【摘要】：隨著高水頭水電資源的減少，中低水頭電站的開發(fā)將成為水電資源開發(fā)的一大趨勢。中低水頭電站具有水頭小、流量大、低傅汝德數(shù)、閘壩建在覆蓋層較厚的砂礫石河床上的特點(diǎn)。因此閘壩下游的護(hù)坦、海漫發(fā)生沖刷破壞較為普遍，特別是兩岸邊坡沖刷更為嚴(yán)重，甚至導(dǎo)致建筑物損毀，直接影響著水閘運(yùn)行安全。因此正確的預(yù)測、預(yù)報(bào)泄水建筑物下游沖刷坑的形態(tài)、深度以及其他沖刷坑內(nèi)部流場信息對于泄水建筑物的安全具有重要意義。 本文以巨亭水電站為研究對象，對其泄流過程水流流場及沖刷過程進(jìn)行了三維數(shù)值模擬，主要結(jié)論如下： （1）通過對巨亭水電站流場進(jìn)行三維模擬，得到了典型斷面流速分布、水面線、壓力等信息。通過對比發(fā)現(xiàn)，數(shù)值模擬結(jié)果與水工模型試驗(yàn)結(jié)果吻合良好，從而驗(yàn)證了數(shù)學(xué)模型的正確性； （2）把剪切力作為床沙的起動(dòng)判據(jù)，采用ANSYS FLUENT UDF，c語言編寫程序控制沖刷區(qū)域底部邊界網(wǎng)格運(yùn)動(dòng)，計(jì)算流場信息，借助動(dòng)網(wǎng)格模型來實(shí)現(xiàn)網(wǎng)格重構(gòu)，，在每個(gè)時(shí)間步后更新計(jì)算區(qū)域網(wǎng)格，實(shí)現(xiàn)對河床下游局部沖刷的數(shù)值模擬，得到?jīng)_刷坑內(nèi)部流場信息、沖刷坑形態(tài)及最大沖刷深度。經(jīng)實(shí)測資料驗(yàn)證，沖刷坑形態(tài)及最大沖刷深度計(jì)算值與實(shí)測值吻合良好； （3）在沖刷過程中，壁面切應(yīng)力隨著沖刷時(shí)間的增加而逐漸減小；在空間上的分布規(guī)律：在沖刷坑最深點(diǎn)斷面，壁面切應(yīng)力值最�。辉谄渖嫌�，壁面切應(yīng)力沿程逐漸減小；在其下游，壁面切應(yīng)力沿程逐漸增大。
[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.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TV147

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 李艷富;;沖刷坑沖刷過程的數(shù)值模擬[J];科學(xué)技術(shù)與工程;2009年05期

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