Publicado 12 números por año
ISSN Imprimir: 1044-5110
ISSN En Línea: 1936-2684
Indexed in
PHYSICAL PROCESSES INFLUENCING EFFERVESCENT ATOMIZER PERFORMANCE IN THE SLUG AND ANNULAR FLOW REGIMES
SINOPSIS
Department of Chemical and Process Engineering, University of Sheffield, Sheffield, United Kingdom Effervescent atomizers made from Perspex with rectangular-cross-section mixing channels have enabled a high-speed video study of the interaction between the internal two-phase flow and the external atomization process. Droplet sizes were measured using a laser diffraction instrument. The gas is seen to vent at sonic velocity in bursts along the axis of an annular liquid jet. Theoretical analysis indicates that the annulus is eroded by the Kelvin-Helmholtz instability ultimately exciting sheet instabilities. The relative contributions of the two instabilities, combined with coalescence of the smaller droplets, is considered to determine the differences between the size distributions generated by circular and slot-shaped orifices. Instabilities have also been observed in the liquid film on the wall of the mixing channel which degrade atomization quality. A new correlation has been developed for the liquid discharge coefficient which extends previous work on bubbly flows to the slug and annular flow regimes.