Free-fall atomizer design

Figure 5.2. Calculated gas flow fields in the near-nozzle region of free-fall atomizers. Primary gas pressure 0.140 MPa secondary gas pressure 0.189 MPa angle of secondary gas nozzle relative to the spray centerline 10° angle of primary gas nozzle relative to the spray centerline (a) 0°, (b) 22.5°, and (c) 30° designed for minimizing recirculation gas flow. (Reprinted from Ref. 612.)...

For the delivery of atomization gas, different types of nozzles have been employed, such as straight, converging, and converging-diverging nozzles. Two major types of atomizers, i.e., free-fall and close-coupled atomizers, have been used, in which gas flows may be subsonic, sonic, or supersonic, depending on process parameters and gas nozzle designs. In sonic or supersonic flows, the mass flow rate of atomization gas can be calculated with the following equation based on the compressible fluid dynamics ... 

The gas atomizer can be classified into two basic types, open-type (free-fall design) and close-type (confined design) atomizers as shown in Fig. 36.2, according to the relative position between the atomization gas jets and molten metal stream [5, 8]. 

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