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numerical simulation of 3D electromagnetic–thermal phenomena in an induction heated slab

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Journal of Iron and Steel Research(International) 2020年第4期27卷 420-432页

作者： He-ping Liu Xian-hui Wang Liang-ying Si Jian Gong Central Iron and Steel Research Institute Beijing 100081China Shougang Zhixin Qian’an Electromagnetic Material Co. Ltd.Qian’an 064404HebeiChina

A mathematical model was developed to get an insight into 3D electromagnetic–thermal phenomena in an induction heated steel slab with a large width/thickness ratio by solving a fully coupled Maxwell equations and energy conservation equation.The spatial heat radiation between the slab surface and the refractory wall in an induction furnace was considered.The electromagnetic induction and temperature distribution features inside the slab with time evolution were described.The effects of electromagnetic induction parameters,thermal conductivity of the material and process parameters on the induction heating process were theoretically examined.numerical results show that the spatial distribution of induction heat generation inside the slab is non-uniform.The high work frequency and the low heat conductivity of slab increase the non-uniformity of slab induction heating process.The radiative heat loss and heat transfer between the slab and the metal parts used for holding the slab have an important effect on the slab surface temperature.It is necessary to separately control the current input in the multi-layer coil windings along the height direction of furnace and adopt the multi-step heating strategies with time evolution to improve the homogenization of the slab temperature.

关键词： Slab Electromagnetic feld Induction heating numerical simulation

numerical simulation of Stall Flow Control Using a DBD Plasma Actuator in Pulse Mode

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Plasma Science and Technology 2016年第9期18卷 933-942页

作者： R.KHOSHKHOO A.JAHANGIRIAN Aerospace Engineering Department Amirkabir University of Technology

A numerical simulation method is employed to investigate the effects of the unsteady plasma body force over the stalled NACA 0015 airfoil at low Reynolds number flow conditions. The plasma body force created by a dielectric barrier discharge actuator is modeled with a phenomenological method for plasma simulation coupled with the compressible Navier-Stokes equations. The governing equations are solved using an efficient implicit finitevolume method. The responses of the separated flow field to the effects of an unsteady body force in various inter- pulses and duty cycles as well as different locations and magnitudes are studied. It is shown that the duty cycle and inter-pulse are key parameters for flow separation control. Additionally, it is concluded that the body force is able to attach the flow and can affect boundary layer grow that Mach number 0.1 and Reynolds number of 45000.

关键词： flow control, pulse plasma actuation unsteady flow, low Reynolds number numerical simulation

numerical simulation OF ATOMIZATION RAINFALL AND THE GENERATED FLOW ON A SLOPE

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Journal of Hydrodynamics 2012年第2期24卷 273-279页

作者： LIU Shi-he TAI Wei FAN Min LUO Qiu-shi State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China Yellow River Engineering Consulting Co. Ltd Zhengzhou 450003 China

This article studies the atomization rainfall and the generated flow on a slope by numerical simulations.The atomization rainfall is simulated by a unified model for splash droplets and a suspended mist,and the distribution of the diameter of splash rain drops is analyzed.The slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model,and the localization of the rainfall intensity in space is specially considered.The simulation results show that：（1） the median rain size of the atomization rainfall increases in the longitudinal direction at first,then monotonously decreases,and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is taken.In the lateral direction the median rain size monotonously decreases,（2） since the atomization rainfall is distributed in a strongly localized area,it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall,the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.

关键词： atomized flow unified model slope runoff numerical simulation

numerical simulation OF 2D HORIZONTAL COOLING WATER DISCHARGE IN GENERALIZED CURVILINEAR COORDINATE

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Journal of Hydrodynamics 2006年第1期18卷 91-96页

作者： XIE Zuo-tao ZHANG Xiao-feng TAN Guang-ming YANG Fang-li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072 China

2D horizontal model is one of the major mathematical methods for the research on cooling water discharge from the power plant. In this paper, the shallow water equations are transformed under the generalized curvilinear coordinate system and the elliptic differential equations are used to generate curvilinear grids, so a model in generalized curviline ar coordinate is presented to simulate 2D horizontal cooling water, Governing equations of the model are discretized by finite volume method, and non-staggered grids and SIMPLE algorithm are introduced to simplify the program during the discretization. This model is used to simulate the movement of cooling water in a simplified meandering channel and a natural channel, calculating results indicate this model can correctly reflect the movement rules of cooling water, which verifies the model can be applied in engineering practice.

关键词： cooling water generalized curvilinear coordinate non-staggered grids numerical simulation SIMPLE algorithm

A numerical simulation OF CHANNEL RESERVOIRS CONTAINING VERTICAL AND HORIZONTAL WELLS

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Journal of Hydrodynamics 2006年第5期18卷 527-536页

作者： LIU Fu-ping WANG Xu-song WANG Jun WANG An-ling Beijing Institute of Graphic Communication Beijing 102600 China Institute of Geology and Geophysics Chinese Academy of Sciences Beij ing 100029 China

In this article, the bounding surfaces of channels were modeled by Bayesian stochastic simulation, which is a boundary-valued problem with observed valley erosion thickness at the locations of wells （hard data）. In this study, it was assumed that the cross-section of the channel shows a parabolic shape, and the case that the vertical well and the horizontal well are located in the channel was considered. Peaceman＇s equations were modified to simultaneously solve both the vertical well problem and the horizontal well problem. In porous media, a 3D fluid equation was solved with iteration in the spatial domain, which had channels, vertical wells, and horizontal wells. As an example, the spatial distributions of pressure were calculated for channel reservoirs containing vertical and horizontal wells.

