采用电容层析成像(electrical capacitance tomography,ECT)方法研究冰水两相系统中冰在水中的运动和冰锋面的移动等。研究过程中,先采用传统的闭合电极电容层析成像传感器,即电极布置于被测管道某一截面的外侧一周,得到被测截面的冰-水分布,以及冰在水中的运动轨迹。之后,为研究冰锋面的迁移情况,针对测试件的特殊结构设计了新型非闭合电极电容层析成像传感器,即沿容器高度上布置了几组电极,每组电极两两相对。当冰锋面浸没过某一对电极时,该对电极电容值迅速减小,因此采用这种布置方式可以获得冰锋面的运动。采用电容层析成像这种非接触测量方式可以获得冰在水中的移动及冻结情况,为进一步研究冻土中的复杂现象提供新型测试手段。
Electrical capacitance tomography (ECT) was introduced to investigate the movement of ice in water and the freezing front movement in ice-water two phase system.First,the traditional closed electrode sensors were put into use.In this arrangement,the electrodes were attached to the outside of the pipe or vessel,and the cross-sectional distribution of ice and water could be reconstructed from the capacitances measured.Also,the ice moving track at the cross section could be reflected thoroughly.Since the traditional closed electrode sensors could not meet the needs of measuring the ice freezing front movement,a new electrodes sensors structure,that was,the unclosed electrodes sensors were designed to satisfy the specific test of frozen soil.In this arrangement,several pairs of electrodes were arranged along the height of the vessel.A sudden decrease in the measured capacitance is observed when the freezing front advances past the electrodes.Therefore,according to the capacitance variation,the freezing front movement can be reflected.In summary,electrical capacitance tomography has the advantages of being non-intrusive.With different electrodes sensor arrangement,ice movement and ice freezing front can be obtained.It can be concluded that ECT can be applied to the investigation of the complicated phenomena in frozen soil.