Comparison of Techniques for Non-intrusive Fuel Drop Size
Measurements in a Subscale Gas Turbine Combustor
Issue title: International Conference on Optical Technology
and Image Processing in Fluid, Thermal, and Combustion Flow, Yokohama, Japan,
December 1998
Affiliations: NASA Glenn Research Center, M.S. 77-1, 21000 Brookpark
Road, Cleveland, OH 44135, USA | Dynacs Engineering Co., Inc., 2001 Aerospace Parkway,
Brook Park, OH 44142, USA
Abstract: In aviation gas turbine combustors, many factors, such as the degree
and extent of fuel/air mixing, and fuel vaporization achieved prior to
combustion, influence the formation of pollutants. To assist in analyzing the
extent of fuel/air mixing, flow visualization techniques have been used to
interrogate the fuel distributions during subcomponent tests of lean-burning
fuel injectors. Combustor pressures (up to 14 bar) and air inlet temperatures
(up to 680K) were typical of actual gas turbine engine operating conditions.
Discrimination between liquid and vapor phases of the fuel was accomplished by
comparing planar laser-induced fluorescence (PLIF) images,
elastically-scattered light images, and phase/Doppler interferometer
measurements. Estimates of Sauter mean diameters are made by ratioing PLIF and
Mie scattered intensities for various sprays, and factors affecting the
accuracy of these estimates are discussed. Mie calculations of absorption
coefficients indicate that the droplet fluorescence intensities are
proportional to their surface areas, instead of their volumes, due to the high
absorbance of the liquid fuel for the selected excitation wavelengths.
