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瓦斯爆炸诱导沉积煤尘爆炸的数值模拟 总被引:2,自引:0,他引:2
建立了描述瓦斯爆炸卷扬沉积煤尘参与爆炸的物理和数学模型,借助流场模拟平台,对瓦斯爆炸
卷扬沉积煤尘参与爆炸的过程进行了数值模拟;并把模拟值与实验值进行了对比;对爆炸过程中的速度场和
温度场进行了深入的分析。通过比较分析爆炸压力、速度场以及温度场,认为模拟结果清楚地展现了沉积煤
尘的扬起和爆炸过程,达到了瓦斯爆炸诱导沉积煤尘爆炸数值模拟的要求。 相似文献
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针对铀材料在爆炸载荷作用下形成放射性气溶胶的过程,采用光滑粒子流体动力学方法开展了数值模拟和实验研究。通过将颗粒动力学和SPH方法结合,建立了炸药爆轰作用于铀金属壳的数值模拟模型,以铀材料比内能为气溶胶转化判据,获得了铀材料转化为气溶胶的物理过程,得到了在相同爆炸当量下,不同质量铀材料的气溶胶转化效率,并与实验结果进行了对比分析。结果显示,铀材料在爆炸载荷作用下,当其比内能达到1.9 MJ/kg时,即可认为完全转变为气溶胶,对于本文中的爆炸装置结构形式,当炸药质量为铀材料质量的6倍时,转化率超过90%。实验验证了数值模拟结果,表明该方法能够对铀材料的气溶胶转化过程进行准确描述。 相似文献
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粉末材料爆炸压实数值模拟 总被引:6,自引:0,他引:6
本文对粉末爆炸压实数值模拟作了系统评述。首先叙述了流体弹塑性体的模型、方程和计算方法;然后对一些典型的程序编码作了介绍;总结了粉末爆炸压实数值模拟最新进展,最后,对未来发展方向提出了我们的看法. 相似文献
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基于ANSYS/LS-DYNA有限元分析软件对加油站埋地储油罐的爆炸过程进行了数值模拟。根据范登伯格和兰诺伊TNT当量法,将汽油转换成相对应的TNT当量;针对埋地储油罐具体覆土情况采用相应的材料模型,建立了有限元分析模型;采用多物质耦合ALE方法进行爆炸过程的模拟,弥补了采用G·M莱克霍夫计算方法对加油站储罐爆炸进行定量分析时因无法充分考虑埋深、自由面影响以及土质材料特性而产生的不足;通过数值模拟得到了爆炸作用下各观测点的冲击波压力时程曲线和峰值压力,并与G·M莱克霍夫公式的计算结果进行了对比,二者具有相同的变化规律。数值模拟得到的地表处各点的峰值压力可作为判断该点人和建筑物的伤害和破坏程度的依据,为事故分析和新项目建设提供参考。 相似文献
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有限元方法在爆炸动力学中的应用 总被引:1,自引:0,他引:1
从动量和能量守恒方程出发,结合爆炸动力学的特点,建立适于模拟爆炸动力学过程的有限元方法,并对两个问题进行了模拟计算。计算结果与实验结果符合表明,通过选择合适的物质模型,有限元方法对爆炸动力学问题的模拟是可行的。 相似文献
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建立了Al2O3陶瓷引弧微爆炸加工(micro-detonationofstrikingarcmachining,MDSAM)过程的
传热模型,基于有限元理论,利用ANSYS软件对加工过程中的温度场分布进行了模拟。结合材料性质,对模
拟和实验得到的蚀坑尺寸进行了比较,并分析了加工参数对温度场的影响。模拟结果表明,Al2O3陶瓷引弧
微爆炸加工时在给定的加工参数下的最高温度可达13435℃,且高温影响区范围很小,加工实验与模拟结果
符合较好。随着脉冲宽度和工作电流的增加,加工区域的温度以及蚀坑的半径和深度增大;随着喷嘴半径的
增大,加工区域的温度降低而蚀坑的径深比增大。模拟结果可为Al2O3 陶瓷引弧微爆炸加工过程中表面形
貌的预测、材料去除机理的揭示以及加工参数的选择等提供参考。 相似文献
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介绍爆炸力学结合其他学科知识, 开展工程应用的理论和实验工作,进行爆炸装置的研究和设计.包括细观结构对材料力学性能的影响、金属自由面微喷以及多尺度数值模拟的应用.描述了作为应用基础学科的爆炸力学,在某些现代爆炸装置研制中多学科融合的爆炸力学将发挥重要作用. 相似文献
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V. M. Sadovskii O. V. Sadovskaya A. A. Luk’yanov 《Journal of Applied Mechanics and Technical Physics》2014,55(4):689-700
A solution describing the displacement and stress fields around expanding spherical and cylindrical cavities with allowance for pore collapse is constructed using the theory of small elastic deformations of a homogeneous isotropic porous medium in closed form. Transition of the medium into a plastic state is modeled using the Tresca-Saint Venant yield condition. Porosity change is described on the basis of a mathematical model developed taking into account the increase in the stiffness of the porous material at the moment of pore collapse. It is shown that in the elastic deformation stage, the porosity does not change; an increase in the pressure leads to the formation of a region of plastic compression, in part of which, the pores collapse. Stress and displacement fields in the porous medium during unloading are constructed. It is shown that under certain conditions, the elastic unloading stage is followed by the plastic reflow stage to form a region of pore expansion. As the pressure decreases, the boundary of this region simultaneously reaches the region of plastic reflow and the region of pore collapse. 相似文献
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提出了多元混合PBX炸药孔隙塌缩热点模型新的处理方法,构建了新的细观反应速率模型,系列数值模拟结果与实验结果均一致,表明该细观反应速率模型可较好地描述和预测炸药组分配比及颗粒度对多元混合PBX炸药冲击起爆过程的影响。PBX炸药冲击起爆过程主要受热点点火过程和燃烧反应过程共同作用:HMX占主导成分的PBXC03炸药,起爆压力低,冲击起爆过程受热点点火影响较明显,热点点火后的燃烧反应速度较快,表现为加速反应特性;TATB占主导成分的钝感PBXC10炸药,起爆压力高,冲击起爆过程主要受点火后的燃烧反应过程控制,且点火后燃烧反应速度较慢,表现为稳定反应特性。 相似文献
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不锈钢/普碳钢爆炸焊接与轧制 总被引:4,自引:0,他引:4
以不锈钢/普碳钢为对象,对爆炸焊接+轧制联合技术进行了研究。爆炸焊接参数通过计算和优化设计,准确地预示了不锈钢/普碳钢大型厚板坯的爆炸焊接窗口;复合后的板坯在选定的轧制参数下进行热轧和冷轧;在保证复合质量的条件下,经过轧制可获得力学性能、尺寸精度完全合格的大面积薄复合板。 相似文献
