Breakup regimes

In the breakup regime, spray characteristics include film angle, film velocity and thickness, breakup length, breakup rate, surface wave frequency, wavelength, growth rate, and penetration distance. These quantities, however, are extremely difficult to measure on account of the very small size and rapidly changing features of disintegrating Hquid jets or films. 

Weber s theory has been further extended by many investi-gators[391 [4ill204 [22°][22-7] t0 account for high-velocity jet breakup and droplet formation under the influence of ambient air. Various mechanisms of jet breakupl40H41Pio][220][227][232] have been pro posed and divided into breakup regimes to reflect the differences in the appearance of jets and to identify the dominant forces leading to jet breakup as operation conditions are changed. 

Table 3.1. Classification and Criteria of Breakup Regimes of Round Liquid Jets in Quiescent Air...

Figure 3.2. Breakup regimes of round liquid jets in quiescent air. I Rayleigh Jet Breakup (Varicose Breakup) II First Wind-Induced Breakup (Sinuous Wave Breakup) III Second Wind-Induced Breakup (Wave-like Breakup with Air Friction) IV Atomization.

Based on their experiments, Tanasawa and Toyoda1411 proposed a new dimensionless number for the classification of jet breakup regimes. This number, called Jet number, is defined as ... 

Table 3.2. Classification and Criteria of Breakup Regimes of Round Liquid Jets in Co-flowing Air as Compared to Those of Thin Liquid Sheets and Spherical Droplets in Air Stream 210 ...

Figure 3.7. Breakup regimes of round liquid jets in co-flowing air. (Reprinted...

Table 3.3 Values of Weber Number for Transitions from No Deformation Regime up to Shear Breakup Regime at 0hd <0.1...

In the breakup regimes, a droplet may undergo secondary breakup when the breakup time is reached. The droplet size distribution after bag or multimode breakup may follow the Simmons root-normal distribution pattern 264 with MMD/SMD equal to 1.1,... 

In the Rayleigh or varicose breakup regime, the Duifie and Marshall equation (40), which is based on experimental data, predicts... 

Chou, W.-H., L.-P. Hsiang, and G. M. Faeth. 1997. Dynamics of drop deformation and formation during secondary breakup in the bag breakup regime. AIAA Paper No. 97-0797. 

List of Previously Published 2 29 Criteria for the Transition between the Different Breakup Regimes... 

The different correlations shown in Table 6.3 are inconsistent according to Ahmed and Youssef, due to different causes such as the difference in breakup regime, the different ranges of variables, the difference in measuring and sampling techniques. The use of a single atomizer to develop these... 

W. H. Chou, G. M. Faeth Temporal Properties of Secondary Drop Breakup in the Bag Breakup Regime, Inti. J. Multi. Flow 24(6), 889-912 (1998). 

The DDB model is applicable to the shear breakup regime, assumed to start at... 

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