【作者】 孙雪岚；

【导师】 孙西欢；

【作者基本信息】 太原理工大学 ， 水力学及河流动力学， 2003， 硕士

【摘要】 螺旋流在自然界十分常见，在工业方面的应用范围极广，也已进入了人们的日常生活领域。圆管螺旋流最近已被用于输沙方面，作为一种新的输沙方式，它具有高浓度、低能耗、远距离和不淤积的优点，克服了平直流管道输送中浓度与能耗之间的矛盾。 一般来说，螺旋流的常规产生办法有三种：切向进流、安装导流条及旋转管道。本文主要针对局部安装扭曲导流条的方式产生的圆管螺旋流做以研究。本文在前人研究的基础上，主要考虑了导流条边界层对水流的影响。边界层虽很薄，但由于其水流特性与一般的层流、紊流特性相差甚大，因而它对水流的影响是不可忽略的。另外，本文在研究中考虑了雷诺应力的影响，使用了紊流模式进行数学建模，通过数值模拟和试验测量的手段探讨了这类圆管螺旋流形成及流动的规律。太原理工大学硕士学位论文 本文以局部起旋条件下的圆管螺旋流为模拟对象，从以速度和压强为自变量的微分方程一Nav ier一5 tokes方程出发，利用有限差分法对柱坐标系下简化后的N一S方程进行离散，建立定常的、轴对称的三维计算模型。采用了数值计算中常用的GauSS一Seidel迭代法求解，得出圆管螺旋流在不同流量工况下的速度场和压强场。 本文还通过物理模型试验的方法，得到在不同流量工况下，局部起旋条件下的圆管螺旋流在各断面的流速和压力的实测值，并将其与数学模型所得计算结果进行了对比分析，其变化规律基本一致，验证了数学模型的可靠性。 分析得出了结论:圆管螺旋流的轴向流速分布为类对数分布，且最大值已偏离轴线，且随着螺旋流的衰减，最大值与轴线处流速之间的差值逐步减小，分布曲线向平坦化过渡;周向流速近似呈线形分布，其峰值随螺旋流的衰减而向轴线靠拢;压强呈现出中心低，边壁高的原因是水流旋转运动产生的离心力造成的，且随着螺旋流的衰减，径向压差趋小，沿轴向方向向下游，壁面处的压强呈顺压，轴线处呈逆压。太原理工大学硕士学位论文 在物理模型研究的基础上应用数值模拟来进一步研究螺旋流特性是可行的，这项研究充实了圆管螺旋流输送理论，并为其在工程上的推广应用奠定基础。更多还原

【Abstract】 Spiral flow can be seen frequently in nature. It was not only wildly used in industry, but also applied in daily life. Sediment transportation by spiral pipe flow has been used. It was a new way of sediment transportation with the advantage of high-concentration, energy-saving and high-efficiency.The paradox of concentration and energy of sediment transportation in smooth flow was conquered.In general, spiral pipe flows are generated by three means: tangentially inletting medium, guiding fluid by vanes with a certain angle and axially rotating pipe. In this paper, spiral pipe flows generated by locally installing guide blade were researched. Based on the previous research, the influences ofboundary layer of guide blade were considered. The characteristics of flow field in boundary layer are different from that of laminar flow and turbulence. So, it was not ignored. For the influences of Reynolds stress, the turbulence model was founded. And then, the formation and development of spiral pipe flow were studied by numerical simulations and experimental measures.Based on the Navier-Stockes equation, the finite difference method was applied to variance the simplified N-S equation on cylindrical coordinate system. Then, 3-D model of the spiral flow locally generated in circular pipe with steady and axial-symmetry condition was founded. The ordinary iterative method of Gauss-Seidel was induced. Finally, the velocity field and pressure field of different discharge was obtained.By means of experiment, experimental data of velocity and pressure of spiral flow generator-generating spiral flow locally in different discharge were acquired. By contrasting the result of numerical simulation with experimental data, the reliability of3-D model was tested.The main conclusions are as follows. The axial velocity distribution of the spiral flow generator is a logarithm-like function. Its maximal value is not at the central. The difference of the axial velocity between the maximum and the central value reduces with the attenuation of the spiral flow. The circumferential velocity distribution is basically a linear function. The maximum value closes to axes with the attenuation of the spiral flow. The pressure is minimum at the pipe centre and maximum near to the pipe wall. The radial difference of pressure is reducing with the attenuation of the spiral flow. Along the axes, the pressure near to the pipe wall is increasing and reducing at the pipe centre.Based on the experiment, research on the characteristics of the spiral flow by using numerical simulation is feasible. This paper enriched the theory of sediment transportation by spiral pipe flow. It also laid a foundation for applying in projects.KEY WORDS: spiral flow,boundary layer,turbulence model,numerical simulation更多还原