Research on measurement of hydraulic properties of two phase flow of water and air

在包气带中，水和空气两相共同占据多孔介质的孔隙中。两相流有限元方法已被开发来解决这些现象。在这种方法中，非饱和土的水和空气的水力特性是预测包气带渗流特性的基本数据。在本文中，这些传统的方法在一个均匀的桑迪土壤进行了修改，并提出了一个新的实验方法来确定非饱和土壤水力特性。主要研究成果如下：1.将电法勘探方法应用于饱和-非饱和渗流的测量，提出了确定电阻率与体积含水率关系的实验方法。2.建立了用压力传感器和低能中子源分别测量压力水头和体积含水率的试验装置和试验方法，并进行了体积含水率与空气渗透率的关系试验，3.探讨了在室内一维瞬态两相流实验中，利用参数估计方法同时确定水和空气的土壤水力特性的数值可行性。

In vadose zone, the phase of water and air are together occupied in void pores of porous media. The two-phase flow finite element approach has been developed to solve these phenomena. In this approach, the unsaturated soil hydraulic properties of water and air are essential data to predict the seepage behavior in the vadose zone. In this paper, these conventional methods on a homogeneous sandy soil are modified and a new experimental methodology of determining unsaturated soil hydraulic properties is proposed. The main results in this research are as follows ;1.Electric prospecting method is applied to measurement of saturated-unsaturated seepage flow.An experimental methodology of determining the relationship between resistivity and volumetric water content is proposed. Unsteady drainage experiments were performed for fine sand in the laboratory.2.An apparatus was constructed and test procedure were developed to measure the pressure head and volumetric water content by using pressure transducer and low-energy neutron source respectively.Experimental test have been performed to determine the relationships between volumetric water content and air permeability, and pressure head and volumetric water content.3.The numerical feasibility of determining soil hydraulic properties of water and air simultaneously from one-dimensional transient two-phase flow experiments in the laboratory by parameter estimation method is evaluated.