离散型多相湍流和湍流燃烧的基础研究和数值模拟

获奖项目简介 离散型多相流指含颗粒或液雾的气体流动、含气泡或颗粒的液体流动以及气泡液体颗粒流动。湍流反应流动指有燃烧或常温反应的流动,它们广泛存在于热能、航空航天、交通、化工冶金、水泥等工业中。多相湍流流动中除了气体或液体有湍流脉动之外,离散相（颗粒或液雾或气泡）也有强烈的湍流脉动。颗粒、液雾或气泡的湍流脉动及其所引起的湍流弥散（扩散）不仅对流动、传热传质和反应有重要作用,     

冻土区埋地输油管道周围土壤温度场数值模拟

在建立埋地输油管道周围土壤温度场的物理模型时,大多数人认为温度分布是关于管道中心对称的,因此只考虑对称的一侧,且都为二维计算,简化了很多方面,这是不精确的。结合横向、纵向建立了三维运算模型,使土壤温度场的模拟更接近现实,所以模拟的结果将会更加精确,对现实生产也具有指导意义。     

多圆柱绕流的数值模拟及力学分析

基于计算流体力学理论,采用Fluent对3种不同雷诺数下多圆柱绕流模型进行了仿真研究,得到了速度云图和升阻力系数随时间变化的曲线。仿真结果表明：尾涡区的长度和紊动强度随来流的雷诺数增大而增强。圆柱的阻力系数随雷诺数的增加而降低,流动由层流变为紊流,且湍动更强烈;第1列小圆柱升力系数随雷诺数的增大而逐渐减小。从第1列至第4列升力系数振荡幅度逐列增加,第4列圆柱的升力系数振荡幅度较大,最大值为其他列圆柱的2倍以上;Re=5 000时的速度云图和实验装置的流动图像接近,与数值模拟实验装置的流动规律相似。     

报废弹药销毁车间TNT粉尘的浓度场数值模拟

介绍了TNT粉尘的危害,对报废弹药销毁车间内不同粒径的TNT粉尘的浓度场进行了数值模拟,并对数值模拟的结果进行了分析。     

祁东矿松散层下第四含水层地下水流场三维数值模拟

近年来我国松散层水体下开采水害事故时有发生.祁东煤矿在2001年发生了一次第四含水层突水事故,损失严重.本次研究正是针对祁东矿突水事件,通过收集和整理地质资料、水文地质资料等,首先概化研究区的水文地质条件,建立水文地质概念模型.并采用基于有限元方法的地下水模拟软件FEFLOW对研究区的地下水流进行数值模拟,取得较好的效果.     

超长钢结构体系的温度应力场及位移场数值模拟分析

应用ANSYS软件对一超长钢结构厂房进行数值模拟分析,分别计算了结构在设置伸缩缝、不设置伸缩缝和设置长圆孔结构这三种情况下,当温度变化时主要构件的内力及整体纵向位移。在不适宜设置伸缩缝时,采用长圆孔构造能弥补设置伸缩缝所带来的工艺要求上的不足,并且也能很好地控制温度应力的大小和确保结构的整体性。     

无压流旋流除砂器速度场的数值模拟

主要讨论了无压状态下旋流除砂器的速度场.针对速度场问题,利用CFD数值模拟软件(Fluent),采用三维模型进行了模拟.得出在入口角度、进(出)水口位置、长、宽、高、圆环直径等几何数据不变时,不同高度差情况下工作圆心内速度的变化关系.进而从理论上分析高度差对除砂效率的影响,确定最大除砂效率下的高度差,为进一步研究打下基础.     

水坝绕流的数值研究

In this paper, the characteristics of two-dimensional viscous flow over two dams were numerically investigated. The results show that the behavior of the vortices is closely related to the space between two dams, water depth, Fr number and Reynolds number. In addition, the flow properties behind each dam are different, and the changes over two dams are more complex than over one dam. Finally, the relevant turbulent characteristics were analyzed.     

双半圆柱平行电极系统的电场及其数值模拟

利用保角变换研究双半圆柱平行电极系统的电场,给出其电势和场强分布函数,通过软件Matlab绘制出其电场线和等势线图,计算其两极的最大场强,并分析最大场强随电极参数的变化情况.     

