紊流时输油管道油流静电带电计算研究

对紊流条件下输油管道内油流静电带电的计算进行了研究。在合理简化紊流扩散系数和油流速度的基础上,推导出油内有关油流带电的电荷输运方程的解析解,并且根据该解析解导出了冲流电流计算公式。该计算公式同时适用于所有电导率范围内液体介质冲流电流的计算。最后利用文中推出的计算公式对一实验油道的油流带电进行了计算,结果显示公式得到的值和实验值非常吻合。     

自动喷水灭火系统水源设施检验应注意的问题

自动喷水灭火系统投入运行后,系统的可靠性则依赖于运行管理,运行管理质量的好坏,决定了自动喷水灭火系统在规定的条件下和规定的时间内完成设计赋予的规定功能的能力。介绍了自动喷水灭火系统水源设施,即消防水池、消防水箱和水泵接合器日常的检验维护,为保证自动喷水灭火系统的正常运行提供了简便可行的方法。     

Effect of tongue clearance on hydraulic performance of double support vortex pump

In order to study influence of tongue clearance on the hydraulic performance of double support vortex pump, three dimensional flow model with symmetric variable size tongue clearance was established by changing section parameter of tongue clearance, and applied to numerically simulate the steady inner flow in a vortex pump based on fixed working conditions and impeller through ANSYS FLUENT. The numerical results show the influence of tongue channel with two sections (non-uniform and uniform sections) on flow field characteristics in vortex pump. Firstly, the variation of tongue channel section changes the vortex structure distribution in circumferential flow channel. Specifically the spiral forward vortex structure in the circumferential direction shifts to large radius side with increasing tongue width. Secondly, the circumferential velocity gradient and axial pressure gradient both diminish with the increase of the tongue section, and the inlet/outlet pressure difference and velocity distribution also reduce with increasing tongue channel section. Finally, for vortex pump with non-uniform section of tongue channel, the head diminishes and the efficiency remains constant approximately with the increase of the tongue width, while the head and the efficiency both diminish for uniform section of tongue channel.     

Formation and impact-induced separation of tandem EFPs

The formation and separation behaviors of tandem EFPs are studied by the combination of experiments and simulations. The results show that different formation and separation processes can be obtained by adjusting the double-layer liners, and simulations agree with experiments well. Then, the interaction process between the two liners is discussed in details, and the formation and separation mechanism are revealed. It can be found that there are four phases in the formation and separation processes, including impact phase, propulsion phase, slide phase and free flight phase. During the impact phase, the velocities of two liners rise in turns with kinetic energy exchange. In the propulsion phase, the axial impact becomes insignificant, but the radial interaction between two liners influences the appearance of tandem EFPs. Meanwhile, it should be mentioned that the inner surface of foregoing EFP remains to be in contact with the outer surface of following EFP in the propulsion phase, and the following one would continue to push the foregoing one for about 10μ to 20 μs, causing the velocities of following and foregoing EFPs gradually decreasing and increasing respectively. In the slide phase, an obvious relative movement occurs between the two EFPs, and there would be barely kinetic energy exchange. Then, the two EFPs separate gradually and get into the phase of free flight. Generally, if the outer and inner liners have the same thickness, the outer copper-inner copper liners form two long EFPs, the outer copper-inner steel liners become a foregoing short steel EFP and a following long copper EFP, and the outer steel-inner copper liners produce a foregoing long copper EFP and a following conical steel EFP. In addition, thickness match also has an important impact on formation appearance and separation process for both outer copper-inner copper liners and outer steel-inner copper liners. With the thickness ratio of outer liner to inner liner decreasing, the length and length-diameter ratio of both foregoing and following EFPs increase gradually.     

