The Development of Electronic Instrument for Studies on the Transient properties of Capillary penetration process and its Application

本文介绍了一种能精确测量液体在多孔材料（如织物）中从接触水的瞬间起的毛细渗透速率和渗透高度的仪器，当两个平行平板电极浸入乙醇水溶液中时，双电极间电容的增加与乙醇水溶液在电极间的高度成正比。该电路用于检测放置在两个平行板电极之间的垂直织物条中的水位，并给出电容与水位之间的线性关系。液体在织物中上升的过程，从而从与液体接触的第一时刻起自动记录电容的增加。这种液位-电容转换法响应速度快，可获得真实的时间记录，并证明了水或乙醇在织物中毛细渗透的实验曲线与根据宏观能量平衡导出的Szekely-Neumann-Chuang理论定量一致，可用于解释毛细渗透的早期阶段。在实验测量的基础上，利用该理论对纤维表面特性和织物几何效应进行了估算。

A new instrument has been designed which gives an accurate measurment of the rate and height of capillary penetration of liquid in a porous material, such as fabrics, from the very initial moment of contact with water.When two parallel plate electrodes are immersed in water of ethanol, the increase of capacitance across the twin electrodes is directly proportional to the height of water of ehtanol between the electrodes. The circuit was used to detect the level of water contained in a vertical strip of fabric put between twin parallel plate electrodes and to give liear relation between capacitance and water level. The progress of liquid rise in a fabric, thus the increase of capacitance is recorded automatically from the first moment of contact with the liquid. Such a liquid level-capacitance conversion metnod has a very quick response, and so we can obtain a real time record of the movment of liquid.Experimental curves obtained on capillary penetration of water or ethanol in fabrics was proved to be in quantitative agreement with Szekely-Neumann-Chuang theory which was derived on the basis of macro energy balance, for the interpretation of the very early stabes of capillary penetration. Thus on the basis of experimental measurements, the fiber surface charcteristic and the fabric geometry effect were estima ted by using the theory.