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| 研究生： |
林彰廷 Lin, Chang-Ting |
|---|---|
| 論文名稱： |
多噴頭效應在氣助式噴嘴中之霧化特性研究 Effects of Multiple Orifices on Atomization Performance of an Air-Assist Atomizer |
| 指導教授： |
王覺寬
Wang, Muh-Rong |
| 學位類別： |
碩士 Master |
| 系所名稱： |
工學院 - 航空太空工程學系 Department of Aeronautics & Astronautics |
| 論文出版年： | 2003 |
| 畢業學年度： | 91 |
| 語文別： | 中文 |
| 論文頁數： | 128 |
| 中文關鍵詞： | 多孔噴頭 、側向噴流 、縮孔 、霧化 、氣助式噴嘴 |
| 外文關鍵詞： | air-assist atomizer, atomization, contraction, side jet, multiple orifices |
| 相關次數： | 點閱：129 下載：4 |
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本研究探討不同噴嘴霧化機構對氣助式霧化器霧化特性之影響，基本上分為直孔型、縮孔型、擴孔型等三種噴嘴型式(分別以CK5-S、CK5-C、CK5-E表示)，探討其霧化特性，並研究在噴嘴出口加側向噴流或多孔噴頭所產生之霧化效應，噴霧之粒度分佈以Malvern公司雷射繞射式RT-Sizer粒徑分析儀量測。
研究結果顯示，縮孔型噴頭之奇點效應有助於噴霧平均粒徑(SMD)與噴霧粒度比(SR)的降低。例如在水壓5.2kg/cm2，氣壓6kg/cm2下，CK5-S單孔霧化器所產生噴霧之SMD為33.20μm，SR值為8.87；而使用CK5-C單孔霧化器則可大幅縮減SMD至15.72μm，SR值亦可降至3.41，霧化效果顯著提昇。噴嘴出口加側向噴流更可進一步提昇噴霧品質，例如在水壓5.2kg/cm2，氣壓6kg/cm2下，CK5-C霧化器加入9LPM之單一側向噴流後，SMD即可降至13.29μm，SR值更只有2.74，且此時之氣液質量比僅為0.618，顯示噴霧不僅具有顆粒細微及粒徑大小一致之優點，同時較小的氣液質量比也降低了操作成本，有利於工程上之應用。研究結果亦顯示，少量之側向噴流即可大幅提昇霧化效能(Ea)，代表側向噴流為控制噴霧之細微化及噴霧粒度範圍窄化之控制機制。對於多孔噴頭效應之研究亦發現，縮孔型多孔噴頭具有比直孔型多孔噴頭優良之霧化特性。就CK5-C單孔霧化器與各式縮孔型多孔噴頭之霧化特性而言，於相同的操作壓力，縮孔型多孔噴頭能夠在大幅提高霧化量下，產生與CK5-C單孔霧化器相同之霧化特性。例如在水壓5.2kg/cm2，氣壓6kg/cm2時，使用Ø0.8mm六孔縮孔噴頭之CK5型霧化器，其水流率可達16.20LPH，SMD與SR值則分別為16.50μm和3.06，氣液質量比僅為0.544，顯示縮孔型多孔噴頭可在大量之噴霧量下，達到良好的霧化特性，故為一產生大量噴霧之控制機制。
The effects of different atomization mechanisms on the atomization performance of an air-assist atomizer are investigated in this research program. The atomizers with straight, contraction and expansion configurations are designated by CK5-S, CK5-C and CK5-E, respectively. Nozzles with side jets and multiple orifices are also characterized. The particle size of the spray is measured by Malvern RT-Sizer. The measurement is based on the diffraction pattern scattered by the spray droplets.
Results show that the singularity configuration of the contraction type nozzle enhanced the atomization processes. Hence reduction of the mean particle size (SMD) and size ratio (SR) of spray is achieved. As a typical example, SMD=33.20μm and SR=8.87 for CK5-S atomizer under Pw=5.2kg/cm2 and Pa=6kg/cm2, while SMD=15.72μm and SR=3.41 for CK5-C atomizer, respectively. Obviously, the CK5-C nozzle has better atomization performance. If the side jet is applied CK5-C atomizer, the quality of spray is further improved. For example, when a side jet with 9LPM airflow is injected into CK5-C atomizer, the particle size and size ratio are further reduced to SMD=13.29μm, SR=2.74, respectively. It turns out that the air-to-liquid mass ratio is 0.618. This indicates that the advantages of the spray from the nozzle with side jet are fine droplets and narrow particle size distribution. Simultaneously, the lower air-to-liquid mass ratio also reduces the operation cost. Results also show that a small amount of side jet can enhance the atomization effect substantially. According to the investigation of multiple orifices nozzle, the atomization performance of the contraction nozzle is better than that of the straight one. Comparison of CK5-C atomizer with single orifice and those contraction nozzles with multiple orifices shows that the water flow rate of the later ones is higher than that of CK5-C atomizer. In addition, the SMD and SR associated with CK5-C atomizer and those with multiple orifices are similar. Hence the contraction nozzle with multiple orifices can be regarded as a better atomization mechanism to produce a large amount of spray with good quality.
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校內：立即公開校外：2003-07-08公開