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Estimating the effect of the main design parameters on the effectiveness of high-purity hydrogen production from raw hydrocarbons in membrane catalytic devices 评价了膜催化装置中主要设计参数对原料烃制氢效率的影响
Pub Date : 2023-08-01 DOI: 10.17804/2410-9908.2023.4.029-046
A. B. Vandyshev
The paper presents the results of the application of a physically grounded mathematical model, verified through numerous practical examples, intended for estimating the effect of some design factors (membrane thickness and the system of high-purity hydrogen outlet from the under-membrane space of membrane elements) on the effectiveness and efficiency of the production of highly pure hydrogen from the products of steam conversion of hydrocarbons in advanced membrane catalytic devices.
本文介绍了一个基于物理基础的数学模型的应用结果,并通过大量实例进行了验证,该模型旨在估计一些设计因素(膜厚度和膜元件膜下空间的高纯氢出口系统)对先进膜催化装置中烃类蒸汽转化产物生产高纯氢的有效性和效率的影响。
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引用次数: 0
The impact of flow induced by rotating magnetic fields on processes in a molten conductive medium 由旋转磁场引起的流动对熔融导电介质过程的影响
Pub Date : 2023-06-01 DOI: 10.17804/2410-9908.2023.3.006-016
R. Khalilov, A. Mamykin, R. Okatev, I. Kolesnichenko
This paper studies a method of stirring liquid metal by the action of rotating magnetic fields using two ring inductors placed next to each other. These inductors generate magnetic fields rotating in opposite directions. The aim of this study is numerical investigation of the generated fluid flow and its impact on the homogenization of a two-phase medium, as well as on the crystallization process. The impact of these electromagnetic forces proves to cause the generation of intense poloidal flow component. The arising flow is accompanied by oscillatory motion of vortex structures and their interaction resulting in effective mixing of the liquid metal. The moderate values of the force parameter have been found to lead to the most homogeneous medium under stirring. Under non-stationary action, the force parameter modulations in a certain frequency range have practically no effect on the homogeneity occurrence time and the homogeneity value. The positive effect of stirring by magnetic fields of complex topology on the rate and homogeneity of metal solidification is stated. The obtained results are relevant for improving the quality of foundry ingots.
本文研究了一种利用两个相邻的环形电感器在旋转磁场的作用下搅拌液态金属的方法。这些电感器产生反向旋转的磁场。本研究的目的是数值研究产生的流体流动及其对两相介质均质化和结晶过程的影响。事实证明,这些电磁力的影响导致了强烈的极向流分量的产生。产生的流动伴随着涡结构的振荡运动及其相互作用,导致液态金属的有效混合。适中的力参数值可以使介质在搅拌过程中达到最均匀的状态。在非平稳作用下,一定频率范围内的力参数调制对均匀性发生时间和均匀性值几乎没有影响。阐述了复合拓扑磁场搅拌对金属凝固速度和均匀性的积极影响。所得结果对提高铸锭质量具有一定的指导意义。
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引用次数: 0
Selecting a dependence for the approximation of experimental data on secondary creep and creep rupture strength 选择二次蠕变和蠕变断裂强度实验数据近似的依赖关系
Pub Date : 2023-06-01 DOI: 10.17804/2410-9908.2023.3.044-049
V. Nazarov
As a rule, for the evaluation of the mechanical characteristics of a metallic material by secondary creep and creep rupture strength, tests are carried out for uniaxial tension of cylindrical specimens under the influence of a stationary axial force. These mechanical characteristics include the experimental dependence of constant strain rate on nominal stress and the experimental dependence of rupture time on nominal stress. In order not to conduct a large number of experiments, so that these mechanical characteristics can be determined at any nominal stress, one of the two empirical dependencies is used, allowing the corresponding experimental dependences to be approximated with the smallest total error. As such empirical dependences, a power dependence with two material parameters and a fractional power dependence with four material parameters are considered, two of which acquire the definite physical meaning of starting creep stress (the maximum stress at which the strain rate is zero) and break creep stress (the minimum stress at which instantaneous rupture occurs). When choosing an empirical dependence, the author used experimental data obtained by him from mechanical tests for uniaxial tension of cylindrical VT5 and VT6 titanium alloy specimens at 650 °C. The calculated total errors testify that both empirical dependences satisfactorily approximate the considered experimental data.
