【作者】 张晓斐；

【导师】 吕宏兴；

【作者基本信息】 西北农林科技大学 ， 农业水土工程， 2009， 硕士

【摘要】 梯形断面渠道是灌区的干、支渠道常用断面形式之一,大多采用流速仪测流的灌区末级渠道,量测精度存在较大误差,且测流工作量很大。因此研究开发和推广造价低、水头损失小、易于自动监控的量水设备,对灌区进行科学用水管理、实行按量计费和节约用水具有十分重要的实际应用价值。本文对梯形渠道机翼形量水槽进行了试验研究,并应用量纲分析得到了梯形渠道机翼形量水槽在自由出流状态下的流量公式,根据量纲分析建立的流量公式满足量纲和谐性,简明实用,测流精度较高,量测流量的平均相对误差为0.47%。试验表明,机翼形量水槽的临界淹没度较高,在试验收缩比的范围内,临界淹没度的变化范围为0.82～0.92,均值可达0.87,能在较大范围内保证机翼形量水槽在自由出流状态下工作。机翼形量水槽的水头损失较小,平均水头损失约占上游总水头的12%左右。初步研究表明:机翼形量水槽是适合梯形渠道上测流的新型量水设备,有较好的推广应用前景。通过在内蒙古河套灌区与鄂尔多斯黄河南岸灌区进行机翼形量水槽的应用实验研究,证明机翼形量水槽量水精度能满足灌区测流误差小于5%的量水规范要求,并且具有水头损失小,结构简单,便于施工的特点,在实测中量水槽的淹没度都比较高,适合平原灌区的需要,试验所采用的量水监测设备能够连续自动精确地测量和记录水量,实现了测流自动化与无线传输,可产生良好的经济效益和社会效益,适合进行信息化建设的灌区推广。更多还原

【Abstract】 Trapezoidal cross-section channel is one of the commonly used cross-sections of the stem and branch channels in irrigation district. Currently most of irrigation channels at final stage are measured by hydrometric propeller which exist lots of calculation error and with heavy workload, Thus, to research and development a new water measuring facility which is lower cost, small head loss and automatic measure has a very important practical application on scientific water management, pay-in-volume-use and water conservation.This paper research on the experiment of airfoil-shaped measuring flume in trapezoidal channel and educe the discharge formula in state of free flow in trapezoidal channel by the dimensional analysis. This formula can meet the requirements of dimensional analysis harmonious, besides it’s concise, practical and high flow measurement precision, the average rate of relative error is only 0.47%. The experiment shows that the critical submergence in airfoil-shaped measuring flume is higher and in the range of experiment contraction ratio which is 0.82～0.92,and the average value is 0.87. It can ensure the airfoil-shaped measuring flume can work in a larger scope under the free flow. The head loss of flume is less, and the average loss is nearly 12% of the total head in upstream. Preliminary study results shows that airfoil-shaped measuring flume is a new type water measuring device, which fit to measuring discharge in trapezoidal channel, and illustrate a good prospect of application and extension.Researching on the experiment of the airfoil-shaped measuring flume in Inner Mongolia Hetao irrigation district and the south bank of Yellow river irrigation district in Oerhtossu, shows that the accuracy of flow measurement can meet the Hydrological norms which require the error less than 5%, it also possesses other severeal characteristics, such as low head loss, simple structure, easy to process, higher critical submergence in the actual experiment and fit for the plain irrigation district. The water measuring facility used in the experiment can automatic measure and record the data continuously and correctly. This facility achieved the goals of automatic flow measurement and wireless transmission, and also produces the better economic and social benefit and promoting informatization construction in irrigation district.更多还原