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IMPROVED TURBINE LUBRICANTS WILL BE NEEDED

IMPROVED TURBINE LUBRICANTS WILL BE NEEDED peratures have been encountered with silicones. The reason is unknown at present. Another drawback IMPROVE D TURBINE to silicone lubricants is their poor wear resistance with steel and carbon. Silicone lubricants appear to LUBRICANT S WILL BE be out of the picture for gas turbines. NEEDE D ALTHOUGH PRESENT AIRCRAFT TURBINE lubricating oils have been very successful, the fact tha t aircraft of the future will need to fly faster and higher, will impose extra heavy duties on th e oil, e.g., it it is expected that bulk oil temperatures may rise a further 150°F. These facts were stated by T. F. Davidson, and J . H. Way (Wright Air Development Center, United States Air Force), in a paper to the Society of Automotive Engineers at New York in April. They said tha t although during 1958 probably 80% of the U.S. Air Force gas turbines would be lubricated with oil to Specification MIL-L-7808, there would be considerable room for improvement. The areas where improvement is required are in con­ nection with corrosion, oxidation and thermal stability, gear and bearing fatigue resistance and load carrying ability. Silanes appear, by laboratory study, to possess The authors said that although MIL-L-7808 oils comparable thermal stability to silicones, but results from mechanical evaluation has varied with the type were relatively inert to even the most active metals of silane used. Aromatic silanes appear poor in wear such as lead and copper, upon storage and deterior­ resistance whereas alkyl and aryl silanes have wear ation they became corrosive, particularly to lead. properties comparable to uninhibited diesters. Fortunately, very little corrosion due to storage Further evaluation is in progress. instability had been encountered in service and then only when the turbines were operated under ab­ Of the esters, at present fluoresters and pentraery- normal conditions. But improvement is required. thritol were thought by the authors to be the most Although data is limited, it appears that bearing promising. Unfortunately most promising high tem­ perature candidates exhibit relatively poor low tem­ fatigue resistance is primarily influenced by lubricant perature properties. It appears that the price of viscosity, whereas with gears, load carrying ability high temperature lubricant performance may well seems to be the key lubricant property effecting gear have to be a compromise of low temperature per­ fatique resistance. In present engines, the oil has to both lubricate and cool, but in the future ram air oil formance. Some investigators believe that a relax­ coolers will not be practicable. At Mach 2.3 the ram ation of 1°F, at low temperatures (—65°) may be reflected in a 2 to 3°F. gain at high temperature (bulk air rise is about 400°F. and so such 'coolers' could oil) performance. Mineral oils have very good high become heaters. temperature properties, especially if their low tem­ Divided System. perature performance is not heavily weighed. It is hoped that certain new developments in mineral oil The system of the future may be of the 'divided' processing such as solvent extraction techniques, type which divorces lubricating from cooling func­ vacuum distillation, hydrogenation and improved tions. Oil for lubrication is supplied to the bearing additives will yield even further improved materials. and cooling may be accomplished by injection of a volatizing coolant, taking advantage of the heat of evaporation, or by circulation around the bearing compartment. The circulating fluid could be either ESSO FORM oil, fuel or some other heat transfer media. IRISH REFINING COMPANY. Future Oils. Silicones have exhibited a very alarming deficiency A new company, the Irish Refining Company as shown in the diagram. Normally, a given size of Limited, has been formed to develop the proposed anti-friction bearing when operated at a specific oil refinery at Whitegate in County Cork, Ireland. speed, with specific lubricant flow and with a known I t will hold a meeting in Dublin in mid-July when a viscosity lubricant will stabilize at some predictable full statement will be issued outlining its plans for temperature. Such a relationship has been found the construction of the refinery. It is anticipated true of both mineral and ester lubricants but much that" th e Lummus Company will commence work on higher than predictable bearing stabilization tem­ the site during August. Scientific LUBRICATION July, 1957 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Industrial Lubrication and Tribology Emerald Publishing

