人類追逐科技的極限時，又需兼顧環境的保護。液態燃料在工業或運輸中有巨大的優勢，但燃燒後之排放受到目前世界各國立定環保法規之限制，過去為追求快速之發展一味追求最大輸出，現今的社會有更多的考量。噴霧之行為關係到液態燃料燃燒之排放，故本研究使用Star ccm+中的VOF 法，針對渦輪發動機常用之預膜式噴最進行，主要破裂[1]之研究，其內容分為可視化與流場之數據分析。由可視化之直接觀察流場中Kelvin-Helmholtz 之現象，使得液膜震盪，並且破裂，此外隨渦漩對液膜撕裂之影響液也可以由可視化看出切線速度對於液膜之撕裂，藉由加入渦漩空氣能加速液膜之破裂，並且軸線方向之空氣由液膜運動方向撕裂液膜，切線方向之空氣由液膜切線方向撕裂液膜。
並分析渦漩數與動量通量比對於液膜破裂的影響，其中分為生長率、液膜張腳與破裂長度。在不同軸向空氣流速觀點下，渦漩氣流在提升液膜張角的同時減短了液膜軸線方向之破裂長度，但又因液膜張角獲得了增加，故隨液膜運動之方向量測的破裂長度因此並為隨渦漩數增加而減少，若換為空氣液體動量通量比，則可發現若渦漩數增加則須更大之動量通量比才能達到相同之破裂長度。
關鍵字：液膜破裂、渦漩數、兩項流、計算流體力學

A pre-film injector with a coaxial swirl air flow is investigated by using CFD method with commercial code named starccm+. The breakup process of liquid film has preformed step by step with an implicit unsteady time model. For this simulation, several gists have to deal by numerical model. VOF model is used as multiphase model, interface tracking is preform as isovalue of volume of fraction of water. Decomposed swirl air into the coaxial one and the tangential one. Both air flow accelerate the breakup process, and the increasement of each one increase momentum ratio. The coaxial air flow induce the oscillation of liquid film, this phenomenon can be quantify by the growth rate. The tangential air flow can be descript by swirl number which is the ratio of tangential momentum flux and axial momentum flux. The effect of coaxial velocity, momentum ratio, swirl number have been analysis in this study by both visualization and data formation.

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