无坎宽顶堰堰流流量系数的探讨

为方便而又精确地确定无坎宽顶堰的堰流流量系数,通过比较、分析几例已建工程水工模型试验数据,指出在进行水闸泄流能力计算或确定水闸规模时,采用SL265—2001《水闸设计规范》中的计算公式,应合理确定堰流流量系数的适宜取值范围.提出在自由出流条件下,按常规设计的闸墩结构和闸室上下游连接段为矩形断面的无坎宽顶堰,堰流流量系数m在0 36～0 375之间取值更为适宜.

Discussion on weir flow coefficient for broad-crest ridge-free weirs

The broad crest ridge free weir is a common structural form of hydraulic structures. In determination of the size of sluice projects, the influence of weir flow coefficient should not be ignored. For convenient and precise determination of the flow coefficient for broad crest ridge free weirs according to the compulsive requirement of the current trade standard, a discussion is made on the adoption of the calculating formula, conforming to "the sluice design specifications" SL265 2001, to derive a suitable value of the flow coefficient for further calculation of the discharge capacity and determination of scale of sluice projects by a comparative analysis of data from hydraulic model tests on some completed hydraulic projects. It is concluded that the flow coefficient in the range of 0.36～0.375 is suitable for broad crest ridge free weirs with a rectangular conjunctive section between the upper and lower reaches of lock chambers under free outflow conditions.