本研究探討各式微流體之無活動元件閥。所謂微流體泛指在微管道中流動之流體，而無動件閥則是指沒有活動元件的閥門。由於在微流道尺度下，具有活動元件之閥門製作不易，且其開闔動作可能對微流體的某些分子造成破壞，或受到流體中雜質的阻塞而失靈，相對的無動件閥則無此類困擾。
　　無動件閥的工作原理是利用特殊的流道設計使流體由不同方向流經此流道時會受到不同的阻力，因而在相同壓差作用下，不同的流向會產生不同的流量，此種具阻力雙極性的流道設計即具有單向閥的功能。本研究所提出之無動件閥為一鋸齒狀之流道設計，本研究先以計算流體力學為分析工具，研讀此無動件閥之外型參數對阻力雙極性之影響，在適當的幫浦工作壓力及結構強度的考慮下，選擇使雙極性極大化的外型參數，最後本研究製作10-3m（毫米）級的微流道，以實驗證實本研究所提出無動件閥之實用性

　　This thesis studies the design of no-moving-part valves (NMPV) for flows in microchannels. By definition, a no-moving-part is a valve without any moving element. Comparing with the valve design with one or more moving parts, a NMPV is advantageous in that it eliminates (1) the difficulty in manufacturing the moving elements in small sizes, (2) the risk of malfunctioning of the moving part due to the impurity in the fluid flow and (3) the risk of damaging certain component of the fluid flow due to the valve movement.
　　A NMPV is a specially-designed flow passage that when the flow direction is reversed, the flow experiences different flow resistances. This is the so-called resistance diodicity. For a NMPV passage under a fixed pressure difference, different flow direction will yield different mass flow rate, and hence it can be used as a check valve. In this study, the resistance diodicity is obtained by the design of sawtooth-like channel wall. Computational Fluid Dynamics is used as a design tool to examine the effect of geometry change on the resistance diodictiy. The geometric parameters are carefully chosen under the consideration of avoiding excessive micropump working pressure and ensuring the structure integrity of the design. Finally, experiments involving 10-3m size microchannels are conducted to verify the final design of NMPV chosen in this study.

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