关键词： fluid equations in porous media porosity channel reservoirs numerical simulation heterogeneous media hrizontal well vertical well

numerical simulation OF ICE CONTROL EFFECT OF SOLAR ENERGY ON TIBETAN CHANNELS

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Journal of Hydrodynamics 2007年第3期19卷 342-348页

作者： AN Rui-dong CHEN Ming-qian LI Ran Banjiuciren SHI Yun-qiang State Key Laboratory of-Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China Rikaze Water Conservancy Institute of Tibet Rikaze 857000 China Tibtan Weather Bureau Lasha 850000 China

With the Tanghe Diversion Channel in Tibet as an example, the theoretical study on the ice control effect of the solar sacks was conducted based on the previous study. The numerical simulation method was adopted and a one-dimensional numerical model for ice crystal in diversion channels in high-altitude cold regions was developed in this article. The heat transfer through the air-water interface and the mass transfer between ice and water were considered in the model. The model was validated by the field observation data on the diversion channel of the Tanghe Hydropower Station. The results show that the ice control effect of the solar sacks is obvious in the channel with large mass flow rate in the high-altitude cold regions.

关键词： solar energy solar sack ice control diversion channel numerical simulation

numerical simulation OF TURBULENT SPOTS IN INCLINED OPEN-CHANNEL FLOW

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Journal of Hydrodynamics 2005年第2期17卷 179-185页

作者： ZHANGLi TANGDeng-bin CollegeofAerospaceEngineering NanjingUniversityofAeronauticsandAstronauticsNanjing210016China

The generation and evolution of turbulent spots in the open-channel flow are simulated numerically by using the Navier-Stokes equations. An effective numerical method with high accuracy and high resolution is developed. The fourth-order time splitting methods with high accuracy is proposed. Three-dimensional coupling difference methods are presented for the spatial discretization of the Poisson equation of pressure and Hemholtz equations of velocity, therefore, the fourth-order three-dimensional coupling central difference schemes are constituted. The fourth-order explicit upwind-biased compact difference schemes are designed to overcome the difficulty for the general higher-order central difference scheme which is inadaptable in the boundary neighborhood. The iterative algorithm and overall time marching is used to enhance efficiency. The method is applied in the numerical simulation of turbulent spots at various complex boundary conditions and flow domains. The generation and the developing process of turbulent spots are given, and the basic characteristics of turbulent spots are shown by simulating the evolution of the wall pulse in inclined open-channel flow.

关键词： turbulent spot Navier-Stokes equation numerical simulation three-dimensional coupling difference scheme wall pulse

numerical simulation for the Optimization of Polygonal Pin Profiles in Friction Stir Welding of Aluminum

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Acta Metallurgica Sinica(English Letters) 2021年第8期34卷 1065-1078页

作者： Hao Su Chuansong Wu MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing Institute of Materials JoiningShandong UniversityJinan 250061China

The tool with polygonal pin profile has been widely employed in friction stir welding(FSW) of aluminum, but there is hardly an effective optimization methodology existed as the thermomechanical characteristics affected by pins with various flats number have not been understood comprehensively. Therefore, the present work employs a 3-dimensional computational fluid dynamics(CFD) model to have an integrated observation of the FSW process with the effect of polygonal pin profiles. Both the heat generation modes due to contact friction at the tool–workpiece interface and volumetric viscous dissipation in the vicinity of the tool are considered. The model is utilized to give a quantitative analysis of the heat generation, temperature distribution, plastic material flow and welding loads during the FSW process for various tools with polygonal pin profiles, as well as a variety of shoulder diameters, welding speeds and tool rotation speeds. The calculated results of thermal cycles, tool torques and joint cross sections for some typical polygonal pins and welding parameters are all found to be compared well with the experimental ones, which demonstrates the feasibility and applicability of the present numerical model. Particularly, a methodology is developed for the optimization of the flats number by identifying the torque components in both parallel and vertical direction of the pin-side flat region. The results show that the optimized pin flats number increases with increasing tool rotation speed, while the influence of both welding speed and shoulder diameter can be supposed to be insignificant. Moreover, the dependability of the optimized results is also discussed by considering wear tendency and service life of the pin for multiple welding conditions.

关键词： Friction stir welding Polygonal pin numerical simulation Optimization design Aluminum

numerical simulation of the internal wave propagation in continuously densitystratified ocean

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Journal of Hydrodynamics 2014年第5期26卷 770-779页

作者：张洪生贾海青辜俊波李朋辉 College of Ocean Science and Engineering Shanghai Maritime University East China Electric Power Design Institute China Power Engineering Consulting Group

A numerical model is proposed to simulate the internal wave propagation in a continuously density-stratified ocean, and in the model, the momentum equations are derived from the Euler equations on the basis of the Boussinesq approximation. The governing equations, including the continuity equation and the momentum equations, are discretized with the finite volume method. The advection terms are treated with the total variation diminishing （TVD） scheme, and the SIMPLE algorithm is employed to solve the discretized governing equations. After the modeling test, the suitable TVD scheme is selected. The SIMPLE algorithm is modified to simplify the calculation process, and it is easily made to adapt to the TVD scheme. The Sommerfeld＇s radiation condition combined with a sponge layer is adopted at the outflow boundary. In the water flume with a constant water depth, the numerical results are compared to the analytical solutions with a good agreement. The numerical simulations are carried out for a wave flume with a submerged dike, and the model results are analyzed in detail. The results show that the present numerical model can effectively simulate the propagation of the internal wave.

关键词： internal wave continuously density-stratified fluid finite volume method SIMPLE algorithm numerical simulation