冰期弯道河冰运动特性数值模拟研究
发布时间：2018-11-17 06:45
【摘要】：河冰的输移是河冰工程研究的重要组成部分，冬季渠道输水必须解决冰凌带来的影响。输排冰运行是寒冷地区引水式水电站冬季运行的主要方式，特别是新疆地区的一些中、小水电站，常采用弯道排冰方式。首先针对浮冰的运动特点，建立三维的S形弯道水槽，基于FLUENT-EDEM耦合的三维两相流数值模型，对不同流速、不同冰流量、不同冰颗粒尺寸条件下河渠弯道内冰颗粒的运动特性进行了分析。之后建立了三维的弯道取水口模型，分析了弯道设置取水口后水流的变化和浮冰运动的特点，讨论了取水口轴线与引水渠道轴线不同角度时的输排冰效果。 模拟研究得到，冰颗粒在水槽的顺直段运动状态稳定，，在进入到两个90°的弯道后，存在横向流速分量，在水流拖曳力的作用下，会向两个弯道的凹岸侧水槽壁面漂流，且随着流速的增大，偏向凹岸侧的幅度越大。冰颗粒在水槽中的运动存在滞留时间。滞留时间影响冰颗粒的聚集停滞范围。滞留时间受水流速度、流冰量、冰颗粒与水槽壁面的摩擦等因素影响。输排冰有其特定的运行条件，水流速度和冰流量是影响渠道输排冰的两个主要因素。弯道取水口的引水分流作用导致弯道主流线的位置发生改变，从而使整个弯道的水流形态结构发生变化，当取水口轴线与引水渠道轴线为10°和15°的时，可以将四分之三左右的冰颗粒排出，排冰效果较好。
[Abstract]:The transport of river ice is an important part of river ice engineering research. Ice transport and drainage operation is the main way of winter operation of diversion hydropower stations in cold regions, especially in some middle and small hydropower stations in Xinjiang area. First of all, according to the motion characteristics of floating ice, a three-dimensional S-shaped channel flume is established. The numerical model of three-dimensional two-phase flow based on FLUENT-EDEM coupling is established, and different velocity and flow rate of ice are obtained. The motion characteristics of ice particles in channel bends were analyzed under different ice particle sizes. After that, a three-dimensional model of the intake channel is established, and the variation of the water flow and the characteristics of the ice floe movement after the bend is set up are analyzed, and the effect of ice transport and discharge at different angles between the inlet axis and the diversion channel axis is discussed. The simulation results show that the ice particles are in a stable state in the straight section of the flume. After entering two 90 掳bends, there is a transverse velocity component. Under the action of the drag force of the water flow, the ice particles drift to the wall of the flume on the concave bank of the two bends. And with the increase of the velocity, the amplitude of deviation to the concave bank is larger. The retention time of ice particles in the flume exists. The retention time affects the agglomeration and stagnation range of ice particles. The residence time is affected by the velocity of flow, the amount of drift ice and the friction between ice particles and flume wall. The flow velocity and ice flow rate are the two main factors that affect the ice transport and discharge in the channel. The diversion effect of the bend intake leads to the change of the position of the main flow line of the bend, which causes the change of the flow pattern structure of the whole bend. When the intake axis and the diversion channel axis are 10 掳and 15 掳, About 3/4 of the ice particles can be expelled, ice removal effect is better.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV133
本文编号：2336812
[Abstract]:The transport of river ice is an important part of river ice engineering research. Ice transport and drainage operation is the main way of winter operation of diversion hydropower stations in cold regions, especially in some middle and small hydropower stations in Xinjiang area. First of all, according to the motion characteristics of floating ice, a three-dimensional S-shaped channel flume is established. The numerical model of three-dimensional two-phase flow based on FLUENT-EDEM coupling is established, and different velocity and flow rate of ice are obtained. The motion characteristics of ice particles in channel bends were analyzed under different ice particle sizes. After that, a three-dimensional model of the intake channel is established, and the variation of the water flow and the characteristics of the ice floe movement after the bend is set up are analyzed, and the effect of ice transport and discharge at different angles between the inlet axis and the diversion channel axis is discussed. The simulation results show that the ice particles are in a stable state in the straight section of the flume. After entering two 90 掳bends, there is a transverse velocity component. Under the action of the drag force of the water flow, the ice particles drift to the wall of the flume on the concave bank of the two bends. And with the increase of the velocity, the amplitude of deviation to the concave bank is larger. The retention time of ice particles in the flume exists. The retention time affects the agglomeration and stagnation range of ice particles. The residence time is affected by the velocity of flow, the amount of drift ice and the friction between ice particles and flume wall. The flow velocity and ice flow rate are the two main factors that affect the ice transport and discharge in the channel. The diversion effect of the bend intake leads to the change of the position of the main flow line of the bend, which causes the change of the flow pattern structure of the whole bend. When the intake axis and the diversion channel axis are 10 掳and 15 掳, About 3/4 of the ice particles can be expelled, ice removal effect is better.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV133
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