渐缩-突扩流道水力特性研究  

Hydraulic Properties of the Flow in a Gradual Shrinking and Sudden Enlarging Channel

作　　者：仵峰[1,2] 董晓爽 吴玉博[1,2] 马地[1,2] 冯雪芳[1,2] 

机构地区：[1]华北水利水电大学水利学院,河南郑州450045 [2]河南省节水农业重点实验室,河南郑州450046

出　　处：《华北水利水电大学学报（自然科学版）》2017年第2期61-67,共7页Journal of North China University of Water Resources and Electric Power：Natural Science Edition

基　　金：国家科技支撑计划课题(2015BAD24B02);河南省科技攻关计划项目(152102110094);华北水利水电大学高层次人才科研启动费资助项目(201336)

摘　　要：滴头是滴灌系统的关键部件,流道设计是其核心技术。为了揭示滴头流道内的水流运动规律,提出一种渐缩-突扩的流道结构,以三角形、圆形和流线型作为分水结构形状因素,以流道收缩后最小断面尺寸(边壁距离)和放大比例等作为设计因素,进行了3因素3水平正交试验设计;建立了流道的CFD模型,利用Fluent软件进行数值计算,对不同正交试验处理下的流道内部流场进行了研究。以滴头流量为评价指标,探讨了以上各因素对滴头流量的影响,分析了流道不同断面位置处的能量及其变化规律。结果表明:1)10 m水头条件下,试验各因素均对滴头流量产生影响,其中流道尺寸比例系数对流量的影响最大,流道内分水结构的形状和边壁距离影响不显著,流道的过流能力可用以上参数的多元线性回归方程定量表示;2)渐缩-突扩流道结构的流态指数为0.494 3~0.509 1,属孔口出流;试验的3种因素对流态指数x的影响由大到小依次为:尺寸比例系数、分水结构形状、边壁距离,但均达不到显著水平;3)流道内水流的雷诺数Re的范围为614~691 5,局部水头损失系数为2.1~10.6。Emitters are important parts in a drip irrigation system. The flow channel design is the key technology for emitters. To reveal the hydraulic properties of water in its path, a new structure of the gradual shrinking and sudden enlarging channel was put forward. An orthogonal experiment under three factors and three levels was built. Three experimental factors are the shape of diversion structure, which include triangle, circle and streamline, the size of the narrowest section and the scale ratio. A CFD model was established and FLUENT was adopted to carry on the numerical simulating water flow field in the structure. The internal flow field was studied under different orthogonal tests. Influences of all above factors on the discharge, the energy and its head loss were analyzed in the different cross-section along the channel. Results show that： 1 ） all factors in the experiment impact on the discharge under 10 m inlet pressure. The influence of the proportional coefficient of channel size on the flow is significant, while the others＇ effects are non-significant. Flow capacity can be quantitatively formulated by a multiple linear regression equation of the above parameters. 2） The flow index of gradual shrinking and sudden enlarging channel is 0. 494 ～ 0. 509. Water flow regime belongs to an orifice outflow in such a gradual shrinking and sudden enlarging channel. The effect order of the three factors on the flow index x from the largest to the smallest is as follows ： pro- portional coefficient of size, shape, the narrowest section. But none of them has reached to the significant level. 3） The Reynolds num- ber of the flow across the channel is 614 ～6 915. The coefficient of local head loss is 2.1～10.6.

关 键 词：流道结构 尺寸 水力性能 水头损失 

分 类 号：TV132.11[水利工程—水力学及河流动力学] S275.6[农业科学—农业水土工程]