無閥流體驅動系統普遍存在於自然界中，近年來也應用於生物微流體及3C產品散熱上之研究。本文中考慮以一條硬管連接水箱兩端所形成之封閉無閥流體迴路，並在水箱底部連接產波器，使水箱中的水產生波動並導致特定方向的平均流量。我們利用微擾理論求解本問題之勢流了數學模型，期望可以計算水波在封閉無閥系統中所產生的流量。具體而言，我們利用兩個不同的例子探討在不同頻率、當產波器放置於不同位置時，其瞬時流量振幅和相位角會如何變化。從這兩個特例的研究結果可以觀察到流量都有相同的定性趨勢，當產波器置於水箱中間，因為此時系統對稱而不會有流量的產生。同時，流量也會隨時間的無因次參數而有週期性的變化。同時，流量振幅會隨頻率增加而變化更快，相位角也相對應於振幅做改變。最後，我們也對系統中的多個無因次參數進行討論，以釐清其對此封閉無閥流體驅動系統的影響。從研究結果中發現此封閉無閥流體系統會受到系統幾何形狀、頻率、阻尼和慣性力影響。例如當慣性力 越大， 的振幅 會隨之減少;而當阻尼越小，流量則隨會之增加。

Valveless pumping systems are systems or devices which exploit system asymmetry and nonlinearity to drive flow without flow direction regulators. Nowadays, valveless micropumps are increasingly needed in micro-electro- mechanical systems (MEMS) and biomedical MEMS (BioMENS).
Here we focus on the effects of wave propagation in a closed-loop valveless pumping system. In particular, a fluid-filled closed-loop system is considered, which consists of a tank with a rigid tube connecting the two sides, with an actuator producing waves that propagate in the tank. A mathematic model is constructed and an analytic solution is derived by perturbation theory here. There are two cases discussed in this thesis, namely lab-size and real-life size system. It shows that both of the two cases have the same trends such as no average flowrate produced when the actuator is located at a symmetry position. Furthermore, the amplitude and phase angle of the instantaneous flowrate are studied carefully to reveal their dependence on varies system parameters. In addition, a study of each of the dimensionless parameters in this system is carried out to demonstrate how the system response depends upon geometry, frequency, damping and inertia force. Specially, the amplitude of flowrate decrease with inertia parameter increase. And increasing , which is proportional to the reciprocal of damping, will lead the amplitude of flowrate increase, too. We can conclude that combining the effects of some dimensionless parameters such as and , frequency and the position of the actuator, the maximum flowrate can be found from such results.

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