Case Studies in the Human Respiratory System - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 310

There is only a small proportion entering the upper lobes of both sides of the airway,
which is due to the lateral curve. It is therefore apparent that the branching angle
has a significant influence on the airflow distribution. This influence transcends to
particle deposition where low inertial particles will be greatly influenced.

8.5.4 Particle Deposition Patterns

Deposition patterns for the computational models allow visualisation and deeper
insight into the connections between the airway geometry and deposition sites.
Figure 8.61 shows the concentration of particles generally impacting at each bifur-
cation as the airflow begins to separate. The percentage values displayed next to
the outlets represent the percentage of particles that escape through those outlets.
This shows that a large proportion of particles are travelling through the right main
bronchus which leads to greater exposure to the particles. In addition, approximately
40 % of inhaled 5 μ m particles penetrate past the sixth bifurcation via the right

16.2%

8.5%

9%

15.7%

24.4%

26.5%

40.4%

39.8%

AA-Model 5μm Dep.Eff. = 10.7% REC-Model 5μm Dep.Eff. = 8.5%

0.1% 0%

0%

0%

0%

1.1%

2.6% 6.5%

AA-Model 40μm Dep.Eff. = 97.3% REC-Model 40μm Dep.Eff. = 92.3%

Fig. 8.61 Particle deposition patterns for 5 and 40 μ m particles for the three computational models