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標題: | 應用垂直旋轉式流變儀搭配理論發展求取流變參數 Applying Rotating Viscometer with Theoretical Development to Calibrate Rheological Parameters |
作者: | Che-Wei Chang 張哲維 |
指導教授: | 劉格非(Ko-Fei Liu) |
關鍵字: | 垂直旋轉式流變儀,流變參數,賓漢流體,Julien and Lan,本構關係式, Rotating viscometer,Rheological parameter,Bingham,Julien and Lan,Constitutive model, |
出版年 : | 2008 |
學位: | 碩士 |
摘要: | 本研究以理論配合實驗求取不同材料的流變參數特性。理論方面,由賓漢流體與Julien and Lan兩種不同的本構關係模式出發,將流變儀內的流體分為強剪層與弱剪層。利用分離計算的概念,分別推得其控制方程式與邊界條件。再藉由正規化與尺度分析,求解兩層流體其第零階的各項未知數-速度剖面、剪應力分布等,並推導出這兩種不同本構模式下個別的流變參數率定公式,以提供日後流變實驗率定之用。
實驗方面,本研究以人工均質材料為基礎,選定兩種顆粒間作用力與運動型態差異較大的三角形與圓珠型細磨石,並以不同的材料用量與儀器轉速進行多組實驗。再由實驗數據配合理論發展之流變參數率定公式,即可檢定出兩種實驗材料在不同本構模式下的流變參數值。利用檢定結果代回推求速度剖面、剪應力分布及強剪層厚度等未知數,可發現流速剖面與實際不符;此外,強剪層厚度數據亦出現不合理的負值。則由此得知,理論發展所採用的賓漢流體與Julien and Lan兩種本構模式並不適用於本研究所進行的顆粒材料流變實驗。 In this study, we combine theory and experiment to calibrate the rheological properties of different materials. Theoretically, we start from two different constitutive models-Bingham and Julien & Lan. We separate the fluid into two layers-shear layer and plug layer, and derive the governing equations and boundary conditions, respectively. Through normalization, we can analyze each equation and solve the leading order velocity and shear stress. For both models, we derive formulas for calibrating rheological properties in rotating viscometer. In experiments, the artificial homogeneous materials are used as a foundation. First, we choose two different flowing type materials-sphere and triangular prism, and then classify the experiments based on different quantity of materials as well as the rotating speed. Since the formulas and the experiment results are acquired, the rheological parameters for both models could be calibrated. With these parameters, we can obtain the unknowns in governing equations-velocity profile, shear stress distribution and the thickness of shear layer. And the velocity profile does not conform to the real state is also found. Besides, there are some data of the shear layer thickness are negative which is wrong. Therefore, we can say the models we adopt- both Bingham and Julien & Lan are not suitable for the granular rheological experiment in this study. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/42047 |
全文授權: | 有償授權 |
顯示於系所單位: | 土木工程學系 |
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