狹窄粒徑分佈氣膠產生器之設計與性能評估

Design and Evaluation of A Narrow Size-Distribution Aerosol Generator

本研究開發一個可產生狹窄粒徑分佈兼具高質量濃度的氣膠產生器，它的主要組件為一個Delavan霧化噴嘴以及一具改良式虛擬衝擊器；使用噴霧揮發的原理，產生多徑分佈的液態氣膠，再利用重力沉降以及衝擊原理去除較大及較小的微粒，產生粒徑分佈之幾何標準偏差（GSD）小於1.5的固態或液態氣膠。本研究分別使用玉米油、氯化鈉和螢光素鈉水溶液產生高濃度之狹窄粒徑分佈氣膠，結果顯示玉米油氣膠的質量中位氣動直徑（MMAD）=7.2μm，GSD=1.48，氣膠質量產生率（AGR）=13.8mg/min。氯化鈉或螢光素鈉的MMAD介於0.93～4.61μm，GSD介於1.40～1.50，而AGR則介於0.04～15.7mg/min。最後並以1％之NaCl溶液測試氣膠產生器經過八小時連續操作的穩定性，得到其MMAD和GSD的相對標準偏差值均為0.8％，而AGR的相對標準偏差值等於9.2％。

An aerosol generator capable of generating a narrow size-distribution aerosol with high mass concentrations was developed. The aerosol generator consists of a Delavan simplex nozzle and an improved virtual impactor. A polydisperse aerosol is generated through atomization/ evaporation processes. Gravity is used to remove large particles and the improved virtual impactor is employed to remove small particles. The geometric standard deviation of the size distribution of the generated aerosol is less than 1.5. The performance of the aerosol generator has been evaluated using corn-oil, sodium chloride and uranine solution, respectively. The results indicated that the MMAD of the corn-oil droplets was 7.2μm and the GSD was 1.48. Aerosols generated from a NaCl or uranine solution was found to have a MMAD in the range of 0.93 to 4.61μm and a GSD varying from 1.40 to 1.50. Aerosol generation rate varied from 0.04 to 15.7 mg/min depending upon the particle size produced.