双视角下的横向射流袋式破碎过程及动力学分析

Experimental study on visualization of bag breakup process under different viewpoints in transverse airflow was conducted using high-speed camera combined with backlighting method. The gas Weber number varied within the range of 5.5—50 and the liquid-to-air momentum flux ratio varied within the range of 20—60. In the tests， the formation and breakup of bags and the effect of aerodynamic conditions on them were analyzed. It was found that in the spreading images，the Weber number of the gas affected the breakup mode; the number of bags generated increased with the increase of the jet flow ratio，the onset length of the bag was linearly related to the dimensionless number consisting of the injection volume ratio and the Reynolds number of the liquid，and the onset time of the bag was a constant; the breakup length and time of the bag were both linearly related to the Weber number，and empirical relations for the characteristic quantities associated with bag breakup in non-turbulent flows were proposed. Finally，the bag breakup instability and the special structure of the flowing and spreading directions were qualitatively analyzed by proper orthogonal decomposition. The results showed that the special phenomenon of jet splitting was observed on the spreading image and dominate the energy; the fast Fourier transform (FFT) frequency ratio of the occurrence of the spreading upward bag ring to the body of the bag fluctuated between 1.5—1.6; and the increase of the liquid-to-air momentum flux ratio made the bag structure complicated.