辅助药型罩材料对超聚能射流性能影响的数值模拟

为了研究超聚能射流形成过程中辅助药型罩材料对射流性能的影响,利用AUTODYN-2D软件,采用高精度多物质求解器Euler-2D Multi-material对辅助药型罩材料分别为Wu、Cu、Fe,锥形药型罩材料为Al的截顶辅助药型罩超聚能装药进行模拟。结果表明,与传统聚能装药相比,超聚能装药结构形成的射流性能更优。辅助药型罩材料密度越大,超聚能射流形态和连续性越好;超聚能射流具有更高的头部速度和能量。用Wu、Cu、Fe作辅助药型罩材料时,超聚能射流的最大速度分别为14 400、13 300和13 100m/s,最大能量分别为10.2×10~7、8.5×10~7、7.5×10~7 J/kg,并且材料密度越大,起爆后相同时刻的射流形态越细越长。     

线性聚能装药切割岩石的数值模拟

运用改进的MOCL程序,数值模拟了线性聚能装药金属射流的形成以及射流侵彻岩石的全过程,得到了锥角为60°的聚能装药结构爆轰产物膨胀、药型罩变形、射流形成过程及锥角为60°和90°时的射流速度梯变分布。不同时刻射流的分布显示,在拉伸过程中,锥角为60°的聚能射流速度变小,速度梯度较大,头部速度为4500m·s-1;锥角为90°的聚能射流,头部速度为3500m·s-1速度梯度较小,与实际物理过程相一致。结果表明,模拟结果基本符合聚能射流的物理现象和规律,说明采用的物理模型和数值算法是合理的。     

聚能装药逆向环形起爆射流形成的数值计算

用LS－DYNA程序对小长径比聚能装药逆向环形起爆时形成高速射流以及正向起爆时形成低速射流进行了三维数值模拟,计算结果与实验吻合,计算的逆向起爆形成射流头部速度为8．78km/s,而正向起爆形成的射流头部速度为4．86km/s。数值模拟证明：长径比聚能装药逆向环形起爆时形成高速金属射流是可行的。     

钨铜粉末药型罩形成聚能射流的数值模拟

利用LS-DYNA3D软件对钨铜粉末药型罩聚能射流的形成过程进行了数值模拟,采用多物质ALE算法,模拟了钨铜聚能射流的形成过程,并与实验结果进行了对比。结果表明,随着药型罩密度的增加,射流直径变细,头部速度降低,数值模拟结果与实验结果较一致。     

聚能射流引爆屏蔽PBX的实验研究

为得到聚能射流引爆屏蔽PBX和B炸药的临界条件,采用某制式聚能装药对不同厚度屏蔽板屏蔽的PBX和B炸药进行了侵彻引爆实验,得到屏蔽炸药临界引爆的屏蔽板厚度;通过闪光X射线照相实验测定了与临界屏蔽板厚度相对应的射流穿靶后的剩余射流头部速度和直径,得出引爆屏蔽PBX和B炸药的射流引爆判据u^2d分别为38．4mm^3／μs^2和15．5mm^3／μs^2。将B炸药射流引爆判据的实验数据与文献报道数据进行对比,证实了实验结果的正确性。此外,在临界屏蔽板厚度相同条件下,对装药厚度不同的屏蔽PBX和B炸药进行了侵彻引爆实验,结果表明,药柱厚度变薄,不利于聚能射流引爆炸药。     

一种截顶线性聚能装药射流特性的数值模拟

为了得到特性更好的线性聚能射流,设计了一种截顶线性药型罩加矩形辅助药型罩的新型装药结构,利用ANSYS/LS-DYNA3D有限元程序对6组新型装药结构及传统装药结构进行了模拟计算,分析了矩形辅助药型罩宽度和截顶间隙长度对线性射流特性的影响。结果表明,该新型结构形成的线性射流的头部最大速度总体较传统线性聚能射流高,形成的线性射流形态更细更长,并且杵体相对较少,药型罩质量利用率较高。在6组方案中,矩形辅助药型罩宽度为1.0cm、截顶间隙为0.4cm时,该结构形成的线性聚能射流头部速度最大,为3.58km/s,连续性较好,有效宽度最大。     

