本研究使用自行設計的預成膜氣衝式噴注器，探討在改變氣體質量流率及渦旋數條件下，對噴霧霧化特性的影響。實驗採用水作為液體，質量流率固定為 20 g/s，氣體則使用氮氣，質量流率分別設定為 1.79 g/s、3.20 g/s 和 4.47 g/s。為產生渦旋氣流，於噴注器內加入渦旋導流葉片，並設定渦旋數為 0、0.39、0.677 和 1.172。實驗過程中，藉由高速攝影機、粒徑量測儀及雷射技術進行觀察與數據分析。
實驗結果顯示，隨著氣體質量流率的增加，氣體將噴霧內部的環境氣體帶離，造成局部壓力下降，使霧化角減小。此外，氣體動量通量的提升透過氣液黏性作用加速了液體運動，增加了流體動力不穩定性，導致破碎長度縮短。氣液速度差的增加亦強化了空氣動力不穩定性，進而有效降低了噴霧的平均粒徑。
另一方面，在固定氣體質量流率的條件下，隨渦旋數的增加，霧化角先因噴霧內部壓力下降而減小，但當渦旋數持續增大時，氣體動量與動壓的增加減緩了噴霧內外壓差對液膜的壓縮作用，導致霧化角回升。同時，渦旋數的增加促使氣體沿著噴注器壁面流動，增強了氣液間的動量傳遞，加劇了流體動力與空氣動力的不穩定性，使得破碎長度顯著下降。

This study aims to investigate the effects of gas mass flow rate and swirl number on the spray characteristics of a prefilming air-blast injector. Gas mass flow rate and swirl number are key parameters influencing atomization performance, significantly affecting spray angle, breakup length, and droplet size distribution. Experimental results indicate that as the gas mass flow rate increases, the spray angle, breakup length, and mean droplet diameter decrease, thereby improving atomization efficiency. However, when the airflow exhibits strong vortex characteristics, large droplets that have not undergone secondary breakup tend to accumulate at the spray periphery, potentially affecting combustion efficiency and mixture uniformity. Additionally, as the swirl number increases, the intensified air–fuel interaction leads to a reduction in spray angle and a shorter breakup length. The findings of this study provide insights into optimizing the design of air-blast injectors by balancing gas mass flow rate and swirl intensity to enhance atomization performance.

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