微流體生物反應器中底床粗糙度對質傳現象影響之數值研究

Numerical study of the effect of surface roughness on the mass transport in a 3D microchannel bioreactor

詹琇雅(Hsiu-Ya Chan)

指導教授 ： 鄧志浩

中原大學/工學院/土木工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000510

摘要

摘要

　 生物反應器環境對肝細胞合成與解毒功能有很大影響，其中最重要的是培養液濃度需大於細胞最低消耗限度才能維持細胞增殖並降低死亡率。因此需要了解反應器底部濃度分佈情形，本文以有限元素軟體數值模擬反應器的幾何形狀對其底部粗糙度培養液濃度分佈的影響。
本研究以三維顆粒粗糙比(α)與顆粒分布比(β)為主軸，探討無因次質傳參數Peclet number(Pe)、Damkohler number(Da)與Michaelis-Menten常數(Km )對於反應器底層氧消耗效率（Δj%）與最低濃度值（Cmin ）之影響，並與平滑底床反應器比較之。反應器中位於顆粒中線沿ｘ軸方向濃度分布因α值增加而具有明顯濃度振動現象，其中平滑部分濃度遠低於顆粒部分及平滑渠道於該位置之濃度且與底床剪應力有明顯影響關係。整體反應器濃度隨Pe值與 值增加而增加或隨Da值增加而降低；顆粒局部濃度方面，Pe值與 值不具明顯影響，但隨Ｄa值的增加使濃度振幅更加顯著。另外，針對底床細胞氧消耗效率（Δj%）與最低濃度值（Cmin ）而言，氧消耗效率（Δj%）隨α值增加而增加或β值減少而增加，隨Pe值增加而增加或Da值增加而減少，其中質傳參數對於最低濃度值（Cmin）的影響較顯著，而幾何參數則無。為細胞整體發展而言，應在α大小、反應器長度及初始流速取得平衡。

關鍵字

細胞濃度 ； 粗糙度 ； 數值模擬 ； 質傳 ； 微渠道生物反應器

並列摘要

Abstract

　　The environment of bioreactor has very tremendous influence on the synthesis and the detoxification function of hepatocytes. Furthermore, the most important consideration inside a bioreactor is that the concentration of the nutrient fluid must be more than the lowest consumption limit which the cell can maintain the multiplication so the mortality can be reduced. In this study, the concentration distribution of the bioreactor is numerically simulated by the finite element software to find out the oxygen distribution of the nutrient fluid due to the geometrical shape and the bottom roughness of the bioreactor.
The main dimensionless parameters in both smooth and roughness three-dimensional microchannels such as roughness size ratio (α) and roughness distribution ratio (β), Peclet number (Pe), Damkohler number (Da) and the Michaelis-Menten constant (Km ) are used to discuss the concentration distribution, the effects of oxygen consumption rate (Δj%) and the lowest concentration ratio（Cmin ）on the bottom of microchannel bioreactors.
The concentration distribution oscillating in the baseline of rough microchannels along the flow direction, it increases significantly when α value increase, and it decreases in smooth regions between particles a lot when compared with the distribution with the smooth channels. The shear stress distributions of the bottom also show significant effect on the concentration distributions.
Overall, the concentrations increase when Pe value and value increases and Da value decreases, in roughness parts, the effects of Pe value and value are not significant but increase as Da value increases. Furthermore, in terms of oxygen consumption rate (Δj%) and the lowest concentration ratio（Cmin ）on the bottom of microchannel bioreactors, Δj% increase when α value and Pe value increase or β value and Da value decrease. The effect of dimensionless parameters are significant in the lowest concentration ratio（Cmin）, but geometric parameters are not. For the cell concentration distributions, when designing a bioreactor, we should take a balance between the α value, channel length and initial velocity of the bioreactor.

並列關鍵字

mass transfer ； cell concentration ； roughness ； numerical simulation ； Microchannel bioreactor

參考文獻

2. Brooks, S. B., and Tozeren, A., 1996, “Flow Past An Array of Cells That Are Adherent to the Bottom Plate of A Flow Channel.” Computers & Fluids, Vol. 25, pp.741-757.

3. Chou, H. W., and Barakat, A. I., “Modulation of ATP/ADP Concentration at the Endothelial Surface by Shear Stress: Effect of Flow Disturbance.” Proceedings of the 26th Annual International Conference of the IEEE EMBS, Sep., 2004.

4. Chou, H. W., Ferrara, K. W., and Barakat, A. I., 2007, “Modulation of ATP/ADP Concentration at the Endothelial Surface by Shear Stress: Effect of Flow Recirculation.” Anal. Biomed. Eng., Vol. 35, pp. 505-516.

6. Griffiths, B., Looby, D., “Fixed immobilized beds for the cultivation of animal cells.” Biotechology. 1991; 17: 165-190.

7. Hu, Y., Werner, C., and Li, D., 2003, “Influence of Three-Dimensional Roughness on Pressure-Driven Flow Through Microchannels” Journal of Fluids Engineering, Vol. 125, pp 871-879.