通常,为了通过二次蠕变和蠕变断裂强度来评估金属材料的力学特性,通常进行圆柱形试样在固定轴向力影响下的单轴拉伸试验。这些力学特性包括恒应变速率对名义应力的实验依赖性和破裂时间对名义应力的实验依赖性。为了不进行大量的实验,以便可以在任何名义应力下确定这些力学特性,使用两个经验依赖关系中的一个,允许以最小的总误差近似相应的实验依赖关系。作为这样的经验依赖关系,考虑了两个材料参数的功率依赖关系和四个材料参数的分数功率依赖关系,其中两个具有确定的物理意义,即开始蠕变应力(应变速率为零时的最大应力)和破裂蠕变应力(瞬时破裂时的最小应力)。在选择经验依赖时,作者使用了他从圆柱形VT5和VT6钛合金试样在650℃下的单轴拉伸力学试验中获得的实验数据。计算的总误差证明两种经验依赖都令人满意地近似于考虑的实验数据。
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引用次数: 0
Based on the temperature correlation principle, the use of a magnetic obstacle to generate pulsations in the flow measurement of a liquid metal coolant 基于温度相关原理,利用磁阻产生脉动对液态金属冷却剂进行流量测量
Pub Date : 2023-06-01 DOI: 10.17804/2410-9908.2023.3.017-028
A. Mamykin, R. Khalilov, E. Golbraikh, I. Kolesnichenko
A promising method for determining the flow rate of a liquid metal coolant is the temperature correlation method (TCM) since it does not require calibration. However, being indirect, it has a number of limitations to be carefully studied. A magnetic obstacle is used as a temperature pulsation generator. The paper presents the results of a numerical study on the influence of the size of a magnetic obstacle and its activity ratio, as well as effect of the temperature difference between the liquid metal and the environment, on the performance and accuracy of the TCM. The main criteria influencing the operation of the method are identified, namely the extent and spatial position of the vorticity and mixing zones.
温度相关法(TCM)是一种很有前途的测定液态金属冷却剂流量的方法,因为它不需要校准。然而,由于它是间接的,它有一些局限性,需要仔细研究。利用磁性障碍物作为温度脉动发生器。本文介绍了磁阻尺寸及其活度比的影响,以及液态金属与环境温差对磁阻器性能和精度影响的数值研究结果。确定了影响该方法运行的主要判据,即涡度区和混合区的范围和空间位置。
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引用次数: 0
Thermophysical properties of a Cu–Ti–C–B SHS composite Cu-Ti-C-B SHS复合材料的热物理性质
Pub Date : 2023-06-01 DOI: 10.17804/2410-9908.2023.3.050-065
N. Pugacheva, T. Bykova, E. Senaeva, L. Goruleva
The paper studies the thermophysical properties of a Cu-Ti-C-B composite produced by self-propagating high-temperature synthesis (SHS) of an initial mixture of copper, titanium, boron carbide (B4C), and carbon powders. The matrix of the composite is a supersaturated solid solution of titanium in a copper lattice with Cu4Ti nanosized particles homogeneously precipitated under cooling. The matrix microhardness is 450 HV 0.1. Particles of titanium carbide (TiC) and titanium diboride (TiB2) resulting from SHS are randomly distributed in the bulk of the composite. The microhardness of the regions with the predominance of TiC particles is 640 HV 0.1, and the microhardness of the regions with the predominance of TiB2 particles is 900 HV 0.1. The average hardness of the composite is 60 HRC. Differential scanning calorimetry demonstrates a unified wide exothermic effect at temperatures ranging from 750 to 1000 °С, with an enthalpy of 148.6 J/g, associated with the exothermic reaction between residual titanium and boron carbide (B4C), which did not react during SHS. The temperature dependences of density, thermal diffusivity, heat capacity, thermal conductivity, and the coefficient of linear thermal expansion are experimentally determined. The particles of the strengthening phases are found to reduce slightly the thermal properties of the composite compared to pure copper. It is shown that annealing at temperatures of 800 and 860°C decreases the level of residual stresses in the composite matrix.
