共查询到19条相似文献,搜索用时 921 毫秒
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铝电解槽内湍流流动与界面波动的数值模拟 总被引:8,自引:0,他引:8
建立了模拟铝电解槽内电解液和铝熔液湍流流及两层熔液界面波动的数学模型,利用交错网格上的一种基于SIMPLE算法的改形格式,计算了280kA电解槽内两层熔液的流动状况与界面形状。 相似文献
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针对铝电解槽故障种类繁多和不易诊断的问题,设计了基于BP网络和专家系统的分层故障诊断系统,包括前层分类和后层预报;通过对槽电阻信号的频谱分析,提取了故障特征信息,并对故障进行分类;建立了基于BP网络的前层分类器,用于诊断特征显著的故障;制定了故障诊断和控制规则,完善了专家系统的知识库,根据前层分类结果对余下故障进行诊断;通过制定规则,将前层分类和后层预报相结合,实现了故障诊断系统的整体设计;仿真结果及理论分析表明,该系统可有效预报单一及复合故障,提高故障诊断的准确率,保证铝电解槽工作状况的稳定。 相似文献
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本文介绍利用电阻网格模拟轴对称场的原理和方法。并把模拟实验结果与数值计算结果对比,证明模拟实验的精确性比较好,克服了用电解槽法模拟所特有的误差。 相似文献
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针对铝电解槽故障特征种类繁多,难以快速准确的实现故障类型诊断,设计了一种基于最大-最小蚂蚁系统(MMAS)优化的极限学习机(ELM)故障诊断方法。介绍了电解槽常见的故障类型及其对槽电压的影响,对采集到的故障情况下的槽电压信号进行降噪处理,根据对降噪后故障信号的局域均值分解(LMD)结果得到故障特征。采用ELM算法辨识故障类型,针对ELM算法存在的参数问题,采用MMAS对ELM隐含层参数寻优。结果表明,MMAS优化的ELM既保证了较快的训练速度,同时获得了更高的故障测试正确率。 相似文献
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选取了代表性水溶液体系铝硅酸钠的典型试样:铝酸钠溶液、硅酸钠溶液、铝硅酸钠溶液,分别测定了它们的拉曼光谱。构建了系列铝硅酸钠溶液微结构模型,应用量子化学从头计算方法优化了空间几何构型,并计算了其拉曼光谱,计算结果分别与相应试样的实验拉曼光谱进行对比。结果表明:在高浓度条件下,铝酸钠溶液中铝物种的主要存在形式是Al(OH)-4(Q0)和Al2O(OH)2-6(2Q1),低浓度时只存在Q0结构的铝酸根离子,以4Q0聚集态的四水合分子形式存在;在2.0M Na2SiO3溶液中,硅酸钠团簇结构可能的存在形式是四水合Na2H2SiO4;在铝硅酸钠溶液中,铝硅酸根离子的形态是由Si-O-Si和Al-O-Si键以不同铝硅原子配比相互连接形成的环状或链状结构。 相似文献
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利用线性自旋波方法并结合Hellmann-Feynman定理引入一种计算量子磁性系统临界磁场的方法.计算两种特殊模型的临界磁场,并将理论结果与数值结果进行比较,理论值与数值结果高度吻合,验证了理论方法的准确性. 相似文献
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R. Lavín C. Gallardo J.L. Palma J. Escrig J.C. Denardin 《Journal of magnetism and magnetic materials》2012
The angular dependence of the coercivity and remanence of ordered hexagonal arrays of Co nanowires prepared using anodic aluminum oxide templates was investigated. The experimental evolution of coercivity as a function of the angle, in which the external field is applied, is interpreted considering micromagnetic simulations. Depending on the angle between the axis of the wire and the applied magnetic field direction our results show that the magnetization reversal mode changes from vortex to a transverse domain wall. Besides, we observed that the dipolar interactions cause a reduction in coercive fields, mainly in the direction of easy magnetization of the nanowires. Good agreement between numerical and experimental data is obtained. 相似文献
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A numerical method is applied to calculate an optimal distribution of currents in air which generate the magnetic field gradients required to spatially encode the radiofrequency signal in a NMR tomographic experiment. We compare the performances of the gradient circuits for the whole body air-core electromagnet described by Bangert and Mansfield (J. Phys. E 15; 1982) with the results of our optimization. 相似文献
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In this study, the behavior of a single bubble in a dielectric viscous fluid under a uniform magnetic field has been simulated numerically using the Level Set method in two-phase bubbly flow. The two-phase bubbly flow was considered to be laminar and homogeneous. Deformation of the bubble was considered to be due to buoyancy and magnetic forces induced from the external applied magnetic field. A computer code was developed to solve the problem using the flow field, the interface of two phases, and