1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2014 SAE International All rights reserved. No part of this pub
3、lication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970
4、(outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/ARP5921AEROSPACERECOMMENDED PRACTICEARP5921Issued 2014-04 Evaluation of Coking Prope
5、nsity of Aviation Lubricants in an Air-Oil Mist Environment using the Vapor Phase Coker RATIONALEThe Vapor Phase Coker apparatus bubbles a stream of dry air through a heated oil sump. The oil mist and vapor generated by the airflow travels through a furnace tube, where it is heated, and then travels
6、 through a stainless steel tube, where the deposition occurs. In general, vapor phase coking is a form of deposition which can be formed by a gas turbine lubricant when it is exposed to high temperatures in a non-oil wetted engine area. After engine shutdown, the airflow through the bearing vent tub
7、es and seals ceases. This mist, vapor mixture is carried in the airflow condenses in the engine and is subjected to high soak back temperatures. The neopentyl polyol ester molecules typically experience thermal and oxidative degradation which form carbonaceous deposits. Over a period of time coke bu
8、ild up can cause back pressure in bearing compartments and lead to seal malfunction. Vent lines need to be clear for the pressure balance within vented bearing compartments to be maintained, allowing proper sealing of oil within these compartments. 1. SCOPE This method is designed to evaluate the co
9、king propensity of synthetic ester-based aviation lubricants under two phase air-oil mist conditions as found in certain parts of a gas turbine engine, for instance, bearing chamber vent lines. Based on the results from round robin data in 2008-2009 from four laboratories, this method is currently i
10、ntended to provide a comparison between lubricants as a research tool; it is not currently a satisfactory pass/fail test. At this juncture a reference oil may improve reproducibility (precision between laboratories); a formal precision statement will be given when there is satisfactory data and an a
11、greed on, suitable reference oil if applicable. 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the
12、 purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 SAE Publications Avail
13、able from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.ARP5088 Test Method for the Determination of Total Acidity in Polyol Ester and Diester Gas Turbine Lubricants by Automatic Potentiometr
14、ic Titration AMS5560 Steel, Corrosion Resistant, Seamless Tubing, 19Cr - 10Ni (SAE 30304) Solution Heat Treated AMS5567 Steel, Corrosion Resistant, Seamless or Welded Hydraulic Tubing, 19Cr - 10Ni (SAE 30304) Solution Heat Treated SAE INTERNATIONAL ARP5921 Page 2 of 11 2.2 ASTM Publications Availabl
15、e from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM D445 Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity). 2.3 U.S. Government Publications Ava
16、ilable from DLA Document Services, Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6396, http:/quicksearch.dla.mil/.MIL-T-8504B Tubing, Steel, Corrosion-Resistant (304), Aerospace Vehicle Hydraulic Systems, Annealed, Seamless and Welded 3. WARNING This document may involv
17、e hazardous materials, operations, and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to establish appropriate safety and health practices and to determine the applicability of regulatory
18、limitations prior to use. 4. APPARATUS NOTE: The Vapor Phase Coker is fundamentally comprised of a Three Neck Flask Section, Test Furnace Section, Insulated Test Tube Section, and a Control Cabinet. Currently the only known manufacturer is Vector House, Inc. of Wheaton, Illinois. The end user provid
19、es a data acquisition system of their choice. Items listed below are for replacement purposes. The original design specifications of the test furnace are drawn in blueprint number E-625, issued by the Operations and Plant Engineering Department of the Naval Air Propulsion Center, Trenton, NJ. 4.1 Th
20、ree Neck Flask Section 4.1.1 Air Inlet Tube Ground glass inlet tube, Joint 24/40, interchangeable, hose connection #2, approximate bottom tube length = 200 mm, approximate overall height = 290 mm, such as Kontes PN 179000-2440 or Lab Glass PN LG-1970-102. NOTE: The air inlet tube will need to be tri
