本文探討具有鈍體結構渦漩產生器之微混合器特性，包括微流場結構及其混合效率等。研究工作使用CFDRC軟體作為數值運算工具，研究結果顯示，微混合器隨雷諾數之增加呈現三種流場形態：(1)層狀流(stratified flow)、(2)渦漩發展流(vortex developing flow)、(3)渦漩完全發展流(vortex fully developed flow)。當雷諾數大於10以後，流場開始產生渦流現象，並可觀察到強烈的二次流現象，有助於流體再第三維方向之混合，進而增進整體混合效率。當雷諾數介於10到100之間，流場屬於渦漩發展流結構，整體迴流比率隨著雷諾數的增加而快速遞增，單、雙鈍體式微混合器之混合效率指標隨雷諾數分別快速遞增至19.80%及36.43%。當雷諾數大於100以後，流場屬於渦漩完全發展流結構，整體迴流比率隨著雷諾數的增加，其增加速率呈現線性成長，單、雙鈍體式微混合器之混合效率指標隨雷諾數分別快速遞增至34.79%及78.11%。雙鈍體式微混合器較單鈍體式微混合器更能有效地將輸入之能量轉為流體混合時所需之能量，這是由於流體在雙鈍體式微混合器中交互作用產生的效應。研究結果顯示，在相同雷諾數下，雙鈍體式微混合器能將混合效率指標提升至單鈍體式微混合器的2.41倍；在相同壓損之下，雙鈍體式微混合器亦能將混合效率提升至單鈍體式微混合器的一倍以上。

This paper investigates the performance of a micro-mixer with vortex enhancer generated by the bluff-body structure. We use CFDRC to simulate the flow structure and the mixing efficiency of the micro-mixer. The performance of the micro-mixers with single and double bluff-bodies are characterized. Results show that the flow structure of the micro-mixer can be divided into three regions based on the Reynolds number: 1.Stratified flow, 2. Vortex developing flow, and 3.Vortex fully developed region. The flow structure of the micro-mixer can be related to the stratified flow as Re of the micro-mixer 10.The mixing process is essentially controlled by the molecular diffusion. The flow becomes the vortex developing structure as 10 ≦ Re ≦ 100. It results in the secondary flow and enhances the mixing processes in the third direction. It turns out that the recirculation flow ratio and the mixing efficiency increase dramatically as the Reynolds number is increased. The mixing efficiency indexes of the cases with single and double bluff-bodies are 19.80% and 36.43%, respectively. The flow becomes the vortex fully developed structure as Re ≧100. The increase of recirculation flow ratio and the mixing efficiency is proportional to Reynolds number. The mixing efficiency indexes of the cases with single and double bluff-bodies are 34.79% and 78.11%, respectively. It is concluded that the performance of the case with double bluff-body is more efficient than the case with single-bluff-body due to the interaction between bluff-bodies. The mixing efficiency index of the case with double-bluff is 2.41 times as comparing to the case with single bluff-body under the same Reynolds number.

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