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

在包气带中，水和空气同时存在于多孔介质的空隙中。两相流有限元方法就是为了解决这些问题而发展起来的。在这种方法中，水和空气的非饱和土壤水力特性是预测包气带渗流行为的基本数据。本文对均匀砂土上的这些常规方法进行了修正，提出了一种新的确定非饱和土水力性质的试验方法。主要研究成果如下：1.将电法应用于饱和-非饱和渗流测量，提出了确定电阻率与体积含水率关系的实验方法。在室内对细砂进行了非定常排水实验。2.建立了利用压力传感器和低能中子源分别测量土壤压头和体积含水率的装置和测试程序，进行了体积含水率与空气渗透率、压头和体积含水率之间的关系的试验研究。3.评价了用参数估计法由室内一维瞬变两相流试验同时测定土壤水和空气水力性质的数值可行性。

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.