| 摘要: |
| 【目的】设计一种体型简单、过流能力强的梯形渠道梯形喉口量水槽,为提高小流量时的测流精度和减小大流量时的水头损失提供支持。【方法】对梯形渠道4种喉口收缩比ε（0.427，0.506，0.557，0.681）的梯形喉口量水槽，分别在12种流量（15.39 L/s，19.44 L/s，23.62 L/s，29.39 L/s，35.91 L/s，39.15 L/s，45.00 L/s，49.59 L/s，54.28 L/s，61.15 L/s，65.70 L/s，71.96 L/s）工况下的测流精度、水头损失、临界淹没度、适宜喉口收缩比等水力性能进行试验研究，通过观测15个控制断面的水深分析水面线的变化规律及流量与收缩比、上游水深的关系，并对自由出流条件下的流量公式进行拟合。【结果】梯形喉口量水槽的上游水深与流量间存在良好的指数关系，相关系数高达0.998 6；设计梯形喉口的量水槽有效改善了梯形渠道测流的测流误差和水头损失，喉口收缩比为0.427～0.557时，实测流量与计算流量的最大相对误差为4.643%；喉口收缩比为0.506～0.681时，水头损失最大为上游总水头的12%左右，较长喉道水头损失有所减小；梯形喉口量水槽具有较高的临界淹没度，临界淹没度变化范围为0.85～0.93；综合考虑水头损失及测流精度，较适宜的喉口收缩比为0.506～0.557，喉口倾角为70°～78°。【结论】梯形喉口量水槽为灌区梯形渠道量水槽的设计提供新思路。 |
| 关键词: 梯形渠道 梯形喉口量水槽 喉口收缩比 流量公式 量水精度 水头损失 |
| DOI： |
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| 基金项目: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（2016YFC0400200）；杨凌示范区科技计划项目（2015NY-30） |
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| Hydraulic performance of trapezoidal-throated flume in trapezoidal channel |
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RAN Danjie,WANG Wen’e,HU Xiaotao
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| Abstract: |
| 【Objective】Trapezoidal channel is commonly used in irrigation area.This study designed a trapezoidal-throated flume with simple shape and strong flow capacity to provide support for improving accuracy of flow measurement at low flow rate and reducing head loss at high flow rate.【Method】Experiments were conducted under 12 flow rates (15.39 L/s,19.44 L/s,23.62 L/s,29.39 L/s,35.91 L/s,39.15 L/s,45.00 L/s,49.59 L/s,54.28 L/s,61.15 L/s,65.70 L/s,and 71.96 L/s) to determine the hydraulic performance of trapezoidal channels including flow measurement formula,water surface profile,head loss and flow measurement precision with four contraction ratios (ε=0.427,0.506,0.557,and 0.681).The variation of water surface line and the relationships between flow and shrinkage ratio and upstream water depth were analyzed through water depths at 15 control sections.The flow rate formulas under free flow conditions were also fitted.【Result】The upstream depth and flow rate of trapezoidal channels had good exponential relationship with coefficient of 0.998 6.When the contraction ratio was within 0.427 to 0.557,the fitted discharge formula met the flow measurement accuracy,and the maximum error between the measured and calculated discharge was 4.643%.When the contraction ratio was within 0.506 to 0.681,the maximum water head loss was less than 12% of the total head,which was lower comparing to long-throat flume.The trapezoidal-throated flume had high critical submergence of 0.85-0.93.Considering water head loss and accuracy of measuring flow,the proper ratio of contraction was 0.506-0.557,and the proper throat angle was 70°-78°.【Conclusion】This study provides reference for further research and application of water measuring facility in North China. |
| Key words: trapezoidal channel trapezoidal-throated flume throat contraction ratio flow formula flow measurement accuracy head loss |
