The Effect of Supply Gas Pressure on the Atomization Characteristics of Medical Air-Compression Nebulizers.

Abstract

In treating respiratory diseases, medical air-compression nebulizers play a crucial role in the noninvasive targeted delivery of medications. Alterations in the operating parameters of the nebulizer can cause significant changes in its atomization characteristics, directly affecting the drug delivery efficiency and therapeutic effect. This study examined the impact of the supply gas pressure on the atomization characteristics of medical air-compression nebulizers. Three nebulizers with different nozzle orifice diameters were designed, and the spray penetration, spray concentration, atomizing rate, and droplet size distribution under different supply pressures were compared. In addition, the effective output dose (EOD) has been proposed to evaluate the mass of the drug contained in each liter of air jetted by the nebulizer, thereby assessing the effective dose inhaled by the patient with each inspiration. The results indicate that the supply gas pressure significantly influences the atomization characteristics of air-compression nebulizers. With the increase in supply gas pressure and nozzle orifice diameter, the nebulizer's supply gas flow rate increased from 2.48 to 16.02 L/min, while the jet gas flow rate increased from 14.28 to 41.38 L/min. Concurrently, both the spray volume and atomizing rate also showed progressive increases. The EOD increases with an increase in supply gas pressure but shows no significant correlation with the orifice diameter. As the supply gas pressure increases, the nebulizer with a 0.4 mm orifice diameter exhibited an anomalous increase in droplet size, with <i>D</i> _v90 growing from 7.09 to 8.47 μm. However, the droplet size of nebulizers with 0.6 and 0.8 mm orifice diameters decreases, resulting in a more uniform droplet size distribution. Another finding is that with the increase in supply gas pressure, the nebulizer with a 0.8 mm orifice diameter has a clear advantage in reducing the proportion of large droplets; when the supply gas pressure increased from 50 to 150 kPa, the <i>D</i> _v90 decreased by 29.5%. This study elucidates the effect of supply gas pressure on the atomization characteristics of medical air-compression nebulizers and analyzes the underlying mechanisms, providing theoretical guidance for the design of nebulizers and the development of personalized atomization inhalation treatment plans.