多共振壓電式無閥門微幫浦在不同管徑和彈性模數的行為研究

Abstract

本論文利用商業軟體ANSYS作為數值模擬的工具，對噴嘴/擴散器式的無閥式微幫浦作數值模擬分析，在建立包覆振動腔及進出口腔的彈性體模型後，將流體壓力列入彈性體受力的外力之一，以達到雙向流固耦合分析，並和實驗的流量比較。文中分別討論了單壓電片驅動及雙壓電片驅動的微幫浦，在單壓電片微幫浦中又針對不同進出口管徑大小及不同彈性體的楊氏模數進行分析，探討其對微幫浦性能的影響。由數值計算結果可以發現，彈性腔體微幫浦在一定頻率的範圍內會有兩個流量區，低頻驅動時的第一流量區及高頻驅動時的第二流量區，第二流量區的流量比第一流量區高。在高頻驅動下，彈性腔體會產生共振而有大趨勢振動現象，推測其為第二流量區發生的原因之一。另外，進出口管徑的增加，會提高微幫浦的流量；楊氏模數增加則共振頻較高，第一流量區的流量增加，第二流量區的流量則減少。最後模擬雙壓電片微幫浦的運作，與單壓電片微幫浦比較，發現雙壓電片微幫浦在第一流量區流量有顯著的提升，在第二流量區則效果較差。

This thesis uses the ANSYS software to perform numerical analysis on the efficiency for valveless nozzle/diffuser-based micropumps are assumed elastic vibration chamber, inlet chamber and outlet chamber. Effects of fluid-structure interactions are considered and resulting flow rates are compared with those obtained from the experimental observations. The micropumps driven by a single piezoelectric actuator and a dual piezoelectric actuators are discussed. For the single piezoelectric micropump the effects of diameter of inlet/outlet tube and Young's modulus are discussed. The numerical results show that, there are two flow zones in the micropump in a certain frequency range; the first zone is present at low frequencies while the second zone at high frequencies. The flow rate of the second zone is higher than that of the first zone. Under high frequency driving, the elastic body resonates and there is a long scale vibration is intensified, which is probably one of the reasons why the second zone occurs. In addition, larger diameter of the inlet and outlet tubes results in an increase of flow rate; when Young's modulus increases, the resonant frequency and the flow rate in the first zone increase, but the flow rate in the second zone decreases. At last, the results of the dual piezoelectric micropump are compared with those of the single piezoelectric micropump. It is found that the dual piezoelectric micropump has a significantly higher flow rate in the first zone and a lower flow rate in the second zone.