Abstract: The primary atomization process of coaxial two-channel air-blast atomizer was investigated experimentally.During the coaxial air-blast atomization process, small initial disturbances were amplified after a certain length (called an undisturbed length,L_u) and evolved into unstable waves eventually, which could be observed on the surface of the liquid jet.Above a critical gas exit velocity (about 25 m·s^-1), liquid ligaments were produced at the wave crests and further stretched into the air stream.Finally, the liquid ligaments broke up into droplets, leading to the primary atomization of liquid jet.The relationship between instability wavelength λ_m and the air velocity U_g and water velocity U_L was λ_m=68.60 U^-0.79_gU^-0.24_L.And the relationship between the undisturbed length L_u and the air velocity U_g and water velocity was L_u=783.8 U^-1.54_gU^-0.16_L.

摘要： 对同轴双通道气流式雾化喷嘴的初次雾化过程进行了实验研究，发现在初次雾化过程中，初始微小扰动经过一段距离（即未扰动长度）后，在液体射流表面发展成为可以观察到的不稳定波.当气速U_g超过一临界值（大约25 m·s^-1）时，在不稳定波的波峰附近，形成小的突起，这些突起迅速被拉成细长液丝，液丝进一步破裂成液滴，最终导致液体的初次雾化.同时得到不稳定波长λ_m与环隙通道出口气速U_g、中心通道出口水速U_L的关系为λ_m＝68.60 U^-0.79_gU^-0.24_L;未扰动长度L_u与气速U_g、水速U_L的关系为L_u＝783.8 U^-1.54_gU^-0.16_L.