同心圓柱間賓漢流體穩態流況之研究

Steady Motion of Bingham Fluid Contained between Two Concentric Cylinders

劉格非(Ko-Fei Liu) ； 吳映昕(Ying-Hsin Wu)

《中華水土保持學報》 43卷3期 (2012/09) Pp. 264-274

https://doi.org/10.29417/JCSWC.201209_43(3).0007

摘要

本研究推導賓漢流體在兩個無限長同心圓柱間的穩態流況。為了模擬一般流變儀由中心旋轉的運動，本研究假設外圓柱靜止不動，而內圓柱是以固定轉速Ω轉動。流體假設為黏滯性跟降伏應力不隨時間改變的簡單賓漢流體。由於有降伏應力的存在，理論可得一臨界轉速Ωcr，大於此臨界轉速，流體內的剪力全部大於降伏應力，反之，則有塞流（plug flow）存在。最後，本研究還分析無因次參數圓柱半徑比和賓漢數對流況的影響，且將結果應用於流變參數之檢定。

關鍵字

賓漢流體 ； 同心圓柱 ； 流變參數

並列摘要

Steady motion of Bingham fluid between two concentric cylinders is investigated in this paper. The inner cylinder rotates at a constant speed with the outer cylinder stationary. There is a critical rotational speed Ωcr which exists due to the yield stress. If rotating speed exceeds the critical one, fluid stress within the whole gap is greater than the yield stress. Plug flow exists only for the rotating speed below Ωcr. The effect of the ratio between radii and Bingham number is discussed. The limiting case that two cylinders are very close is also discussed. Finally, the rheological parameters calibration formulas are derived.

並列關鍵字

Bingham fluid ； concentric cylinders ； rheological parameters