1、AEROSPACE INFORMATION REPORT The Engineering Society .IALIFor Advancing Mobility Land Sea Air and Spaces INTERNATIONAL 400 Commonwealth Drive, Warrendale. PA 15096-0001 Submitted for recognition as an American National Standard HELICOPTER TURBINE ENGINE WASH AIR441 6 - Issued 1995-05 1. SCOPE: Engin
2、es subject to dust, industrial pollution, saltwater contamination or other chemically laden atmosphere (including pesticides and herbicides) lose performance due to deposits of contaminants on surfaces in the aidgas flow path. Engine wash and engine rinse procedures are utilized to restore turbine e
3、ngine performance. These procedures are generated by the engine manufacturer and are included in the Engine Maintenance/Service Manuals. For most turbine engines these procedures are similar in concept and practice; however, application details, choice of solvents and many other service features can
4、 vary from engine manufacturer to engine manufacturer and may even vary within the range of engine models produced by any manufacturer. The intent of this SAE Aerospace Information Report (AIR) is to outline the general nature, considerations, and background of engine wash and engine rinse and is di
5、rected towards the needs of the entry level engineer, service engineer, and those involved in the general maintenance of installed turbine engines. 2. REFERENCES: 2.1 Applicable Documents: The following publications form a part of this specification to the extent specified herein. The latest issue o
6、f SAE publications shall apply. 2.1.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096- 0001. ARP1862 Cleaning Efficiency of Turbine Engine Gas Path Cleaners, Laboratory Test Method SAE Technical Standards Board Rules provide that This report is published by SAE to
7、advance the state of technical and engineering sciences. The use of this repor! is entirely voluntary, and its applicability and suitability tor any particular use. including any patent infringement arising therefrom. is the sole responsibility of the user.“ SAE reviews each technical report at leas
8、t every five years at which time it may be reaffirmed, revised, or cancelled SAE invites your written comments and suggestions. Copyright 1995 Society of Automotive Engineers, Inc All rights reserved. Printed in U SA - SAE AIR*Y41b 95 7943725 0533726 328 = SAE AIR441 6 2.1.2 U.S. Government Publicat
9、ions: Available from DODSSP, Subscription Services Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 191 11-5094. MIL-(2-85704 Military Specification, Cleaning Compound, Turbine Engine Gas Path 2.2 Definitions: 2.2.1 ENGINE WASH: The procedure for cleaning the compressor, inlet guide vanes, et
10、c. in which water and solvent additives are introduced into the engine inlet. 2.2.2 ENGINE RINSE: The procedure which follows engine washing in order to remove the engine wash solvent from the engine internals, or for engine washing when water soluble contaminants only are present within the engine.
11、 3. CONTAMINANTS AND ENGINE PERFORMANCE: 3.1 3.2 Deposits in the Flow Path: Contaminants in the aidgas flow path produce erosion of compressor and diffuser surfaces and deposits on the compressor and turbine airfoils. The result is flow and efficiency decreases due to flow disturbances and changes i
12、n aerodynamics which cause the engine to lose power and/or increase fuel consumption. In addition, fine dust particles may clog cooling passages within the turbine section, eventually elevating engine metal temperatures and creating premature failure. Restoration of Performance: If the performance l
13、oss is caused by contaminant deposits rather than erosion, then performance can be restored when these deposits are removed. Engine wastrinse procedures are effective in reducinghemoving these deposits. Engine manufacturers maintenance/service manuals describe acceptable wash and rinse solutions and
14、 recommend wash/rinse intervals. It is emphasized that the recommended frequency of the wash procedures should be strictly observed (unless local conditions dictate an increased frequency) in order to avoid a condition of engine dirtiness beyond which it is impossible to restore performance by engin
15、e wash. NOTE: 1. In the past, a walnut shell wash of the engine was sometimes used to abrasively remove a buildup of deposits on the compressor blades. This was done if a watersolvent type wash was not effective in restoring engine performance. Again, it is emphasized that the engine manufacturers a
16、pproved wash procedures should be observed. 2. In desert/volcanic environments, special disassembly and wash procedures may be required. These procedures may involve the use of special fixtures and equipment to remove particulate and impacted material from hot section surfaces and cooling air passag
