基于Fluent软件的滴灌双向流流道灌水器水力性能数值模拟  

Numerical simulation of hydraulic performance on bidirectional flow channel of drip irrigation emitter using Fluent

作　　者：田济扬[1] 白丹[2] 于福亮[1] 王新端[2] 郭霖[2] 

机构地区：[1]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100038 [2]西安理工大学水利水电学院,西安710048

出　　处：《农业工程学报》2014年第20期65-71,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(51279156);国家自然科学基金资助项目(51209225);高等学校博士学科点专项科研基金联合资助课题(20116118110010);陕西省农业科技攻关项目(2010K02-08);中国水利水电科学研究院科研专项(1232)

摘　　要：开展滴灌双向流流道数值模拟研究,对提高灌水器研发效率,降低研发成本,分析流道消能机理具有重要意义。通过Fluent软件计算的数值模拟结果和试验数据的对比,重点研究了网格划分和湍流模型选取对模拟精度的影响,以及流道的消能机理。结果表明:当网格划分为0.2 mm,分别采用Realizable k-ε模型与标准k-ω模型模拟时,模拟值与实测值的相关系数均高于0.998,数值模拟精度和计算效率较高;且流道的进口压力越大,反向水流与正向水流的比值越大,流态指数越小,水力性能越好,特别是在灌水器压力低于0.10 MPa区间,流态指数低于迷宫式流道;从流道的速度矢量图可以明显的看出正向水流与反向水流的分布与混掺过程;分析流道压力分布图,发现流道内压力在正、反向水流混掺后大幅度下降,进一步验证了双向流流道的消能机理与消能效果。The hydraulic performance of bidirectional flow channel is better than the hydraulic performance of labyrinth-channel, especially in 0.05-0.10 MPa. So bidirectional flow emitter can save more energy and the drip irrigation tube can be thinner, it can reduce investment cost and has good application in irrigation. In this study, numerical simulation method was used to accurately and efficiently design various kinds of channels of drip irrigation emitters. In order to improve the efficiency of research and reduce the cost of development, Fluent was used to simulate the bidirectional flow channel and analyze the mechanism of energy dissipation. A channel was designed within a reasonable range of structural parameters to study the grid partition and model selection. The results showed that unstructured grid was suitable for numerical simulation of bidirectional flow channel. Mesh cell sizes of 0.1 mm, 0.2 mm and 0.5 mm were chosen to calculate the flux of the channel under different pressures. Mesh cell size 0.2 mm under the numerical simulation was more accurate and efficient than the ones of 0.1 mm and 0.5 mm. In this paper, five turbulence models including standardk-ε, RNGk-ε, realizablek-ε, standardk-ω and SSTk-ω were compared. The simulating results of realizablek-ε and standardk-ω were better than that from other models. The correlation coefficients between the test results and the simulation values of these two models were 0.998 and 0.998, respectively, in 0.05-0.30 MPa. In 0.10-0.25 MPa, the simulation values were much closer to the test results. So Fluent can be used to simulate the water flow of the bidirectional flow channel and the simulation results had high precision. In addition, by orthogonal design method, we chose three key factors from the structural parameters and arranged nine experimental schemes to study the hydraulic performance and mechanism of energy dissipation. According to the main principle of the bidirectional flow channel, the flux of the backward flow to the flux of the forward

关 键 词：滴灌 数值方法 湍流 灌水器 双向流流道 水力性能 

分 类 号：S275.4[农业科学—农业水土工程]