溫室效應造成的全球暖化問題越來越被受重視，其中以CO2排放量為暖化主要原因之一。為解決CO2排放量之問題，產業界針對此方向投入大量研究開發CO2 之新用途，以其降低生物傷害與環境衝擊，如：CO2洗淨技術。CO2洗淨技術已廣泛應用於工業及醫療用途上，舉凡精密電子電路元件、微機電元件、半導體元件、光電產品及無菌醫療器材等。
本研究利用CO2流體藉由不同噴嘴型態(流道結構、材質、管長)改變流場之特性以比較其清洗效能，並觀察不同型態噴嘴所噴出之CO2雪花顆粒大小是否影響清洗效能。由實驗結果得知，多孔流道平板之噴嘴因噴嘴間距近，較單孔流道平板噴嘴易產生擾流現象，且多孔流道平板噴嘴其噴出之清洗面積大、噴出氣流強、雪花顆粒小且分佈密集，故能將清洗距離有效提升至45cm；採用熱傳導性差之單孔壓克力圓管噴嘴，會造成噴嘴周期性之堵塞現象，且其堵塞會形成顆粒較大固態CO2雪花；不銹鋼單孔圓管型噴嘴則無堵塞，其噴出之CO2固體顆粒較小且均勻，雖清洗品質穩定但清除能力較單孔壓克力圓管型噴嘴者差；觀察不同管長之單孔不銹鋼圓管型噴嘴之清洗效率，以管長較長之噴嘴其流場集中、清洗效果較為顯著。

CO2 emission is one of the main reasons causing green house effect which impacts the global climate and requires special attention. In order to reduce the quantities of CO2 emission, industrial circles make much research on new applications of CO2 to reduce environment at impact and harmful effects. CO2 cleaning technology is one of them.
This study uses different nozzle types (different channel structure、material and tube length) to make CO2 flows to compare the CO2 cleaning performance. The snow sizes from different nozzles and their effects on the cleaning performance are explored. The experimental results show that the multi-orifice flat plate type nozzle has short distance between nozzles and produces turbulence more easily than the single-orifice flat plate type nozzle. Thus, the jet has large cleaning area、higher speed、small snow size and tight distribution. The effective cleaning distance can be prolonged to 45cm. Using low conductivity single-orifice tube type nozzle of acrilan material leads to nozzle blockage periodically which enlarges CO2 snow particles. On the other hand, single-orifice tube type nozzle of stainless steel material has no blockage and smaller CO2 snow particles are generated more uniformly and result in less efficient cleaning. From the cleaning performance of nozzles of different tube length, the one with a longer tube perform better.

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