Flow of Molten Arsenic Selenide in a Cylindrical Channel

The flow rate of molten arsenic selenide in cylindrical channels is measured at channel diameters of 3.0 to 5.5 mm, channel lengths of 40 to 120 mm, temperatures of 285–320 and 375–470°C, and inert gas gage pressures of up to 1.5 × 10⁵ Pa. It is found that there is a motionless melt layer on the inner surface of the channel. For a channel 4.6 mm in diameter, its thickness is 0.7 mm at 290°C and 0.1 mm at 420°C. In the temperature range 280–315°C, there is a threshold gas pressure below which the melt does not flow. Partial crystallization may occur in the flowing melt. Its effect on the melt flow rate grows as the holding time at 270–320°C increases. The data obtained can be used to choose conditions for producing As₂Se₃ optical fibers by the crucible method.     

Modeling the Distribution of Dispersed Phase in a Cylindrical Flow Using Computational Fluid Dynamics

Technical Physics Letters - This work analyzes the effect of the diameter of a water-filled cylindrical region on the structure of a bubble polydisperse flow. Numerical flow simulation is based on...     

柱状药包爆炸应力场模拟研究

文章以ANSYS/LS-DYNA有限元软件为基础,针对工程实际中所采用的起爆方法,计算了在一定条件下,不同起爆方式的柱状装药在岩石中的爆炸作用,探讨了柱状药包在不同起爆方式下的应力场及端部效应等特征,为工程应用和安全施工提供参考.     

Calculation of Heat Transfer upon the Laminar Flow of Liquid in a Cylindrical Channel in the Presence of Axial Thermal Conductivity

High Temperature - An analytical method that takes into account axial thermal conductivity was proposed for the calculation of eigenvalues and eigenfunction in a problem of heat exchange for...     

Two-Phase Flow of Blood with Magnetic Dusty Particles in Cylindrical Region: A Caputo Fabrizio Fractional Model

The present study is focused on the unsteady two-phase flow of blood in a cylindrical region. Blood is taken as a counter-example of Brinkman type fluid containing magnetic (dust) particles. The oscillating pressure gradient has been considered because for blood flow it is necessary to investigate in the form of a diastolic and systolic pressure. The transverse magnetic field has been applied externally to the cylindrical tube to study its impact on both fluids as well as particles. The system of derived governing equations based on Navier Stoke’s, Maxwell and heat equations has been generalized using the well-known Caputo–Fabrizio (C–F) fractional derivative. The considered fractional model has been solved analytically using the joint Laplace and Hankel (L&H) transformations. The effect of various physical parameters such as fractional parameter, Gr, M and γ on blood and magnetic particles has been shown graphically using the Mathcad software. The fluid behaviour is thinner in fractional order as compared to the classical one.     

矩形换热通道流动与强化换热特性数值模拟研究

采用切应力输运湍流模型(SST k-ω)分别对光滑矩形通道、连续肋矩形通道和间断肋矩形通道在五种典型工况下的流动换热进行了三维数值模拟研究。结果表明,基于SST k-ω湍流模型的光滑矩形通道流动阻力和换热系数模拟结果与经验公式计算结果可以较好符合,验证了本文所采用的数学模型的预测能力。在本文所研究的雷诺数(Re=8000~15000)范围内,连续肋和间断肋通道阻力较光滑通道都相应增加,连续肋片通道较光滑通道阻力增加2倍以上,间断肋片通道较光滑矩形通道阻力增加4.8倍以上,且随Re的增大而增加,同时,连续肋换热能力较光滑通道提升1.1倍以上,而间断肋较光滑通道换热能力提升约1.7倍以上。通过采用综合热学性能参数,对强化传热和阻力减小这两个因素进行评估,分析表明间断肋的综合热学性能明显优于连续肋。     

烟道凝聚器流场及细颗粒凝聚特性研究

为研究烟道凝聚器的凝聚机制及颗粒物减排特性,通过商业计算流体力学（computational fluid dynamics,CFD）软件,模拟并得到了凝聚器湍流区定常/非定常工况条件下的流场特性;理论计算了凝聚器内颗粒的凝聚过程,并通过扫描电镜进行了验证;实验室中凝聚器对PM2.5的减排幅度为20.8%,实际工程中,300 MW和660 MW机组PM2.5的减排幅度分别为30.1%和37%。研究结果可为颗粒凝聚技术的大规模工程应用提供参考。     

Vortex Flow Past a Plate in a Channel

Generalized hydrodynamic equations [1], which explicitly include the Kolmogorov small-scale fluctuations of hydrodynamic quantities, are used for mathematical simulation of vortex flows of gas. The calculations are performed in the range of Reynolds number values from 1000 to 10000 for two-dimensional unsteady-state nonisothermal flows of compressible gas, with a finite or semi-infinite plate momentarily appearing in the channel.     

