三河口水利枢纽泄洪建筑物水力特性研究

发布时间：2018-07-17 01:33

【摘要】：近年来,在我国西南高山峡谷地区,修建了一大批高水头、大泄量、高泄洪功率的超高坝工程,随之暴露了一系列问题,例如,枢纽上游蓄水造成两岸地质滑坡问题、枢纽下游严重雾化引起下游河道边坡稳定问题及下游河道严重的局部冲刷及沿程冲刷问题等。因此,根据具体工程位置及特点,合理设计泄洪建筑物布置、优化泄洪建筑物体型,对于保障枢纽工程安全运行和正常效益发挥具有非常重要的意义。本文以“引汉济渭”工程调蓄中枢工程——三河口水利枢纽为研究对象,通过物理模型试验,对原设计方案及推荐方案泄水建筑物水力特性进行了试验研究;并采用RNG k-?紊流模型和VOF模型对泄洪底孔窄缝挑坎的水力特性及中表孔泄流水垫塘底板脉动压力进行了三维数值模拟,取得以下主要研究成果:(1)原方案表、底孔泄流能力满足设计要求;表孔水舌横向扩散充分,底孔水舌纵向拉开良好;中孔水舌落点最远,水舌呈单层横向扩散;左右表孔水舌挑距略小,水舌呈前后两层扩散。原设计方案存在的主要问题:两底孔水舌末端落点较近,没有完全分开;左表孔及中表孔水舌时常砸到水垫塘边坡;校核水位时,局部水垫塘底板承受的冲击压力超过了15×9.8k Pa的要求;闸门启闭瞬间,左表孔泄流齿坎右边角时有滴水砸落到底孔闸房。(2)推荐方案较好的解决了原方案存在的问题,但因左右表孔水舌落点有些交叉,导致底板局部脉动压力强度较大。在表孔水舌已充分扩散的情况下,提出了增加下游水垫深度以减小水垫塘底板脉动压力强度的建议及实施方案。(3)模拟得到的泄洪底孔窄缝挑坎射流水舌挑距、纵向入水长度、最高点高程及洞身段压力值均与模型试验实测值吻合良好。(4)模拟得到的脉动压力时均值、脉动压力强度、概率密度分布和功率谱密度与物理模型试验结果吻合较好,说明采用数值模拟方法研究水垫塘底板脉动压力是可行的。
[Abstract]:In recent years, a large number of super-high dam projects with high water head, large discharge capacity and high flood discharge power have been built in the mountainous canyon area of southwest China, which has exposed a series of problems, such as the problem of geological landslide along the banks caused by water storage in the upper reaches of the hub. The serious atomization in the downstream of the hub will cause the slope stability of the downstream channel and the serious local scour and scour along the downstream channel. Therefore, according to the specific project location and characteristics, reasonable design of flood discharge building layout, optimization of flood discharge building shape, to ensure the safe operation of the hub project and normal benefit play a very important significance. In this paper, the hydraulic characteristics of the original design scheme and the recommended scheme of the drainage structure are studied through physical model test, taking Sanhekou water conservancy project, a central project of the diversion of Han Jiwei project, as the research object, and the RNG k-? The turbulent model and VOF model are used to simulate the hydraulic characteristics of the narrow slit and the fluctuating pressure of the bottom plate of the middle surface hole. The main research results are as follows: (1) the original scheme table and the discharge capacity of the bottom hole meet the design requirements; The horizontal diffusion of the water tongue in the surface hole is sufficient and the water tongue in the bottom hole is well pulled out in the longitudinal direction; the water tongue in the middle hole falls farthest, and the water tongue diffuses in a single layer, and the distance between the water tongue of the left and right surface holes is slightly small, and the water tongue is diffused in the front and rear layers. The main problems existing in the original design scheme are: the end point of the water tongue of the two bottom holes is near and it is not completely separated; the left surface hole and the middle surface hole water tongue often hit the water cushion pond slope; when checking the water level, The impact pressure on the bottom plate of the local water cushion pond exceeds the requirement of 15 脳 9.8kPa, and at the moment of the gate opening and closing, there is a drop of water at the right corner of the left surface hole to the right of the drain hole. (2) the recommended scheme solves the problems of the original scheme. However, the local pulsating pressure intensity of the bottom plate is larger because of the crossing of the water tongue on the left and right surface holes. Under the condition that the water tongue of the surface hole has been fully diffused, the suggestion and implementation scheme of increasing the depth of the downstream water cushion to reduce the pulsating pressure intensity of the bottom plate of the water cushion pond are put forward. (3) the narrow slit of the bottom hole of the flood spillway, the length of the longitudinal inlet water, is obtained by simulation. (4) the simulated mean value of pulsating pressure, the intensity of pulsating pressure, the distribution of probability density and power spectrum density are in good agreement with the results of physical model test. It is feasible to use numerical simulation method to study the fluctuating pressure of the bottom plate of water cushion pond.
【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】：2017
【分类号】：TV135.2

【相似文献】