Droplet disintegration processes

Coulombic explosion The process by which a droplet disintegrates into a number of smaller droplets which occurs when the repulsive forces between charges on the surface of a droplet are greater than the cohesive force of surface tension. 

Finally the studies [314, 392] should be mentioned, which also deal with the effect of mixing time on the droplet size distribution. Logarithmic cumulative volume distributions were presented as a function of droplet volume for different mixing times, was made so small, that the mixing time only caused parallel shifts of the distribution curves (without changing the slope) this confirmed, that the disintegration process did not change with time. 

The many words employed to describe particulate systems attest to their ubiquity and to ilie impression they have made on humans from early times. Smoke, dust, haze, fume, mist, and soot are all terms in common use with somewhat different popular meanings. Thus dust usually refers to solid particles produced by disintegration processes, while smoke i nd fume particles are generally smaller and formed from the gas phase. Af/.vr.v are composed of liquid droplets. Soot usually refers to small carbon particles generated in fuel combu.stton but is now frequently used to describe very fine solid particles of silica and other inorganic oxides generated intentionally in industrial processes. In this text, however, we will rarely employ these special terms because of the difficulty of exact definition and the complexity of many real systems composed of mixtures of particles. Instead, we employ the generic term aeiosol to describe all such sy.siems of small particles suspended in air or another gas. 

How the droplets produced upon ESI are transformed to the ions observed in the mass spectrum is not yet well xmderstood. As the solvent in the droplets evaporates, the droplets shrink and the ions contained in them accumulate at the surface to minimize coulombic repulsion between the charges. This process can continue until the Rayleigh instability limit is reached, at which the droplets disintegrate ("explode") into smaller droplets (Figure 1.15) that also shrink by solvent loss. Sequential subdivision through coulombic explosion at the Rayleigh limit may be repeated until the... 

Roller atomization is a mechanical atomization process. It was invented in the mid 1970 sJ188] In this process, as schematically depicted in Fig. 2.22, a stream of molten metal is fed into the gap between two counter-rotating rolls and forms a thin liquid sheet that subsequently disintegrates into droplets by the mechanical forces. In the original design, a pair of rollers of 100 mm in diameter are mounted in the same horizontal plane and rotate at speeds up to 1250 radians/s. The roll gap is about 50-100 pm, and the metal flow rate is up to 6 kg/min. 

This process, also termed rapid spinning cup (RSC) process, was invented in the early 1980 s contemporarily by Osaka University in Japan[191] and Battelle s Columbus Division in the US)192 Unlike water atomization where water streams or droplets are used to disintegrate a molten metal, a coherent fast-moving liquid layer is used in the RSC process. Liquid quenchants include water, oil, glycerine, and other commercial quenching liquids. The materials atomized with the spinning cup method include a wide variety of metals and alloys such as tin, lead, aluminum alloys, copper alloys, iron alloys (stainless steels and high speed tool steels), zinc alloys and superalloys.[192]... 

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