蓄水坑灌下果园土壤水-热-氧三维分布数值模拟  

Three-dimensional Numerical Simulation of Water,Heat and Oxygen Distribution in Soil in Orchard Irrigated by Water Storage Pit

作　　者：苏媛媛 郭向红[1,2] 胡飞鹏 孙西欢 马娟娟[1] 郑利剑[1] 雷涛 SU Yuanyuan;GUO Xianghong;HU Feipeng;SUN Xihuan;MA Juanjuan;ZHENG Lijian;LEI Tao(Taiyuan University of Technology,Taiyuan 030024,China;State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)

机构地区：[1]太原理工大学,太原030024 [2]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

出　　处：《灌溉排水学报》2023年第5期67-74,共8页Journal of Irrigation and Drainage

基　　金：国家重点实验室开放研究基金项目(IWHR-SKL-202110);山西省水利科学技术研究与推广项目(2022GM012)。

摘　　要：【目的】构建蓄水坑灌条件下的土壤水-热-氧三维分布耦合模型,探究蓄水坑灌对土壤水、热、氧分布的影响,揭示蓄水坑灌下的土壤水、热、氧空间分布特征。【方法】基于土壤水分运动方程,土壤热量传输方程和土壤氧传输方程,建立蓄水坑灌下的土壤水-热-氧三维耦合模型,利用COMSOL Multiphysics软件进行数值求解,采用田间实测数据对模型进行验证,基于验证后的模型模拟增设蓄水坑和灌水对果园土壤水、热、氧分布状况的影响。【结果】三维耦合模型具有较高的精度,模型模拟土壤含水率、土壤温度和土壤氧浓度的RMSE分别为0.0367、1.6099和0.0138。增设蓄水坑后,坑壁土壤水、热、氧状况发生较大改变;随着时间的推移,蓄水坑周围的土壤含水率降低,土壤含氧量升高,坑壁与地表土壤温度呈相同的变化规律,均随着气温的降低而降低。蓄水坑灌水后,水分通过坑壁渗入土壤,形成以坑底为中心的椭球状含水率高值区和土壤温度、含氧量低值区,三者分布随着时间推移趋于均匀,但灌水对土壤温度的影响时间远低于对土壤含水率和含氧量的影响时间。灌水对土壤氧浓度影响较小,氧浓度在地表和坑壁处较高;距地表和坑壁处越远,土壤氧浓度越低。【结论】蓄水坑增大了坑壁处的土壤水、热、氧交换界面,坑壁处土壤水、热、氧状况受蒸发、降水、大气温度和氧浓度的影响,与地表具有相似的变化;蓄水坑灌下的土壤水、热、氧状况更有利于作物根系的生长。【Objective】Water storage pit is a technology used in arid regions in northwestern China to collect rainwater for irrigation.In this paper,we studied the three-dimensional distribution of water,heat and oxygen in soil in an orchard under water storage pit irrigation using numerical simulation.【Method】Water flow was based on the Richard equation and heat transfer and oxygen diffusion in soil were modelled by convection-diffusion equations.These coupled equations were solved using the COMSOL–a Multiphysics software.The model was verified against data measured from a field,and the validated model was then used to analyze the effect of the water storage pit on distribution of water,heat and oxygen in soils in the proximity of the pit.【Result】The three-dimensional coupled model is accurate and can reproduce the measured spatiotemporal changes in soil water,temperature and oxygen,with the RMSE for soil water,temperature and oxygen being 0.0367,1.6099 and 0.0138,respectively.The water storage pit changed the distribution of water,heat and oxygen in the pit wall greatly.As time elapsed,soil water content in the regions proximal to the pit decreased,while oxygen concentration increased.Temperatures in the pit and soil surface were mainly impacted by atmospheric temperature.Spatial water distribution was ellipsoidal around the pit.Soil water content was the highest in the proximity of the pit bottom,while oxygen concentration and temperature in this region were the lowest.The distribution of water,temperature and oxygen tended to uniformize as time elapsed,despite that temperature and oxygen are less sensitive to irrigation than soil water.Oxygen concentration decreased with the distance from the soil surface and pit wall.【Conclusion】Water storage pit irrigation increased the interface between soil and water,thereby affecting transport of water,heat and oxygen in the soil.Numerical simulations indicated that the dynamics of water,heat and oxygen in the soil was affected by evaporation,rainfall,atmospheric

关 键 词：蓄水坑灌 水-热-氧耦合 COMSOL 数值模拟 

分 类 号：S626.5[农业科学—园艺学]