Biomedical Engineering Reference
In-Depth Information
Fig. 8.12
The coronal sections are divided into sub-sections which are indicated by letters
A
-
E
for the
right
cavity side and
A-E
for the
left
cavity side.
a
Cross-section located at 6.1 cm from the
anterior tip of the nose used in this paper.
b
Cross-section located at 6.2 cm from the anterior tip of
the nose used by Keyhani et al. (1995).
c
Cross-section located at 6.0 cm from the anterior end of
the nose used by Subramaniam et al. (1998)
Table 8.2
Flow distribution on the plane in the middle of turbinate for flow rate of 15 L/min
Left
Right
Region
A
Q
%
U
U
x
A
Q
%
U
U
x
(mm
2
)
(mm
2
)
(ml/s)
Q
tot
(m/s)
(%)
(ml/s)
Q
tot
(m/s)
(%)
A
13.7
13.9
11.6
1.3
78.1
10.4
3.1
2.5
0.42
70.5
B
9.7
1.4
1.2
0.2
62.6
8.6
1.6
1.3
0.24
75.6
C
23.2
25.6
21.4
1.4
79.2
29.1
28.5
23.7
1.12
87.1
D
21.6
24.4
20.3
1.2
90.8
36.9
34.7
28.8
1.00
94.2
E
50.3
52.4
43.7
1.1
95.8
50.5
50.2
41.7
1.06
93.8
F
42.8
2.2
1.8
0.1
80.0
53.5
2.5
2.1
0.11
41.8
Total
161.3
119.9
189.0
120.5
than in the nasal valve region as the geometry has expanded. The downward direc-
tion is due to the airway which is now heading toward the nasopharynx. Therefore,
the overall flow path undertakes a U-turn shape where the flow enters upwards and
travels horizontally, ending downwards towards the lungs.
To further study and compare the distribution of airflow in the turbinate region
with other work in the literature, the cross-section in the middle turbinate region was
subdivided into separate regions and labelled from
A
through to
E
. This enabled mea-
surement of the local distribution (Fig.
8.12
). Local volumetric flow was determined
by integrating the velocity component normal to the plane over the cross-sectional
area of each region. The results of the airflow distribution at a flow rate of 15 L/min
for left and right sides are given in Table
8.2
.
There are obvious differences between the nasal geometries of Keyhani et al.
(1995); Subramaniam et al. (1998) and the current model in this study (Fig.
8.12
).
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