Transport and deposition of aerosols in human respiratory tract is an active area of research. Aerosol inhalation is one method for delivering medication to the human body. On the other hand, inhaled air sometimes contains harmful particles like particulate matter. Besides spherical aerosols such as droplets or dust also fibrous particles are investigated. Due to their irregular shape, they can penetrate deeper into the respiratory system and may be more efficient for medical purposes. Nevertheless, the complex shape poses challenges for simulation because the drag force depends on the current orientation to the flow. Furthermore, in the area of bifurcations fibrous particles tend to change the orientation or start flipping. The Euler-Lagrange Euler-Rotation (ELER) method computes particle movement via Lagrangian tracking and particle rotation via Euler kinematical equations. These equations are computationally more expensive than the standard Lagrange approach of effective diameter but yield more accurate results. \\
  The primary objective of this thesis was to extend the ELER method into the Lattice Boltzmann Method (LBM), a mesoscopic approach that models fluid dynamics based on the statistical behaviour of fluid particles. This integrated framework was then applied to simulate fibrous particle transport within a realistic anatomical model of human airways, extending down to the seventh generation of branching.
The findings confirm that the deployed ELER method provides higher accuracy in predicting deposition fractions compared to the effective diameter approach, as validated against experimental data. Nevertheless, a comprehensive analysis of the rotational motion of fibers against high-speeed camera experimental measurements still revealed significant discrepancies. As a potential source of them, the observed fibers in the experiment indicate asymmetrical deformations, created during the fabrication procedure. To account for these real-world shape changes, a novel approach for particles with inhomogeneous mass distribution was derived and implemented. While these inhomogeoneities were shown to significantly disturb rotational motion compared to homogenous ones, their impact on particle trajectories was less substantial. Consequently, fully resolving the complex rotational behavior of fibrous particles in realistic airway flows remains an area for further investigation.