的无效层厚度和吸附容量均随着苯蒸汽浓度的降低而降低;相同的苯蒸气评价浓度和比速条件下,由于置于气流末端的MFS材料能提升复合床层的传质效率,由MFS和常规GAC床层组成的双床层比单独的GAC床层具备更高的苯吸附性能;Yoon-Nelson方程模拟结果曲线与实验数据吻合良好。  相似文献   

17.
基于表面活性剂对油水界面的作用,建立了活性剂作用下饱和多孔介质中多相渗流模型,模型中考虑了活性剂在介质表面的吸附,高温下的热降解以及活性剂分子与介质中矿离子的化学反应,利用有限差分法隐式格式将该模型进行了数值求解,讨论了活性浓度,活性剂性质等因素对饱和多孔介质多相渗流的影响。  相似文献   

18.
两种氟聚合物在TATB晶体表面吸附的动力学模拟   总被引:6,自引:2,他引:4       下载免费PDF全文
采用Discover/Material Studio中的分子动力学(COMPASS力场、NVT)方法及smart minimizer结构优化方法,对两种氟聚合物在TATB不同晶面上吸附行为进行模拟和结构优化后发现:(1)二者相互作用时,TATB原子位置变化的大小次序为:(010)〉(100)〉(001);而氟聚合物的展开程度按以上次序增加。(2)TATB晶体对两种聚合物都是吸引的,可以用F2311及F2314来包覆TATB晶体;且F2314对TATB晶体的包覆效果要优于F2311。(3)TATB不同晶面吸附能力的大小次序为:(010)〉(001)〉(100)。  相似文献   

19.
功能高分子亚氨基二乙酸树脂对钕的吸附行为研究   总被引:6,自引:0,他引:6  
本文用亚氨基二乙酸树脂(D401)采用静态的方法吸附钕(Ⅲ),获得一些参数以指导实际应用.结果pH=5.73为最佳吸附pH;298K时每克树脂的静态饱和吸附容量179mg;用2.0mol·L-1HCl解吸,解析率达100%;等温吸附服从Freundlich经验式;298K时的表观速率常数k298=2.22×10-5s-1;吸附反应的焓变为ΔaHm= 18.8kJ·mol-1;D401对钕(Ⅲ)吸附反应的表观吸附活化能为51.3kJ·mol-1;树脂功能基与钕(Ⅲ)的配位比为3:1;用红外光谱探讨了该树脂和钕(Ⅲ)的成键情况.  相似文献   

20.
新型爬壁机器人磁吸附单元优化设计   总被引:4,自引:2,他引:2  
陈勇  王昌明  包建东 《兵工学报》2012,33(12):1539-1544
为满足爬壁机器人负载能力和运动灵活性的要求,提出了一种新型变磁力吸附单元机构。首先介绍了机构的构型并建立了三维磁场模型,然后基于有限元方法对新型磁吸附单元的磁场进行了分析,得到了其磁感应强度分布和磁吸附力。运用ANSYS的APDL参数技术对吸附单元参数进行了优化,分析得出优化原则。通过与传统H形磁吸附机构性能参数仿真比较,表明新型结构具有永磁利用率高、最大最小吸附力比值大、自重轻而负载能力强的特点。实验验证了优化结果的准确性,为设计爬壁机器人磁吸附机构提供了依据。  相似文献   

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