21、mmed to a length of approximately 175 mm so it able to sit flush in the angled flask neck and is centered in flask. 4.1.2 Adapter, Thermocouple (1) Ground glass adapter, Joint 24/40 to #7 THD with ferrule and bushing, such as Ace Glass PN 5028-31 or (2) PTFE thermocouple adapter 24/25 joint, such as
22、 Lab Glass PN LG-10477-306. 4.1.3 Flask, Three-Neck Distilling, three-neck, angled type, Joint 24/40 interchangeable, round bottom, 2000 mL capacity, such as Ace Glass PN 6948-232 or Lab Glass PN LG-7331-202. 4.1.4 Mantle, Heating Spherical Mantel, Glass Fabric Construction, holds 2000 mL three neck
23、 flasks, 700 W, such as Glass-Col PN 01103. SAE INTERNATIONAL ARP5921 Page 3 of 11 4.1.5 Thermocouple, Control High Temperature Quick Disconnect, Type J thermocouple, Type 304 Stainless steel sheath, sheath diameter = 0.125 inch, length = 12 inch, ungrounded, dual connector, such as Omega PN SICSS-1
24、25U-12-DUAL. 4.2 Test Furnace Section 4.2.1 Furnace Section Heater Spare heater coils are 120 V and 1200 W. The only known current source is HCS (Heaters, Controls, and Sensors) Limited, London, Ontario: PN AZ 71. 4.2.2 PTFE Adapter 50.8 mm (2 inches) tall stopper for 24/40 ground glass joint with a
25、n inner diameter through-hole of approximately 14.7 mm (0.578 inch). 4.2.3 Thermocouple, Test Furnace High Temperature Quick Disconnect, Type J thermocouple, Type 304 Stainless steel sheath, sheath diameter = 0.125 inch, length = 6 inch, ungrounded, dual connector, such as Omega PN: SICSS-125U-6-DUA
26、L or Omega PN ICSS-18U-6-DUAL.NOTE: Appendix A.1 depicts the Flask and Furance Sections along with the test tube. 4.3 Insulated Test Tube Section 4.3.1 Test Tube Tubing Type 304, conforming to AMS5567E/AMS5560M, Annealed (bright), Seamless, Outer Diameter = 0.5 inch NOTE: The original USN VPC method
27、 referred to MIL-T-8504B type tubing, which has been cancelled, but can still be referenced for ordering purposes. 4.3.2 Thermocouples, Test Tube High Temperature Quick Disconnect, Type J thermocouple, Type 304 Stainless steel sheath, sheath diameter = 0.125 inch, length = 12 inches, ungrounded, at
28、the tip of the thermocouple a 0.5 inch O.D. hose clamp is silver soldered to the outside of the thermocouple. 4.4 Control Cabinet and Data Acquisition 4.4.1 The design and layout of the instrument control of the Vapor Phase Coker design can be tailored to each laboratorys specifications and requirem
29、ents. Appendix A.2 depicts an example of a control cabinet. The Vector House, Inc manufactured unit comes with a control cabinet, but the user provides their own data acquisition system. The important parameters that must be adhered to are listed below: 4.4.1.1 Recording and Temperature Control Data
30、 Acquisition - Capable of reading Type J thermocouples, sensitivity within 1 C, acquire data for greater than 20 hours. Controller, Flask - Time Variable programmable, Ramp/Soak capability, single loop, input Type J thermocouple, output relay or contact, capable of maintaining control points within
31、1 C accuracy. Controller, Furnace - Time Variable programmable, Ramp/Soak capability, single loop, input Type J thermocouple, output relay or contact, capable of maintaining control points within 1 C accuracy. SAE INTERNATIONAL ARP5921 Page 4 of 11 Power Control, Flask - Silicon Controller Rectifier
32、 (SCR), accept Flask Controller input Power Control, Furnace - SCR, accept Furnace Controller input 4.4.1.2 Air Flow Controlled to 765 mL/min 5 mL/min by a rotormeter or a controller such as Brooks Mass Flow Controller model 5850 Series E. To ensure dry, clean air the use of a gas purifier is recomm
33、ended, such as Matheson Gas Purifier model 450B. Appendix A.3 depicts an example of the air flow path. 4.5 Additional Apparatus Requirements 4.5.1 Ultrasonic Cleaner Minimum 2 L capacity 4.5.2 Oven Non circulatory air, capable of maintaining a temperature of 100 C.4.5.3 Balance, Analytical Sensitivi
34、ty greater than or equal to 0.1 mg. 4.5.4 Balance, Analytical Sensitivity greater than or equal to 0.1 g. 4.5.5 Band Saw 5. REAGENTS AND/OR MATERIALS 5.1 Suitable solvents, technical grade or better, which are used for cleaning. Examples are heptane, acetone, and toluene. If a particular solvent is
35、referred to in this method, that particular solvent shall be used. 5.2 Air - house air, dry 5.3 Laboratory glassware soap such as Microsoap or Mallinckrodt Chem-Solve 5.4 Caustic cleaner such as Oakite LRS (optional) 6. PREPARATION AND ASSEMBLY 6.1 Preparation of Three-Neck Flask 6.1.1 Rinse flask w
