Please use this identifier to cite or link to this item:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/46843
Title: | 壓電板波霧化器雙峰現象之消除 Eliminating the Phenomenon of Double Peaks of Piezoelectric Plate Wave Atomizer |
Authors: | Yi-De Chen 陳易德 |
Advisor: | 周元昉(Yuan-Tang Chou) |
Keyword: | 霧化器,指叉電極,鈮酸鋰,表面聲波, atomizer,IDT,lithium niobate,SAW, |
Publication Year : | 2010 |
Degree: | 碩士 |
Abstract: | 本研究利用Z-cut鈮酸鋰的對稱性,於其表面上製作一有三組等角度間隔之激發電極的霧化器,選擇對應於能量集中於上表面之場型的頻率激振,藉由鈮酸鋰的壓電性使表面形成位移場,利用表面的大位移使其上液體霧化為均勻微小液滴。在約15MHz至50MHz的範圍,此霧化器成功的激發出Sauter Mean Diameter約為5μm至8μm範圍的液滴。
本研究發現在兩組或三組電極激發於霧化器表面產生相互干涉的特殊型式位移場時,有利於減少霧化時產生較大顆粒的液滴,使霧化液滴的分佈更加集中。且利用三組指叉電極激振下產生之液滴會以垂直表面的方向飛出。 而比較霧化器在不同運作溫度時霧化液滴分佈後發現,霧化器於高溫運作時所產生的液滴其粒徑分佈有兩個峰值;而霧化器於較低運作溫度時霧化的液滴分佈只有一個峰值,因此推斷霧化器於高溫運作時除了表面激振所造成的霧化液滴外,同時伴隨了因熱效應所產生的水汽,所以造成量測結果有兩個峰值。 Surface acoustic waves are excited by three pairs of inter-digital transducers (IDT), parallel with the X-axes of Z-cut lithium niobate individually, to atomize liquid on the device. The working frequency of the atomizers range between 15 MHz to 50 MHz. The Sauter Mean Diameter of the droplets are between 5μm to 8μm. Because of the superposition of displacement field, atomization by two pairs or three pairs of IDT can reduce the generation of the bigger droplets and the droplets size distribution is more concentrated than the atomization by only one pair. The droplets leave the atomizer vertically when three pairs of IDT working simultaneously. The atomization droplets size distribution has two peaks when the atomizer operated at higher temperature, but only one peak at lower operation temperature. Therefore, the second peak of atomization may be the result of the vaporization by heat. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/46843 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 機械工程學系 |
Files in This Item:
File | Size | Format | |
---|---|---|---|
ntu-99-1.pdf Restricted Access | 7.82 MB | Adobe PDF |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.