地基桩周围绕流流场的三维数值模拟

针对土木工程中地基桩强度分布不合理的问题,建立地基桩的三维物理模型,基于Simple算法,运用RNG k-ε湍流方程,结合有限体积法对控制方程进行离散,在风速10m/s的情况下,对地基桩周围绕流流场分布进行分析。结果表明,地基桩中间区域所受风力作用较大,易受损,其周围流场变化经历平稳—剧烈—平稳的过程,部分区域地基桩易受到破坏。因此,应重视加固工作,完善和发展地基桩绕流阻力特性理论,为实际工程提供参考依据。     

CFD技术在无环量圆柱绕流多媒体教学中的应用研究

CFD技术是当前高等院校多媒体教学的热门手段和方法,特别是在如流体力学这样概念抽象,理论性强,与实际流动现象结合紧密的课程中显得尤为突出。文章应用Gambit,Fluent和Tecplot等相关软件,对无环量圆柱绕流的流动机理进行数值模拟与分析。目的在于验证无环量圆柱绕流数学、物理理论的正确性,观察流动现象,分析产生各种现象的原因。通过研究表明,以直观演示和定量分析相结合的方法,能够非常好地解决许多教学中的难点和重点问题,使学生对抽象的教学内容产生深刻的印象,增强了学习兴趣。     

Large eddy simulation of the gas-particle turbulent wake flow

To find out the detailed characteristics of the coherent structures and associated particle dispersion in free shear flow, large eddy simulation method was adopted to investigate a two-dimensional particle-laden wake flow. The well-known Sub-grid Scale mode introduced by Smagorinsky was employed to simulate the gas flow field and Lagrangian approach was used to trace the particles. The results showed that the typical large-scale vortex structures exhibit a stable counter rotating arrangement of opposite sign, and alternately form from the near wall region, shed and move towards the downstream positions of the wake with the development of the flow. For particle dispersion, the Stokes number of particles is a key parameter. At the Stokes numbers of 1.4 and 3.8 the particles concentrate highly in the outer boundary regions. While the particles congregate densely in the vortex core regions at the Stokes number of 0.15, and the particles at Stokes number of 15 assemble in the vortex braid regions and the rib regions between the adjoining vortex structures.     

Large eddy simulation of the gas-particle turbulent wake flow

INTRODUCTIONPlanewakeflowisonetypeoffreeshearflowandexistswidelyinnatureandmanyengi neeringsystems.Tounderstandthekineticchar acterofthelarge scalecoherentvortexstructuresandparticledispersioninplanewakeflowishelpfulforimprovingmanyprocessesinenergyengineering,chemicalengineeringandmaterialengineering .LargeeddysimulationinvolvesbothdirectsimulationandReynolds averagedapproaches.MethodshavebeendevelopedinrecentyearstosolvetheproblemofinstantaneousgasflowfieldandtosimulatehighReynoldsnumb…     

明渠分层湍流的动力学亚格子模型大涡模拟研究

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Influence of coherent structures in the gas-particle circular cylinder wake flow

INTRODUCTION Turbulent gas-particle flows are frequently found in natural phenomena and industrial processes.Cases of cylinders in cross flows with particles occur in heat exchange equipment,including the convective zone of a fluidized-bed combustor,and in the primary superheaters,reheaters,and economizers of coal-fired boilers.Coherent structures often occur in the above-mentioned gas-particle flow,and have great effect on such different systems,while some features of tur-bulent multiphas…     

Numerical simulation and experimental investigation of 3-D separated flow field around a blunt body

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Performance investigation of 2D lattice Boltzmann simulation of forces on a circular cylinder

The lattice Boltzmann method (LBM) is employed to simulate the uniform flow past a circular cylinder. The performance of the two-dimensional LBM model on the prediction of force coefficients and vortex shedding frequency is investigated. The local grid refinement technique and second-order boundary condition for curved walls are applied in the calculations. It is found that the calculated vortex shedding frequency, drag coefficient and lift coefficient are consistent with experimental results at Reynolds nu...     

Numerical simulation of wind flow fields around buildings using the lattice Boltzmann method

This paper presents the simulation results of the wind environment around a single high-rise building and that around two tall buildings in tandem arrangement by using the lattice Boltzmann method with an aim to understand the ventilation issues around high-rise buildings in an urban environment. We analyzed the velocity distribution around the buildings and performed numericl simulations to reveal the formation and evolution law of the complex vortex system around the high-rise buildings. Numerical simulation results manifest a periodicity phenamenon in the process of the vortex evolution. For the case of two high-rise buildings, wind velocity in the space between the two buildings is very small, which is nearly a silent regime. Wind velocity above the front building is relatively larger and the maximum wind velocity is approximately 2.5 times the incoming wind velocity. The numerical results can be used in layout planning of high-rise residential buildings to create better environment for ventilation purpose in an urban area.     

Large eddy simulation of a particle-laden turbulent plane jet

Gas-solid two-phase turbulent plane jet is applied to many natural situations and in engineering systems. To predict the particle dispersion in the gas jet is of great importance in industrial applications and in the designing of engineering systems. A large eddy simulation of the two-phase plane jet was conducted to investigate the particle dispersion patterns. The particles with Stokes numbers equal to 0.0028, 0.3, 2.5, 28 (corresponding to particle diameter 1 μm, 10μm, 30μm, 100μm, respectively) inRe=11 300 gas flow were studied. The simulation results of gas phase motion agreed well with previous experimental results. And the simulation results of the solid particles motion showed that particles with different Stokes number have different spatial dispersion; and that particles with intermediate Stokes number have the largest dispersion ratio. Project (No. G19990222) supported by the Special Funds for Major State Basic Research of China