Aircraft turbine

Niobium is important as an alloy addition in steels (see Steel). This use consumes over 90% of the niobium produced. Niobium is also vital as an alloying element in superalloys for aircraft turbine engines. Other uses, mainly in aerospace appHcations, take advantage of its heat resistance when alloyed singly or with groups of elements such as titanium, tirconium, hafnium, or tungsten. Niobium alloyed with titanium or with tin is also important in the superconductor industry (see High temperature alloys Refractories). 

Survey of Electrical Conductivity and Charging Tendemy Characteristics of Aircraft Turbine Fuels, CRC Report No. 478, Coordinating Research Council, Inc., Atianta, Ga., Apr. 1975. 

Balir, D.W., Smith, J.R., and Kenwortliy, N.J., Development of Low Smoke Emission Combustors for Large Aircraft Turbine Engines, AIAA Paper Number 69-493. 

Combustors for Large Aircraft Turbine Engines, AIAA Paper Number 69-493. 

Aircraft and land-based turbines have different performance criteria. Aircraft turbine engine performance is measured in terms of output, efficiency, and... 

Indeed, for operation at temperatures above 1 000°C (now required of advanced aircraft turbine blading materials) it appears that reliance must be placed on alumina as the protective layer, partly because in high velocity oxidising gas streams volatility of CrO, leads to appreciable loss of scale by the oxidation of the CrjO, layer, and partly because alumina is inherently a much better diffusion barrier. 

Titanium finds uses as diverse as aircraft turbine blades, lightweight bicycle frames, and Ti02 smoke for skywriting. 

Garnets are important gems, abrasives, microwave systems components, magnetic bubble memories, and laser hosts. For the latter, yttrium aluminum garnet is the most important. It also plays an important role in aircraft turbines where it forms a protective coating on the turbine blades. 

Aircraft turbines in jet engines are usually fabricated from nickel-based alloys, and these are subject to combustion products containing compounds of sulphur, such as S02, and oxides of vanadium. Early studies of the corrosion of pure nickel by a 1 1 mixture of S02 and 02 showed that the rate of attack increased substantially between 922 K and 961 K. The nickel-sulphur phase diagram shows that a eutectic is formed at 910 K, and hence a liquid phase could play a significant role in the process. Microscopic observation of corroded samples showed islands of a separate phase in the nickel oxide formed by oxidation, which were concentrated near the nickel/oxide interface. The islands were shown by electron microprobe analysis to contain between 30 and 40 atom per cent of sulphur, hence suggesting the composition Ni3S2 when the composition of the corroding gas was varied between S02 02 equal to 12 1 to 1 9. The rate of corrosion decreased at temperatures above 922 K. 

Jet fuel fuel meeting the required properties for use in jet engines and aircraft turbine engines. 

A measured quantity of fuel is evaporated under controlled conditions of temperature and airflow or steam. For aviation gasoline and aircraft turbine fuel, the resulting residue is weighed and reported as milligrams per 100 mL. For motor gasoline, the residue is weighed... 

Scope. This specification covers fuel for aircraft turbine engines, ramjet engines, and rocket engines... 

In addition to aluminum, other types of metal matrices in MMCs include magnesium, which is relatively easy to fabricate due to its low melting point, lead for batteries, titanium for aircraft turbine engines, copper for magnetohydrodynamics, and iron, nickel, or cobalt alloys. 

Neopemrl Polyol Esters. These polyesters are prepared by the esterification of. -carbon polyfunclional alcohols with mono-lunctional acids. Because the beta carbon of the starting alcohol does not contain hydrogen, these esters are superior in thermal stability to the diesters. Most of the oilier characteristics arc similar to those of the dicsters. As a result of their superior stability, the neopentyl esters are finding increasing use as the luhricuni for aircraft turbine engines. 

Ta Aircraft turbines, rocket nozzles, HT vessels Aus., Brazil, i hailand. Can. 

TM—Si—B, eutectic (I) BNi powder, tape, RS foil AISI 300 and 400 aircraft turbine... 

Emissions from Aircraft Turbine Engines, Aerospace Recommended Practice 1256, SAE, 1971. 

Aircraft Turbine Fuels Icrtojet fuels 33 <360 a g no inevertftle etig/ BASF Ultraicrm... 

Aircraft Turbine Fuels turtiojai fuels 65 <360 B no ifTevarsibla change u... 

Defence Standard 91-99. Lubricating Oil, Aircraft Turbine Engine, Petroleum, NATO Code 0-135, Joint Service Designation OM-11. UK Defence Standardization. 

Unlike the aircraft turbine, the ground-based gas turbine operates continuously at the same power setting, usually 60—80% of maximum power output except when starting. Air and fuel flow patterns are constant and the combustor can be tuned to minimize smoke formation and high metal temperatures. 

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