薄壁内镶贴片式滴灌带有限元水力计算方法及设计  

Finite element hydraulic calculation method and design of thin-wall drip irrigation pipes

作　　者：魏涛 王剑[1] 袁寿其[1] WEI Tao;WANG Jian;YUAN Shouqi(National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China)

机构地区：[1]江苏大学国家水泵及系统工程技术研究中心,江苏镇江212013

出　　处：《排灌机械工程学报》2022年第4期427-432,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：中国博士后科学基金资助项目(2017M621653);国家自然科学基金资助项目(51709130)。

摘　　要：为了提高滴灌系统水力设计的准确性,基于有限元原理,提出一种计算薄壁内镶贴片式滴灌带能量损失和灌水均匀度的方法,局部水头损失根据贴片式滴头结构、管内压力和管道壁厚确定,沿程水头损失通过改进Darcy-Weisbach公式编写计算机程序,分析了不同滴灌带的水头损失及均匀度变化规律,并与《微灌工程技术规范》中推荐计算方法的结果进行对比.结果表明:管道总水头损失h_(w)随入口压力的增大而增大.随着滴头间距的增大,相同管长和压力下滴头个数减少,毛管总水头损失h_(w)减小;滴头间距较大时,水头损失的规范值远低于本模型计算值,滴头间距较小时,规范推荐的计算结果才较为合理;工作压力较低时,毛管壁厚对灌水均匀度影响较明显,且随着壁厚增大,过水断面减小,均匀度降低;当滴头额定流量较小时,相对于工作压力,壁厚对毛管的极限铺设长度影响较小.In order to improve the accuracy of the hydraulic design of drip irrigation laterals,a finite element method for calculating the energy loss and irrigation uniformity of thin-wall drip irrigation pipes was proposed.The local head loss was determined by the structure of the emitter,working pressure head and lateral wall thickness.The friction head loss along the lateral was calculated by the modified Darcy-Weisbach formula.A computer program was developed to analyze the head loss and uniformity of different drip irrigation pipes.In addition,the results of the proposed method were compared with those of the recommended calculation method in our country′s Technical Specifications for Micro-irrigation Engineering(GB/T 50485—2009).The results show that the total head loss h_(w) of the pipeline increases with the increase of the inlet pressure head.With the increase of the emitter spacing,the emitter number and total head loss h_(w) decrease under the same pressure head and lateral length.The h_(w) calculated by the technical specifications is much lower than that calculated by this model,when the emitter spacing is large.When the emitter spacing is small,the results of the recommended method are appropriate.When the working pressure is low,the lateral wall thickness has an obvious impact on the irrigation uniformity,which decreases with the increase in wall thickness and the corresponding decrease in cross section.When the emitter nominal flow rate is low,compared with the pressure head,the wall thickness has a low influence on the design maximum lateral length.

关 键 词：滴灌 支管单元 水力计算 水头损失 有限元 

分 类 号：S275.6[农业科学—农业水土工程]