克里金模型用于预测聚能射流速度的方法研究

为了快速预测聚能装药射流速度,减少数值模拟的计算成本,构建了自适应克里金模型,通过少量的数值模拟结果,对参数在一定范围内的聚能装药射流速度进行了预测。在Matlab平台中,以药型罩锥角、罩壁厚、装填炸药参数作为输入值、射流速度作为输出值,构建了自适应克里金模型,通过学习函数反复加入训练样本,直至模型收敛,实现了对测试样本射流速度的预测。为了验证所建立克里金模型的准确度,将其预测结果与数值模拟结果进行了对比。结果表明,克里金模型对聚能射流速度的预测结果与数值模拟结果之间的误差小于2%,说明所构建的自适应克里金模型能够在保证计算精度的情况下,实现在不同炸药装药、不同药型罩参数的条件下,对聚能射流速度的快速预测,该方法能够兼顾预测精度和计算成本,并提高其计算效率。     

聚能射流冲击起爆屏蔽压装PBX炸药的试验研究

为了分析由聚能射流引起的两种典型屏蔽压装PBX炸药的冲击起爆感度,采用某Ф80mm制式破甲弹作为标准射流源,在炸高为150mm的条件下,对不同厚度45~#钢覆盖板屏蔽的PBX-1和PBX-2炸药进行了射流冲击起爆感度试验;采用"兰利法"对覆盖板的厚度进行选取,得到了聚能射流引爆两种典型压装PBX炸药的临界隔板厚度。结果表明,临界爆轰时,PBX-1炸药覆盖板厚度为35～40mm,PBX-2炸药覆盖板厚度为140～150mm,即PBX-1的临界隔板厚度比PBX-2炸药减少73.3%;PBX-1炸药起爆所需的射流能量为185mm~3/μs~2,远高于PBX-2炸药,因此PBX-1炸药的射流安全性显著优于PBX-2炸药。     

粉末药型罩金属粒度级配及热处理对聚能射流性能的影响

利用筛分法,将127型石油射孔弹药型罩中的铜粉进行颗粒分级,并与其他金属粉进行粒度级配,通过粒度分布分析及射孔弹侵彻钢靶试验,研究了粉末药型罩中金属颗粒的粒度级配及分布对聚能射流性能的影响,同时对药型罩进行了热处理研究.结果表明,射孔弹药型罩中铜粉的粒度对聚能射流性能有重要影响,合理的金属粒度级配及分布能提高射孔弹侵彻钢靶的能力.粉末药型罩经热处理后,可提高药型罩的致密性和强度,能有效地改善聚能射流性能.优化后的药型罩使127型石油射孔弹侵彻钢靶深度提高11.6%.     

线性聚能装药对自锻弹丸干扰的数值模拟

为了研究线性聚能装药以不同角度干扰自锻弹丸的效果,采用有限元软件ANSYS/ls-dyna对线性聚能装药从不同角度(0°、30°、60°、90°)干扰自锻弹丸以及自锻弹丸被干扰后侵彻45号钢板的全过程进行数值模拟,然后运用Lsprepost后处理软件分析了自锻弹丸与聚能装药的射流头部在相遇前、相遇过程以及相遇后侵彻45号钢板过程中3个阶段的物理变化,通过分析对比自锻弹丸被干扰后的偏转距离、破碎程度、侵彻能力等确定了线性聚能装药干扰自锻弹丸的最佳干扰角度。结果表明,线性聚能装药可以对自锻弹丸进行有效的干扰,其干扰角度对干扰效果有较大影响。在0°~90°范围内,干扰角度为60°时干扰效果最佳。     

Hollow corundum spheres for high temperature thermal insulation

Conclusions We developed a technological route for the production of hollow electrocorundum spheres intended for manufacturing highly refractory thermal insulation products, concrete bodies, and loose charges. The technology was tested under industrial conditions.Translated from Ogneupory, No. 7, pp. 27–30, July, 1987.     

TiO2/SnO2 double-shelled hollow spheres-highly efficient photocatalyst for the degradation of rhodamine B

TiO₂/SnO₂ double-shelled hollow spheres are successfully synthesized by two-step liquid-phase deposition method using carbon sphere templates. The formation process of TiO₂/SnO₂ hollow spheres is discussed. The samples are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and UV–vis absorption spectroscopy. The behavior of photogenerated charges in the TiO₂/SnO₂ heterojunction structures has been investigated through surface photovoltage spectroscopy. The TiO₂/SnO₂ hollow spheres which are realized show significantly enhanced photocatalytic activities, with respect to the cases of SnO₂ and TiO₂ hollow spheres. Furthermore, TiO₂/SnO₂ hollow spheres show good recyclable photocatalytic activities.     

