Biomedical Engineering Reference
In-Depth Information
It is straightforward to apply airway altering/remodeling effects in this simple
model representation, but limitations should be taken into account. The major errors
which may occur in this study are determined by the heterogeneity of the human
lung, i.e. inter-subject variability can affect the values from Table
2.1
and Table
2.2
.
However, these values are reported in several studies [
59
,
66
,
85
,
100
,
164
] and they
had offered a good basis for investigations, originally measured from excised lungs
[
114
,
163
] and then in plastic casts [
135
].
Another further simplification in our reasoning is considering the effects from the
branching angles negligible. These angles influence the flow to change direction,
may lead to an asymmetrical velocity profile, to develop a secondary flow in the
daughter branches and the inner airway walls to be slightly stretched [
135
]. The
change in cross-sectional areas which occurs from parent to daughter branches in a
bifurcation causes the fluid to undergo a deceleration and may cause separation of
adjoining streamlines. However, this kind of information may be more useful to the
study of airflow dynamics in aerosol deposition models.
The model developed in this chapter can be now employed in building an elec-
trical analogue ladder network model preserving the geometry of the respiratory
system.
