沟灌三角形长喉道田间量水槽水力特性试验及数值模拟  

Numerical simulation and test of hydraulic performance for triangle long-throat flume for water measurement in furrow irrigation

作　　者：王文娥[1] 薛城 胡笑涛[1] Wang Wene;Xue Cheng;Hu Xiaotao(Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas,Ministry of Education,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学旱区农业水土工程教育部重点实验室,杨凌712100

出　　处：《农业工程学报》2019年第3期109-116,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：公益性行业(农业)科研专项(201503125);"十三五"国家重点研发计划项目(2016YFC0400203)

摘　　要：针对目前北方灌区田间沟灌缺乏有效量水设施的现状,提出了一种针对田间小流量情况的新型量水设备—便携式三角形长喉道量水槽,为进一步研究其水力特性,在沟灌简易长喉道量水槽原型试验的基础上,采用基于Flow-3D的计算流体力学方法对该量水槽的内部水流运动进行了模拟计算,对水流流态、水深、傅汝德数、纵向时均流速、紊动强度进行了分析。结果表明:试验水深值与模拟值的最大相对误差小于10%,二者水面线变化规律吻合,模拟结果精度较高;通过临界流理论推导与回归分析得到沟灌简易长喉道量水槽测流公式,其计算结果与实际流量的最大相对误差为4.34%;量水槽收缩段及喉道段纵向时均流速沿程不断增大,流速最大值的位置存在于水面以下,越靠近收缩段、喉道段出口,最大纵向流速位置越低,断面流速分布越不均匀;紊动强度总体呈现沿程增加的趋势,各断面的紊动强度最大值相对位置在0.13到0.30倍水深之间,沿程逐渐上升。In view of the lack of effective water measuring facilities for furrow irrigation areas in North China,a portable triangular long-throated flume was proposed as a small flow water measuring equipment in the field.This study was to investigated its hydraulic performance of the triangular long-throated flume based on both test and numerical analysis.The prototype test was carried out in Northwest A&F University in Yangling,Shannxi of China.The flume was installed at 6.25 m far from the inlet of upstream of U-shaped channel.The base slope of the channel was 1/10 000.The triangular weir was installed at the end of the discharge pond downstream of the channel.A total of 14 sections were designed to observe the flow characteristics.The numerical simulation was used to study its hydraulic characteristics of the flume by using the flow-3D-based CFD method.Based on the RNG k-εthree-dimensional turbulence model together with the TruVOF technique,experiments and the corresponding simulations were performed for 16 working conditions(the flow rate of 1.03,3.03,5.06,7.07,9.00,11.07,13.07 and 15.05 L/s under free and submerged outflow conditions)on the trapezoidal triangle long-throat flume with flow rate up to 15 L/s.The flow pattern,water depth and Froude number,the longitudinal mean velocity and turbulence intensity were analyzed.The results from the prototype experiment was used to validate the simulation results.The results showed that the maximum relative error between the tested water depth and the simulated value was less than 10%under all the 16 flow rate conditions.The variation of the tested and simulated flow pattern were consistent with each other,indicating that the simulation had a high accuracy.The longitudinal mean flow velocity of the shrinkage section and the throat section of the flume continuously increased along the water flow.The maximum flow velocity existed below the water surface.The longitudinal mean flow velocity increased along the flume at the contraction section and throat section.The maximum flo

关 键 词：数值分析 流速 流量 三角形长喉道量水槽 紊动强度 

分 类 号：S274.4[农业科学—农业水土工程]