Tribochemical Polymerization of Adsorbedn-Pentanol on SiO2during Rubbing: When Does It Occur and Is It Responsible for Effective Vapor Phase Lubrication?†

Langmuir ◽  
2010 ◽  
Vol 26 (21) ◽  
pp. 16299-16304 ◽  
Author(s):  
Anna L. Barnette ◽  
David B. Asay ◽  
James A. Ohlhausen ◽  
Michael T. Dugger ◽  
Seong H. Kim
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Lubrication

Vapor-Phase Lubrication:  Reaction of Phosphate Ester Vapors with Iron and Steel

2002 ◽  
Vol 14 (9) ◽  
pp. 3767-3775 ◽  
Author(s):  
David W. Johnson ◽  
Samantha Morrow ◽  
Nelson H. Forster ◽  
Costandy S. Saba
Keyword(s):  
Vapor Phase ◽  
Phosphate Ester ◽  
Vapor Phase Lubrication ◽  
Iron And Steel

Investigation of Vapor-Phase Lubrication in a Gas Turbine Engine

1997 ◽  
Author(s):  
Kenneth W. Van Treuren ◽  
D. Neal Barlow ◽  
William H. Heiser ◽  
Matthew J. Wagner ◽  
Nelson H. Forster
Keyword(s):  
Gas Turbine ◽  
Vapor Phase ◽  
Gas Turbine Engine ◽  
Rolling Contact ◽  
Phosphate Ester ◽  
Lubrication System ◽  
Oil Lubrication ◽  
Vapor Phase Lubrication ◽  
Engine Operation ◽  
Turbine Engine

The liquid oil lubrication system of current aircraft jet engines accounts for approximately 10–15% of the total weight of the engine. It has long been a goal of the aircraft gas turbine industry to reduce this weight. Vapor-Phase Lubrication (VPL) is a promising technology to eliminate liquid oil lubrication. The current investigation resulted in the first gas turbine to operate in the absence of conventional liquid lubrication. A phosphate ester, commercially known as DURAD 620B, was chosen for the test. Extensive research at Wright Laboratory demonstrated that this lubricant could reliably lubricate railing element bearings in the gas turbine engine environment. The Allison T63 engine was selected as the test vehicle because of its small size and bearing configuration. Specifically, VPL was evaluated in the number eight bearing because it is located in a relatively hot environment, in line with the combustor discharge, and it can be isolated from the other bearings and the liquid lubrication system. The bearing was fully instrumented and its performance with standard oil lubrication was documented. Results of this baseline study were used to develop a thermodynamic model to predict the bearing temperature with VPL. The engine was then operated at a ground idle condition with VPL with the lubricant misted into the #8 bearing at 13 ml/hr. The bearing temperature stabilized at 283°C within 10 minutes. Engine operation was continued successfully for a total of one hour. No abnormal wear of the rolling contact surfaces was found when the bearing was later examined. Bearing temperatures after engine shutdown indicated the bearing had reached thermodynamic equilibrium with its surroundings during the test. After shutdown bearing temperatures steadily decreased without the soakback effect seen after shutdown in standard lubricated bearings. In contrast, the oil lubricated bearing ran at a considerably lower operating temperature (83°C) and was significantly heated by its surroundings after engine shutdown. In the baseline tests, the final bearing temperatures never reached that of the operating VPL system.

Wear Reduction of Borosilicate Glass Microballs Using Vapor-Phase Lubrication With n-Pentanol

2016 ◽  
Vol 59 (3) ◽  
pp. 507-512
Author(s):  
Su Yee Yau ◽  
Shin-Sung Yoo ◽  
Oleksiy V. Penkov ◽  
Dae-Eun Kim
Keyword(s):  
Vapor Phase ◽  
Borosilicate Glass ◽  
Vapor Phase Lubrication ◽  
Wear Reduction

scholarly journals Effects of Gas Adsorption in Nanotribology and Demonstration of In-Situ Vapor Phase Lubrication of MEMS Devices

2007 ◽  
Author(s):  
David B. Asay ◽  
Michael T. Dugger ◽  
Seong H. Kim
Keyword(s):  
Vapor Phase ◽  
Microelectromechanical Systems ◽  
Silicon Oxide ◽  
Gas Adsorption ◽  
Extended Period ◽  
Adsorbed Water ◽  
Oxide Surface ◽  
Mems Devices ◽  
Vapor Phase Lubrication

This paper discusses the important role of gas adsorption in nanotribology and demonstrates in-situ vapor phase lubrication of microelectromechanical systems (MEMS) devices. We have elucidated the molecular ordering and thickness of the adsorbed water layer on the clean silicon oxide surface and found the molecular-level origin for the high adhesion between nano-asperity silicon oxide contacts in humid ambient. The same gas adsorption process can be utilized for continuous supply of lubricant molecules to form a few Å thick lubricant films on solid surfaces. Using alcohol vapor adsorption, we demonstrated that the adhesion, friction, and wear of the silicon oxide surface can significantly be reduced. This process made it possible to operate sliding MEMS without failure for an extended period of time.