Investigation of Flow in the Vicinity of Porous Material on a Cylindrical Body Subjected to Flow

The results are given of an experimental investigation of the distribution of velocity components in a flow of air in the vicinity of a hemispherical permeable blunting of a cylindrical body under conditions of low injection intensity. A numerical simulation of the flow structure is performed for the parameters corresponding to those used in the experiments. Comparison of the results of physical and numerical simulation revealed a number of special features of flow in the boundary layer on a curved surface under conditions of its gasdynamic conjugation with the inner cavity.     

Anisotropic and Particle-Particle Interaction Effect in a One-Dimensional System of Magnetic Particles

We have studied the effect of the shape anisotropy in a system that consists of a chain of N identical spherical particles each of magnetic dipole moment μ and that has an easy axis. By considering two particle interactions (Dimer Model) we have investigated two different distinct cases depending on the direction of the applied field H and the orientation (ξ) of the easy axis relative to H. We found that for the randomly oriented easy axis (ξ) and for H parallel or perpendicular to the chain the anisotropy has no effect on the ferromagnetic state. For fixed orientation (ξ) an interplay between ferromagnetic-like and anti-ferromagnetic-like behavior exists. The existence of each behavior is strongly dependent on the anisotropy K and the direction of H relative to the chain.     

Determining the Form of a Hydrodynamic Flow upon Creep of an Amorphous Cobalt-Based Metal Alloy in a Variable Temperature Field

Deformation of an amorphous cobalt alloy of strip configuration in creep tests in a variable temperature field is studied. An analytical form of the creep curve is found, and a prediction calculation of the resistivity by means of the proposed creep function is carried out. The physical meaning of the parameters of the creep equation is established, and their dimensionality is found. It is shown that, under the action of a variable temperature field, the creep of the alloy is not Newtonian and the material under strain exhibits pseudoplastic properties. It was found that, in the absence of heating, the viscosity of amorphous strip alloys can be considered within the Bingham plastic model.     

Numerical Investigation of the Thermal Efficiency of a Two-Phase Gas-Droplet Wall Screen in a Cylindrical Channel

A calculation model is developed and numerical investigation performed of the heat and mass transfer characteristics in a turbulent gas-droplet wall screen. The effect of the characteristics of a two-phase vapor-gas-droplet flow on the thermal efficiency is analyzed. The evaporation of droplets in a two-phase wall screen brings about a significant improvement in the protective properties of an adiabatic wall compared with a single-phase flow mode. The results of calculations of two-phase cooling are compared with experimental data.     

An Investigation of Spatial Distribution of Characteristics of a Plasma Stream Formed by a Hall Discharge in a Channel with Metal Walls

The effect of the system of delivery of the working medium on the characteristics of a plasma stream in a Hall accelerator with closed azimuthal current is experimentally investigated. The gas delivery system utilizes a porous diaphragm from a carbon–carbon composite material whose pore size is comparable with the Debye radius of the electrons of plasma formed in a discharge channel. The calorimetric method is used to determine the degree of azimuthal and radial nonuniformity of distribution of the energy of plasma stream developed by the accelerator, namely, the distribution of temperature of a titanium target mounted perpendicularly to the incident stream is taken with the aid of an infrared imager. The probe method is used to measure the spatial distribution of temperature and the concentration of charge-exchange plasma at the accelerator channel exit. It is shown that the ratio of the kinetic energy of the flow of heavy particles to the expended electric energy (energy efficiency) exceeds 0.5.     

Wave Motion of Solid Particles in a Pulsed Gas Flow

The effect of lowfrequency pulsations of gas on the motion of solid particles has been studied on the basis of numerical solution of equations of the dynamics of a monodisperse gas suspension with account for interphase forces of hydrodynamic drag, virtual masses, and forces due to nonstationary effects around particles. It is found that at certain parameters gas pulsations lead to enhancement of interphase heat transfer. The dependences of the time of particle residence in a pneumochannel on the frequency of gas pulsations have been obtained.     

Distribution of Residual Stresses in a Layer Containing a Welded Cylindrical Disk

By the method of conventional plastic strains, we study the distribution of residual stresses in a plane layer containing a welded cylindrical disk. For plastic strains symmetric about the median surface of the layer, we perform the numerical analysis of the distribution of residual stresses. It is shown that the radial stresses on the surfaces of the welded joint decrease and the hoop stresses increase as the radius of the disk increases.