Title: Laminar/turbulent airflow and microsphere deposition in a patient-specific airway geometry using an open-source solver

Authors: Mayank Vaish; Clement Kleinstreuer; Arun V. Kolanjiyil; Nadish Saini; Narasimha R. Pillalamarri

Addresses: Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA ' Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA; Joint UNC-NCSU Department of Biomedical Engineering, North Carolina State University, Raleigh, NC 27695, USA ' Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA ' Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA ' Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, MA 01059, USA

Abstract: Using the open-source software OpenFOAM as the solver, airflow and microsphere transport have been simulated in a patient-specific lung-airway model. A suitable transitional turbulence model was validated and implemented to accurately simulate airflow fields, as the laryngeal jet occurring in the throat region may induce turbulence immediately downstream. Furthermore, a modified eddy interaction model with a generalised near-wall correction factor is presented that more accurately simulates the particle trajectories and subsequent deposition phenomena which are especially affected by near-wall velocity fluctuations. Particle depositions in the realistic lung-airway configuration are compared with those in an idealised upper airway model. The results indicate that for microsphere deposition in turbulent airflow regions, selection of an appropriate near-wall correction factor can reduce the problem of subject variability for different lung-airway configurations. Open-source solvers for lung-aerosol dynamics simulations, such as OpenFOAM, are predictive tools which are basically cost-free, flexible, largely user-friendly, and portable.

Keywords: OpenFOAM solver; idealised configuration; modified eddy interaction; lung airway modelling; microsphere transport; microsphere deposition; practical Stokes number range; laminar flow; turbulent flow; air flow; patient-specific airway geometry; open source software; OSS; simulation; turbulence modelling; near-wall velocity; particle deposition; upper airway; lung aerosol dynamics.

DOI: 10.1504/IJBET.2016.079145

International Journal of Biomedical Engineering and Technology, 2016 Vol.22 No.2, pp.145 - 161

Received: 16 Oct 2015
Accepted: 11 Jan 2016
Published online: 14 Sep 2016 *

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