| Cite this article: | 廖伟,张维乐,王文娥,等.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,():-. |
| 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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| Influence Analysis of Bottom Slope on U-Shaped Channel Flow Measurement with Horizontal Plate |
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liaowei, zhang weile, wang wene, hu xiaotao
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Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University
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| Abstract: |
| 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 |
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