本研究使用商用計算軟體(CFDRC)模擬加入玫瑰紅螢光之去離子水溶液於具大曲率S形流道之微混合器中的流動與混合行為。並探討微混合器的幾何外形(特別是在大曲率的情況下)與流體流速對流體的流動與混合行為的影響。並參考他人提出之混合式方法以CFDRC計算出的速度場為基礎進行流體顆粒追跡，而分子擴散方面，則利用物種方程式計算質量擴散，此混合式方法可得到另一濃度數值解，可跟CFDRC模擬出的結果比較。根據CFDRC模擬的結果，有以下的結論：(一)因彎曲流道的大曲率或在較大的雷諾數時，主流道截面會出現多重渦流，拉伸流體間的交界面，有助混合。(二)大致上，曲率比(彎曲流道之曲率半徑/水力直徑)1左右的微混合器相較於較大曲率比的微混合器有較好的混合效果。(三)當橫向流動主導流體混合時，除了曲率比小於等於0.75的流道外，雷諾數越大，微混合器之出口混合度越高。(四) 曲率比越小，微混合器的壓降越大。比較CFDRC與混合式方法兩者的計算結果，在高流速區域，CFDRC會高估混合效果，而在低流速範圍，CFDRC與混合式方法兩者有一致的結果。

In this work, we use commercial codes (CFDRC) to simulate the flow and mixing behaviors of pure water and water with Rhodamine in S-shaped micromixers with strong curvature. We investigate the effects of geometry and flow speed on the flow and mixing behaviors in the micromixers, especially those due to strong curvature. Besides, a hybrid method of the fluid particle tracking based on the velocity field preliminarily solved by the CFDRC and the mass diffusion calculated by a species equation for molecular diffusion is adopted to generate another numerical solution for comparison. The hybrid method may remedy the numerical diffusion of solution at high Schmidt number. The results of the CFDRC show the following trends. (i) Multi-vortices due to strong curvature and/or large Reynolds number stretch the interface between different fluids and so enhance fluid mixing. (ii) In general, the mixing performance of the micromixer with a curvature ratio (i.e., curvature radius/hydraulic diameter) around unity is better than that of the micromixer with a large curvature ratio. The preliminary comparisons of the results obtained by the CFDRC and those obtained by the hybrid method indicate following conclusion. For the high flow speed regime, the mixing performance of the micromixer is overestimated by the CFDRC. For the low flow speed regime, the estimations obtained by the CFDRC agree with the estimations obtained by the hybrid method.

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