• 作者： Wang, Yeh
• 中文摘要： 黏塑性流體在工業界有廣泛之應用。雖然關於線性賓漢流體之研究文獻甚多,然而對其他非線性塑性流體在非圓管內之流動研究則甚為欠缺。本研究係應用有限元素法作流動分析,而以常態化方法決定未降服栓狀區之邊界。本文則解出不同心圓環及正方形流道內之流場。一般而言,在流道中央均存在流動之栓狀區,但是當賓漢數增大時,或在高偏心率不同心圓環之窄邊,或在正方形流道之直角區,均存在停滯之栓狀區。栓狀區之外形及大小則由橫向剪力與降服應力間之力平衡所決定。雖然不同之非線性塑性流體具有不同之剪切稀特性,然而此等流體之栓狀區幾乎完全一致。
• 英文摘要： Viscoplastic fluids have wide industrial applications. There have been a lot of research works published on plastic flow of the Bingham type, but comparatively few have been devoted to flow of nonlinear viscoplastic fluids in non- circular ducts. The duct flow of nonlinear viscoplastic fluids is analyzed through the finite-element method. The location of the yield surface is determined by the regularization technique. Two kinds of duct, namely the eccentric annulus and square duct, are investigated. These flows are seen to consist of mobile plug zones in the duct center with stagnant plugs at the narrow side in eccentric annuli at large eccentricity or large Bingham number, and near the apex of corners in a square duct. It is shown that the sizes and the contours of the plug zones are mainly determined by the force balance between transverse shearing and yield stress. In addition these zones are almost identical for various plastic models considered here despite their different shear-thinning behaviors.
• 中文關鍵字： 非線性黏彈性流體; 賓漢流體; 非圓管; 常態化; 賓漢數
• 英文關鍵字： Nonlinear Viscoplastic Fluid; Bingham Fluid; Noncircular Duct; Regularization; Bingham Number