A320 pneumatics
Thread Starter
A320 pneumatics
I was having a look at the chapter on Pneumatics in the FCOM and I was wondering what the temperature and pressures are of the air when it initially is fed into the pneumatic system from the engine and then having passed through the pre-cooler . Ecam only shows pre-cooler outlet temperature and pre-cooler inlet pressure.
Would any of you be able to supply the figures involved?
Would any of you be able to supply the figures involved?
Thread Starter
That is the temperature of the precooler output though. i suppose my question is how efficient is the precooler in reducing temperature and is there any pressure drop across it.
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I am asking because I was interested to know. I know the whole thing is automatic, but I would like to know how efficient it is. Judging by the size of the cooling vanes on the pylon I would imagine that the temperature change is not huge, but is there a pressure drop across the unit? There is obviously a pressure reduction from the input of air from the engine to the final flow of air to the cabin.
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@ tubby Linton
Don't have figures for A320 but A330 system setup is more or less identical.
The displayed pressure is called Pr (Regulated Pressure) and is the pressure downstream of the (PRV) Pressure Regulator Valve.
The pressure upstream the PRV is called Pt (Transferred Pressure) this pressure is not displayed but is an input to the BMC.
The measured Precooler Outlet Temp is displayed and also regulates the cooling air(fan outlet air) by a modulating valve (FAV)
The values of the transferred pressure and temperature at TO could go up to ~145psi/~370°C.
Normally the PRV will reduce this pressure to 48psi and the Precooler cools it down to 200°C.
Some specific system demands/overpressure/overtemp will have an effect on the output values.
The displayed pressure is called Pr (Regulated Pressure) and is the pressure downstream of the (PRV) Pressure Regulator Valve.
The pressure upstream the PRV is called Pt (Transferred Pressure) this pressure is not displayed but is an input to the BMC.
The measured Precooler Outlet Temp is displayed and also regulates the cooling air(fan outlet air) by a modulating valve (FAV)
The values of the transferred pressure and temperature at TO could go up to ~145psi/~370°C.
Normally the PRV will reduce this pressure to 48psi and the Precooler cools it down to 200°C.
Some specific system demands/overpressure/overtemp will have an effect on the output values.
Thread Starter
Thank you for the info.
My next question is how is this output pressure (Pr)reduced to the pressure that finds it way into the cabin, is it reduced in the pack?
My next question is how is this output pressure (Pr)reduced to the pressure that finds it way into the cabin, is it reduced in the pack?
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By the FCV (Flow Control Valve) before air enters the pack, although the FCV regulates flow instead of pressure there is a relation between output pressure and flow.
The cold pack discharge air is mixed with hot air regulated by a TAPRV (Trim Air Pressure Regulating Valve) which regulates to 4 psi above Cabin Air Pressure.
The cold pack discharge air is mixed with hot air regulated by a TAPRV (Trim Air Pressure Regulating Valve) which regulates to 4 psi above Cabin Air Pressure.
Thread Starter
A33Zab if the flow is excessive how does the FCV regulate the flow? is there a return or vent or does the valve move to limit the flow?
Within the pack are a Main Heat Exchanger and a Primary Heat exchanger, would you be able to give values for temperatures and pressures within these sections and also at the outlet of the pack turbine please?
Within the pack are a Main Heat Exchanger and a Primary Heat exchanger, would you be able to give values for temperatures and pressures within these sections and also at the outlet of the pack turbine please?
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The flow is limited depending on demand.
The exact press/temp values depend on zone demand, cargo cooling demand, pack demand, other pack state and bleed source supply state and system state, but to give you an general idea:
The exact press/temp values depend on zone demand, cargo cooling demand, pack demand, other pack state and bleed source supply state and system state, but to give you an general idea:
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For example here https://www.myboeingfleet.com, https://w3.airbus.com or Lufthansa Technical Training.