36、ith suitable solvent(s) to remove oily residue from the previous test. Remove any deposits by any conventional laboratory glassware cleaning method.6.1.2 Rinse the flask three times with water and then rinse well with acetone. Allow the flask to completely dry. 6.1.3 Weigh the empty flask to the nea
37、rest 0.1 of a gram; record this weight as the initial weight of the flask. 6.1.4 Weigh 900 g of the test fluid into the clean 2000 mL flask to the nearest 0.1 of a gram; record this as the oil net weight.SAE INTERNATIONAL ARP5921 Page 5 of 11 6.2 Preparation of Furnace 6.2.1 Rinse the inside walls o
38、f the heater with acetone to remove any residue. 6.2.2 Run a suitable stiff brush, which is compatible with acetone, on the inside of the heater section being careful to not damage the thermocouple. 6.2.3 Check the heater thermocouple to insure the point of thermocouple is flush with the inner wall
39、diameter of the heater.6.3 Preparation of Air Inlet Tube 6.3.1 Wash the air inlet tube with a suitable solvent to remove the oily residue from the previous test. Remove any deposits by any conventional laboratory glassware cleaning method.6.3.2 Rinse the air inlet tube well with acetone. Allow it to
40、 completely dry. 6.4 Preparation of Thermocouples 6.4.1 Rinse all the thermocouples with a suitable solvent. 6.4.2 Inspect the test tube thermocouples for buildup of carbon deposits. Remove any deposits with a suitable solvent and light sanding or steel wool. 6.5 Preparation of Stainless Steel Test
41、Tube 6.5.1 Cut the test tube length to 16.5 cm 0.08 cm (6.5 inches 1/32 inches). 6.5.2 Slightly bevel the inside edge of the ends of the tube and then remove any burrs on the ends of the tube. NOTE: For ease of tube identification, it is suggested to etch one end of the tube with the test number twi
42、ce; 180 degrees apart.NOTE: For ease of placing the six thermocouples on the test tube, the test tube can be etched in the appropriate six locations. 6.5.3 Clean the test tube(s) by use of an ultrasonic cleaner for no less than 30 minutes in a suitable solvent or caustic cleaner. If the solvent is v
43、isually “dirty” after the ultrasonic cleaning, repeat step 6.5.3. NOTE: If a caustic cleaner is used for the above ultrasonic cleaner step, remove the tube and thoroughly rinse it with water and rinse with a suitable solvent to prevent rusting. NOTE: A good practice for step 6.5.3 is to place the tu
44、bes vertically into a beaker, cover with a suitable solvent or caustic cleaner, and then place the beaker in a water filled ultrasonic cleaner. This allows “dirt” (if any) from the inside of the tubes to fall to the bottom of the beaker.6.5.4 Clean the test tube(s) by use of an ultrasonic cleaner fo
45、r no less than 30 minutes with the tube(s) submerged in acetone. Remove the tubes from the solvent using gloves or forceps. 6.5.5 Place the clean tubes in an oven set at 100 C for 30 minutes. 6.5.6 Store the test tubes in an air tight storage cabinet containing desiccant until the tube is needed for
46、 the buildup of the test. 6.5.7 Weigh the tube to the nearest 0.1 mg at the time of test set-up; record this as the initial weight of the test tube. SAE INTERNATIONAL ARP5921 Page 6 of 11 7. PROCEDURE 7.1 Set-Up of the VPC Unit 7.1.1 Clamp the thermocouples on the test tube at the distances indicate
47、d in Table 1. The numbered end (if used) of the test tube should be at closest to the highest thermocouple number (in this case thermocouple 6).TABLE 1 - THERMOCOUPLE PLACEMENT ThermocoupleNumberPosition From Bottom of Tube (inches)1 1.25 2 2.0 3 3.0 4 4.0 5 5.0 6 6.0 7.1.2 Connect the test tube and
48、 thermocouple assembly to the heater assembly by inserting the tube into the opening at the top of the insulation pack above the furnace. Pass it through the insulation pack and insert the tube into the nut-ferrule at the top of the furnace section. Placing firm downward pressure on the tube to ensu
49、re that it is bottomed out in the furnace receptacle, lightly tighten the fitting nut with a wrench so the tube cannot be removed without loosening the nut. 7.1.3 Check to see there is no gap between the top of the furnace and the bottom of the test tube insulation stack. 7.1.4 Place the three-neck flask containing the test fluid in the heating mantle and zip the mantle shut. 7.1.5 Position the mantle and flask underneath
