新式振動腔設計對無閥式微幫浦效能影響之數值模擬

Numerical Simulations on the Effect of the New design of the Chamber in Valveless Micropump

黃士瑋(Shih-Wei Huang)

指導教授 ： 張正憲

國立臺灣大學/工學院/應用力學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.10991

摘要

本文利用商業軟體ANSYS作為數值模擬的工具，對噴嘴/擴散器式的壓電無閥式微幫浦作數值模擬分析，藉由改變振動腔設計，以及改變振動腔與進出口層的厚度，探討其對微幫浦性能的影響。除了比對實驗的流量之外，同時將模擬計算出的流場與實驗上的流場顯影作比較與討論，以對微幫浦內流場變化對於流量的影響有更清楚的交代。
與一般常用的模擬微幫浦之方法不同，本文的模型沒有經過簡化，而是考慮壓電材料與微幫浦之間的電、流、固多重耦合分析。本文處理流固耦合所使用的模擬計算方法也有別於一般CFD軟體的移動邊界(moving boundary)，而是透過ANSYS與ANSYS CFX將結構場與流場結合的同步雙向耦合，比起一般的移動邊界法，本文所得到的流場更為擬真且可信。
由數值計算結果可以發現，當振動腔設計為雙心型時會有最佳的流量。儘管模擬的流量數值誤差稍大，流量變化的趨勢仍然和實驗大致相符。另外，模擬結果也可以看出將振動腔上層厚度改變對流量確實有所影響，當振動腔上層厚度為1mm時，圓型腔體會有最佳流量；當振動腔與進出口層的厚度為0.5mm時，雙心腔體會有最佳流量。

關鍵字

壓電無閥式微幫浦 ； 流固耦合數值模擬 ； 振動腔設計 ； 振動腔與進出口層的厚度

並列摘要

This paper used the ANSYS software to do numerical analysis of efficiency for the valveless nozzle/diffuser-based micropump. By designing the chamber, and changing the thickness of layer of chamber and inlet and outlet to the micropump in order to discuss its influence on the pumping effiency.This paper not only compared the flow rate between simulations and experiments, but also discussed and analyzed the simulation fluid field with experimental results,in order to know more detailed explanation of the fluid mechanism.
Unlike the common method in the simulation of micropump, the simulating model in this paper is established to be more completeby considering piezoelectric materials, the structure of micropump, and the flow field in all.The general CFD software processes fluid-structure interaction by using moving boundary method.Instead of moving boundary method, this paper used ANSYS and ANSYS CFX for the structural and fluid domains, respectively. Both the structural and fluid domains are coupled in the three-dimensional simulation. The simulation results are closer to reality than the moving boundary.
According to the result of the simulations, we found that when designing the chamber of double-heart, the flow rate was more efficient than others.Although ,there are some errors between the simulation and experimental results,the trends of flow rate between simulations and experiments are quiet similar.In addition,simulation results also showed that changed the thickness of layer of chamber and inlet and outlet had influence on the pumping effiency.When the thickness of upper layer of chamber was 1mm, the flow rate was the best for the circle pump. When the thickness of upper layer of chamber was 0.5mm, the flow rate was optimal for the double-heart pump.

並列關鍵字

PZT valveless micropump ； FSI numerical simulation ； design chamber ； thickness of layer of chamber and inlet and outlet

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