標題: 三維擴張管分離流之探討
A Study of the Separation Flow in Three-Dimensional Sudden Expansion Ducts
作者: 王宏文
Hong-Wen Wang
崔燕勇
Yeng-Yung Tsui
機械工程學系
關鍵字: 三維;擴張管;分離流;數值模擬;層流;不可壓縮流;three-dimensional;sudden expansion;separation flow;numerical;laminar;incompressible
公開日期: 2003
摘要:  本文是以數值方法探討穩態,不可壓縮流體,層流,且為牛頓流體之三維突張管流體分離現象,使用有限體積法作為離散化的方法,並使用非結構性網格,以SIMPLE 法則求解。   由於影響流場的主要參數為雷諾數(Reynolds number),擴張比(expansion ratio)和高寬比(aspect ratio),因此本文主要是探討擴張比固定不變時,雷諾數(Reynolds number)和高寬比(aspect ratio) 對流場的影響。   由於在三維突張管入口之速度分佈為均勻流場,為了使速度分佈能在擴張部前形成完全發展流,因此計算不同高寬比時能形成完全發展流所需之管道長度,而決定三維突張管之入口管道長度。對於計算結果的驗證,則是模擬相關之實驗,並且比對計算結果和實驗數據,同時測試格點對流場的影響。   對於雷諾數對流場的影響,則是計算在不同高寬比時,雷諾數的變化對流場對稱性所造成的影響,並且以管道中之迴流大小作為討論的依據,同時以管道的四週璧面及不同截面之流線圖,來表示流場之結構,以及探討流場之分離現象。   高寬比對流場的影響,則是計算雷諾數在固定不變時,不同高寬比對流場所造成的影響。最後則是探討探討不同高寬比管道及二維管道之臨界雷諾數,並且計算管道的些微不對稱對流場的影響,同時以迴流大小及速度分歧圖(Bifurcation Diagram) 作為討論的依據。
In this thesis,we study the bifurcation phenomenon of the steady, laminar, and incompressible flow in three- dimensional, sudden expansion ducts by numerical simulation, and the SIMPLE algorithm is applied;in literature, a symmetric flow in sudden expansion duct become asymmetric as the Reynolds number is increased beyond a critical value and such a symmetry breaking flow phenomenon is influenced by the expansion ratio, and the aspect ratio of the duct. Our study is mainly in discussing the influence of the Reynolds number of the flow of ducts with different aspect ratio and using flow topology to describe the flow structure. And compute the critical Reynolds numbers including the two-dimensional sudden expansion duct and compare with slightly asymmetric ducts by using bifurcation diagram.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT009114548
http://hdl.handle.net/11536/47779
Appears in Collections:Thesis


Files in This Item:

  1. 454801.pdf
  2. 454802.pdf
  3. 454803.pdf
  4. 454804.pdf
  5. 454805.pdf
  6. 454806.pdf
  7. 454807.pdf
  8. 454808.pdf

If it is a zip file, please download the file and unzip it, then open index.html in a browser to view the full text content.