Contamination of Bleed Air
Thread Starter
Joined: Oct 2006
Posts: 17
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From: europe
Contamination of Bleed Air
Hello, I talked to a maintanance engineer the other day who told ma about a new method of cleaning the inside of an jet engine and thereby augmenting its performance.Itīs basically achieved by water injected under high pressure.The water leaving the compressor stage of the engine is supposed to be that contaminated by traces of heavy metals like nickel,cobalt and chrome that the washings cannot be disposed into the regular sewage water and have to be handled like hazardous waste.
Of course there are more sources for bleed air contamination further downstream as well.
Has anyone ever heard about, or made the experience of physical reactions caused by respirating bleed air through the air conditioning system ?
Is that an issue already discussed earlier ?
Best regards, RvB.
Of course there are more sources for bleed air contamination further downstream as well.
Has anyone ever heard about, or made the experience of physical reactions caused by respirating bleed air through the air conditioning system ?
Is that an issue already discussed earlier ?
Best regards, RvB.
Joined: Feb 2004
Posts: 1,410
Likes: 37
From: Australia
Is that an issue already discussed earlier ?
Try, maybe, "fumes" as a search word???
"Hello, I talked to a maintanance engineer the other day who told me about a new method of cleaning the inside of an jet engine ..."
Rgds
NSEU
Joined: Dec 2004
Posts: 30
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From: Jeddah, Saudi Arabia
Water will mostly take off loose dust, flakes etc, and does increase performance. Normally a detergent of some sort will also be added to the water, to remove the stuff that has solidified on the compressor blades, and remove carbon from the combustion chamber(s) and turbine. Unfortunately, these detergents do need to be collected and special procedures followed for disposal.
Joined: Aug 2001
Posts: 36
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From: England
RvB,
As well as all the nasties from engine oil entering the bleed air, I think it is very likely that the heavy metals you talk about get into the bleed air too. Blood test results from a group of pilots in 2006 showed unusually high levels of Nickel in most of them, and antimony, beryllium and cadmium were also found. Nickel is extensively used in alloys for compressor blades, and I believe the other metals are also to be found in jet engines. If this stuff can get squirted off the compressor blades by water, it seems logical that it can also get sucked into the bleed air.
As well as all the nasties from engine oil entering the bleed air, I think it is very likely that the heavy metals you talk about get into the bleed air too. Blood test results from a group of pilots in 2006 showed unusually high levels of Nickel in most of them, and antimony, beryllium and cadmium were also found. Nickel is extensively used in alloys for compressor blades, and I believe the other metals are also to be found in jet engines. If this stuff can get squirted off the compressor blades by water, it seems logical that it can also get sucked into the bleed air.
Joined: Feb 2005
Posts: 4,581
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From: flyover country USA
Forty years ago I worked on engines with water jets in the front frame for the purpose of compressor cleaning. At that time we used a petroleum-based solvent mixed with the water, injected it while cranking on the starter, then let it soak a while to soften the deposits. Then crank it again while spraying demineralized water to flush the flowpath.
As NSEU says, the improvement was noteworthy.
The cleaner solvent was later decreed unfriendly to the environment, and a new protocol was developed, but I don't have those details at hand.
As NSEU says, the improvement was noteworthy.
The cleaner solvent was later decreed unfriendly to the environment, and a new protocol was developed, but I don't have those details at hand.