17、es. SAE AIR*44Lb 95 7943725 0533727 264 SAE AIR441 6 4. GENERATION OF ENGINE WASH PROCEDURES: 4.1 Test Cell: It is customary for the engine manufacturer to establish engine wash procedures by iterative process in the test cell. During this process, flow distribution, nozzle sizes, length of time of
18、wash, washing intervals, and all features pertaining to engine wash are established. Engine wash is thus a customized feature for each engine model. 4.1.1 4.1.2 4.1.3 4.1.4 Single Wash Versus Double Wash: During the exercise of establishing engine wash procedures, serious consideration has to be giv
19、en to any benefits that may be derived for short duration double washes, as opposed to longer single washes. Choice of Solvents: It is imperative that safe solvents be used for washing from the standpoint of personnel and environmental safety and to prevent engine/airframe damage. An extensive range
20、 of proprietary solvents are commercially available for engine cleaning. In order to establish engine/solvent compatibility, extensive testing with the solvent is usually undertaken by the engine manufacturer, which by virtue of test cost limitations results in a limited range of recommended solvent
21、s for any specific engine. Certification Testing: During certification testing of the engine/aircraft, satisfactory performance of the engine washing procedures should be evaluated to ensure that the system is functional over the engine washing temperature range and should include icing conditions f
22、or those engines with built in spray rings. Intervals Between Engine Wash: The main factor in determining intervals between engine washes is the environment to which the engine is exposed. For instance, it is routine U.S. Navy practice, when on sea duty, to perform an engine wash at the end of each
23、day of aircraft use. In establishing a basis for routine engine washes, consideration has to be given to the concern that too long an interval between washes can result in baked on deposits. 5. EQUIPMENT: 5.1 Engine Wash/Rinse Equipment: 5.1.1 Spray Rings: The equipment required for engine wash or r
24、insing depends on the design of the engine inlet and the engine manufacturers requirements for engine wash. Some engines have built in spray rings at or near the forward face of the engine with a threaded connection provided for use with operator supplied engine wash ground equipment. Other engines
25、require hand held spray rings or wands for the introduction of the engine wash or rinse solutions into the engine inlet. This equipment is available either from the engine manufacturer, commercial vendor, or other engine manufacturer defined sources. SAE AIRxY41b 95 7943725 0533728 LTD W SAE AIR4416
26、 5.1.2 Engine Wash/Rinse Ground Equipment: In addition to spray rings for wash/rinse introduction, additional ground equipment may be required. This equipment can usually be obtained from the engine manufacturer or a commercial vendor and can be as sophisticated as a portable ground cart with self-c
27、ontained tanks of rinse solution and engine wash solution powered by aidnitrogen cylinders for pressurization with associated hardware for pressure control, blow down, shutoff, etc. In the case of small engines such as APUs, it can be as simple as a hand held spray gun purchased from a hardware stor
28、e. 5.1.3 Aircraft Engine Wash Interconnects: For engines with “built in“ spray rings, the airframe manufacturer provides plumbing in the aircraft to the spray ring(s) with a suitably located quick disconnect for ground cart attachment. The preferred location for this interconnect is one which provid
29、es the minimum problems of access for maintenance personnel. For multiple engine installations, consideration should be given to a single interconnect with selector valve capability for individual wash of each engine. Similarly, the engine manufacturer should provide connectors on the engine that al
30、low for simple plumbing of the wash system in multiple engine installations (,e., right and left hand engine specific connectors are discouraged). 6. 7. 8. 9. ENGINE WASH SOLUTION: The solutions and proportions of cleaning solvents used should be those recommended by the engine manufacturer. The sol
31、vents available are many and vary from readily available chemicals such as methanol or alcohol to commercially produced cleaning compounds. Cleaners should be compatible with the materials/paints normally used for engine installations. ENGINE RINSE SOLUTION: Clean water must be used. Demineralized,
32、distilled, rainwater, or air conditioner condensate is preferred in some engines. For ambient temperatures in the range of -20 to 40 OF (-29 to 4 OC) the general rule is to add engine manufacturer recommended percentages of isopropyl alcohol or methanol (or both); rinsing below the engine manufactur
33、ers specified minimum ambient temperature should not be conducted as the solution will freeze. ADDITIONAL EQUIPMENT: Additional equipment required includes gloves, goggles, face shield, external cleaning solvent per engine manufacturers instructions (which may or may not be the same as the wash solu
