地表滴灌条件下水热耦合迁移数值模拟与验证

土壤水热分布状况是作物优质高产的关键环境条件之一,基于土壤水、热运动基本方程,结合地表滴灌水分运动特点,建立了地表滴灌水、热运移数学模型,利用HYDRUS-2D软件对构建的数学模型进行了数值求解,并对数值模拟得到的土壤水热值与田间实测数值进行了对比验证。结果表明, 所构建的数学模型对地表滴灌条件下的土壤水分运动和土壤温度变化及分布的动态变化具有较好的模拟效果;当土壤、气象以及灌水资料等可知时,利用该数学模型可以较准确地预测地表滴灌条件下水热耦合迁移与分布规律,模型可用来适时监测和调控地表滴灌条件下作物生长所需的土壤水、热环境条件。此外,数值模拟值和实测结果都显示,地表滴灌条件下上层土壤的水分和温度值较下层土壤易受到土壤蒸发和大气温度剧烈波动的影响。

Verification and numerical simulation for water flow and heat transport under drip irrigation

The soil and water distribution condition is one of the key parameters for crop good quality and high yields, and the mathematical model was set up on the basis of combining soil water and heat moving basic equations with water moving features under drip irrigation. The HYDRUS-2D software was used to solve the mathematical model. The simulation value and the observation value gained from field measurement were compared. The results showed that the mathematical model could be commendably used to describe the soil water and heat transport properties, and the mathematical model could be used for monitoring and adjusting soil water and heat distribution in time when the soil information and weather data and drip irrigation arrangements could be attained. In addition, the comparison result between simulation value and the observation value revealed that the soil water and heat value in the upper soil layer was obviously affected by soil evaporation and atmosphere temperature fluctuation compared with deeper soil layer.