Internal mixing atomization

Atomizers for large boiler burners are usually of the swid pressure jet or internally mixed twin-fluid types, producing hoUow conical sprays. Less common are the externally mixed twin-fluid types (89,90). 

Figure 2.6. Schematic of internal-mixing two-fluid atomizers.

A variety of atomizer designs have been developed in an effort to control the droplet size distribution and to increase the yield of fine powders. Gas atomizers used for the atomization of melts may be loosely classified into two primary categories in terms of the interaction mode between a liquid metal and an atomization gas during atomization, i.e., (1) internal mixing and (2) external mixing. 

In internal mixing atomization (for example centrifugal-pneumatic atomization), 159] the liquid metal and gas enter the swirl jet atomizer tangentially under pressure (Fig. 2.13)J159] The two fluids rotate, form a mixture, and accelerate in the confuser. Due to the strong centrifugal force, the liquid metal forms a film at the nozzle exit even without the presence of the gas. With the applied gas, the liquid film is atomized into a fine dispersion of droplets outside the nozzle. 

Figure 2.13. Schematic of an internal-mixing atomizer for atomization of melts.

Internal mixing air-assist atomizer. Derived from wax spray data in Ref. 461 using NOTE atomizer Good agreement with fuel-air or fiiel-steam spray data 11031 Discrepant with water-air spray data 179114621 MMD is to be multiplied by an empirical correction factor for conditions of droplet coalescence. 

Internal-mixing air-assist atomizer. Derived from water-air spray data mT... 

FIGURE 3 Atomization nozzle designs for internal mixing and external mixing... 

Miinnich, K. O., and W. Roether (1967). Transfer of bomb C-14 and tritium from the atmosphere to the ocean. Internal mixing of the ocean on the basis of tritium and C-14 profiles, In "Radioactive Dating and Methods of Low Level Counting , Symp. Proc., Int. Atom. Agency, Monaco, pp. 93-104. Vienna (STI/PUB/152). 

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