【作者】 孙斌；

【导师】 吕宏兴；

【作者基本信息】 西北农林科技大学 ， 水利水电工程， 2013， 博士

【摘要】 渠道输水是我国农田灌溉的主要形式，在渠系中开展量水工作是强化节水意识、推动灌区定额灌溉和提高灌区灌溉用水利用系数的主要途径，是我国发展节水型农业和实现农业高效用水的关键技术之一。受地域性差异影响，我国大中型灌区的经济基础、管理模式、发展水平以及水力条件不尽相同，而槽类量水建筑物因具有经济实用和稳定可靠等特点，更适合于在我国灌区大面积推广应用。因此，根据灌区实际需求，研制出具有结构简单、量测精准、适应度高、应用便捷的渠道量水设施，对灌区节水和实现可持续发展具有重要意义。机翼形量水槽是一种适应我国灌区特点的新型量水设备，其流线形的外形使得过流不易发生壅阻，因此与同类型量水建筑物相比，具有过流顺畅、结构简单、易于施工等优点。本文采用模型试验与数值仿真相结合的手段，对机翼形量水槽的结构形式、测流机理以及相关水力参数进行了分析与研究，并且通过构建自动集成与优化体系，对其外形进行多目标水力优化，得到了如下结论：（1）选用3组收缩比并制定试验方案，根据量纲分析法拟合出矩形渠道机翼形量水槽的流量计算公式，该式形式简单，流量计算值与实测值误差较小，具有较高的量测精度；利用Fluent软件对量水槽进行三维数值仿真计算，并与模型试验结果进行对比，结果表明，二者吻合较好；分析了紊动流场及相关水力参数，量水槽临界淹没度S较高，上游傅汝德数Fr小于0.5，满足测流规范要求。（2）以某小型灌区末级灌溉渠系改造工程为原型，采用基于TruVOF方法跟踪自由液面、Favor技术实现网格优化的紊流数学模型，对U形渠道机翼形量水槽水跃问题进行三维数值模拟，分析了水跃的时均流场、共轭水深、发生位置、跃长、断面流速分布以及水跃段能量损失等相关水力特性，并且采用与原型1:1比尺的水工模型试验资料对模拟结果进行验证。通过对实测与数值仿真的共轭水深数据进行统计分析，得到了适用于U形渠道机翼形量水槽水跃共轭水深的近似计算公式；研究了不同工况下量水槽水跃的紊动情况和相应的水头损失，并将其作为判别标准之一，对原型量水槽的选型方案提出了一定建议。（3）选用矩形渠道机翼形量水槽为研究对象，基于Isight数值优化平台，通过Hicks-Henne型函数实现翼型参数化、多岛遗传算法（MIGA）筛选最优解，构建自动集成与优化体系，对机翼形量水槽进行多目标水力优化。基于Flow-3D软件，通过选取较有代表性的机翼形量水槽的两种工况作为算例，对优化结果的各项水力参数进行三维仿真验证和对比分析，结果表明采用优化翼型方案的量水槽对过流的侧收缩能力增强且水头损失更小，使得渠道过流更加顺畅，有利于在满足量水需求的同时提高灌溉效率，更加适用于水头条件较差平原缓坡灌区。（4）从开发环境、网格划分以及对自由液面的追踪方式三个方面，将Fluent与Flow-3D软件的数值仿真能力进行了比较。分析表明，二者均能较好的应用于水力学问题的研究，但是Fluent因其具有较好收敛速度，所以更适合应用于大计算量情况下或对某问题的定性分析；Flow-3D对自由液面的处理效果更佳，相关水力参数精度更好，因此更适合应用于对模型试验的验证或对某问题的深入研究。更多还原

【Abstract】 In China, most irrigation water is delivered in canal from source to field. Development ofcanal water gauge technology is crucial for standard irrigation and improvement of irrigationwater use efficiency. In other word, it is important for water saving agriculture and a way toachieve efficient water use in agriculture. However, as restricted to the situations in diversityregions, the economic background, irrigation management, development level and fieldhydraulic character is different for irrigation area in China. Therefore, it is urgent to develop acanal water measurement technology which is suitable for all regions. In relation to the higheconomic profitability and stability, a flume measuring equipment is suitable for applicationin large parcels. The explosion of a flow gauge technology with flume structure plays asignificant role in sustained development of irrigation area. Under specific situation, tt shouldhave the advantages like simple structure, high measuring accuracy, high adaptability andconvenient manipulation.Airfoil-shaped measuring flume is a new technology applicable to irrigation region inour nation. The streamline structure makes water flowing smoothly along the flume withouthigh resistance. Compared with the traditional flow measuring method, it has the advantageslike smooth water flow, low cost and easy to build. Therefore, in this paper, modelexperiments and computational numerical simulation was combined to analyze mechanism offlow gauge and related hydraulic parameters under different structures of airfoil-shapedmeasuring flume. Then a multi-automatic optimizing method was developed to accomplish amulti-objective optimization of flume structure. The results obtained are as follows:(1) The experiment was conducted with3contraction ratios for airfoil-shaped measuringflume in a rectangle canal. The equation was proposed by dimensional analysis method tocalculate flow rate. The equation is with a simple form and the differences between calculatedand experiment results are small.3-dimensional numerical simulation was conducted byFluent software. The results was compared with model experiment and shows a highcoincident. Turbulent flow field and related hydraulic parameters were analyzed. Criticalsubmergence coefficient S in flume is relatively high. Upstream Froude number Fr is smallerthan0.5, which is satisfied flow measuring standard. (2) With two different experimental conditions, a last stage of irrigation canal renovationproject in a certain small irrigation area was taken as an archetype. Water jump in U-ShapedCanal Airfoil-shaped flume in three dimensions was simulated, with the turbulencemathematical model tracking the free surface of liquid based on TruVOF method and meshoptimization based on Favor. The hydraulic parameter were also analyzed such astime-averaged flow field, conjugate depth, occurring position, jump length, distribution ofhydraulic velocity in cross section and the loss of energy of hydraulic jump section.Simulation results were verified using model experiment data with a model ratio at1:1.Finally, the conjugate depths of experimental data and simulation results were analyzed, andthe calculation formula of conjugate depths for U-Shaped Canal Airfoil-shaped flume wasproposed. Turbulence characters and head loss was studied under different experimentcondition, which provides recommendation for determination of flow measuring flumestructure.(3) Taking airfoil-shaped flume in a rectangle canal as study objective. An optimizationmodel was established based on Isight platform. In this model, airfoil parameterization wasrealized by Hicks-Henne Shaped function. Parameters were selected and optimized byMulti-Island Genetic Algorithm. It is used to realize a multi-objectives hydraulic optimizationof airfoil-shaped flume. Taking two representative conditions of airfoil-shaped flume as studycases, optimization results were simulated and verified by Flow-3D. It was shown that, for theoptimum flume structure, there is an enhancement in side contraction capacity. Head loss issmaller, which leads to a more smoothly flow. It is benefit for improve the irrigationefficiency and more applicable for plain with gentle slope and weak hydraulic situation.(4) The application of Fluent and Flow-3D was compared in respect to explosion method,mesh divided and liquid free surface tracking method. The results show that, either of thesoftware is applicable to the study of hydraulics. However, convergence rate is better forFluent and it is more suitable for qualitative analysis with a massive calculation. Flow-3D isbetter at dealing with free surface. Simulation accuracy is higher and it is more suitable forverification of model experiment results.更多还原