【作者】 肖柏青；

【导师】 周著； 邱秀云； 侯杰；

【作者基本信息】 新疆农业大学 ， 水力学及河流动力学， 2007， 硕士

【摘要】 排沙漏斗是一种新型的泥沙处理技术,以其截沙率高,耗水率小等优点已广泛应用。但是对于它的流场结构特性和排沙机理迄今尚未彻底探明。近年来,随着数值模拟技术的发展,尝试对排沙漏斗内流场进行较全面准确的数值模拟成为一种新的研究途径。由于漏斗室内水流形成自由表面旋涡,并且存在两个出口,所以对其进行三维流场数值模拟具有很大难度。本文通过一系列的简化和处理,有效地降低了数值模拟难度,建立了的无调流墩和有调流墩的排沙漏斗物理模型。本文结合RNG k ?ε湍流模型和VOF方法建立了排沙漏斗的水气两相流数学模型。利用计算流体力学软件FLUENT进行求解计算,得到了排沙漏斗内水流的流速场、压力、湍动能和涡量等的分布规律。将数值计算得到的流速分布与试验实测结果进行了对比,两者吻合较好。通过对数值模拟结果的分析,得出了以下主要成果:(1)底坡附近的水流有较大的向内的径向速度,证实了排沙漏斗内存在二次流。(2)向上的轴向流速和向外的径向流速处在漏斗室内合适的区域,从而保证了排沙漏斗的耗水率小。(3)首次提出了排沙漏斗的二次流排沙原理。更多还原

【Abstract】 The Sand Funnel is one kind of new sediment ejection technology and is widely applied for its merits such as high interception efficiency and low water consumption rate. But the flow field characteristics of the Sand Funnel and its mechanism of sediment transport are not yet fully understood heretofore. In recent years, along with the numerical simulation technology development, it is one new research way to try to numerically simulate the flow in the Sand Funnel accurately. Since there is a surface vortex and two exits in the Sand Funnel, the 3-D numerical simulation of turbulent flow in the Sand Funnel has a very great difficulty. This paper has effectively reduced its difficulty through a series of simplifications and disposal, finally establish two physical model of the Sand Funnel respectively with and without adjusting pier.This paper combines the RNG k ?εturbulence model and Volume of Fluid method (VOF) to establish the two phase mathematical model of the Sand Funnel. The commercial computational fluid dynamics (CFD) package FLUENT is used to solve the equations of the model. Distribution of velocity, pressure, turbulence kinetic and vorticity are obtained by simulation. The numerical simulation results are compared with test results, and they are agreed well with each other.Analyzing the result of numerical simulation of 3-D turbulent flow in the Sand Funnel, the author obtains the flowing main conclusions and findings:(1) The current near the base slope has greater radial velocity, proving that there is secondary flow in the Sand Funnel.(2) The upward axial velocity and outward radial velocity of the flow in the Sand Funnel are at suitable region, thus ensuring its low water consumption rate.(3) This paper proposes a secondary flow principle for sediment transportation in the Sand Funnel for the first time.更多还原