侧式进水口吸气漩涡的控制机制及消涡规律研究

Study on control mechanism and vortex suppression law of air-entraining vortices in side intake structures

摘要

【目的】在水利工程中，漩涡问题不容忽视，会降低枢纽的泄流能力、恶化水流流态、增大水头损失等，危及建筑物的运行安全。为降低侧式进水口漩涡的潜在风险，提出合理的消涡方案，【方法】以侧式进水口为研究主体，以吸气漩涡为对象，通过物理模型试验研究了单层、双层消涡梁的消涡特性和消涡规律。【结果】结果显示：消涡梁主要是通过减小漩涡区的切向流速V_θ和径向流速V_r,从而减弱进水口前水流表面环量，实现消除进水口吸气漩涡的目的。对于单层消涡梁，减小消涡梁的相对间距∑Δl/l或增大消涡梁安装高度h_e/D可提高消涡梁的消涡效果，较未布置消涡梁方案(∑Δl/l=1.000),∑Δl/l=0.357下漩涡的强度减小了约80.0%;较消涡梁安装在进水口顶部(h_e/D=0.00)方案，当消涡梁的安装高度提升为h_e/D=0.40,漩涡强度减小了约78.8%。对于双层消涡梁，当双层消涡梁采用横、纵梁布置时，将纵梁间距由∑ΔL/L_z=0.710减小至∑ΔL/L_z=0.310时，漩涡强度可减小约70.0%;当双层消涡梁均采用消涡横梁时，较V型布置、阶梯立式布置，采用交叉布置时消涡效果最好。【结论】消涡梁的间距、安装高度、布置方式等对消涡特性影响显著，通过该研究对消涡梁的消涡规律有了进一步认知，可为今后侧式进水口漩涡问题的解决提供参考。

Abstract

[Objective] Vortex issues in hydraulic engineering cannot be ignored, as they reduce the discharge capacity of the hub, deteriorate the flow pattern, increase head loss, and pose risks to the safe operation of structures. To mitigate the potential risks of vortices in side intake structures and to propose a reasonable vortex suppression scheme, [Methods]vortex suppression characteristics and mechanisms of single-layer and double-layer vortex suppression beams were investigated through physical model experiments, focusing on side intake structures and air-entraining vortices. [Results] The result showed that the vortex suppression beams mainly reduce the tangential velocity V_θ and radial velocity V_r in the vortex region. This reduction weakens the circulation on the water surface in front of the intake, ultimately leading to the elimination of air-entraining vortices. For single-layer vortex suppression beams, reducing the relative spacing∑Δ l/l or increasing the installation height h_e/D enhances the vortex suppression effect. Compared to the scheme without vortex suppression beams(∑Δ l/l=1.000), when ∑Δ l/l=0.357, the intensity of the lower vortex is reduced by about 80.0%. Compared to the scheme where the beam is installed at the top of the intake(h_e/D=0.00), when h_e/D=0.40, the vortex intensity is reduced by about 78.8%. For double-layer vortex suppression beams, when using both transverse and longitudinal beams and ∑Δ L/L_z being reduced from 0.710 to 0.310, the vortex intensity is reduced by about 70.0%. The cross-arranged configuration achieves the best vortex dissipation effect compared to the V-shaped and stepped vertical configurations. [Conclusion] The spacing, installation height, and arrangement of vortex suppression beams significantly impact their suppression characteristics. A deeper understanding of vortex suppression laws is gained, providing a reference for future solutions to vortex problems in side intake structures.

关键词

侧式进水口 / 吸气漩涡 / 消涡梁 / 消涡机理 / 模型试验

Key words

side intake structure / air-entraining vortex / vortex suppression beam / vortex suppression mechanism / model experiment

基金资助

中央级公益性科研院所基本科研专项(Y125003)

国家重点研发计划(2022YFC3202605)