The Navy is engaged in programs to reduce the visible smoke emitted by gas turbine engines. These programs include the use of alternate fuels, the use of smoke suppressant fuel additives, and the use of combustor design technology. The current status in each of these areas is presented, as is a review of previous investigations.
Tests of alternate fuels have shown that a significant but inadequate reduction of smoke was obtained. Of the fuel additives tested, one additive has shown superior performance to the others, and is suitable for use in certain engines. In order to determine the potential smoke reduction possible through combustor design, the combustion system of several engines is being redesigned. Some of the results of the redesign programs are discussed. Also presented is a brief description of the most commonly used methods of smoke measurement.