| 引用本文: | 凌 刚,王文娥,王 惠,等.堰槽组合量水设施水力性能数值模拟研究[J].灌溉排水学报,2023,42(10):136-144. |
| LING Gang,WANG Wen’e,WANG Hui,et al.堰槽组合量水设施水力性能数值模拟研究[J].灌溉排水学报,2023,42(10):136-144. |
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| 摘要: |
| 【目的】堰槽组合量水设施适用于流量变幅较大的山区溪流流量测量，以数值模拟的手段全面分析其流场分布规律和水力特性，以期为堰槽组合量水设施的结构优化提供理论依据。【方法】在模型试验的基础上，采用FLOW-3D软件对10.13~200.00 L/s（试验最大流量的2.8倍）范围内的17种流量工况下该设施的水力性能进行数值模拟，分析了槽内流和堰槽流的沿程水深、佛汝德数（Fr）及流速的变化规律。【结果】所有流量工况下堰槽组合量水设施中心纵剖面Fr和流速均沿程先增大后减小，呈单峰分布；设施上游水流平稳，Fr为0.1~0.3，流速为0.08~0.5 m/s，随流量的增加逐渐加大；水流进入该设施后，Fr和流速急剧增大；设施下游出现较大范围的薄水层区域，Fr最大值达到3.0~4.6，流速最大值为1.05~2.06 m/s；槽内流时下游产生弱水跃，堰槽流时下游均为急流（Fr＞1），同时扩散水流在侧岸处发生折冲，产生菱形波；流量小于100 L/s时，模型试验建立的测流公式最大相对误差为6.11%，流量超过100 L/s时，相对误差逐渐增大。对流量大于100 L/s的模拟结果进行分析，建立了流量大于100 L/s时的测流公式，该公式相对误差小于0.87%，满足河流量水要求。【结论】基于FLOW-3D软件对堰槽组合量水设施进行的水力性能数值模拟与模型试验有着较好的一致性，建立了大流量下的测流公式，扩充了堰槽组合量水设施的测量范围。 |
| 关键词: 堰槽组合；数值模拟；佛汝德数；水力特性；FLOW-3D |
| DOI：10.13522/j.cnki.ggps.2023049 |
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| Numerical Study of Hydraulic Performance of Weir-flume Combined Device |
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LING Gang, WANG Wen’e, WANG Hui, 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, Yangling 712100, China
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| Abstract: |
| 【Objective】The weir-flume apparatus, consisting of a measuring flume and a measuring weir, is an innovative device for monitoring and controlling open channel flow. Installed across channels, it can measure water flow, elevates upstream water level, and enhances ecological connectivity in rivers in diverse geographical conditions. While measurement formulas and hydraulic characteristics have been experimentally investigated for small flow with shallow water depth, there is a lack of study for large flow. This paper aims to bridge this gap by studying the vertical and longitudinal velocity profiles as well as spatial distribution of flow field under high flow conditions. 【Method】The analysis was based on numerical modelling. The FLOW-3D software was used to simulate hydraulic performance of a weir-flume device under 17 flow rates ranging from 10.13 to 200 L/s. From the simulated results we analyzed the impact of flow rate on water depth, Froude number (Fr), and velocities within both the in-groove flow and the weir flow. 【Result】As the flow rate increased, the Fr and velocity in the central longitudinal section of the device initially increased and then tapered off. The flow in the upstream of the device remained stable, with Fr ranging from 0.1 to 0.3 and velocities varying between 0.08 and 0.5 m/s. Both Fr and velocity gradually increased with the increase in flow rate. After entering the device, Fr and flow velocity exhibited a significant surge. A wide range of thin water layers emerged in the downstream of the device, with the maximum Fr and velocities being 3 to 4.6 and 1.05 to 2.06 m/s, respectively. A subdued water jump was observed downstream of the in-groove flow, while the downstream of the weir showed a jet stream with Fr>1. Additionally, diffused water generated a rhomboid wave at the side bank. We derived a formula from the numerical simulations; its maximum relative error was 6.11% for flow rate below 100 L/s, beyond which the relative error gradually increased.【Conclusion】The numerical results obtained from FLOW-3D agreed well with the test data, validating the accuracy and consistency of the derived formula for analyzing measurement data from the weir-flume device. This work bridges a critical knowledge gap, enabling more precise assessment and control of open channel flow under various conditions. |
| Key words: weir-flume combination; numerical simulation; Froude number; hydraulic characteristics; FLOW-3D |
