週期式圓錐平板裝置之流場分析

Analyze the flow field in the periodical Cone-and-Plate apparatus

林清盛(Ching-Sheng Lin)

指導教授 ： 鍾志昂

國立中央大學/工學院/機械工程學系/碩士(2006年)

摘要

在近代的醫學工程中，發展出了一項新技術—組織工程，此技術的最終目的是希望能在體外培養出與人體器官相同的組織或細胞，進而去修補人體內受損或失去機能的部分以維持身體的機能。在培養細胞的生物反應器中，其中一種為圓錐平板型生物反應器，其特色是可同時提供層流及紊流形式的流場，且可維持平板上之剪應力近乎定值，方便我們控制生長環境的剪應力。本文希望分析細胞培養於平板表面時，所承受之剪應力，以提供培養細胞時的一個參考依據。利用套裝軟體Fluent模擬圓錐平板式裝置中的流場，改變參數Re(慣性力與黏滯力的比值)、 (轉速振幅與平均轉速的比值)、 (非定常慣性力與黏滯力的比值)來瞭解其對流場及平板上剪應力的影響，並與先前學者的研究結果相比較，以確認結果的準確性。計算結果顯示，隨著以上三項參數的增加，流場更容易形成紊流。觀察流場中各項速度及紊流動能的分布，發現系統中紊流是由圓錐表面開始形成再向平板表面延伸，同時由圓錐外圍開始形成再向內部延伸；以及隨著 增加，流體會跟不上圓錐轉動的速度而產生延遲現象。

關鍵字

組織工程 ； 圓錐平板型生物反應器 ； 剪應力 ； 紊流動能

並列摘要

Tissue engineering is a new biomedical technology which makes an attempt to cultivate tissues or cells in vitro so as to repair damaged or malfunctioned parts of human organ and maintain normal functions of the body. Cone-and-plate apparatus is a bioreactor which provides laminar and turbulent flows at the same time, and the shear stresses over the plate are virtually constant. Such a feature provides a convenient way to control the shear force that is applied on the cultured cells.To mimic the physiological environment, the shear stresses produced in a bioreactor should be unsteady. Although the shear flow in a cone-and-plate device was well studied before, the parameter regimes of the laminar and turbulent flows have not been well defined for unsteady cases.
In this search, we employed a commercial software to simulate the flow domain in a Cone-and-plate apparatus and changed parameters Re (the ratio of inertial force to viscous force)、 (the ratio of angular velocity amplitude to average angular velocity)、 (the ratio of unsteady inertial force to viscous force) to understand how these parameters influence flow behavior and the shear force on the plate. Results show the unsteady laminar flow transited to turbulence flow easier and the theoretical range became smaller when these parameters were increased. By observing the distribution of the velocity and the turbulence kinetic energy in the flow, we found turbulent flow commenced from the surface and outer region of the cone, then extended simultaneously toward the surface of the plate and the inner region of the cone. Results also show the fluid could not follow the rotational velocity of the cone so that velocity lag phenomena occured when was increased.

並列關鍵字

shear stress ； cone-and-plate ； tissue engineering ； turbulence kinetic energy

參考文獻

1. Brown, T.D., 2000. Techniques for mechanical stimulation of cells in vitro：a review. Journal of Biomechanics 33, 3-14.

2. Bussolari, S.R., Dewey, C.F. and Gimbrone, M.A.,1981. Apparatus for subjectingliving cells to fluid shear stress. Rev. Sci. Instrum 53(12), 1851-1854.

3. Buschmann, M.H., Dieterich, P., Adams, N.A. and Schnittler, H.-J., 2005. Analysis of flow in a Cone-and-Plate apparatus with respect to spatial and temporal effects on endothelial cells. Biotechnology and Bioengineering 89, 493-501.

4. Butler, D.L., 2000. Functional tissue engineering: The role of biomechanics. Journal of Biomechanical Engineering. 122,570-575.

5. Chung. C. A., M. R. Tzou, R. W. Ho, 2005. Oscillatory flow in a Cone-and-Plate Bioreactor. Journal of Biomechanical Engineering 127, 601-610.