ID 330

Investigation of Particle Size Distributions from Low-flow Jet Nebulizers

 

Abstract:

This work aims to address a critical knowledge gap in jet nebulizers used with hand-cranked compressors (commonly known as human-powered nebulizers). By observing nebulizer operation, the possibility for a lower flow rate (4 LPM) while maintaining a particle drop size of 5 μm is investigated through experimentation. Worldwide respiratory disease remains a leading cause of death and disability. Accessibility to health care in low resource countries is quite challenging, resulting to the use of hand cranked compressors with nebulizers that require high airflow rates, decreasing ease of operation. Therefore, the primary focus will be on modifying the internal geometry of the jet nebulizer, specifically the baffle shape, to allow a lower airflow rate while maintaining the required drop size. To do this, QVI metrology equipment was used to investigate geometric parameters of several off-the-shelf jet nebulizers. From these measurements, a standard model was developed to serve as a template for new designs. An investigation of airflow and particle size distribution of the Hudson Micro Mist was conducted using a Sympatec Laser Diffraction system and compared with industry data to validate the experimental setup. New designs were created by changing baffle shape, hemispherical to conical, or adding additional outputs to increase atomization. These novel designs were printed using ABS and an experimental investigation of the resulting airflow and particle size distribution is in progress. From the experimental data, a computational fluid dynamic analysis was modeled to determine the output atomized liquid velocity towards the baffle for final spray distribution.