IMPROVED TURBINE LUBRICANTS WILL BE NEEDED

Industrial Lubrication and Tribology , Volume 9 (7): 1 – Jul 1, 1957

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0036-8792
DOI
10.1108/eb052464
Publisher site
See Article on Publisher Site

Abstract

peratures have been encountered with silicones. The reason is unknown at present. Another drawback IMPROVE D TURBINE to silicone lubricants is their poor wear resistance with steel and carbon. Silicone lubricants appear to LUBRICANT S WILL BE be out of the picture for gas turbines. NEEDE D ALTHOUGH PRESENT AIRCRAFT TURBINE lubricating oils have been very successful, the fact tha t aircraft of the future will need to fly faster and higher, will impose extra heavy duties on th e oil, e.g., it it is expected that bulk oil temperatures may rise a further 150°F. These facts were stated by T. F. Davidson, and J . H. Way (Wright Air Development Center, United States Air Force), in a paper to the Society of Automotive Engineers at New York in April. They said tha t although during 1958 probably 80% of the U.S. Air Force gas turbines would be lubricated with oil to Specification MIL-L-7808, there would be considerable room for improvement. The areas where improvement is required are in con­ nection with corrosion, oxidation and thermal stability, gear and bearing fatigue resistance and load carrying ability. Silanes appear, by laboratory study, to possess The authors said that although MIL-L-7808 oils comparable thermal stability to silicones, but results from mechanical evaluation has varied with the type were relatively inert to even the most active metals of silane used. Aromatic silanes appear poor in wear such as lead and copper, upon storage and deterior­ resistance whereas alkyl and aryl silanes have wear ation they became corrosive, particularly to lead. properties comparable to uninhibited diesters. Fortunately, very little corrosion due to storage Further evaluation is in progress. instability had been encountered in service and then only when the turbines were operated under ab­ Of the esters, at present fluoresters and pentraery- normal conditions. But improvement is required. thritol were thought by the authors to be the most Although data is limited, it appears that bearing promising. Unfortunately most promising high tem­ perature candidates exhibit relatively poor low tem­ fatigue resistance is primarily influenced by lubricant perature properties. It appears that the price of viscosity, whereas with gears, load carrying ability high temperature lubricant performance may well seems to be the key lubricant property effecting gear have to be a compromise of low temperature per­ fatique resistance. In present engines, the oil has to both lubricate and cool, but in the future ram air oil formance. Some investigators believe that a relax­ coolers will not be practicable. At Mach 2.3 the ram ation of 1°F, at low temperatures (—65°) may be reflected in a 2 to 3°F. gain at high temperature (bulk air rise is about 400°F. and so such 'coolers' could oil) performance. Mineral oils have very good high become heaters. temperature properties, especially if their low tem­ Divided System. perature performance is not heavily weighed. It is hoped that certain new developments in mineral oil The system of the future may be of the 'divided' processing such as solvent extraction techniques, type which divorces lubricating from cooling func­ vacuum distillation, hydrogenation and improved tions. Oil for lubrication is supplied to the bearing additives will yield even further improved materials. and cooling may be accomplished by injection of a volatizing coolant, taking advantage of the heat of evaporation, or by circulation around the bearing compartment. The circulating fluid could be either ESSO FORM oil, fuel or some other heat transfer media. IRISH REFINING COMPANY. Future Oils. Silicones have exhibited a very alarming deficiency A new company, the Irish Refining Company as shown in the diagram. Normally, a given size of Limited, has been formed to develop the proposed anti-friction bearing when operated at a specific oil refinery at Whitegate in County Cork, Ireland. speed, with specific lubricant flow and with a known I t will hold a meeting in Dublin in mid-July when a viscosity lubricant will stabilize at some predictable full statement will be issued outlining its plans for temperature. Such a relationship has been found the construction of the refinery. It is anticipated true of both mineral and ester lubricants but much that" th e Lummus Company will commence work on higher than predictable bearing stabilization tem­ the site during August. Scientific LUBRICATION July, 1957

Journal

Industrial Lubrication and TribologyEmerald Publishing

Published: Jul 1, 1957

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