Humidity Effects on In Situ Vapor Phase Lubrication with n-Pentanol

2014 ◽  
Vol 55 (1) ◽  
pp. 177-186 ◽  
Author(s):  
Anna L. Barnette ◽  
J. Anthony Ohlhausen ◽  
Michael T. Dugger ◽  
Seong H. Kim
Keyword(s):  
Vapor Phase ◽  
Vapor Phase Lubrication ◽  
Humidity Effects

Vapor-Phase Lubrication in Combined Rolling and Sliding Contacts: Modeling and Experimentation

2000 ◽  
Vol 123 (3) ◽  
pp. 572-581 ◽  
Author(s):  
W. Gregory Sawyer ◽  
Thierry A. Blanchet
Keyword(s):  
Steady State ◽  
Friction Coefficient ◽  
Partial Pressure ◽  
Vapor Phase ◽  
Wear Track ◽  
Rolling Speed ◽  
Vapor Phase Lubrication ◽  
Sliding Contacts ◽  
Sliding Speed ◽  
Track Diameter

The in situ vapor-phase lubrication of M50 steel, in combined rolling and sliding contacts at 540°C using nitrogen atmospheres containing acetylene, is achieved. Acetylene partial pressures of 0.05 atmospheres are capable of providing continuous lubrication to combined rolling and sliding contacts through pyrolytic carbon deposition. In these tests, friction coefficients as low as μ=0.01 are found for contacts at 2.0 m/s rolling speed, 10 cm/s sliding speed, 100 N load (1.3 GPa Hertzian contact pressure), and ambient temperature of 540°C, with even lower values observed at more modest sliding speeds. One example of a model for vapor phase lubrication of combined rolling and sliding contacts is developed which predicts the lubricant steady-state fractional coverage of the contact surfaces, and from this makes friction coefficient predictions using a linear rule-of-mixture. Friction coefficient responses to step changes in acetylene partial pressure, sliding speed, and disk wear-track diameter are measured. Increased partial pressure of acetylene and increased area available for deposition are observed to be beneficial, while increased sliding speed is detrimental to lubrication performance. Shapes and trends of steady-state friction coefficient versus acetylene partial pressure, sliding speed, and disk wear-track diameter are described and curve-fit by the model. In combined rolling and sliding this example model predicts large regions of operating conditions over which friction coefficient is independent of rolling speed, as well as regions of independence of vapor partial pressure. In the special case of pure sliding, a region of friction coefficient independence of a ratio of partial pressure to sliding speed and another region of independence of a ratio of partial pressure to the product of sliding speed and normal load are predicted.

scholarly journals Vapor Phase Lubrication for Expendable Gas Turbine Engines

1999 ◽  
Author(s):  
Matthew J. Wagner ◽  
Nelson H. Forster ◽  
Kenneth W. Van Treuren ◽  
David T. Gerardi
Keyword(s):  
Vapor Phase ◽  
Carbon Composite ◽  
Operating Conditions ◽  
Cruise Missile ◽  
Vapor Phase Lubrication ◽  
Limited Life ◽  
Custom Made ◽  
Bearing Materials ◽  
Full Power ◽  
The Cost

Vapor Phase Lubrication (VPL) is an emerging technology that is currently targeted for application in limited life, expendable engines. It has the potential to cut 90% of the cost and weight of the lubrication system, when compared to a conventional liquid lubricated system. VPL is effective at much higher temperatures than conventional liquid lubrication (600°C vs. 200°C), so considerably less cooling for the bearing is required, to the extent that the bearing materials often dictate the maximum upper temperature for its use. The hot #8 bearing and the cold #1 bearing of the T63 engine were used to evaluate the applicability of this technology to the expendable engine environment. The #8 bearing was a custom made hybrid with T15 steel races, silicon nitride balls, and a carbon-carbon composite cage; it was run for 10.7 hours at a race temperature of 450°C at full power, without incident. Prior to engine tests, a bearing rig test of the #8 bearing demonstrated an 18.6-hour life at a race temperature of 500°C at engine full power speed of 50,000 rpm. Cold bearing performance was tested with the standard #1 bearing, which consisted of 52100 steel races and bails, and a bronze cage; it was run for 7.5 hours at a race temperature of 34°C at flight idle power, without incident. A self-contained lubricant misting system, running off compressor bleed air, provided lubricant at flow rates of 7–25 ml/hr, depending on engine operating conditions. These tests have demonstrated for the first time, that a single self-contained VPL system can provide adequate lubrication to both the hot and cold bearings for the required life of an expendable cruise missile engine.

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