Environmental Engineering Reference
In-Depth Information
Fig. 7.46 Individual cell
voltage for five significant
instants of the experiment of
Fig.
7.44
1
0,8
0,6
25 A/s
0,4
t=0
t = 10 s
t = 20 s
t = 34 s
t = 45 s
0,2
1
8
15
22
29
36
43
50
57
64
71
78
Cell number
Fig. 7.47 a Stack voltage
and current acquisition versus
time during the dynamic
cycle characterized by the
maximum stack current vari-
ation of 50 A/s. Air manage-
ment strategy N.2.
b Stoichiometric ratio and air
flow rate acquisition versus
time for the experiment (a)
a
80
250
Stack Current
Stack Voltage
75
200
70
150
65
60
100
55
50
50
45
0
0
10
20
30
40
50
60
Time [s]
b
35
5
4
30
3
2
25
1
Stoichiometric Ratio
Air Flow Rate
20
0
0
10
20
30
40
50
60
Time [s]
stoichiometric ratio values (Fig.
7.44
b), while the cell voltage recovery at t [ 10 s
indicates the correlation between R values and voltage behavior.
The current cycle of Figs.
7.42
,
7.43
, and
7.44
can be utilized to verify the
stack-compressor interaction in higher dynamic conditions. Figure
7.47
a, b
reports the results obtained with a ramp of 50 A/s and the compressor management
strategy N.2 (Fig.
7.40
), corresponding to a constant air flow rate of 24 Nm
3
/h,
