矩形侧堰水力性能参数研究

A Study on Hydraulic Performance Parameters of Rectangular Side Weir

为研究矩形侧堰自由出流水力性能,探索侧堰泄流公式,试验采用控制变量法,设置不同堰高、堰宽,研究流量与各水力性能参数的关系。结果表明:(1)理想状况下,矩形侧堰泄流时水流的总能损失在10%以内,能量损失主要体现在堰口处;(2)水面线在堰口近上游端低于远离上游端;(3)侧堰流量与堰宽、堰上水头成正比。流量系数md与弗汝德数Fr1,上游水深与堰高比h/P,上游水深与堰宽比h/b关系显著,与弗汝德数Fr1正相关,与h/P,h/b负相关。得出0~30 L/s流量范围内侧堰泄流公式,Q=Fr10.162(h/P)-0.113(h/b)-0.045b21/2H3/2,实测流量与计算流量误差范围在-0.01%~6.86%之间,符合测流误差范围,测流精确。研究成果可为侧堰测流提供理论依据,对灌区量水设备、方法的发展和改进具有重大意义。

In order to study the hydraulic performance of rectangular side weir under free flow condition,and to explore the calculation formula for discharge,the Control Variate Method was adopted to conduct experiment,setting different weir heights and weir widths to study the relationship between the discharge and various hydraulic performance parameters.The result showed that:(1)under ideal conditions,the total flow energy loss of the rectangular side weir was within 10%,and the energy loss was mainly at the weir mouth;(2)the water surface line near the upstream end of the weir mouth was lower than that far away from the upstream end;(3)The side weir flow was proportional to the weir width and the head above the weir.The flow coefficient md had a significant relationship with the Froude number Fr1,the ratio of upstream water depth to weir height h/P,the ratio of upstream water depth to weir width h/b,and was positively correlated with the Froude number,and negatively correlated with h/P,h/b.When the formula of Q=Fr10.162(h/P)-0.113(h/b)-0.045b21/2H3/2 was used to calculate discharge in the range of 0~30 L/s,the error range between the measured flow and the calculated flow was between-0.01%~6.86%,which was within the designated flow error range.The study results can provide theoretical basis for lateral weir flow measurement,which is of great significance to the development and improvement of water measuring equipment and methods in irrigation areas.