Acoustic atomization

There may be many other types of periodical vibrations for liquid disintegration or dispersion in various applications. The features, operation parameters, performance and applications of various experimental and commercially available ultrasonic and acoustic atomizers have been described and compared by Topp and EisenklamJ129 ... 

The Hartmann-whistle acoustic atomizer requires gas pressures in excess of 0.3 MPa and air to liquid mass ratios greater than 0.2. Flow rates as large as 1.7 kg/min (water or oil) can be handled with large atomizers. Water droplets as fine as 7 pm can be generated at a flow rate of 0.125 kg/min, a gas pressure of 0.33 MPa, and a... 

Atomization of melts has, in principle, some similarity to the atomization of normal liquids. The atomization processes originally developed for normal liquids, such as swirl jet atomization, two-fluid atomization, centrifugal atomization, effervescent atomization, ultrasonic piezoelectric vibratory atomization, and Hartmann-whistle acoustic atomization, have been deployed, modified, and/or further developed for the atomization of melts. However, water atomization used for melts is not a viable technique for normal liquids. Nevertheless, useful information and insights derived from the atomization of normal liquids, such as the fundamental knowledge of design and performance of atomizers, can be applied to the atomization of melts. 

In an acoustic atomizer, high-frequency sound waves are used to create capillary ripples that ultimately break up into droplets. Ultrasonic atomization can produce a fairly narrow droplet size distribution. 

Formation of droplets from a fluid-fluid interface of a scale at least an order of magnitude smaller than the characteristic scale of the interface. Acoustic atomizers are typical examples of free-surface atomization. 

In the crystal, the total number of vibrations is determined by the number of atoms per molecule, N, and the nmnber of molecules per primitive cell, Z, multiplied by the degrees of freedom of each atom 3ZN. In the case of a-Sg (Z =4, N =8) this gives a total of 96 vibrations ( ) which can be separated in (3N-6)—Z = 72 intramolecular or "internal" vibrations and 6Z = 24 intermo-lecular vibrations or lattice phonons ("external" vibrations). The total of the external vibrations consists of 3Z = 12 librational modes due to the molecular rotations, 3Z-3 = 9 translational modes, and 3 acoustic phonons, respectively. 

The composition factor for the acoustic branch of the NIS spectrum is derived from (9.10) by assuming (in the approximation of total decoupling of inter- and intramolecular vibrations) that the msd in acoustic modes are identical for all the atoms in the molecular crystal ... 

The simple rules of (9.11) and (9.12) were also successfully used to assign the stretching mode of the central iron atom in FC, Fe(C5H5)2, relative to the rest of the molecule as well as the acoustic modes [89]. 

In the molecular approximation used in (14) only the L = 3W — 6 (W is the number of atoms) discrete intramolecular vibrations of the molecular complex in vacuo are considered. In general these vibrations correspond to the L highest optical branches of the phonon spectrum. The intermolecular vibrations, which correspond to the three acoustical branches and to the three lowest optical branches are disregarded, i.e., the center of mass and - in case of small amplitudes - the inertial tensor of the complex are assumed to be fixed in space... 

Bergles, A. E., P. Goldberg, and J. S. Maulbetsch, 1967a, Acoustic Oscillations in a High Pressure Single Channel Boiling System, EUR ATOM Rep., Proc. Symp. on Two-Phase Flow Dynamics, Eindhoven, pp. 525-550. (6)... 

Fig. 13.8 Dependences of the line width of Na atom emission on acoustic power for 2 M NaCl solutions with ethanol concentrations of 0.5 mM (asterisks), 1 mM (triangles) and 2 mM (closed circles). The Na line width without the addition of ethanol is denoted by open circles and has a maximum at 4.8 W...

Ashokkumar M, Vu T, Grieser F (2004) A quest to find the mechanism for the formation of excited state metal atoms during acoustic cavitation. Proc 18th Int Congr Acoust 4 2935-2936... 

Hayashi Y, Choi P-K (2010) Effects of rare gases on MBSL spectrum of K atom emission. Proc 20th Inter Congr Acoust 248-251... 

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