巨亭水电站下游冲刷过程三维数值模拟研究
发布时间：2018-12-14 00:42
【摘要】：随着高水头水电资源的减少，中低水头电站的开发将成为水电资源开发的一大趋势。中低水头电站具有水头小、流量大、低傅汝德数、闸坝建在覆盖层较厚的砂砾石河床上的特点。因此闸坝下游的护坦、海漫发生冲刷破坏较为普遍，特别是两岸边坡冲刷更为严重，甚至导致建筑物损毁，直接影响着水闸运行安全。因此正确的预测、预报泄水建筑物下游冲刷坑的形态、深度以及其他冲刷坑内部流场信息对于泄水建筑物的安全具有重要意义。 本文以巨亭水电站为研究对象，对其泄流过程水流流场及冲刷过程进行了三维数值模拟，主要结论如下： （1）通过对巨亭水电站流场进行三维模拟，得到了典型断面流速分布、水面线、压力等信息。通过对比发现，数值模拟结果与水工模型试验结果吻合良好，从而验证了数学模型的正确性； （2）把剪切力作为床沙的起动判据，采用ANSYS FLUENT UDF，c语言编写程序控制冲刷区域底部边界网格运动，计算流场信息，借助动网格模型来实现网格重构，，在每个时间步后更新计算区域网格，实现对河床下游局部冲刷的数值模拟，得到冲刷坑内部流场信息、冲刷坑形态及最大冲刷深度。经实测资料验证，冲刷坑形态及最大冲刷深度计算值与实测值吻合良好； （3）在冲刷过程中，壁面切应力随着冲刷时间的增加而逐渐减小；在空间上的分布规律：在冲刷坑最深点断面，壁面切应力值最小；在其上游，壁面切应力沿程逐渐减小；在其下游，壁面切应力沿程逐渐增大。
[Abstract]:With the decrease of high water head hydropower resources, the development of middle and low water head hydropower stations will become a major trend of hydropower resources development. The middle and low water head power station has the characteristics of small head, large discharge, low Fu Rude number, and the gate dam is built on the sand gravel river bed with thick overburden. Therefore, scour damage in the downstream of dam is more common, especially the slope on both banks is more serious, even leading to the damage of buildings, which directly affects the safety of sluice operation. Therefore, it is important for the safety of drainage structures to correctly predict the shape, depth and flow field information of the scour pits downstream of the drainage structures. This paper takes Juting Hydropower Station as the research object, carries on the three-dimensional numerical simulation to its discharge process water flow field and the scour process. The main conclusions are as follows: (1) through the three-dimensional simulation of the Juting Hydropower Station flow field, The information of velocity distribution, water surface line and pressure of typical section are obtained. It is found that the numerical simulation results are in good agreement with the hydraulic model test results, which verifies the correctness of the mathematical model. (2) the shear force is taken as the starting criterion of bed sand, and ANSYS FLUENT UDF,c language is used to program to control the movement of the boundary grid at the bottom of the scouring area, to calculate the flow field information, and to realize the mesh reconstruction with the help of the moving grid model. The computational grid is updated after each time step to simulate the local scour of the lower reaches of the river bed. The information of the flow field inside the scour pit, the shape of the scour pit and the maximum scour depth are obtained. The measured data show that the calculated values of the scour pit shape and the maximum scour depth are in good agreement with the measured values. (3) during the scouring process, the wall shear stress decreases gradually with the increase of scouring time. The spatial distribution law: at the deepest section of the scour pit, the wall shear stress value is the smallest; in its upstream, the wall shear stress along the side gradually decreases; in its downstream, the wall shear stress along the gradually increase.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV147
本文编号：2377564
[Abstract]:With the decrease of high water head hydropower resources, the development of middle and low water head hydropower stations will become a major trend of hydropower resources development. The middle and low water head power station has the characteristics of small head, large discharge, low Fu Rude number, and the gate dam is built on the sand gravel river bed with thick overburden. Therefore, scour damage in the downstream of dam is more common, especially the slope on both banks is more serious, even leading to the damage of buildings, which directly affects the safety of sluice operation. Therefore, it is important for the safety of drainage structures to correctly predict the shape, depth and flow field information of the scour pits downstream of the drainage structures. This paper takes Juting Hydropower Station as the research object, carries on the three-dimensional numerical simulation to its discharge process water flow field and the scour process. The main conclusions are as follows: (1) through the three-dimensional simulation of the Juting Hydropower Station flow field, The information of velocity distribution, water surface line and pressure of typical section are obtained. It is found that the numerical simulation results are in good agreement with the hydraulic model test results, which verifies the correctness of the mathematical model. (2) the shear force is taken as the starting criterion of bed sand, and ANSYS FLUENT UDF,c language is used to program to control the movement of the boundary grid at the bottom of the scouring area, to calculate the flow field information, and to realize the mesh reconstruction with the help of the moving grid model. The computational grid is updated after each time step to simulate the local scour of the lower reaches of the river bed. The information of the flow field inside the scour pit, the shape of the scour pit and the maximum scour depth are obtained. The measured data show that the calculated values of the scour pit shape and the maximum scour depth are in good agreement with the measured values. (3) during the scouring process, the wall shear stress decreases gradually with the increase of scouring time. The spatial distribution law: at the deepest section of the scour pit, the wall shear stress value is the smallest; in its upstream, the wall shear stress along the side gradually decreases; in its downstream, the wall shear stress along the gradually increase.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV147
【参考文献】
相关期刊论文 前1条
1 李艳富;;冲刷坑冲刷过程的数值模拟[J];科学技术与工程;2009年05期
本文编号：2377564
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