Talk:Bleed air
From Wikipedia, the free encyclopedia
I've been working on the pro-contra section, although if you want to take a look at it and possibly edit it, go ahead! I've tried my best to be neutral, but if you see room for improvement, please enhance it. I'm still learning the Wikipedia ropes! --QuantumEleven 09:59, Nov 10, 2004 (UTC)
Contents |
[edit] Heating vs. pressurization
Actually, the main use of bleed air on modern aircraft is pressurization rather than heating. The ambient temperature at 40,000 ft is indeed -67 deg F, but the ambient pressure is only 2.36 psi. (Data from "Airplane Performance..." by Perkins & Hage, 1949)
Heating the cabin to 75 deg F is comparitively easy because the cabin is insulated and full of kilowatts of heat-producing people and electonics. Some airplanes even need to be cooled down during cruise instead of heated. Raising the air pressure from 2.36 psi to 11 psi (max cabin altitude) is the real duty of bleed air during cruise. Komodon 07:26, 30 Mar 2005 (UTC)
[edit] temp of bleed air ??
I suspect the 1000C and 1200C figures to be incorrect... The EXHAUST of a jet engine is under 800C, as far as I know... The bleed air from the a compressor stage would certainly have to be much cooler wouldn't it?
- Yes, those figures are way off and the article contradicts itself (1200C vs. 300C). The 300C figure is on the high side but still accurate. It's not "superheated" by any means. --Mexcellent
[edit] bleed valves control stall and surge
Very new at this, would some mention of the use of engine bleed to control compressor stall or surge be justified? Oldspoonhead 12:52, 31 March 2006 (UTC)
[edit] New planes (Airbus 350/Boeing 787) to stop using bleed air
I believe we can consider modifying the comment about A350 not eliminating bleed air. As far as I can see on General_Electric_GEnx, A350 is being offered only with either the same engine as the 787 (which is bleed-less), or with Rolls-Royce_Trent#Trent_1700 (which is also bleed-less). (Although Factbites claims that Airbus is in talks about modifying both alternatives so that they still can supply bleed air for their A350) --Filik
