摘要
提出了一种针对小流量的、制作安装简易的量水设备——便携式三角形喉道量水槽.该量水槽的原型过流试验在9种流量(0.90,1.44,1.88,2.36,2.84,3.36,3.92,4.57,4.90 L/s)的自由出流和淹没出流工况下进行,设置于断面形式与田间灌水沟相近的U型渠道内,通过测量量水槽内13个控制断面水位,对水面线、傅汝德数、临界淹没度、测流精度等水力性能进行试验分析.三角形喉道量水槽的过槽流量与上游水深具有良好的乘幂关系,复相关系数达到0.999 5;拟合得出自由出流和淹没出流状态下的水深流量公式,计算流量与实际流量比较,平均误差和最大误差均在5%以内.分析了不同流量工况下傅汝德数变化规律,进而确定了临界水深断面产生的具体位置在喉道段后半段,距离量水槽进口为334~355 mm;该三角形喉道量水槽的临界淹没度稳定,范围为0.80~0.86;单个量水槽的流量适用为0.90~5.00 L/s.
A new type of water measuring device, the portable triangle-throated measuring flume, which is suitable for small flow conditions and easily to be manufactured and installed, was presented. The hydraulic performance of a prototype flume was tested under free flow and submerged outflow conditions at 9 flow rates such as 0.90, 1.44, 1.88, 2.36, 2.84, 3.36, 3.92, 4.57 and 4.90 L/s. The flume was located in a U-shaped channel that was similar to a field irrigation ditch in cross-section, and the water levels at 13 control sections were measured. The hydraulic performance variables such as water surface line, Froude number, critical inundation degree, and measurement accuracy were analyzed. The results show that there is a good exponential relationship between the flow rate and the upstream water depth with a correlation coefficient of 0.999 5. A formula for flow rate in terms of water depth is obtained by curve fitting under free and inundation flow conditions. Compared with the experimental flow rates, the average and maximum errors are smaller than 5%. The change rules of Froude number are analyzed, and the specific position for the critical water depth is determined, which is downstream the throat within a distance of 334-355 mm from the flume inlet. The critical submergence of the long triangular-throated flume is stable, ranging from 0.80 to 0.86. The suitable range of flow range is 0.90- 5.00 L/s for a single flume.
作者
薛城
王文娥
胡笑涛
XUE Cheng;WANG Wene;HU Xiaotao(Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas,Ministry of Education,Northwest A ＆ F University,Yangling,Shaanxi 712100,China)
出处
《排灌机械工程学报》
EI
CSCD
北大核心
2018年第11期1104-1108,共5页
Journal of Drainage and Irrigation Machinery Engineering
基金
公益性行业(农业)科研专项(201503125)
"十三五"国家重点研发计划项目(2016YFC0400203)
关键词
量水槽
沟灌
水深流量公式
傅汝德数
水力性能
portable triangle-throated flume
furrow irrigation
formula of water depth versus discharge
Froude number
hydraulic performance
