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標題: | 剛性橢球粒子垂直於平板運動之拖曳係數 Drag Coefficient of a Rigid Spheriod Moving Normal to a Plane |
作者: | Jung-Chieh Chen 陳榮傑 |
指導教授: | 徐治平 |
關鍵字: | 拖曳係數,橢球,平板, drag coefficient,spheroid,plane, |
出版年 : | 2007 |
學位: | 碩士 |
摘要: | 本文主要是利用FIDAP軟體使用數值模擬的方法來探討一個平板的邊界對於橢球形狀之粒子在牛頓流體(Newtonian fluid)及卡羅流體(Carreau fluid)中沉降之拖曳力及其拖曳係數,並改變流體之性質參數來比較平板邊界對粒子的影響。可以發現在牛頓流體中以及卡羅流體中,粒子皆會受到了雷諾數以及橢球粒子比例a/b,和平板距離的影響。當雷諾數大,或是橢球粒子比例a/b大,亦或離板距離較遠時,其拖曳係數較小。另外也討論了卡羅流體參數n與Cu對拖曳係數造成的影響,由於卡羅流體為一shear thinning的流體模型,故當n變小或是Cu變大時,也就是shear thinning之效果變明顯時,粒子之拖曳係數便會下降,不過差異不大。最後由所得到的數值做回歸分析,可得到在低雷諾數下,兩個數學回歸式,他們分別可用來描述當橢球粒子a/b大於1時,以及小於1時,橢球粒子之拖曳係數,其誤差約在7%。 A spheroid moves perpendicularly to the plane in a fluid governed by both the Carreau fluid and Newtonian fluid was presented in this study. In the present work, FIDAP which is based on the Galerkins method has been used to obtain a numerical solution for the drag coefficient and the drag force of the particles. There are several important variables for both Carreau and Newtonian fluid in this problem, such as the distance between the particles and the plane, spheroidal shape factor a/b, and Reynolds number. Also, the characteristics of Carreau fluid such as Cu and n are discussed in this work. These can be used to make a discussion for how the drag coefficient influenced by changing those variables. Finally, deriving a simple correlation gives a good approximation to the drag coefficient of a spheriodal particle at both the Carreau fluid and Newtonian fluid. The percentage deviation is under 7% for the low Reynolds number. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/25394 |
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顯示於系所單位: | 化學工程學系 |
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