滴灌灌水器三角形迷宫流道优化设计

为了研究三角形迷宫流道滴灌灌水器的水力特性,将其结构作为研究单元,以流道转角、流道宽度和齿高3个结构参数为因素,采用均匀设计方法设计出10个结构参数组合方案.对于每个参数方案,通过AutoCAD对灌水器流道进行三维造型设计,采用计算流体动力学软件Fluent 6.2对流道内部流体的流动状态进行数值模拟,并且模拟分析灌水器内部流道的水力性能和流场特性,得到流道内部流场可视化图像,同时计算不同压力对应的流量值,通过回归分析建立压力与流量之间的量化关系和回归曲线图,并获得其流态指数.在此基础上,根据10个组合方案数据,通过多元回归计算,建立流态指数与结构参数之间的数学关系.以流态指数最小为目标,采用遗传算法,获得结构参数优化设计方案,得到一种流道内速度均匀分布、压力变化均匀递减、流量大小控制在滴灌允许范围之内、水力性能优良的三角形迷宫流道灌水器,可为三角形迷宫流道灌水器的参数化结构设计、制造中的精度控制以及最终的研发提供理论依据.

Optimization design of triangular labyrinth channel in drip irrigation emitter

In order to study the hydraulic properties of triangular labyrinth channels in drip irrigation emitter, a basic structure of the channels is specified and severed as the investigational model which is defined by the three geometrical parameters such as turning angle, width and height of triangular labyrinth channel. Then, 10 cases are designed based on these parameters by means of uniform design method. Computational fluid dynamics software Fluent 6.2 is adopted to simulate the flow field in the channel of emitters numerically. The geometrical model is generated for each case by using 3D software AutoCAD. Subsequently, the flow in each model is simulated by making use of CFD software Fluent 6.2 to analyze the hydraulic performance and flow characteristics of the model and to obtain flow visualization pictures. Additionally, the flow rate is extracted and correlated to the pressure drop across the model by employing linear regression method, and an index is established for flow pattern. A mathematical relationship between the index and the geometrical parameters is developed based on the results of 10 cases by using multivariable linear regression approach. The genetic algorithm is adopted to optimize the three parameters by minimizing the flow index. The optimized triangular labyrinth channel is subject to an excellent hydraulic performance, namely uniform velocity profile and steadily reduced pressure distribution, and the flow rate through it is in an allowable range as well. This optimized channel can be a reference case for parameterized design, precision control of geometrical parameters in manufacturing and final research and development of triangular labyrinth channel in drip irrigation emitter.