AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Multi-component Droplet-Vapor Interaction in a Realistic Human Whole-Lung Airway Model
ARUN V KOLANJIYIL, Clement Kleinstreuer, North Carolina State University
Abstract Number: 411 Working Group: Health Related Aerosols
Abstract Respiratory drug delivery is becoming an increasingly popular way of administering medicine. In many cases validated computer simulations can be useful for establishing guidelines for effective treatment of both adverse pulmonary and systemic conditions. However, the sheer complexity of the human lung, featuring a total of 16 million tubular airways, prohibits detailed computer simulations of the fluid-particle dynamics for the entire respiratory system. Thus, in order to obtain realistic and accurate particle deposition results, a new modeling approach is necessary where the whole-lung geometry is approximated with physiological boundary conditions which simulate actual breathing. So, a whole-lung-airway model (WLAM), covering the entire human lung was developed by using any subject-specific human upper airway followed by triple bifurcation units both in series and parallel. Physiologically breathing modes were implemented via realistic expanding and contracting motion of the alveoli. The airflow and particle transport through the lung airways were successfully validated with in vivo and in vitro data sets. As a practical application, the fate of inhaled multi-component droplets and associated vapors emanating from an inhaler (e.g., a pMDI or nebulizer) was simulated and analyzed. Specifically, in the upper airways the transport of these droplets was modeled with hygroscopic growth during droplet–vapor interaction. In the lower airways, where the droplets are in equilibrium with the vapor, transport and deposition of these droplets were simulated, neglecting droplet–vapor interactions. The computer simulation results provide critical insight to and quantitative information of drug-aerosol deposition in the human whole-lung airway model. In summary, WLAM can predict inhaled therapeutic (or toxic) multi-component aerosol deposition. It is also useful for establishing inhaler-design guidelines to improve drug-aerosol delivery.