Numerical study of fiber deposition in airway replica using CFD-DEM simulation

Abstract

Inhalation of fibers has been a health concern for several decades. Although the use of some fibers, such as asbestos, was banned altogether in many countries, global demand for other fibers, such as man-made vitreous or carbon fibers, increases every year. The health hazard of fibers is given by their ability to penetrate deep into human lungs and avoid defensive mechanisms. This is mainly given by their anisometric shape and complex behavior in fluid flow, e.g. drag force acting on a fiber depends significantly on fiber orientation. The objective of the present work was to numerically investigate fiber transport and deposition in the model of child respiratory airways including the upper respiratory tract and tracheobronchial tree down to 2nd generation of branching. Computational fluid dynamics–discrete element method was employed to model a fiber motion during which the drag force was calculated based on actual fiber orientation in a flow. This method was compared to a simpler approach in which a modified drag coefficient accounting for fiber non-spherical shape was used. The results of the employed methods were compared.