直角折线堰堰体各组成部分过流能力分析

Analysis of the Overflow Capacity of Each Component of Right Angle Broken Line Weir

直角折线堰堰体各组成部分(前堰、侧堰、后堰)过堰水流形态各异。采用FLOW-3D软件,基于RNG k-ε湍流模型与Tru⁃VOF方法对直角折线堰进行数值模拟计算,得到前堰、侧堰、后堰溢流特性与过流能力情况:1)就水流流线而言,随堰顶水头增大,前堰始终与堰体保持正交,侧堰则由正交逐步趋向平行,后堰由正交到斜交再恢复到正交;2)堰顶水头增大到100~150 mm范围时,前堰、侧堰、后堰堰顶下游侧开始出现负压、继而消失;3)随堰顶水头增大,前堰溢流前缘长度基本没有变化、侧堰有效溢流前缘长度则下降明显,后堰溢流前缘长度变化不大,但堰顶有效水头低于前堰。在此基础上,给出了前堰和后堰长度相同时不同堰体在直角折线堰中的具体过流变化情况。

The overflow patterns of each component(front weir,side weir and back weir)of the right⁃angle broken line weir are different.Numerical simulations of the right⁃angle broken line weir were carried out by using FLOW⁃3D software and based on the RNG k⁃εturbulence model and TruVOF method,the overflow characteristics and overflow capacity distribution of different weirs at the front,side and back were obtained.The results show that a)in terms of the streamline,the front weir always remains orthogonal to the weir as the head at the top of the weir increases;the side weir gradually tends to be parallel from orthogonal to oblique;the back weir returns to orthogonal from orthogonal to oblique.b)When the head at the top of the weir increases to the range of 100-150 mm,the negative pressure begins to appear at the down⁃stream side of the top of the front weir,side weir and back weir,and then disappears.c)With the increase of the head at the top of the weir,the length of overflow edge at the front weir is basically unchanged,the length of effective overflow edge at the side weir decreases significantly,and the length of overflow edge of the back weir has little change,but the effective head at the top of the back weir is lower than that of the front weir.On this basis,the concrete overflow variations of different weirs in the right⁃angle broken line weir with the same length of front weir and back weir are given.