锦屏一级泄洪洞不同掺气坎的水流特性的数值模拟研究

摘要

掺气减蚀对于溢洪坝和泄洪洞的安全运行具有重要的作用，在本文中，对锦屏电站采用不同掺气坎的泄洪洞进行了数值模拟，研究不同的特性。本研究可归纳为以下二个部分:
　　第一部分，根据k-ε湍流模型，结合水气两相流界面追踪方法—VOF法，建立了泄洪洞掺气减蚀的数学模型。对不同的掺气坎的泄洪洞、进行了共4次数值模拟，即以下4种情况:无掺气坎、跌坎型掺气坎、挑坎+跌坎组合掺气坎、挑坎+跌坎+掺气槽组合掺气坎。获得了水流的水力特性参数、如自由面、压力分布、速度分布、掺气长度等。
　　第二部分，对不同掺气坎的模拟结果与实验结果进行了比较研究和分析。挑坎+跌坎组合掺气坎比其它类型掺气坎更可靠、有效。该掺气坎在模拟中不存在发生空蚀的可能性、其在所有截面的最小空化数都大于0.2、空腔长度稳定、且没有回水。且该掺气坎的各截面的平均流速的模拟结果与实验结果接近。

目录

声明

Acknowledgement

Abstract

摘要

Contents

Chapter-1 Introduction on Aeration and Cavitation in Spillway

1．1 General description on aeration and cavitation

1．2 Objectives of the study

1．3 Methodology

1．4 Software

1．5 Limitations

1．6 Experimental data

Chapter-2 Literature Review on Cavitation and Aeration

2．1 Introduction

2．2 Cavitation on spillway

2．3 Methods to reduce cavitation damages

2．4 Effect of air content

2．5 Air entrainment on the spillway

2．6 Self-aerated flow

2．7 Artificial Aerations

2．7．1 Types of aerators

2．7．2 Aerator submergence

2．7．3 Aerators locations and Aerator spacing

Chapter-3 Theory on the Mathematical model for Simulation

3．1 calculation model

3．2 Turbulence model

3．3 VOF Model

Chapter-4 General Description and Aerators Design of Jingping-1 Hydropower Dam

4．1 Description of Jingping-1 hydropower project

4．2 Different types of aerators used for simulation

Chapter-5 Numerical method and Boundary condition of the model

5．1 Solver

5．2 Computational domain and mesh

5．2．1 Three Dimensional case without aerators

5．2．2 Three Dimensional case with aerator type-1

5．2．3 Three Dimensional case with aerator type-2

5．2．4 Three Dimensional case with aerator type-3

Chapter-6 Comparative Study and Analysis of Water Flow Characteristics

6．1 Changes in Water Flow Characteristics of Tunnel Spillway

6．1．1 Water Surface profile

6．1．2 Velocity Distribution

6．1．3 Bottom Pressure and Cavitation Index

6．1．4 Aeration Charaeteristies

6．2 Discussion and Accuracy

6．2．1 Verification of the model

6．2．2 Uncertainty and Error in CFD simulations

Chapter-7 Conclusion

References