Laminar jet breakup

They also proposed an empirical correlation for laminar jet breakup length ... 

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... 

FIGURE 32.8 Schematic representation of the different techniques for drop formation employed in gelation (a) droplet extrusion (b) electrostatic dripping (c) laminar jet breakup (d) jet-cutting (e) jet nebulizer and (f) disk nebulizer. 

Polymeric miaospheres are candidates for use in dmg delivery because of their ease of delivery and the ability to regulate drug release kinetics. Many examples of silk fibroin-based microspheres have been demonstrated. The methods used to produce silk spheres include emulsification, spray drying laminar jet breakup, miaofluidics, lipid templating ... 

Burkholder, H.C. and Berg, J.C., Effect of mass transfer on laminar jet breakup part I. Liquid jets in gases, AIChE J., 20, 863, 872, 1974. 

In this section we give an insight into the validation procedure of droplet generation via laminar jet breakup. The experiments were conducted by the group of Prof. 

A link between laminar and turbulent lifted flames has been demonstrated based on the observation of a continuous transition from laminar to turbulent lifted flames, as shown in Figure 4.3.13 [56]. The flame attached to the nozzle lifted off in the laminar regime, experienced the transition by the jet breakup characteristics, and became turbulent lifted flames as the nozzle flow became turbulent. Subsequently, the liftoff height increased linearly and finally blowout (BO) occurred. This continuous transition suggested that tribrachial flames observed in laminar lifted flames could play an important role in the stabilization of turbulent lifted flames. Recent measurements supported the existence of tribrachial structure at turbulent lifted edges [57], with the OH zone indicating that the diffusion reaction zone is surrounded by the rich and lean reaction zones. 

The liquid jet formed by a pressure nozzle is inherently unstable. The breakup of the laminar jet occurs by symmetrical oscillation, sinusoidal oscillation, and atomization. 

At the current time, the annular jet processes most commonly used in food, pharma, cosmetic, and chemistry that produce particles of one or another kind are certainly laminar flow breakup processes. It has to be kept in mind, that the absolute majority of annular jet processes are used in other fields—as fuel engines—or to produce matrix particles, as two material nozzles used in atomization. Those, however, will not be subject to this chapter. 

From the numerical simulation point of view the encapsulation process consists of (see Fig. 13.1) the components (1) a concentric nozzle being responsible for contacting of the core and shell phases, (2) a modulator being able to introduce modulation disturbances into the system so to enable the controlled breakup and the (3) laminar jet itself being broken into preferably monodisperse composite droplets. 

To overcome the discrepancies between the predictions of Weber s correlations and subsequent experiments, Mahoney and Sterling 248] modified Weber s theory, and derived a universal equation for the breakup length of laminar Newtonian jets ... 

The temperature of a liquid metal stream discharged from the delivery tube prior to primary breakup can be calculated by integrating the energy equation in time. The cooling rate can be estimated from a cylinder cooling relation for the liquid jet-ligament breakup mechanism (with free-fall atomizers), or from a laminar flat plate boundary layer relation for the liquid film-sheet breakup mechanism (with close-coupled atomizers). 

Lafrance, P. Nonlinear breakup of a laminar liquid jet. Phys. Fluids 18, 428 32 (1975). 

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). 

Inamura and Tomoda [28], and Inamura et al. [2] investigated the behavior of liquid sheet generated by impingement of a liquid jet onto a solid wall. They [2] combined Dombrowski s model of sheet breakup with the sheet thickness model developed based laminar boundary-layer analysis to predict the droplet size. However, they did not provide any correlation for droplet size. Fard et al. [10] studied numerically the effect of liquid properties and nozzle geometry on the droplet size distribution produced by splash plate nozzle. Again, no correlation to relate the droplet size with the studied parameters was provided. 

Theoretical and experimental studies on three-dimensional path and Rayleigh-type breakup of laminar particle-laden liquid jets were presented. The investigation focused on spiraling jets emerging from rotary atomizers which were additionally... 

Mun, R. P., Byars, J. A., Boger, D. V. (1998). The effects of polymer concentration and molecular weight on the breakup of laminar capillary jets. Journal cf Non-Newtonian Fluid Mechanics, 74, 285-297. 

Pan, Y., Suga, K. (2006). A numerical study on the breakup process of laminar liquid jets into a gas. Physics of Fluids, 18, 052101. 

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