本文研究了以铜、钛、碳化硼(B4C)和碳粉为初始混合物,通过自蔓延高温合成(SHS)制备的Cu-Ti-C-B复合材料的热物理性能。复合材料的基体是钛在铜晶格中的过饱和固溶体,在冷却下均匀析出Cu4Ti纳米颗粒。基体显微硬度为450hv0.1。由SHS产生的碳化钛(TiC)和二硼化钛(TiB2)颗粒在复合材料中随机分布。TiC颗粒优势区显微硬度为640 HV 0.1, TiB2颗粒优势区显微硬度为900 HV 0.1。复合材料的平均硬度为60 HRC。差示扫描量热法表明,在750 ~ 1000°С温度范围内存在统一的宽放热效应,其焓为148.6 J/g,与残余钛和碳化硼(B4C)之间的放热反应有关,而在SHS过程中没有发生反应。通过实验确定了密度、热扩散系数、热容、导热系数和线性热膨胀系数对温度的依赖关系。与纯铜相比,强化相颗粒略微降低了复合材料的热性能。结果表明,800℃和860℃退火可降低复合材料基体的残余应力水平。
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引用次数: 0
The effect of the chemical activity of the implanted element to metal alloy components on the formation of surface layers under ion irradiation 离子辐照下注入元素对金属合金成分化学活性对表层形成的影响
Pub Date : 2023-06-01 DOI: 10.17804/2410-9908.2023.3.029-043
V. L. Vorobyev, P. Bykov, S. G. Bystrov, A. Kolotov, V. Bayankin
The paper comparatively studies the effect of implanting O+ ions into the Cu50Ni50 and Cu56Mn44 alloys and M0 copper, as well as N+ ions into the VT6 titanium alloy, the 03Kh17N12M2T stainless steel, and Armco iron, on the formation of the chemical composition and changes in the structural and phase state of the surface layers. It is shown that, under conditions of implantation of ions of chemically active elements, the accumulation of the implanted impurity, the formation of chemical compounds, and their precipitation in the form of phase inclusions are determined by the chemical activity of the implanted element to the alloy components. The results obtained will allow the further development of scientific foundations for the formation of the chemical and structural-phase state in materials under nonequilibrium conditions of ion implantation.
对比研究了在Cu50Ni50、Cu56Mn44合金和M0铜中注入O+离子,在VT6钛合金、03Kh17N12M2T不锈钢和Armco铁中注入N+离子,对表层化学成分的形成、组织和相态变化的影响。结果表明,在注入化学活性元素离子的条件下,注入杂质的积累、化合物的形成以及以相夹杂形式析出是由注入元素对合金组分的化学活性决定的。所得结果将为离子注入非平衡条件下材料的化学相和结构相的形成提供进一步的科学基础。
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引用次数: 0
The impact of bridge crossing span damage under moving load 移动荷载作用下桥梁跨跨损伤的影响
Pub Date : 2023-04-01 DOI: 10.17804/2410-9908.2023.2.065-074
V. Korepanov, T. Korepanova, R. Tsvetkov
The structure of the bridge crossing span structure is simulated in order to determine the most informative parameters, which need to be measured in the process of monitoring system operation. To assess the influence of structural component integrity on the static deflections and dynamic response, damages were introduced into the model, which were simulated by removal of a part of the structural components. On the basis of a numerical model of calculating a span structure under static and dynamic moving load, it is shown how increasing damage changes deflection and natural frequencies, which can be reliably recorded by the monitoring system.
