Wave disintegration

Liquid sheet formation by an appropriate nozzle is followed by rim disintegration, aerodynamic wave disintegration, and turbulent breakup. 

As discharge velocity at the nozzle outlet increases, the following states appear in succession dripping, laminar jet breakup, wave disintegration, and atomization. These states of fiow are described in a pi space Re, Fr, Wep, whereby Wep = pv dp/a represents the Weber number formed by the droplet diameter, dp. To eliminate the fiow velocity, v, these numbers are combined to give... 

The fitting line corresponds to the analytical expression for the wave disintegration of pure liquids by hollow cone nozzles ... 

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. 

The situation is different on GC where only one irreversible cathodic wave is observed at —1.6 V, associated with disintegration of the compound, and one anodic wave on the reverse scan, caused by stripping of the lead released by the reduction ... 

Taylod205 also conducted mathematical analysis of the generation of ripples by wind blowing over a viscous fluid. Using a relationship between the growth of the amplitude of disturbance waves and the surface stress, Taylor derived a criterion for the instability of waves. In Taylor s instability theory, the disintegration of a liquid sheet/film is visualized as a process in which droplets are detached from the liquid surface with a wave of optimum amplitude. The diameter of the most frequent droplets is then formulated as a function of air velocity over the liquid surface, liquid density, surface tension and viscosity, as well as air density. 

Although a liquid sheet may leave the nozzle with some perturbations, the principal cause of the instabilities is the interaction of the sheet with the high-velocity air streams whereby rapidly growing waves are imposed on the sheet. Disintegration may occur when the amplitude of these waves reaches a critical value. Each full sinusoidal wave is initially distorted to yield two half-waves of very similar forms. The constant stretching of the half-waves increases... 

Flat Sheets. Generally, the interface between a liquid sheet and air can be perturbed by aerodynamic, turbulent, inertial, surface tension, viscous, acoustic, or electrical forces. The stability of the sheet and the growth rate of unstable disturbances are determined by the relative magnitude of these forces. Theoretical and experimental studies 255112561 on disintegration mechanisms of flat sheets showed that the instability and wave formation at the interface between the continuous and discontinuous phases are the maj or factors leading to... 

Suddenly exposed to a high-velocity gas stream, a droplet is deformed into a saucer shape with a convex surface to the gas flow. The edges of the saucer shape are drawn out into thin sheets and then fine filaments are sheared from the outer part of the sheets, which subsequently disintegrate into smaller droplets and are swept rapidly downstream by the high-velocity gas. Unstable growth of short wavelength surface waves appears to be involved in the breakup process. 21° This is known as shear breakup (Fig. 3.10)J246f... 

Many cells, especially bacteria, yeast, etc., require very drastic measures to disrupt them and various cell disintegrators are available for this purpose. Ultrasonic vibrations cause the formation of minute bubbles, a phenomenon known as cavitation, which is caused by the extreme variations in pressure generated by the sound waves, although the generation of heat may cause problems unless the samples are cooled frequently during the treatment. An additional... 

The influence of conditions on the droplet size where the spray sheet disintegrates through aerodynamic wave motion may be represented by the following expression proposed by Dombrowski and Monday134 for ambient densities around normal atmospheric conditions ... 

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