Fear of flying

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Originally Posted by FowVay
xB, the heat for a commercial airliner comes from the high pressure compressor. This is also what pressurizes the cabin. The high pressure compressor compresses inlet air - all prior to any fuel or combustion has contaminated it. Using the Boeing 767 as an example, the pressure to heat and pressurize the cabin comes from the 8th stage of the high pressure compressor. This air is ducted back to the conditioning packs and is cooled prior to being sent to the cabin. The air to cool the high and low pressure turbine is also ducted from the high pressure compressor. This HPC air is approximately 700ºF and is used to cool the low pressure turbine case in order to tighten the blade gap for improved egt ratio. This is called active clearance cooling.

The fuel in the tanks is exposed to those -80ºF temps so before the fuel is pumped to the combustor it goes through a fuel heater which is simply an oil-to-fuel heat exchanger. The engine oil warms the fuel in a small intercooler looking thing hanging off of the accessory drive module.


That is quite interesting, always wondered how they heated them. Thanks for the info.
 
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