高嶺土泥漿體流變參數時變性之實驗研究

An Experimental Study on the Time-dependent Rheological Parameters for Kaolin Slurries

10.29417/JCSWC.201109_42(3).0003

詹錢登(Chyan-Deng Jan)；郭峰豪(Feng-Hao Kuo)；張良亦(Liang-Yi Chang)

高嶺土 ； 流變方程式 ； 流變參數 ； 黏滯度 ； 降伏應力 ； kaolin slurries ； rheological equation ； rheological parameters ； viscosity ； yield stress

中華水土保持學報

42卷3期（2011 / 09 / 01）

196 - 206

繁體中文

高嶺土泥漿體內細顆粒間由於絮凝作用相互吸引所形成的微結構，在受剪切作用的過程中遭受破壞並降低微結構的強度，因而影響泥漿體的流變特性，使得泥漿體流變參數（如降伏應力及黏滯度）具有明顯的時變特性。本研究在固定高嶺土泥漿體含砂體積濃度為30%的條件下，改變不同剪切率以進行流變實驗探討。流變實驗結果顯示高嶺土泥漿體具有明顯之時變性流變特性。根據所量測之剪應力、剪切率及受剪時間資料，本研究並提出具時變性之流變方程式，藉以探討高嶺土泥漿體流變參數之時變特性。結果顯示高嶺土泥漿體之降伏應力會隨著受剪時間增長而遞減，黏滯度則會隨受剪時間及剪切率增加而遞減；而且降伏應力隨受剪時間之遞減速率明顯大於黏滯度之遞減速率。

The micro-structures formed by the flocculation of fine particles in kaolin slurries break down and decrease in strength after continuous shearing, and then influence their rheological properties, causing the rheological parameters (such as the yield stress and viscosity) to have obvious time-dependent properties. Under the condition of a sediment volume concentration of 30%, this study conducted different rheological experiments by varying different shear-rate settings. The measured results showed the kaolin slurries have obvious time-dependent rheological properties. Based on the measured shear-stress, shear-rate, and shearing time data, this study proposed a time-dependent rheological equation for analyzing the time-dependent properties of the rheological parameters for kaolin slurries. The analyzed result showed the yield stress of kaolin slurries decreases with shearing time, while the viscosity decreases with both the shear rate and shearing time. The decreasing rate of yield stress occurs much faster than that of viscosity.