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-   -   Fired compressor washing (https://www.pprune.org/engineers-technicians/600880-fired-compressor-washing.html)

peterccole 19th Oct 2017 16:29

Fired compressor washing
 
In the 1980s I was working as a chemist for Rolls-Royce and was involved in some trials of fired compressor washes to see if they were cost-effective. This involved clamping a manifold behind the fan of the port engine (RB211-535, can't remember if it was 535C or 535E4) of an Air2000 757, and then spraying a detergent/water mix directly into the IP compressor while the engine was at ground idle. Starboard engine was not washed. The idea was to wash the IP and HP compressor rotors and stators, removing any surface crud, hence improving airflow and, hopefully, reducing fuel consumption. (Not possible to fire detergent mix at the fan as the darn thing would just fling most of it straight down the bypass duct!) On the following flight (from Manchester to Arecife), the performance of both engines was monitored and compared, and the purpose of the exercise was to establish whether or not the cost and effort of the compressor washing would be more than compensated for by fuel savings.
My particular involvement in the exercise was to sample the cabin air supply during the flight following the fired wash, as there had been suggestions following previous washes of slight odour in the cabin air, possibly caused by the washing fluid. The trials did indeed demonstrate that there was the potential for contamination, but I recall that we suggested that by selecting fan anti-icing during the wash, this problem could be minimised or eliminated.
Since the trials were essentially a contract between Air2000 and the company providing the washing service (whose name escapes me), I never got to find out if the procedure was ever adopted by Air2000 or indeed by anyone else. Purely out of interest I wonder if any of you guys could advise whether or not this type of washing has been adopted in the industry. I have searched the forum and found some references to washing, but I am unsure as to the extent of its adoption. If so, what are the typical frequencies for engine washing, and what are the typical fuel savings?
Hope someone can shed some light on this.
P.S. No longer at Rolls-Royce but enjoying retirement!

Exup 20th Oct 2017 14:49

I have done compressor washes with equipment fairly similar. A spray ring that attaches to the Fan with a hose connect to the center of the ring which in turn is connected to a wash plant. No detergent was used, water was heated to about 60 deg C (I think) then engine was dry motored for 2 mins, this cycle was repeated a couple of times. The whole wash plant has built in programs for various eng types.

TURIN 20th Oct 2017 15:00

Many years ago we used to do routine compressor washes on our fleet of B737-200s. This involved disconnecting the generator cooling duct to avoid contamination, and then dry motoring the engine for a couple of minutes while we fired a powerful jet of cold water in the intake.
No idea if it did any good.

Corrosion 20th Oct 2017 18:21

Done comp washes for S340, S2000 turboprops and BR715 (turbofan) engines.
Saab engines, GE CT7 and RR Allison AE2100 engines were washed with water/detergent solution which sprayed to compressor. At least AE2100 have port to connect washing fluid "sprayer" which is nothing more than just a pressurized can filled with washing solution. Think we wash CT7 same way but cannot recall after all these years. Rotate eng with starter, do it ~twice and after this rinse with water + eng ground run to get rid of remaining fluid which may create smell. There is also procedure to disconnect some bleeds, and/or close some valves with compressed air, to avoid fluid getting there.

BR715 wash performed only with fresh warm water, which sprayed intake using spray nozzles attached to intake lip behind fan. This work also requires to prepare some of the bleed/press valves etc etc to avoid water getting there. Rotate eng with starter few times and after all eng run.

Canīt remember any digits for Saab engines, but if my memory serves right with BR715 we may find +20c deg reduction with EGT according to eng data. So, it will affect eng positively. Think numbers might be even bigger on more polluted area.
BR715 fan blades washed by hand regularly as well, no idea how much it helps eng but lots of dirt removed from blades anyway.

