同心圓柱間賓漢流體之時變現象

Abstract

本研究以前人理論配合實驗求取高嶺土溶液於不同濃度下之流變參數特性，理論方面採用賓漢流體之本構關係式，解析賓漢流體在同心軸圓柱旋轉式流變儀之運動狀況，而在本實驗中，流體於流變儀中之運動分為強剪層與弱剪層，將此分層之現象以前人理論解析，得到流體運動之穩態與非穩態解析解。再藉由流變儀實驗之剪應力量測資料以及轉速量測資料，推導出非穩態以及穩態之流變參數檢定公式，檢定流變儀試驗之賓漢流體之穩態流變參數，並且探討穩態和非穩態理論發展之檢定公式於日後流變實驗檢定之用途。 實驗部分，本研究以標準之實驗材料：高嶺土，與水混合成高嶺土溶液，並且律定此材料本身之特性，例如膨脹性。以材料特性率定之結果，根據目標濃度配置高嶺土溶液，並且設計實驗得高嶺土溶液能夠配合理論假設以及邊界條件和初始條件，去除底部效應，方可以理論發展之流變參數檢定公式檢定其流變參數。 本研究以非穩態參數檢定公式檢定非穩態資料之穩態參數，接著與穩態參數檢定公式檢定之穩態參數進行比較。本研究結果發現，降伏應力部分，在低濃度的高嶺土溶液，使用非穩態之流變參數檢定式檢定成果較有成效，高濃度之高嶺土溶液無法準確收斂至穩態降伏應力值；而在黏滯係數部分，以非穩態檢定式檢定出來之結果皆與穩態檢定式之結果不同。

To predict mud flow rheological property, the rheological parameters of a Bingham fluid are verified with empirical data in this paper. In our experiment, kaolinite suspension is chosen to be the experimental material. The design of the experiment serves the assumption and boundary conditions of the analytical solutions developed in both steady and unsteady state. Moreover, we quantify the end effect in experiment way, and we derive the verification formulas of rheological parameters with analytical solutions. After verifying the data from our rheological experiment, two different groups of rheological parameters can be obtained. One of them is obtained with the equilibrium data calculated by the steady verification formula and so-called the steady state rheological parameters. In the contrast, the other group is verified with transient data by the unsteady verification formula, and the parameters in this group are time-dependent, yet still being steady state rheological parameter. Subsequently, we discuss the discrepancies of the equilibrium time of the rheological parameters verified in different verification formula. The rheological parameters verified with transient data by unsteady verification formula can convergent with the steady state parameters faster, when the concentration of the kaolinite suspension is higher.