| 摘要: | 有鑒現存物性量測方法中，多集中於特定環境條件、單一物性的量測，且儀器成本高昂，本研究旨於發展一具建置成本低廉，並可彈性因應不同操作條件的多物性量測方法。以排液容器法為基礎，本研究摒去習知文獻中對於理論方程式與排放修正係數的使用，並結合計算流體力學與據敏感度分析所設計之多階段回歸流程，最小化實驗與數值模擬間質量流率權重均方誤差，從而獲取欲測定之目標物性值。試以40℃純水為牛頓流體代表，量測其密度、黏度與表面張力係數，可得悉其密度以及表面張力係數與文獻參考值有平均相對誤差約5%以下，並以後者有較佳量測穩定性，而受實驗與模擬間既存偏誤影響，黏度則有平均誤差約15%，最佳可達10%以下。並延伸本量測方法之應用，進行非牛頓流體之黏性參數測定，以30℃下0.1wt%黃原膠水溶液作為代表，探求卡羅黏性模型下的零剪應變率黏度、無限剪應變黏度、時間常數以及冪次指數，並與市售儀器所得剪應變率-視黏度資料群進行擬合，平均可得R2(決定係數)為0.9的匹配程度，最佳來到0.94。然而，相比直接匹配零剪應變率黏度、無限剪應變黏度、時間常數與冪次指數的結果，本研究所得參數與之有著顯著的差異，故針對非牛頓流體的適用性，尚待未來進一步討論與改良。;Due to the fact that the existing measuring techniques for physical properties nowadays mostly concentrate on single subject and constrain with specified environmental conditions. Furthermore, the cost of the equipment are usually expensive. This study aims to develop an innovative approach which features with relatively low set-up expense and could be adjusted flexibly to respond for different operating circumstances. On the basis of draining vessel method, this study eliminates the use of the theoretical formula and discharge coefficient instead, combining computational fluid dynamic(CFD) approach with multi-state regression procedure established by the results of sensitivity analysis to minimize the weighting mean square error between the mass flow rate of the experiment and those obtained by simulation to acquire the values of targeting properties. Take the pure water at 40℃ as representative of Newtonian fluid, measuring the corresponding density, viscosity and surface tension coefficient. The results show that compared with values quoted from literature, the density and the surface tension coefficient have the averaging error not more than 5%, besides, the latter demonstrate with better measuring stability. On the other hand, affected by the embedded difference between experiment and simulation, there is the averaging error of 15% of the results of the viscosity, and less than 10% for the best. We expand the application of such the approach to measure the viscous parameters of non-Newtonian fluid, and employ it to explore zero shear strain viscosity, infinite shear strain viscosity, time constant and power law index of the apparent viscosity of 0.1wt% xanthan gum aqueous solution at 30℃ under Carerau model. Fit the obtained parameters to the data attained by commercial equipment which obtain with the R2(coefficient of determination) being 0.9 in the mean, and 0.94 for the best. However, obvious differences could be observed between zero shear strain viscosity, infinite shear strain viscosity, time constant and power law index got by the designed approach and by direct regression, for the feasibility of the property-measuring technique proposed by this study to the non-Newtonian fluid, it still take further discussion and improvement in the near future. |
