SIZE AND VELOCITY CHARACTERIZATION OF ASYMMETRIC TWIN-FLUID NEBULIZER SPRAYS

摘要

Drop size and velocity measurements were obtained for two nebulizers unique in their asymmetric configuration—a "quarter-moon" liquid exit port, whose axis of symmetry is located nearly co-axially with a circular air exit port. The two devices, a Mira Mist and an LB-30, are commercially available units originally designed for mass-spectrometry applications, but also useful for medicinal/pharmaceutical spray purposes. Sprays were characterized in terms of droplet velocity and size at a number of axial and radial positions. Measurements were performed using a Dantec DualPDA. Air injection pressures of 270 to 410 kPa (25 to 45 psig) and liquid flow rates of 75 to 1200 ml/hr were the operating conditions considered in this study. Water and ethanol were used as test fluids since their physical properties span the range of typical products. The results are useful because they show, for the first time, how sprays formed from such asymmetric devices evolve as they move away from the atomizer.