Abstract

Jet nebulizers are a common form of nebulizer used for aerosol treatment. They are known to function poorly in children under five due to differences in patient attributes. They must reduce their mass median aerodynamic diameter (MMAD) to work more effectively. This allows more medicine to be deposited in the lungs and absorbed. Solving this problem can affect 9 million annual deaths worldwide due to repository disease. While lowering the billions of dollars, the U.S. spends on these deaths. This study focused on the standard Hudson Micro Mist Nebulizer and investigated spray physics using experimental and simulation methods to enhance its design. The present investigation aims to fill a research gap on jet nebulizers. Unlike previous studies, this analysis divides the primary atomization into one simulation and the secondary atomization into a separate simulation. This methodology accelerates simulation speed from months or years to a single week and facilitates parametric optimization. Moreover, it provides more insights into the primary atomization region and particle transport, which no experimental technique can obtain simultaneously. The numerical results optimize multiple metrics, including MMAD, geometric standard deviation (GSD), and air-to-liquid ratio (ALR). The present study introduces modifications to the conventional Hudson Micro Mist nebulizer by manipulating the inlet pressure (10, 20, 30 psi), the baffle geometry (spherical, baffle), and the nozzle orifice area ratio (0.59, 0.70, 1.10). The original design uses a pulsating 12 psi inlet pressure, spherical baffle, and the 0.59 orifice area ratio. The investigation identifies superior designs and elucidates the underlying mechanisms that enhance spray distribution. The numerical simulations exhibited a trend-following behavior and generally agreed with the experimental outcomes, providing valuable insights into the design factors that affect the critical metrics of MMAD, ALR, and GSD. The results indicated that the orifice area ratio had little effect on these metrics, while the inlet pressure and baffle geometry had significant impacts, corroborated by experiments. Both the experiments and simulations suggested that the 30-psi bar baffle design was optimal for achieving the desired MMAD and GSD values, reducing the MMAD by 70% in experiments and 66% in simulation. However, it was found to be suboptimal for ALR. Therefore the 30-psi bar baffle design is suggested for use.

Library of Congress Subject Headings

Atomizers--Design and construction--Computer simulation; Atomizers--Design and construction--Testing; Pediatric respiratory diseases--Treatment; Aerosol therapy; Computational fluid dynamics

Publication Date

5-9-2023

Document Type

Thesis

Student Type

Graduate

Degree Name

Manufacturing and Mechanical Systems Integration (MS)

Department, Program, or Center

Manufacturing and Mechanical Engineering Technology (CET)

Advisor

Larry Villasmil

Advisor/Committee Member

Jennifer O'Neil

Advisor/Committee Member

Martin K. Anselm

Campus

RIT – Main Campus

Plan Codes

MMSI-MS

Download

Share

COinS