Design and Performance Evaluation of Flat Cone Charge

The performance of flat cone charge cannot be calculated by the well known hydrodynamic equations used for conventional hollow charges. As such, experimental studies have been carried out to evaluate the effects of liner cone angle, liner thickness, explosive charge to liner mass ratio and stand-off on the penetration performance. Generalized equations are established relating the basic parameters with the performance of flat cone charge. A simplified computerized design approach has been suggested which would be useful to the practical weapon designers.     

无机电解质和有机高分子絮凝剂对污泥表面Zeta电位的影响

选择几种不同金属价位的无机电解质和几种带有不同电的有机高分子絮凝剂，研究了它们在水中溶解后对污泥颗粒表面Ｚｅｔａ电位的影响，同时对其作用机理作了探讨。     

Critical detonation diameter of highly desensitized low-sensitivity explosive formulations

This paper studies the detonability of low-sensitivity multicomponent explosive formulations based on RDX or HMX containing 12–20% polymer binder and, if necessary, ammonium perchlorate and aluminum. An analytical dependence of the critical diameter of low-sensitivity charges on the content of the explosive component is obtained based on the theory of the critical detonation diameter of nonuniform high-density explosive charges developed earlier by the author. The effect of the particle size of the explosive component on the critical diameter is discussed. For a 5–70% content of the explosive component, satisfactory agreement with available experimental data is obtained.     

Near Field Blast Load

The momentum equation used by the author to describe the transferred momentum in the near field of detonating high explosive charges can be very well applied to the test results of steel disks at very near distances to detonating high explosive cylinders of the publication of Weaver and Walters⁽¹⁾.     

A Model for the Collapse of Explosively Driven Liners in spinning warheads

An analytical model has been developed for the rapid collapse of explosively driven metal shells that includes the effects of material strength and shell spin. The model can be used to approximate the collapse process of shaped charges and EFPs. A closed form solution for shell velocity as a function of shell position is developed and compared to several two-dimensional and three-dimensional continuum mechanic numerical simulations. Comparisons with the simulations include a parametric evaluation of shell geometry, initial conditions, and material strengths. The analytical model compares well with the numerical simulations for very thin shells. It shows that spin can significantly affect the final collapse velocity, and may even result in hollow penetrators. The model also shows that strength has a similar effect, and can greatly reduce the final collapse velocity.     

用250孔板纺圆中空纤维的生产技术

本文主要从干热收缩率和中空度两大工艺因素入手,分析并总结了影响圆中空纤维质量的主要因素。确定了熔体温度280℃、单丝纤度20.0dtex、风速0.55m/s、风温24℃、泵供量288g/min的最佳工艺条件。     

Study of an analytical model for hollow fiber reverse osmosis module systems

A number of investigators have made efforts to develop various analytical models for hollow fiber type reverse osmosis (RO) module systems since the 1970s. However, a perfect analytical model, which can precisely explain the observed RO performances under a wide range of operating conditions has not been developed yet. The author previously proposed a precise analytical model called a friction-concentration-polarization model (FCP model) [1], which used the Kimura-Sourirajan model for transport phenomena of solute and water transport through a membrane, taking a mass transfer coefficient as local variables and taking a fiber-bore side pressure drop into account. In the application of this model, fundamental transport parameter of hollow fiber membranes were needed, and they were initially determined by a U-tube membrane test where the effect of concentration polarization could be neglected. Then a local mass transfer coefficient was estimated from experimental data using actual modules as a function of Reynolds and Schimidt numbers by a trial-and-error method for both brackfish water and seawater desalination cases. Using all of the above results, behaviors of hollow fiber modules under various operating conditions were estimated and compared with the results obtained from commercial size module experiments. Compared to other previous models, the FCP model is verified to be the best one to predict actual module performances. This model will be further extended to anlyze a change of transport parameters during long-term runs.     

ADHESION OF A LIQUID-FILLED SPHERICAL MEMBRANE

Solid/solid interfacial interactions have been successfully characterised using the Johnson, Kendall, and Roberts (JKR) analysis for many years now. Following a suggestion and accompanying analysis by the present author to replace a solid sphere by a gas-filled, hollow, spherical membrane in contact experiments, we now propose a liquid-filled "balloon." Free energy changes due to stretching, bending, the mechanical contact force and adhesion are assessed and minimised to obtain an exploitable equation permitting estimation of the energy of adhesion of the system as a function of various, in principle more easily measured, parameters.