为了确定监测系统运行过程中需要测量的最具信息量的参数,对桥梁跨跨结构进行了模拟。为了评估结构构件完整性对静挠度和动态响应的影响,在模型中引入了损伤,并通过移除部分结构构件来模拟损伤。通过对某跨结构在静动力移动荷载作用下的数值计算模型,分析了损伤的增加对结构挠度和固有频率的影响,并通过监测系统可靠地记录了其变化。
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引用次数: 0
Analytical and numerical radially symmetric solutions to a heat equation with arbitrary nonlinearity 任意非线性热方程的解析和数值径向对称解
Pub Date : 2023-04-01 DOI: 10.17804/2410-9908.2023.2.049-064
A. L. Kazakov, L. Spevak
The paper deals with the construction of radially symmetric heat waves, which are solutions to the heat conduction equation with an arbitrary form of nonlinearity under nonzero boundary condition specified on a moving manifold. The boundary value problem under study is a generalization of those solved by us earlier. Firstly, the class of the considered parabolic equations is extended; secondly, the boundary condition generating a heat wave in a space of arbitrary dimensionality has a more general form. A new theorem of the existence and uniqueness of the heat-wave-type analytical solution is proved for this problem. An approximate method of constructing solutions of the required form is proposed, which is based on expansion in radial basis functions combined with the collocation method. At each time step, the solution is constructed in two stages. The first stage is solving a problem in the region bounded by a specified moving manifold and a heat wave front, which is a priori unknown and evaluated during solving. Herewith, a special substitution is used, i.e. the required function and the spatial variable change their roles. In the second stage, the solution is completed in the region bounded by the positions of the specified moving manifold on a current step and at the initial time. The boundary conditions are defined from the first-step solution. In the test example, the solutions constructed by the developed algorithm are compared with the known exact solution. Calculations show a good accuracy of the numerical solutions at various values of the numerical parameters, including space dimensionality. The observed numerical convergence with respect to the time step shows the correctness of the proposed computational procedure.
本文研究了在运动流形上非零边界条件下具有任意形式非线性的热传导方程的径向对称波的构造。本文所研究的边值问题是我们以前所解决的边值问题的推广。首先,对所考虑的抛物型方程进行了扩展;其次,在任意维空间中产生热浪的边界条件具有更一般的形式。证明了该问题的热浪型解析解的存在唯一性定理。提出了一种基于径向基函数展开与配点法相结合的构造所需形式解的近似方法。在每个时间步骤中,解决方案分为两个阶段构造。第一阶段是在给定的运动流形和热浪锋面交界的区域内求解一个先验未知的问题。这里使用了一种特殊的替换,即所需要的函数和空间变量改变了它们的作用。在第二阶段,在当前步长和初始时间的指定移动流形的位置所限定的区域内完成求解。边界条件由第一步解定义。在测试实例中,将该算法构造的解与已知的精确解进行了比较。计算表明,在不同数值参数值下,包括空间维数,数值解具有良好的精度。对时间步长的数值收敛表明了所提计算方法的正确性。
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引用次数: 0
Ensuring safe operation of monolithic structures in undermined areas 确保破坏区域整体结构的安全运行
Pub Date : 2023-04-01 DOI: 10.17804/2410-9908.2023.2.006-018
G. Gusev, A. Baryakh, I. Shardakov, R. Tsvetkov
In order to ensure safe operation of buildings in undermined areas, it is necessary to take into account the influence of loads extrinsic to typical structures. The solution of the generalized boundary value problem on the evaluation of the stress-strain state (SSS) of the building–foundation–soil system with due regard for the complete geometry and physically nonlinear behavior of all the elements is inexpedient since it is complicated by the large dimensionality of the problem. This paper discusses an approach allowing the state of monolithic reinforced concrete building structures located in an undermined area to be estimated by solving boundary value problems on different scales, from modeling the whole system in an elastic formulation to modeling joints between load-bearing members (columns and floors) in a nonlinear formulation for concrete and reinforcement. In these problems, strain energy is taken as the parameter characterizing the deformation process at critical deformation stages and connecting the boundary value problems. The obtained loading diagrams for a unit and the evaluation of the SSS of the whole structure enable one to find the values of maximum permissible horizontal soil deformations in the vicinity of the foundation, at which the bearing members reach the SSS preceding the loss of bearing capacity.