层流介质中金属板腐蚀电位分布研究

为了研究流动介质中产生的静电场,结合电化学和流体力学相关知识建立层流介质中金属板模型,利用贝塞尔函数展开及其逆运算推导出在三层介质中基于点电荷模型的腐蚀电位解析表达式,同时计算出金属板产生的电场。运用推导出的解析表达式计算出在流动介质中任意场点处金属板随不同流速产生的腐蚀电位,并通过实验验证结果的正确性。结果表明,对层流条件下电化学反应产生的电流密度所建模型的结果与实验测量数据吻合度较高,同时电场分布也会随着流体流速及层流方向上长度的变化而发生变化。     

Mg／PTFE／添加剂红外诱饵剂的红外辐射性能研究

研究了Mg／PTFE／添加剂红外诱饵剂的压药直径和压药密度对红外辐射性能的影响。在同一种配方下,经过试验发现辐射强度同质量燃烧速度成线性关系;辐射强度随着压药密度的增加而减小,最后趋于稳定;有效辐射率随着压药密度和压药直径的改变变化不大,表明压药密度和压药直径对有效辐射率基本没有影响。     

22 nm全耗尽型绝缘体上硅器件单粒子瞬态效应的敏感区域

基于3D-TCAD模拟,研究了22 nm全耗尽型绝缘体上硅(fully depleted silicon-on-insulator,FDSOI)器件单粒子瞬态(single-event transient,SET)效应的敏感性区域。对比了使用单管和使用反相器来研究器件SET敏感性区域的方法,从而分析实际电路中重离子轰击位置对22 nm FDSOI器件SET敏感性的影响,并从电荷收集机制的角度进行了解释。深入分析发现寄生双极放大效应对重粒子轰击位置敏感是造成器件不同区域SET敏感性不同的原因。而单管漏极接恒压源造成漏极敏感性增强是导致单管与反相器中器件SET敏感区域不同的原因。修正了FDSOI工艺下器件SET敏感性区域的研究方法,与单管相比,采用反相器进行仿真,结果更符合实际情况,这将为器件SET加固提供理论指导。     

Reaction characteristic of PTFE/Al/Cu/Pb composites and application in shaped charge liner

In this paper, the reaction characteristic and its application in shaped charge warhead of a novel reactive material, which introduced copper (Cu) and plumbum (Pb) into traditional polytetrafluoroethylene/aluminum (PTFE/Al), are studied. The thermal analysis and chemical reaction behavior of the PTFE/Al/Cu/Pb mixture are investigated by Differential Scanning Calorimetry (DSC),Thermo-gravimetry (TG), and X-ray Diffraction (XRD) techniques. Then, the shaped charge liners with PTFE/Al/Cu/Pb reactive materials are fabricated, and the X-ray experiments show that they could form reactive jets with excellent performance under the detonation effects of the shaped charge. Based on that, the penetration experiments of shaped charge with PTFE/Al/Cu/Pb reactive liner against steel plates are carried out, and the results demonstrate that the PTFE/Al/Cu/Pb reactive jets could produce a deeper penetration depth compared to the traditional PTFE/Al reactive jets. Meanwhile, the PTFE/Al/Cu/Pb reactive jets also show significant inner-blast effects, leading to dramatically cracking or fragmentation behavior of the penetrated steel plates. This new PTFE/Al/Cu/Pb reactive liner shaped charge presents enhanced penetration behavior for steel targets that incorporates the penetration capability of a high-density and ductility jet, and the chemical energy release of PTFE-matrix reactive materials.     

双层反应装甲干扰射流影响因素分析

通过对双层反应装甲与射流作用过程进行分析和数值模拟,得到双层反应装甲飞板飞散及与射流作用物理过程,通过模拟结果与物理实验比较可知,数值模拟过程基本正确.同时,利用ANSYS-DYNA针对双层反应装甲不同结构参数与射流作用过程进行数值模拟,分析双层反应装甲两组件距离、与主靶板距离及两组件的夹角对干扰射流的影响,从而为双层反应装甲结构改进及设计优化提供理论参考.     

火箭自导深弹空中段关键指标研究

文中依据火箭自导深弹的组成及攻潜过程,建立了相关仿真模型,在典型条件下,分别采用对目标当前点和对目标提前点两种射击策略,利用蒙特卡罗法仿真分析了弹箭分离高度、入水速度、溅落点散布误差和助飞段平均飞行速度等空中段主要指标对发现概率的影响。仿真结果表明：溅落点散布误差和助飞段平均飞行速度对发现概率影响显著,为火箭自导深弹空中段关键指标;溅落点散布误差控制在200m以内,助飞段平均飞行速度高于250m/s时,具有较高的发现概率。