【作者】 韩丹；

【导师】 李龙；

【作者基本信息】 河海大学 ， 水利水电工程， 2005， 硕士

【摘要】 随着现代计算机软硬件技术的高速发展,计算流体动力学(CFD)在研究流体机械和水利工程内部三维湍流场的领域里,有了长足的发展和广泛的应用。本文运用CFD技术,对双向灯泡贯流式泵站进出水流道流场进行数值模拟,分析泵站进出水流道内流场的流动状况,预测流场内的流动规律,对减少流道内水力损失,优化泵站设计,提高泵站效率和稳定性具有重要的理论意义和实用价值。 本文通过基于时均N—S方程(雷诺方程)及标准K—ε湍流模型,采用非结构网格划分,速度进口、自由出流边界条件,无滑移条件,用壁面函数法处理近壁流动;应用有限体积法、一阶迎风格式、全隐式方案对控制方程组进行离散化处理,运用SIMPLEC算法对离散方程进行求解,对双向灯泡贯流式泵站进出水流道流场的三维定常不可压湍流流场进行了数值模拟,得到以下成果: 1.在灯泡体前置及不同收缩段收缩角工况下,得到了有扭曲前导叶的进水流道和无前导叶的进水流道的水力损失、纵向剖面流道速度分布和等值线图、流道出口断面速度等值线图。 2.在灯泡体后置及不同扩散段扩散角工况下,得到了无旋速度进口和有旋速度进口条件下出水流道的水力损失、纵向剖面流道速度分布和等值线图,扩散段出口断面速度等值线图。 3.进出水流道压力损失与导叶体锥角的关系曲线。 4.分析了在不同收缩角工况下有无导叶对进水流道流场的影响,在不同扩散角工况下无旋流动和有旋流动对出水流道流场的影响,导叶体锥角的大小对进出水流道流场的影响,并总结规律,给出优化泵站设计的合理化建议。更多还原

【Abstract】 With the rapid development of modern computer software and hardware technology, CFD have been achieved the considerable development and wide application in the area of fluid machinery research and three dimensional turbulence field.Based on the CFD technology, not only a numerical simulation with the inlet and outlet channels of two-way tubular pumping station of bulb is performed in this paper, but also an analysis of channels flow condition and a prediction about flow regularities inside are proposed. The results showed that this technology is effective in reducing the water head loss and optimizing the pumping station design. An important theory significance and practical value in improving the efficiency and stability have been achieved by using this technology.A new scheme was developed in this paper on the basis of N-S equation and standard k-s model. Near-wall flow was resolved by wall function with the application of sliding net model, velocity inlet, free outlet boundary, non-slip velocity condition; control equations were dealt with by means of finite volume scheme, first-order upwind scheme, implicit model and made a discretization using SIMPLEC algorithm. Thus, the following results can be achieved with the numerical simulation on three dimensional steady incompressible turbulent flow fields.1. When bulb placed before, according to the operating conditions of different contraction angle, the water head loss of inlet channel whether guide vane was distorted or not, the velocity distribution and equivalent value line map of the lengthways section channel, the velocity equivalent value line map of outlet channel section can be obtained altogether.2. When bulb placed behind, according to the operating conditions of different expanding angle, the water head loss of outlet channel on condition that non-rotation flow inlet or rotation flow inlet, the velocity distribution and equivalent value line map of the lengthways section channel, the outlet velocity equivalent value line map of expanding section can be obtained altogether.3. The relation curve between the pressure loss of outlet channel and guide vane cone angle was acquired.4. The guide vane affects the inlet and outlet channel flow field on the basis of different contraction angle. The non-rotation flow or rotation flow affects the outlet channel flow field on the basis of different expanding angle. The guide vane cone angle affects the inlet and outlet channels flow field. An analysis was made about these influences, and regularities were summarized to propose the reasonable suggestions of the pumping station design optimization.更多还原