34、tion), and wipers . PREWASH/RINSE PROCEDURES: The prewash/rinse procedures are specifically defined by the engine manufacturer and are designed for the protection of personnel and for safe operation of the engine during the washing procedure. Typically the prewashhinse procedure is as follows: a. De
35、couple the engine from electrical power (either by pulling the ignition circuit breaker or by switching the ignition switch off). SAE AIR84416 95 M 7943725 0533727 037 SAE AIR441 6 9. (Continued): b. Shut off bleed air valves. c. Address needs of anti-ice systems per engine manufacturer instructions
36、. d. Drain valve position to be as per engine manufacturer instructions. e. Disconnect engine components (e.g., control sensors) per engine manufacturers instructions. 10. ENGINE WASH PROCEDURE: The engine wash procedure will typically be as follows: a. b. C. d. e. f. g. h. I. Unless the engine is q
37、ualified for hot washing, a hot engine should be allowed to cool to the engine manufacturer specified temperature. Evenly spray a specified amount of wash solution (see Section 6) into the compressor inlet while motoring the engine over for a required period of time at a specified gas generator spee
38、d. (Do not exceed starter limitations.) Allow the engine wash solution to soak within the compressor for 15 to 30 min. Spray a specified quantity of rinse solution (see Section 7) into the compressor inlet while motoring. Engine manufacturer instructions for gas generator speed, time, and starter co
39、oling limitations should be observed. Repeat operation d. Inspect for cleanliness; if necessary repeat operations a through d. Perform an additional 30 s of dry motoring to purge the engine of volatile fumes. This operation is applicable only when a flammable agent such as alcohol has been used in t
40、he wash solution. Run the engine to dry at idle speed for the specified period of time with the anti-icing switch in the recommended position per the engine manufacturers instructions. Shut the engine down. -5- SAE AIRr44Lb 95 7943725 0533730 859 SAE AIR441 6 11. 12. 13. ENGINE RINSE PROCEDURE: Rins
41、e procedures of the engine manufacturer should be followed and are similar to the following: a. b. C. d. e. f. 9- h. I. Unless the engine is qualified for hot washing, a hot engine should be allowed to cool to the engine manufacturer specified temperature. Motor the engine over for a given (engine m
42、anufacturer specified) period of time, while directing a spray of clean fresh water evenly into the inlet housing at the engine manufacturers specified rate of flow. (Do not exceed starter duty cycle.) CAUTION: High energy streams of water striking rotating compressor blades have resulted in fatigue
43、 failures. Using clean fresh water (and specified external solvent) wash the exterior of the engine per engine manufacturer recommendations. Inspect the compressor for cleanliness; repeat the cleaning procedure if necessary. Allow the engine to drain. Run the engine to dry at idle speed for the spec
44、ified period of time with the anti-icing switch in the recommended position per the engine manufacturers instructions. Shut the engine down. Reconnect any removed engine components. An inspection of inlet scrolls should be made to ensure that excess water has drained properly, especially during free
45、zing conditions. ENGINE RUNNING WASH: The procedure for engine running wash is similar, but not necessarily identical with that for motoring washes. Engine manufacturer recommended procedures should be observed. It should be noted that engines not qualified for engine running wash must not be washed
46、 with the engine started. DISPOSAL OF ENGINE WASHMNSE FLUIDS: The disposal of engine wash solvents and plain water rinse fluid in an environmentally acceptable manner is dependent upon the specific solvents being used and the contaminants being removed from the turbomachinery. Material Safety Data S
47、heet (MSDS) information is available from all solvent suppliers. Section VI1 of the MSDS (Precautions for Safe Handling and Use) addresses the recommended waste disposal method for the engine wash chemical. -6- SAE AIR*44Lb 95 m 7943725 0533733 795 SAE AIR441 6 13. (Continued): The problem becomes m
48、ore complex when the solvent is used to clean an engine, and the user must determine how to dispose of the effluent in an environmentally safe manner. The waste fluid contains not only the engine wash solvent but also the material which made the engine “dirty“. It is recommended that the local office of the Environmental Protection Agency (EPA) be contacted to determine an acceptable method for disposal of engine wash waste. 14. NOTES: 14.1 Key Words: Helicopter engine, engine cleaning, engine rinse, engine wash. PREPARED BY SAE COMMITTEE S-12, HELICOPTER POWERPLANT -7-
