重力式地下滴灌土壤水分运动规律的模拟研究

Finite Element Simulation Study on Soil Water Movement under Gravity Subsurface Drip Irrigation

基于非饱和土壤水运动理论,建立了重力式地下滴灌条件下土壤水分运动数学模型,用Galerkin有限元法推导了重力式地下滴灌土壤水分运动有限元方程,并通过试验进行了验证,在此基础上模拟分析了中壤土条件下的滴灌管道埋深、出水孔孔径、供水压力对简易重力式地下滴灌土壤湿润特征和滴孔出水量的影响。结果表明所建模型可以分析地下滴灌土壤水分入渗规律,在中壤土条件下,不同供水压力、滴孔孔径虽对重力式地下滴灌的滴孔出流量有较大影响,但对土壤湿润特征影响微弱,地下滴灌管道埋深对土壤水分湿润特征影响较大,这些结论可为重力式地下滴灌合理的设计及运行提供理论依据。

Based on the unsaturated soil water movement theory, a soil-water movement mathematical model is set up under gravity subsurface drip irrigation （SDI）, a finite element equation with Galerkin finite element method for the model is inferred, and it is testified with experiments. The effect of pipe depth, emitter diameter and water pressure on wetting distribution pattern and discharge of emitter in soil is simulated in medium loam. The results show that this model can be used to analysis gravity SDI soil water infiltration pattern. In medium loam, the water pressure and emitter diameter have great effect on discharge of emitter in soil, while little effect on the wetting distribution, the pipe depth has great effect on wetting distribution. All these results can provide theoretical basis for reasonable gravity SDI design and operation.