Case Studies in the Human Respiratory System - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 295

Fig. 8.50 (continued)

m particles at u ∗

1 are mainly concentrated within the
vestibule, nasal valve regions and along the septum walls. Differences appear be-
tween the left-side and right-side of the cavity which is due to anatomical variations.
The concentration of particles within the middle passage of the nasal cavity is lighter
than that shown in 10

Deposition of 15 μ =

m particles because the larger particles have a higher con-
centration within the anterior section of the nasal cavity. When u ∗ is increased to 10
the particle is no longer just governed by its Stokes number, but also by the driving
force of the initial injected velocity that adds initial momentum to the particle. This
increase in momentum is dissipated by the difference in the velocities of the gas and
particle phases. The particles travel further linearly in the normal direction to the
nostril inlet with 88 % impacting at the top of the vestibule. Only 12 % of particles
are able to adjust to the curvature in time, and these particles remain in the upper
regions of the nasal cavity throughout the flow.

μ