RADIATION FROM FLAMES
- in gas turbine combustors
THE EFFECT of monocyclic versus polycyclic aromatic components, in JP-5 fuels having the same ASTM Smoke Points, on total flame radiant energy was investigated. The performance of research combustors and a J79 aircraft gas turbine engine single combustor operated at low (atmospheric) pressure showed that variations in aromatic type or content within the present JP-5 specification have no significant effect on flame radiation.
The performance of research combustors and a J57 aircraft gas turbine engine single combustor operated at high (5-15 atm) pressure showed that polycyclic aromatic fuel blends burn with higher flame emissivities than monocyclic aromatic fuel blends of comparable ASTM Smoke Point. Radiant heating of metal parts was shown to be a function of their location in the combustor because quenched combustion products can effectively absorb flame radiation.
A characteristic relationship between total flame radiant energy from a J57 combustor and CRC Luminometer number was obtained with 12 test fuels covering a broad range in burning characteristics. Because of the excellent correlation between fuel ratings obtained with the ASTM Smoke Lamp and the CRC Luminometer, it seems desirable to consider the latter as an alternate for characterizing fuels beyond the limit of the present test method.
The use of low-luminosity fuels gave major reductions in liner temperatures in the J57 combustor. However, such fuels do not insure large reductions in heat transfer to metal parts, as shown by a reduction of only 40 F in the afterburner liner temperature of a J75 aircraft gas turbine engine obtained with “JP-150.”*