Magnetohydrodynamics slip flow of a nanofluid through an oscillatory disk under porous medium supremacy

Unsteady, three‐dimensional, hydromagnetic, nanofluid flow via a circular disk in porous medium is considered. The fluid motion is subject to disk rotation and time‐based sinusoidal oscillations. The flow problem is normalized via similarity variables. Partial slip boundary conditions on velocity, concentration, and temperature are considered. A well‐established numerical technique (successive over relaxation method) is used for the time‐based flow problem. Results are discussed for both the time‐based and linearly rotating disk case. Graphical representations for one, two, and three dimensions are sketched. The results are also discussed through tabular forms.     

Model for MHD viscoelastic nanofluid flow with prominence effects of radiation

Present phenomenon is dedicated to analyze the problem of steady state flow of an incompressible fluid model pertained to as magnetohydrodynamics viscoelastic nanofluid through a permeable plate. Continuity, momentum, energy, and concentration expressions are elaborated to comprehend nature of the fluid flow. Numerical solutions are presented. The arising mathematical problem is governed by interesting parameters which include viscoelastic parameter, magnetic field parameter, nanofluid parameter, radiation parameter, skin friction, Prandtle number, and Sherwood number. Solutions for the dimensionless velocity, temperature, and concentration fields and the corresponding skin friction, Nusselt number, and Sherwood number are determined and canvassed with the help of graphs for the distinct values of pertinent parameters.     

Global and Kinetic MHD Simulation by the Gpic-MHD Code

In order to implement large-scale and high-beta tokamak simulation, a new algorithm of the electromagnetic gyrokinetic PIC （particle-in-cell） code was proposed ...     

Homotopy analysis method for fully developed MHD micropolar fluid flow between vertical porous plates

In this paper, the fully developed natural convection of MHD micropolar fluid flow between two vertical porous plates is considered. The coupled system of non‐linear differential equations governing the flow is solved analytically by the homotopy analysis method (HAM). The HAM contains an auxiliary parameter ?, which provides us with a simple way to adjust and control the convergence region and rate of convergence of the series solution. Velocity, microrotation and temperature profiles are presented for several values of the Hartmann number and the micropolar parameter. Copyright © 2008 John Wiley & Sons, Ltd.     

电渣重熔过程中熔滴形成与滴落过程的数值模拟

利用计算流体力学FLUENT软件中的磁流体动力学模块,建立了描述电渣重熔过程的多场耦合三维数学模型,对电渣重熔过程进行数值模拟,计算值与实验结果吻合较好,证明计算方法的可靠性. 模拟结果表明,随熔滴滴落过程进行,渣池的等效电阻逐渐减小,渣池内电流重新分配,直接影响电渣炉的电耗和生产率;电流密度、电磁力和速度的最大值都出现在大熔滴即将发生分离时,与电极开始熔化时相比,电流密度最大值增大近1个数量级,电磁力和速度场最大值分别增大2.5和4.7倍;而焦耳热和温度最大值出现在熔滴落入渣金界面时,分别增大174.7%和26.8%.     

Nonlinear Simulations of Coalescence Instability Using a Flux Difference Splitting Method

A flux difference splitting numerical scheme based on the finite volume method is applied to study ideal/resistive magnetohydrodynamics. The ideal/resistive MHD equations are cast as a set of hyperbolic conservation laws, and we develop a numerical capability to solve the weak solutions of these hyperbolic conservation laws by combining a multi-state Harten-Lax-Van Leer approximate Riemann solver with the hyperbolic divergence cleaning technique, high order shock-capturing reconstruction schemes, and a third order total variance diminishing Runge-Kutta time evolving scheme. The developed simulation code is applied to study the long time nonlinear evolution of the coalescence instability. It is verified that small structures in the instability oscillate with time and then merge into medium structures in a coherent manner. The medium structures then evolve and merge into large structures, and this trend continues through all scale-lengths.The physics of this interesting nonlinear dynamics is numerically analyzed.     

金属熔体的电磁成形与凝固

材料的电磁加工是当今材料加工技术领域研究和发展的一个重点。本文简述作为材料电磁加工技术理论基础的电磁流体力学的基本内容，给出电磁场各种的基本原理，着重阐述电磁力和焦耳热在金属熔体电磁成形与凝固过程中的应用。     

Experimental Design of a Magnetic Flux Compression Experiment

Generation of ultrahigh magnetic fields is an interesting topic of high-energy-density physics, and an essential aspect of Magnetized Target Fusion (MTF). To examine plasma formation from conductors impinged upon by ultrahigh magnetic fields, in a geometry similar to that of the MAGO experiments, an experiment is under design to compress magnetic flux in a toroidal cavity, using the Shiva Star or Atlas generator. An initial toroidal bias magnetic field is provided by a current on a central conductor. The central current is generated by diverting a fraction of the liner current using an innovative inductive current divider, thus avoiding the need for an auxiliary power supply. A 50-mm-radius cylindrical aluminum liner implodes along glide planes with velocity of about 5 km/s. Inward liner motion causes electrical closure of the toroidal chamber, after which flux in the chamber is conserved and compressed, yielding magnetic fields of 2–3 MG. Plasma is generated on the liner and central rod surfaces by Ohmic heating. Diagnostics include B-dot probes, Faraday rotation, radiography, filtered photodiodes, and VUV spectroscopy. Optical access to the chamber is provided through small holes in the walls.     

利用爆炸能发电的研究进展

介绍了利用爆炸能发电的研究进展，概述了其原理及发电装置。     

The effect of Joule heating and viscous dissipation on the boundary layer flow of a magnetohydrodynamics micropolar-nanofluid over a stretching vertical Riga plate

Joule heating and viscous dissipation effects on the behavior of the boundary layer flow of a micropolar nanofluid over a stretching vertical Riga plate (electro magnetize plate) are considered. The flow is disturbed by an external electric magnetic field. The problem is formulated mathematically by nonlinear system of partial differential equations (PDEs). By using suitable variables transformations, this system is transformed onto a system of nonlinear ordinary differential equations (ODEs). The Parametric NDsolve package of the commercial software Mathematica is used to solve the obtained ODEs as well as the considered numerical results for different physical parameters with appropriate boundary conditions. Novel results are obtained by studying the stream lines flow around the plate in two and three dimensions. Moreover, the effects of the pertinent parameters on the skin friction coefficient, couple stress, local Nusselt, and Sherwood number are discussed. Special cases of the obtained results show excellent agreements with previous works. The results showed that as the magnetic field parameter increases the velocity of the boundary layer adjacent to the stretching sheet decreases. Also, for a productive chemical reaction near the sheet surface, the angular velocity decreases but opposite trend is observed far from the sheet surface. The importance of this study comes from its significant applications in many scientific fields, such as nuclear reactors, industry, medicine, and geophysics.