기체주입노즐의 미립화 성능에 관한 연구

Abstract

An experimental study was conducted to examine the effect of internal flow patterns inside the mixing chamber on the atomization performance of effervescent atomizers. The mixing chamber has the rectangular cross section (8㎜×2㎜) and made of transparent acrylic plate for flow visualization. The parameters tested were the air/liquid ratio (ALR), injection pressure, and the nozzle orifice diameter. Three different flow regimes were observed; bubbly, annular, and transition flows. In the bubbly flow regime, the discharged mixture is disintegrated into drops through the bubble expansion and the ligament breakup. On the other hand, in the annular flow regime, the liquid annulus is disintegrated into small drops by the aerodynamic interaction between the phases due to the high relative velocities between the gas and the liquid. In the transition flow regime, the bubble-expansion/ligament-disintegration mode and the annulus-disintegration mode appeared alternatively. Finally, based on the size measurement, the drop size correlations were proposed pertinent to each flow regime.