Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model

This study investigates the atomization process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers (SMIs) using a validated Volume of Fluid (VOF)-to-Discrete Phase Model (DPM) to simulate the transition from colliding liquid jets to aerosolized droplets. Key parameters,...

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Main Authors: Ted Sperry, Yu Feng
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Bioengineering
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Online Access:https://www.mdpi.com/2306-5354/12/3/264
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author Ted Sperry
Yu Feng
author_facet Ted Sperry
Yu Feng
author_sort Ted Sperry
collection DOAJ
description This study investigates the atomization process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers (SMIs) using a validated Volume of Fluid (VOF)-to-Discrete Phase Model (DPM) to simulate the transition from colliding liquid jets to aerosolized droplets. Key parameters, including colliding jet inlet velocity, surface tension, and liquid viscosity, were systematically varied to analyze their impact on the atomization, i.e., aerosolized droplet size distributions. The VOF-to-DPM simulation results indicate that higher jet inlet velocities enhance ligament fragmentation, producing finer and more uniform droplets while reducing total atomized droplet mass. The relationship between surface tension and atomization performance in colliding jet atomization is not monotonic. Reducing surface tension plays a complex dual role in the atomization process. On the one hand, lower surface tension enhances the likelihood of liquid jet breakup into a liquid sheet, leading to the formation of smaller ligaments under the same airflow conditions and shear forces. This increases the probability of generating more secondary droplets. On the other hand, reduced surface tension also destabilizes the liquid surface shape, decreasing the formation of fine, high-sphericity droplets in regimes where surface tension is a dominant force. Viscosity also influences atomization through complex mechanisms, i.e., lower viscosity reduces resistance to ligament breakup but promotes droplet interactions and coalescence, while higher viscosity suppresses ligament fragmentation, generating larger droplets and reducing atomization efficiency. The validated VOF-to-DPM framework provides critical insights for enhancing the performance and efficiency of inhalation therapies. Future work will incorporate nozzle geometry, jet impingement angles, and surfactant effects to better understand and optimize the atomization process in SMIs, focusing on achieving preferred droplet size distributions and emitted doses for enhanced drug delivery efficiency in human respiratory systems.
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spelling doaj-art-8e7538fae2b848ea8451043c09f494302025-08-20T02:11:00ZengMDPI AGBioengineering2306-53542025-03-0112326410.3390/bioengineering12030264Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase ModelTed Sperry0Yu Feng1School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078, USASchool of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078, USAThis study investigates the atomization process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers (SMIs) using a validated Volume of Fluid (VOF)-to-Discrete Phase Model (DPM) to simulate the transition from colliding liquid jets to aerosolized droplets. Key parameters, including colliding jet inlet velocity, surface tension, and liquid viscosity, were systematically varied to analyze their impact on the atomization, i.e., aerosolized droplet size distributions. The VOF-to-DPM simulation results indicate that higher jet inlet velocities enhance ligament fragmentation, producing finer and more uniform droplets while reducing total atomized droplet mass. The relationship between surface tension and atomization performance in colliding jet atomization is not monotonic. Reducing surface tension plays a complex dual role in the atomization process. On the one hand, lower surface tension enhances the likelihood of liquid jet breakup into a liquid sheet, leading to the formation of smaller ligaments under the same airflow conditions and shear forces. This increases the probability of generating more secondary droplets. On the other hand, reduced surface tension also destabilizes the liquid surface shape, decreasing the formation of fine, high-sphericity droplets in regimes where surface tension is a dominant force. Viscosity also influences atomization through complex mechanisms, i.e., lower viscosity reduces resistance to ligament breakup but promotes droplet interactions and coalescence, while higher viscosity suppresses ligament fragmentation, generating larger droplets and reducing atomization efficiency. The validated VOF-to-DPM framework provides critical insights for enhancing the performance and efficiency of inhalation therapies. Future work will incorporate nozzle geometry, jet impingement angles, and surfactant effects to better understand and optimize the atomization process in SMIs, focusing on achieving preferred droplet size distributions and emitted doses for enhanced drug delivery efficiency in human respiratory systems.https://www.mdpi.com/2306-5354/12/3/264Soft Mist inhaler (SMI)volume of fluid-to-discrete phase model (VOF-to-DPM)atomizationemitted droplet size distribution
spellingShingle Ted Sperry
Yu Feng
Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model
Bioengineering
Soft Mist inhaler (SMI)
volume of fluid-to-discrete phase model (VOF-to-DPM)
atomization
emitted droplet size distribution
title Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model
title_full Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model
title_fullStr Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model
title_full_unstemmed Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model
title_short Prediction of the Atomization Process in Respimat<sup>®</sup> Soft Mist<sup>TM</sup> Inhalers Using a Volume of Fluid-to-Discrete Phase Model
title_sort prediction of the atomization process in respimat sup r sup soft mist sup tm sup inhalers using a volume of fluid to discrete phase model
topic Soft Mist inhaler (SMI)
volume of fluid-to-discrete phase model (VOF-to-DPM)
atomization
emitted droplet size distribution
url https://www.mdpi.com/2306-5354/12/3/264
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AT yufeng predictionoftheatomizationprocessinrespimatsupsupsoftmistsuptmsupinhalersusingavolumeoffluidtodiscretephasemodel