壓電式噴孔片之液滴噴出行為之田口式分析

Abstract

本研究擬透過實驗觀察，探討噴孔片在不同的噴孔直徑以及不同的噴孔片厚度下，噴孔表面的親疏水性對液滴噴射行為的影響，並運用田口式品質分析方法，判斷出在哪種條件下，噴出液珠的效果較好。研究中採用微電鑄技術來製作噴孔片，並在其上施以塗層改變其表面親疏水性。經由可視化分析，本實驗詳細討論噴孔直徑與噴孔片厚度以及表面親疏水性的變化對液滴噴射速度、液滴斷裂時間與液滴體積之影響。 經由實驗結果，本實驗發現當噴孔直徑越小，噴孔片的厚度越厚，噴孔片的內表面呈現疏水性，上面任一條件皆可使噴出的液滴縮小，液珠脫離液柱的時間縮短，並且液珠不會因為倍頻的振幅干擾，而出現噴出的液珠體積不均勻或是速度不均勻的現象。三個控制因素用S/N的比値作為比較，本實驗發現液珠受到的影響以噴孔直徑與噴孔片厚度為主，內表面的接觸角雖有影響，但影響並沒有比前兩者為大。

In this study, we use the experiment to observe the effect of wetting conditions on droplet ejection process at different nozzle size and different thickness of nozzle plate. In addition, using the Taguchi quality analytics to diagnosis droplet ejection process, which droplet ejection process is superior. The nozzle plate is fabricated using electroforming process and coated to vary wetting conditions at the air-water-solid interfaces. In the study, Using the high speed CCD camera connected to a video recorder will be utilized to visualize the droplet ejection process and further to analyze the droplet velocity, breakup time, and droplet volume at various wetting conditions. In the study diagnosis, we dig out the diameter of nozzle is small, or the thickness of nozzle space is thick, or the surface of spraying sheet is anti-water. Any of these factors make the ejecting droplet shrinking, let abridgement of time to the ejecting droplet come off the water cylinder, and abatement Clock Multiplier affection of ejecting droplet. Abatement appearance unevenness affection of ejecting droplet and speed. The diameter, thickness size and contact angle by compare using the signal to noise ratio. According to the comparison of diameter, thickness and contact angle. It is found that the nozzle geometry including orifice diameter and nozzle thickness is more dominant than the contact angle of nozzle wall.