Rayleigh breakup

Surface tension is also responsible for the varicose or Rayleigh breakup of Hquid strands into droplets. By virtue of surface tension the pressure within a strand is slightly higher than that in the ambient gas by the amount ... 

Determine the spray dried particle diameter resulting from the Rayleigh breakup of a jet 1 nun in diameter operating on a 0.001 molar doped iron nitrate solution of Ni—Al-Ga spinel ferrite (i.e., MFe204 M = Nio.5-Alo 3—Gao.2). Assume that the dr3dng conditions are sufficient to evaporate the water but not thermally decompose the hydrated metal nitrates. 

Pressure nozzle spray diameter 70 to 10,00 pm capacity 0.03 to 0.3 L/s low viscosity and clean fluids. Spinning disc spray diameter 50 to 250 pm capacity 0.0015 to 0.4 L/s for usual fluids and for viscous fluid or fluid containing solids. Twin fluid spray diameter 2 to 80 pm capacity 0.03 L/s increasing the ratio of atomizing fluid to liquid from 1 to 10, will decrease the spray diameter by a factor of 10. Rayleigh breakup to produce uniform drops of diameter 1.8 x diameter of orifice. A related topic is prilling (Section 16.11.9.14). Surface aerators for activated sludge oxidation (instead of diffused air aeration. Section 16.11.8.1). Brush aerators for oxidation ditches. Motionless mixers spray flow. 

G. Brenn, St. Kalcmdcrsld, I. Ivanov Investigation of the stochastic collisions of drops produced by Rayleigh breakup of two laminar Uquid jets, Phys. Fluids 9, 349—364 (1997). 

Fig. 27.2 Jet stability curve dripping flow (A-B-C), Rayleigh breakup (C-D), wind-induced regime (D-F), atomization regime (F-G oiH)...

Fig. 27.4 Experimental photo [10] (a) compared with boundary element cranputation (b) [11] for a liquid jet within Rayleigh breakup regime...

Rayleigh breakup to produce uniform drops of diameter 1.8 X diameter of orifice. Related topic prilling. Section 9.12. 

Rayleigh breakup is a continuous mode rather than an on-demand mode which means that... 

In addition to the critical Weber number for a drop-on-demand breakup, the criterion of We > 8 for a Rayleigh breakup has also been reported [16]. This limit can also be motivated by the lower limit of jet formation in the case of dripping out of a vertical capillary with diameter Dnozzis under the action of gravity. The static pressure pstat inside a hanging droplet is... 

Rayleigh breakup regime Drop-on-demand regime Atomization regime... 

Rayleigh breakup is a continuous mode rather than an on-demand mode which means that a liquid jet is ejected out of a nozzle continuously. This jet disperses into single droplets due to the so-called Rayleigh instability after a certain distance from the nozzle. This Rayleigh instability is either caused by naturally occurring disturbances on the jet or by additionally applied external disturbances. In this case the droplet volume almost only depends on the nozzle diameter. The actuation has to be applied for much longer compared to the on-demand modes and can be relatively small. 

There have been a number of studies of the breakup of viscoelastic filaments because of interfacial tension, all of which show that the viscoelastic response results in dynamics that differ markedly from the Rayleigh breakup of inelastic filaments, but the focus for interfacial tension-driven breakup has been on dilute polymer solutions of interest in aerial spraying and inkjet technology applications. The hterature is less extensive for breakup of polymer melts, and some of the issues relevant to dilute solutions are probably not of concern for melts because of the orders-of-magnitude difference in the ratio of interfacial to viscous (or elastic) stresses. 

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