the magnetic field. The Finite Volume method was applied using the SIMPLE algorithm to discretize the governing equations. Using this algorithm enables us to calculate the pressure parameter, which has been eliminated by previous researchers because of the complexity of the two-phase flow. The finite difference method was used to solve the magnetic field equation. The results outlined in the present study agree well with the existing experimental data and numerical results. These results show that the magnetic field affects and controls the shape, size, velocity, and location of the bubble. 相似文献
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In this paper, the reflection properties and sensitivity of a D-shape optical fibre sensor are investigated theoretically and numerically with the emphasis on the metal layer [gold (Au), silver (Ag), copper (Cu), and aluminum (Al)]. Maxwell’s equations are used to determine the electric and magnetic fields of the incident waves at each layer. Snell’s law is applied and the boundary conditions are imposed at each layer interface to calculate the reflected power and sensitivity of the sensor. In the numerical results, the mentioned power is computed and illustrated as a function of wavelength, angle of incidence, metal layer thickness and refractive index of the external medium when the metal layer changes. The variation of sensitivity with the wavelength of the incident radiations is also proposed for some of the given metals. 相似文献
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双周期加速结构腔间耦合系数的模拟计算 总被引:1,自引:0,他引:1
在直线加速器加速管的设计中, 腔间耦合系数是一个关键参量, 它的误差是影响场分布误差的主要因素. 准确计算耦合系数,对于腔间耦合孔几何参数的设计十分重要. 目前, 采用电磁场计算软件进行数值模拟是计算耦合系数的主要
方法. 文献调研发现, 使用MAFIA程序计算耦合系数, 对于单周期的盘荷波导结构, 根据MAFIA程序内部电(磁)边界条件和周期性边界条件, 对应两者有行波模拟、驻波模拟两种方法计算色散曲线. 本文结合这两种方法, 对计算双周期加速结构耦合系数的方法进行了探索, 它们可得到相近的结果, 与实验测量值的差别小于15%. 相似文献
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B.P. Alho A. Magnus G. CarvalhoP.J. von Ranke 《Journal of magnetism and magnetic materials》2012,324(2):210-214
In this work a numerical methodology is theoretically proposed to calculate the magnetization of a polycrystalline system, considering a microscopic Hamiltonian model, which describes a magnetic system consisting of two sublattices of different magnetic ions coupled by exchange interactions and with parallel and perpendicular direction of the magnetic field. The influence of changing the applied magnetic field direction on an antiferromagnetic system was systematically analyzed. The proposed numerical method was applied to the cubic perovskite EuTiO3 and a good agreement with the experimental data was obtained. 相似文献
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磁场作为一个环境能够诱导近藤单态的退相干。我们采用格林函数方法,计算磁场下量子点耦合Aharonov-Bohm环系统的退相干特性,数值结果显示磁场引起的近藤单态的退相干是一个突然的过程。 相似文献
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The deuteron theory is renewed and completed for non-local Hamiltonians. A method to calculate deuteron wave functions is given. The formula for the current density and the magnetic dipole moment of a non-local potential is derived, and applied to the GCT, GT, and HJ-potential. The effects of a unitary transformation on the deuteron data — electric quadrupole moment, magnetic dipole moment, and radius — are shown. For the numerical calculations the Ristig-Kistler transformation and the HJ-potential were used. It is shown that an overall fit cannot be reached. 相似文献