非對稱結構剛性對微幫浦效能提升之探討與分析研究

Abstract

微幫浦作為微流體系統中的核心技術，已在生物醫學、藥物傳遞、微反應器、燃料電池等領域得到廣泛應用。相較於傳統具閥門的設計，無閥微幫浦不僅簡化了結構設計，亦顯著提升了系統的穩定性與可靠性，同時有效降低了因機械構件造成卡死堵塞的風險，微幫浦的設計與應用近年來越來越引起大家的注意。但如何進一步大幅提升其效率的問題卻一直缺乏有系統的探討於解決。 對此，本研究延續實驗室過去對無閥式微幫浦之研究基礎，在設計上進一步擴充微幫浦的幾何設計變因至三項，並以兩個無因次幾何參數加以表徵，系統性地探討入口、振動腔與出口尺寸配置對幫浦輸出行為的影響。並且聚焦於非對稱結構剛性對無閥微幫浦效能的影響，藉由系統化的設計變因與實驗驗證，探討幾何結構與材料配置對微幫浦流量與穩定性的影響。研究中，我們設計並製作變化不同結構配置之微幫浦原型，包括單腔體至五腔體的結構，並變化驅動腔體的位置及流道幾何（直管與漸擴管）進行變異設計。此外，也用電路模擬比對非對稱剛性所產生的系統效率差異。 實驗結果顯示，腔體數量增加有助於提升微幫浦之輸出流量，但以三腔體結構呈現最佳整體效率，顯示在三腔體配置下可在能量傳遞與結構共振之間取得較佳平衡。基於此最佳腔體數量作為設計基準，本研究進一步引入更明顯的幾何非對稱性對出入口腔體尺寸比值進行探討，結果顯示非對稱效應可使淨流量相較於對稱配置有進一步提升的趨勢。此外，出口尺寸的變化不僅改變流道阻抗分布，也會同步影響系統的共振條件與峰值頻率位置，反映幾何比例對動態響應具有高度敏感性。綜上，本研究驗證了透過結構非對稱性引導流體方向性輸送的可行性與效能，並為後續無閥微幫浦設計提供具體參數依據與實驗驗證基礎，為無閥微幫浦在應用中提供穩健且具可行性的設計參考。

Micropumps serve as a core technology in microfluidic systems and have been widely applied in fields such as biomedical engineering, drug delivery, microreactors, and fuel cells. Compared with conventional valve-based designs, valveless micropumps significantly simplify structural complexity while improving system stability and reliability, and effectively reduce the risk of clogging or mechanical failure associated with moving components. Consequently, the design and application of micropumps have attracted increasing attention in recent years. However, how to further and substantially enhance their operational efficiency remains an issue that has not yet been systematically investigated or resolved. In response to this challenge, the present study builds upon our laboratory’s previous research on valveless micropumps and further extends the geometric design variables to three key parameters. These parameters are characterized using two dimensionless geometric quantities, enabling a systematic investigation of how the size configuration of the inlet, vibrating chamber, and outlet influences the pump’s output performance. In particular, this study focuses on the effect of asymmetric structural stiffness on the performance of valveless micropumps. Through a combination of systematic geometric variation and experimental validation, the influence of structural geometry and material configuration on flow rate and operational stability is thoroughly examined. A series of micropump prototypes with different structural configurations were designed and fabricated, ranging from single-chamber to five-chamber architectures, with variations in the location of the driving chamber and channel geometry (straight channels and nozzle/diffuser channels). In addition, an equivalent electrical circuit model was employed to compare the system efficiency differences induced by asymmetric stiffness effects. The experimental results indicate that increasing the number of chambers contributes to an enhancement in the output flow rate of the micropump. Among the configurations tested, the three-chamber design exhibits the best overall efficiency, suggesting that this configuration achieves a favorable balance between energy transmission and structural resonance. Based on this optimal chamber number as the design baseline, the present study further introduces more pronounced geometric asymmetry by investigating the size ratio between the inlet and outlet chambers. The results demonstrate that the asymmetric effect leads to a further increase in net flow rate compared with the symmetric configuration. Moreover, variations in outlet size not only alter the flow-channel impedance distribution but also affect the resonance conditions and peak operating frequencies, highlighting the high sensitivity of the system’s dynamic response to geometric proportions. Overall, this study validates the feasibility and effectiveness of utilizing structural asymmetry to induce directional fluid transport, and provides concrete parametric guidelines and experimental evidence for the design of valveless micro-pumps, offering a robust and practical reference for future applications.