为了保证破坏区域建筑物的安全运行,有必要考虑典型结构的外部荷载的影响。在求解建筑-基础-土壤系统应力-应变状态的广义边值问题时,考虑到所有单元的完全几何和物理非线性行为是不合适的,因为问题的高维性使其变得复杂。本文讨论了一种方法,通过求解不同尺度的边值问题来估计位于破坏区域的整体钢筋混凝土建筑结构的状态,从用弹性公式对整个系统建模到用混凝土和钢筋的非线性公式对承重构件(柱和楼板)之间的接缝建模。在这些问题中,在关键变形阶段以应变能作为表征变形过程的参数,并将边值问题联系起来。获得的单元加载图和整个结构的SSS评估使人们能够找到基础附近最大允许水平土体变形的值,在此值上,承载构件在失去承载能力之前达到SSS。
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引用次数: 0
Studying the mechanical properties of iron ore concentrate briquettes 对铁精矿型煤的力学性能进行了研究
Pub Date : 2023-04-01 DOI: 10.17804/2410-9908.2023.2.041-048
L. I. Polyansky, N. Babailov, Y. Loginov
This paper studies the properties of metallurgical briquettes of iron ore concentrate with coke screenings and liquid glass as a binder. The briquettes are produced by one-sided pressing in a closed die mounted on the plates of a vertical press with a force of 100 kN. The studies were carried out in the laboratory of Spidermash LLC. The following properties of briquettes were determined: density, impact strength and compressive strength (for green and dry briquettes). The functional dependences of the mechanical properties on 4 parameters are plotted, namely on charge mixture composition (the content of iron ore concentrate and coke), binder (liquid glass) percentage in the mixture, moisture content in the mixture, and charge mixture compacting pressure. The obtained experimental data are approximated with the use of a multiplicative model, with the application of the least squares method. Various analytical models for describing the behavior of the material to be briquetted are studied. It is concluded that the multiplicative model provides a more adequate description of the mechanical properties. The quality of the multiple regression model is assessed by the adjusted coefficient of determination. The significance of the regression equation is evaluated by the Fisher criterion, and the significance of the regression coefficients is evaluated according to Student. The mechanical properties of briquettes from iron ore concentrate with coke screenings, presented in the form of analytical dependencies, are necessary to assess the strength of the briquettes when designing the briquetting process. For example, it is necessary to take into account the change in yield during briquette transportation after briquetting. These dependences are also necessary for formulating and solving problems of pressing/briquetting of finely dispersed materials, including iron ore concentrate with coke screenings.
研究了以焦炭筛分和液态玻璃为粘结剂的铁精矿冶金型煤的性能。压块是在一个封闭的模具中,用100千牛的力在垂直压力机的板上进行单侧压制的。研究是在Spidermash LLC的实验室进行的。压型煤的以下特性被确定:密度、冲击强度和抗压强度(用于绿色和干型煤)。绘制了混合料组成(铁精矿和焦炭的含量)、混合料中粘结剂(液态玻璃)的含量、混合料中水分含量、混合料压实压力4个参数对力学性能的函数依赖性。利用乘法模型和最小二乘法对得到的实验数据进行近似。研究了用于描述待压块材料行为的各种分析模型。结果表明,乘法模型能较好地描述材料的力学性能。用调整后的决定系数来评价多元回归模型的质量。回归方程的显著性采用Fisher准则进行评价,回归系数的显著性采用Student准则进行评价。采用焦炭筛分的铁矿精矿型煤的力学性能以分析依赖关系的形式呈现,这对于设计型煤工艺时评估型煤的强度是必要的。例如,有必要考虑成型后型煤运输过程中产量的变化。这些依赖关系对于制定和解决精细分散物料(包括带焦炭筛分的铁矿精矿)的压制/压块问题也是必要的。
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引用次数: 0
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Diagnostics, Resource and Mechanics of materials and structures
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