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4.3.1.2 Dynamic chamber-air thermal balance subsystem
The Dynamic chamber-air thermal balance subsystem consists of 3 subsystems. They
are listed below:
Fluid dynamic section subsystem (for dynamic fluctuating flow)
Chamber air specific humidity subsystem
Chamber-air fluctuating thermal balance subsystem
The “Fluid dynamic section subsystem (for dynamic fluctuating flow)” is the same as
the one in the Fluid dynamic and exhaled air re-breath model. The Chamber air specific
humidity subsystem is the same as the one described in Appendix VIII. The differences
are that the inputs are all fluctuating and its input of “specific humidity of inlet” is from
a switch block. The block provides specific humidity of inlet from the blower when
flow direction is from the blower and from the HADT lump 1 when the flow is reverse.
For the Chamber-air fluctuating thermal balance subsystem, it is basically the same as
the steady state chamber-air thermal balance subsystem described in Appendix VIII.
The differences are also that the inputs are all fluctuating and the inlet specific humidity
and inlet temperature are from the blower when flow is positive and from the HADT
lump 1 when the flow is reverse.
The inputs are listed in Table 4.17 below.
Input port
number
Table 4.17 Inputs to the dynamic chamber-air thermal balance subsystem
Input Unit
1 Ambient air specific humidity In decimal
2 Specific humidity of air from HADT due to reverse flow In decimal
3 Temperature of inlet to the chamber from ADU °C
4 Temperature of air from HADT due to reverse flow °C
5 Breath load g/s
6 Water temperature °C
7 CPAP pressure setting cmH2O
8 Portion of impact area to total water surface area In decimal
9 Mask capacity m 3
10 Temperature of wall 2 and 3 °C
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