应用斜坎改善弯道流态的可行性研究

发布时间：2018-03-26 05:34

本文选题：泄洪洞　切入点：弯道急流　出处：《西北农林科技大学学报(自然科学版)》2017年01期

【摘要】：【目的】基于模型试验对使用斜坎改善泄洪洞弯道流态的可行性进行研究,为同类工程提供参考。【方法】在泄洪洞弯道段沿程分别布置5道3种形式的斜坎(高0.35m矩形斜坎、高0.25m矩形斜坎及高0.25m梯形斜坎),对3种工程措施下弯道的水流流态、水面超高、流速和压强分布进行量测,通过流态优劣和流速、压强分布的合理性对比,对其改善流态的可行性进行研究。【结果】3种形式的斜坎均能有效消除弯道水面超高,改善流态,但矩形斜坎的改善效果优于梯形斜坎。布置0.35m矩形斜坎可使弯道最大水面超高减小至2.70m,但局部出现水面击打洞顶现象;布置0.25m矩形斜坎和0.25m梯形斜坎后,弯道水面超高分别减小至3.42和4.21m,且无击打洞顶现象,但压强量测均出现极大负压。【结论】对于已建工程,斜坎对消减弯道水面超高、改善水流流态非常适用,且矩形斜坎优于梯形斜坎;但在高速水流工况下,斜坎坎顶、坎后及坎后侧壁会出现负压,为避免出现负压,建议将斜坎应用于低速水流弯道。
[Abstract]:[objective] based on the model test, the feasibility of improving the flow state of flood discharge tunnel by using inclined ridge is studied, which can provide reference for the similar project. [methods] five slant ridges (0.35m high rectangular sloping ridge) are arranged along the bend section of flood discharge tunnel separately. In this paper, the flow state, water surface superhigh, velocity and pressure distribution of curved channel under three kinds of engineering measures are measured, and the reasonableness of flow state and velocity and pressure distribution are compared through the comparison of flow state and velocity and pressure distribution, which is 0.25m high rectangular inclined ridge and 0.25 m high trapezoidal slanting ridge. The feasibility of improving the flow state is studied. [results] three kinds of slanting can effectively eliminate the high water level and improve the flow state of the curved channel. However, the improvement effect of rectangular inclined ridge is better than that of trapezoidal inclined ridge. The maximum water surface height of the bend can be reduced to 2.70 m by 0.35 m rectangular inclined ridge, but the phenomenon of local water surface hitting the top of the tunnel can be observed, and the 0.25m rectangular inclined ridge and 0.25 m trapezoidal inclined ridge are arranged after placing 0.25m rectangular inclined ridge and 0.25 m trapezoidal inclined ridge. The water surface superelevation of the bend is reduced to 3.42 and 4.21 m, respectively, and there is no impact on the roof of the tunnel, but the pressure measurement shows a great negative pressure. [conclusion] for the existing projects, the slanting ridge is very suitable for reducing the high water level of the bend and improving the water flow pattern. The rectangular inclined ridge is better than the trapezoidal slant ridge, but under the high speed water flow condition, the top, back and side wall of the inclined ridge will appear negative pressure. In order to avoid the negative pressure, it is suggested that the inclined ridge should be applied to the low speed flow bend.
【作者单位】：安徽水利开发股份有限公司;西安理工大学水利水电学院;咸阳市水利水电规划勘测设计研究院;铜川市王益区水务局水利水保中心;
【分类号】：TV135.2

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