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Pore pressure development in a soil specimen due to electro-osmosis under alternating current conditions is examined theoretically. Solutions to the governing equation are derived for one-dimensional flow with boundary conditions corresponding to an impervious (conventional no-flow boundary), a partially drained boundary, and a partially drained boundary with an intervening permeable zone between the boundary and the soil. These latter two boundary conditions can arise from details of pore pressure measuring systems at the specimen boundaries during laboratory experiments. An analysis of the solutions indicates that for a perfect no-flow boundary, excess pore pressures measured at an electrode consist of a steady state and rapidly-decaying transient response. The pore pressures exhibit a 45 degree phase shift relative to the applied electric current. The effect of the partially drained boundary is to reduce the peak to peak amplitude of the pore pressure and to increase the phase shift to as much as 90 degrees depending on the compressibility of the pore pressure measuring system. The effect of the impeded and partially drained boundary is to further reduce the amplitude of the pore pressures and to increase the phase shift to as much as 180 degrees depending on the relative permeability of the impeded boundary. 相似文献
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多层爆炸复合中的成波研究 总被引:1,自引:0,他引:1
用爆炸复合法制成了15层每层1mm厚的紫铜板组成的长1.2m,宽90mm的软电览。进行了2层至14层的对称爆炸复合实验,在多层对称爆炸复合中,总存在一个较大波纹的复合界面。对奇数层复合来说,存在一个稳定的复合模式。在对称多层复合中,最后二个碰撞界面的碰撞角较大,所以在该界面产生大的波纹.但比波长/H不遵循在单层复合时的公式。数值计算指出多层复合时碰撞压力的峰值与廓图均异于对应的单层复合中的情况。 相似文献
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We present a pore-scale network model of two- and three-phase flow in disordered porous media. The model reads three-dimensional pore networks representing the pore space in different porous materials. It simulates wide range of two- and three-phase pore-scale displacements in porous media with mixed-wet wettability. The networks are composed of pores and throats with circular and angular cross sections. The model allows the presence of multiple phases in each angular pore. It uses Helmholtz free energy balance and Mayer–Stowe–Princen (MSP) method to compute threshold capillary pressures for two- and three-phase displacements (fluid configuration changes) based on pore wettability, pore geometry, interfacial tension, and initial pore fluid occupancy. In particular, it generates thermodynamically consistent threshold capillary pressures for wetting and spreading fluid layers resulting from different displacement events. Threshold capillary pressure equations are presented for various possible fluid configuration changes. By solving the equations for the most favorable displacements, we show how threshold capillary pressures and final fluid configurations may vary with wettability, shape factor, and the maximum capillary pressure reached during preceding displacement processes. A new cusp pore fluid configuration is introduced to handle the connectivity of the intermediate wetting phase at low saturations and to improve model’s predictive capabilities. Based on energy balance and geometric equations, we show that, for instance, a gas-to-oil piston-like displacement in an angular pore can result in a pore fluid configuration with no oil, with oil layers, or with oil cusps. Oil layers can then collapse to form cusps. Cusps can shrink and disappear leaving no oil behind. Different displacement mechanisms for layer and cusp formation and collapse based on the MSP analysis are implemented in the model. We introduce four different layer collapse rules. A selected collapse rule may generate different corner configuration depending on fluid occupancies of the neighboring elements and capillary pressures. A new methodology based on the MSP method is introduced to handle newly created gas/water interfaces that eliminates inconsistencies in relation between capillary pressures and pore fluid occupancies. Minimization of Helmholtz free energy for each relevant displacement enables the model to accurately determine the most favorable displacement, and hence, improve its predictive capabilities for relative permeabilities, capillary pressures, and residual saturations. The results indicate that absence of oil cusps and the previously used geometric criterion for the collapse of oil layers could yield lower residual oil saturations than the experimentally measured values in two- and three-phase systems. 相似文献