摘要
为了研究双点源滴灌条件下土壤水分运动规律,为滴灌多点源系统的合理设计提供理论依据,基于非饱和土壤水分入渗理论和双点源滴灌条件下土壤水分分布特征,建立了滴灌条件下双点源土壤水分入渗数值模型,利用流体建模有限元分析软件HYDRUS-3D对数值模型进行了运算。将湿润区内土壤含水率运算与实测结果进行对比可得:实测与模拟值一致性较好,均遵循滴灌点源入渗土壤水分运动和双点源交汇湿润体的演变规律。用所建模型对一定灌水技术要素下的土壤湿润体水分分布状况进行数值模拟,结果表明:当q=1.2 L/h,滴头间距为30 cm时,湿润锋交汇时间为268 min。灌水时间增加,交汇区土壤含水率增大,最大值为0.32 cm3/cm3。远离滴头的湿润区内土壤等值线图融合为一条曲线,随着时间的推移,曲线向下移动,形状从屋脊形过渡为水平。当灌水时间相同时,湿润锋运移速率、湿润体剖面面积、滴头附近高含水区土壤湿润体体积及湿润体内相同位置处土壤含水率均随流量增大而变大。结论滴头流量、灌水时间对双点源滴灌土壤水分入渗有一定影响,土壤水分入渗数值模拟能较准确反映双点源入渗条件下土壤水分运动规律。
In order to study the soil water movement rule under double point source drip irrigation system and to provide the theory guidance for drip system design,based on the unsaturated soil water dynamics theory and the character of soil water movement under drip irrigation from multiple point sources,the mathematic model was established and solved numerically by using the HYDRUS3D software.The comparison between the simulated and measured results shows that the difference between the simulated and measured soil moisture content in the humid area is small and basically consistent,and both follow the evolution rule of the convergence of point source infiltration and the humid area to form the humid body.The model was used to simulate the moisture distribution of soil wetting pattern under certain irrigation technology.The results showed that the wet front intersection time was 268 min when the dropper flow was 1.2 L/h and the dripper spacing was 30 cm.As the irrigation time increased,the soil moisture content of the intersection area increased,the maximum value was 0.32 cm3/cm3.The contour map of the soil in the humid area away from the emitters merged into a curve that moved downward over time,transitioning from a ridge to a horizontal shape.When the irrigation time was the same,the flow rate increased,the migration rate of the wetting front increased,the area of the wetting body section increased,the area of the soil wetting body section in the high water-bearing area at the drip head increased,and the soil moisture content at the same position in the wetting body increased.It can be concluded that the dropper flow and irrigation time have a certain influence on soil water infiltration,and the numerical simulation model of soil water infiltration can accurately reflect the soil water movement law under the condition of double-point source infiltration.
作者
李耀刚
蒋存仁
LI Yao-gang;JIANG Cun-ren(Tianshui Water Conservancy Bureau,Tianshui 741000,Gansu Province,China;Gansu Institute of Water Conservancy and Hydropower Survey and Design,Lanzhou 730000,China)
出处
《节水灌溉》
北大核心
2021年第1期33-38,共6页
Water Saving Irrigation
关键词
双点源入渗
湿润体
滴灌
HYDRUS3D
水分入渗特性
数值模拟
double point source infiltration
the wetting body
drip irrigation
HYDRUS3D
water infiltration characteristics
numerical simulation
