3 airflow blockers, 4 system airflow, Airflow blockers – Kontron AT8242 User Manual
Page 97: System airflow, Table 6-3 pressure curve at8242
Thermal Considerations
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6.1.3
Airflow blockers
It is highly recommended to use airflow blockers (ATCA slot) with the AT8242 to block any slot open to
exterior air. Failure to do so would go against forced air principles applied on ATCA components, reducing
system's cooling efficiency. Moreover, airflow blockers offer higher impedance to forced air than typical
board, who tend to let more air into slots filled with AT8242 or other ATCA boards.
6.1.4
System Airflow
The airflow impedance (pressure) curve gives multiple information and tips about thermal operational range
of the system carrying the AT8242. Once volumetric airflow capability of your chassis is known, the PQ curve
can help determine the ambient (room) temperature setpoint that should be used for optimal operation. If
you are using various models of ATCA blades into the same chassis, it is possible to find the best thermal fit.
Having the volumetric airflow value for each chassis slot is it then possible to decide the layout using the
pressure curves.
Table 6-3:Pressure curve AT8242
Test Point
Airflow (CFM)
Pressure drop
(in H2O)
Airflow (m³/h)
Pressure Drop
(Pa)
1
5
0.010
8.5
2.5
2
10
0.030
17.0
7.4
3
20
0.080
34.0
19.8
4
30
0.144
51.0
35.8
5
40
0.222
68.0
55.2
6
50
0.314
85.0
78.2
7
60
0.420
101.9
104.7
8
70
0.540
135.9
134.7
9
80
0.674
152.9
168.3