泄水建筑物下游局部沖刷問題是水利水電工程安全穩(wěn)定運(yùn)行的關(guān)鍵問題。為了研究泄水建筑物下游沖刷平衡狀態(tài)下沖刷坑的形狀和深度,本文以當(dāng)卡水電站為研究對象,以模型試驗(yàn)的16組實(shí)驗(yàn)數(shù)據(jù)作為數(shù)值模擬的驗(yàn)證依據(jù),基于FLOW-3D對4種網(wǎng)格計(jì)算結(jié)果進(jìn)行了敏感性分析,對不同流速和不同中值粒徑條件下電站下游沖刷過程進(jìn)行了三維數(shù)值模擬研究,對三種推移質(zhì)輸沙率公式(Meyer-Peter,Nielsen,Vanrijn)計(jì)算結(jié)果進(jìn)行了分析比較。論文結(jié)論如下:(1)在不同流量條件下,4種網(wǎng)格模擬得到的流量相對誤差都較小。在較大流量時(shí),模擬得到的進(jìn)口平均速度和沖刷深度與實(shí)驗(yàn)數(shù)據(jù)具有良好的一致性;在較小的流量下,模擬結(jié)果誤差較大。(2)沖刷過程可以分為以下三個(gè)階段。在初始沖刷階段,流速大,沖刷強(qiáng)度高。在第二沖刷階段,沖刷坑深度和范圍迅速增加。在沖刷第三階段,沖刷坑的形態(tài)改變較小,接近平衡。在開始沖刷的40%時(shí)段內(nèi),沖刷坑深度可達(dá)到?jīng)_刷平衡深度的80%。(3)在泥沙中值粒徑為50mm、進(jìn)口流量為345.36 m³/s條件下,模擬得到的沖刷坑深度和長度與實(shí)驗(yàn)的相對誤差分別為0.87%和1.5%。...

【文章頁數(shù)】：70 頁

【學(xué)位級別】：碩士

【文章目錄】：
摘要
ABSTRACT
ABBREVIATIONS
CHAPTER1 INTRODUCTION
    1.1 Research backgrounds and significances
        1.1.1 Research backgrounds
        1.1.2 Research significances
    1.2 Literature Reviews
        1.2.1 Theoretical sediment scouring
        1.2.2 Numerical study
    1.3 Research Contents and methods
        1.3.1 Research contents
        1.3.2 Research methods
CHAPTER2 MODEL TEST OBSERVATION RESULTS AND NUMERICAL MODEL
    2.1 Overview of Dangka hydropower station
    2.2 Model test results
    2.3 Numerical modeling
        2.3.1 Governing equations and turbulence models
        2.3.2 Sediment scour model
    2.4 Numerical setup
        2.4.1 Numerical simulation condition
        2.4.2 Calculation domain
        2.4.3 Boundary condition
        2.4.4 Meshing
        2.4.5 Summery
CHAPTER3 LOCAL SCOUR DOWNSTREAM SIMULATION OF THE RELEASE STRUCTURE
    3.1 Mesh sensitive analysis
        3.1.1 Flowrate
        3.1.2 Velocity distribution at the end of apron
    3.2 Flow field information
        3.2.1 Velocity field information
        3.2.2 Pressure field information
    3.3 Bed shear stress
    3.4 Sediment scour
        3.4.1 The relationship between maximum scour depth and time
        3.4.2 The depth and length of scour hole
        3.4.3 Development shape of scouring hole
        3.4.4 Comparison of sediment transport formulas
        3.4.5 Comparison of different sediment sizes
        3.4.6 Comparison of different flowrates
        3.4.7 Summery
CHAPTER4 CONCLUSIONS AND RECOMMENDATIONS
    4.1 Conclusions
    4.2 Recommendations
REFERENCES
ACKNOWLEDGEMENTS
AUTHOR BIOGRAPHY



本文編號：3978282