YOUNGBUCK 20th Oct 2017 21:26

Hi Peter,
Yes, this is carried out on the rb211 and thru the whole Trent family. See a link to video using a juniper wash rig
https://m.youtube.com/watch?v=z_MJGjisFPI

The odours on the rb211-535 are still apparent but are worse dependant on which combuster is fitted and valve settings.

IFixPlanes 21st Oct 2017 06:19

https://www.lufthansa-technik.com/cyclean :ok:

easaman 25th Oct 2017 17:47


Originally Posted by IFixPlanes (Post 9931797)

A great system!

bcgallacher 25th Oct 2017 20:43

Was involved with routine washes of Tristar APUs in Saudi. On one occasion the chap who mixed the fluid was on vacation so it was mixed by a storekeeper - who used undiluted fluid which was about 90% kerosene. when the valve was opened on the pressurised tank there was a big bang,lots of flames and one of the turbines departed out the jet pipe,scattering sparking metal fragments.Spectacular -but expensive.

easaman 26th Oct 2017 10:29

Fuel Nozzle clean and Water Wash
 
There are two different things, one is the fuel nozzle cleaning from carbon deposits. Therefore one uses a detergent, a milky stuff, which is pumped into the fuel injection system. You let it soak and pump again. This is repeated several times.
The other thing is to clean the compressor/turbine blades. Therefore you can spray simply with a fire hose into the compressor inlet, while dry motoring (no ignition & no fuel) the engine. The Lufthansa tool is of course much better.... Do not forget to drain the moisture trap at the FCU when the job is finished and let the engine run for about five minutes.
At intervals both tasks are completed together in the hangar.

peterccole 26th Oct 2017 10:33

Thanks for the input, guys. Very interesting.
Cheers:ok:

ShyTorque 26th Oct 2017 14:35

Itís commonly done on helicopter turbines. The exact procedure required varies between manufacturers. I was once asked to run a Turmo engine while the ground crew pumped fluid into the open intake. Unfortunately the end of the brass nozzle of their rig came adrift and went into the compressor. It didnít improve the engine one bit.

NutLoose 15th Nov 2017 21:36

Yes, I used to do the Puma Turco washes with the lance, also used to do the Wessex with the crushed walnut shell.
We did a Wessex and main stores had got in the wrong grade of walnut shell unbeknown to us, it did a cracking job of cleaning it, it cleaned most of the blades off the spool. :)

Also used to do Lix washes on the VC10's, we used to do them if they were having relight problems etc, had one crew come in and say No 1, 3 and 4 engines wouldn't relight in low orbit.... Sat there looking at them incredulous and pointed out Rolls Royce say the engines will only relight below XYZ feet... Reply was "but No 2 did"......... We had to wash the lot.




..

gas path 16th Nov 2017 09:38

Cyclean is used on our Trent 800 900 and 1000. Benefits, yes, a reduced fuel burn and slightly lower egt. The engines require a low power engine run afterwards to dry everything out and check for any messages.
The GE90 base and the 115 the 'juniper' rig is used, the spray nozzles being hooked behind the fan spraying water at IIRC 70c into the booster section. However the engine needs the FADEC lines disconnecting and blown thro' with nitrogen afterwards and also the base engine needs high power engine runs to get water out of the oil system and an oil filter change.
Only ever done a few RB211-524 as a trial, no real benefit found but then again that engine has the best performance retention over its life than any of the others!:ok:

Jon Starr 17th Nov 2017 22:13

I performed a wash on a H&S STAD 250 engined start cart, by necessity as the thing couldn't maintain air delivery before the EGT went off-scale high.
We used a pressure-washer with soap dispenser filled with ZOK 27 compressor wash fluid.

Cleaning while motoring didn't seem to accomplish much after a further test, so we started and idled it and then tried again while running. It required one person to lean on the relight button but we successfully emptied the tank though it.
Testing under load showed we now had a 50įC margin instead of being over limits, perfect.

This was a very tired engine that had possibly never been washed before in its life but it had a remarkable result.


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