liaowei,zhang weile,wang wene,et al.底坡对U形渠道量水平板测流影响分析[J].灌溉排水学报,0,():-.
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廖伟, 张维乐, 王文娥, 胡笑涛
西北农林科技大学 旱区农业工程教育部重点实验室
【目的】量水平板具有构造简单、不易淤积等优点,已建立了流量与平板偏转角、上下游水深及板型等因素的关系式,但底坡对量水平板水力特性的影响还缺乏系统研究,很有必要深入分析,以提高量水平板测流公式的适用范围。【方法】以北方灌区常见U形渠道为试验水槽,选择断面最佳收缩比0.439的U形渠道量水平板为试验对象。通过设置3种水槽底坡(0.000 2~0.001)和4~7种流量(10~44 L/s)共18种试验工况,分析了各工况下水面线和平板偏转角的变化规律,研究了底坡对水面线、相对水头损失、能量转化系数、平板偏转角度和综合流量系数的影响。基于闸孔淹没出流公式,拟合出含底坡变量i的半经验流量公式。【结果】在相同流量情况下,板后水跃长度、能量转化系数以及综合流量系数随底坡增大而增大;水面线、相对水头损失和平板偏转角度均随底坡增大而减小;在试验流量范围内,拟合流量公式的平均相对误差为2.6%,最大相对误差为6.5%,满足灌区量水要求。【结论】底坡对U形渠道量水平板测流影响显著,建立了包含渠道底坡的U形量水平板测流公式,提高了其适用性。
关键词:  U形渠道;量水平板;流量公式;底坡
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(2016YFC0400203)
Influence Analysis of Bottom Slope on U-Shaped Channel Flow Measurement with Horizontal Plate
liaowei, zhang weile, wang wene, hu xiaotao
Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University
Abstract: 【Background】Due to the gently topography and the sediment concentration of water in the northern irrigation area of China, the existing water facilities (sinks) are easy to cause upstream backwater and sediment deposition. As a new type of measuring water facilities, the horizontal plate has the advantages of no deposition and simple structure in flow measurement. 【Objective】The relationship between discharge and other factors such as plate deflection angle, water depth of upstream and downstream, plate profile have established in existing studies, but the impact of bottom slope on the hydraulic characteristics of horizontal plate has not been studied systematically. In order to extend the applicable scope of the formula, it is necessary to analyze deeply. 【Method】the u-shaped channel commonly used in the northern irrigation area was selected as the test water flume and the volume horizontal plate with the optimal contraction ratio of cross-section (0.439) was selected as the test object. By setting a total of 18 test conditions, including 3 kinds of bottom slope (0.000 2~0.001) and 4~7 kinds of flow rate (10~44 L/s), the variation rules of water surface line and plate deflection angles under each condition were analyzed, and the influence of bottom slope on water surface line, relative water head loss, energy conversion coefficient, plate deflection angle and comprehensive flow coefficient was studied. Based on the Formula of Sluice Flooding Discharge, the semi-empirical flow formula with the variable i (slope) was fitted. 【Result】the hydraulic jump length behind the plate, energy conversion coefficient and comprehensive flow coefficient increase with the increase of the bottom slope under the same flow rate; the surface line, the relative water head loss and the plate deflection angle all decrease with the increase of the bottom slope; within the range of test flow rate, the average relative error of the fitting flow rate formula is 2.6%, and the maximum relative error is 6.5%, which meets the water volume requirement of the irrigated area. 【Conclusion】The bottom slope has a significant influence on the measurement of horizontal plate (U-shaped) flow in u-shaped channel and the formula of horizontal plate (U-shaped) on u-shaped channel including channel bottom slope is established, which improves its applicability.
Key words:  U-shaped channel; volume level plate; flow formula; bottom slope