本文關鍵詞：泄洪閘下游沖刷過程三維數(shù)值模擬研究　出處：《西北農(nóng)林科技大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： 局部沖刷 動網(wǎng)格技術 壁面切應力 湍流動能

【摘要】：低水頭樞紐具有水頭低、流量大、低佛汝德數(shù)、消能不充分等特點,造成泄洪閘下游護坦,海漫往往發(fā)生不同程度沖刷破壞,甚至導致建筑物損毀,直接影響著水閘運行安全。為此準確預測泄水閘下游局部沖刷坑內流場信息沖刷過程、沖坑形態(tài)和最大沖刷深度對于泄水建筑物的安全具有重要意義。本文以巨亭水電站斷面模型為研究對象,采用ANSYS FLUENT軟件,對其泄流過程及沖刷過程進行了數(shù)值模擬,主要結論如下:(1)以RNG k-ε湍流模型封閉N-S方程、有限體積法在計算網(wǎng)格上離散求解、VOF方法追蹤自由水面位置,對巨亭水電站模型泄流及沖刷進行了三維數(shù)值模擬;通過對比泄流流量、水面線和流速分布等信息,表明數(shù)值模擬結果與水工模型試驗結果吻合良好,驗證了數(shù)學模型的正確性;(2)采用C語言編寫用戶自定義函數(shù),選取起動切應力作為床面泥沙起動判別標準,控制沖刷區(qū)域底部邊界變化,模擬得到了閘下游局部沖刷過程。與試驗數(shù)據(jù)對比,較大沖刷深度的沖刷坑形態(tài)與實測結果符合良好;(3)采用彈簧光順模型和局部重構模型更新計算區(qū)域網(wǎng)格,并使網(wǎng)格重構集中于邊界區(qū)域,提高了邊界區(qū)域網(wǎng)格的適應能力及計算結果的準確性;(4)壁面切應力和湍流動能在沖刷過程中基本表現(xiàn)為逐漸減小趨勢;在平衡沖刷坑最深點上游,壁面切應力和湍流動能沿程逐漸減小;在其下游,壁面切應力和湍流動能沿程變化不大。
[Abstract]:Low head hub with low head and large discharge, low Froude number, without sufficient energy dissipation characteristics, resulting in Sluice Downstream apron apron, often have different degree of erosion, and even cause damage to buildings, directly affects the safe operation of sluice. Therefore, accurately predicting the flow field information in the local scour pit downstream of the sluice, scouring process, scour pit shape and maximum scour depth is of great significance for the safety of discharge structures. In this paper, Juting hydropower station section model as the research object, using the ANSYS FLUENT software, the discharge process and the scour process was simulated and the main conclusions are as follows: (1) using RNG k- turbulence model closed N-S equation, finite volume method in the calculation of VOF, solving method of discrete grid to track the free surface position. A three-dimensional numerical simulation of Juting hydropower station model of discharge and erosion; by comparing the discharge flow, water level and velocity distribution and other information, show that the numerical results are in good agreement with the results of hydraulic model test, verify the correctness of the mathematical model; (2) using C language user defined functions, select Start shear stress as the bed surface sediment erosion control criterion, change area at the bottom boundary was obtained for downstream local scouring process. Compared with the experimental data, the larger the scour depth of the scour pit pattern and in good agreement with the measured result; (3) using the spring smoothing model and local model updating mesh reconstruction, mesh reconstruction and to focus on the border areas, to improve the accuracy of boundary grid adaptation and calculation results; (4) the wall shear stress and turbulent kinetic energy in the scouring process was gradually reduced; the deepest in the equilibrium scour pit upstream, wall shear stress and turbulent kinetic energy decreases gradually along the way; in the downstream, the wall shear stress and turbulent kinetic energy along the little change.
【學位授予單位】：西北農(nóng)林科技大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TV66

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本文編號：1339380