%0 Journal Article %A Idota, Yoshinori %A Ohkubo, Yoichiro %A Kawamura, Kiyomi %D 1997 %I Begell House %N 1-3 %P 283-293 %R 10.1615/InterJFluidMechRes.v24.i1-3.280 %T Comparison between Laser Diffraction Method and Phase Doppler Method for Spray Characteristics of Air-Assisted Swirl Atomized %U https://www.dl.begellhouse.com/journals/71cb29ca5b40f8f8,43bb5586004d5e8d,2501025c472df1bc.html %V 24 %X An air-assisted swirl atomizer has been developed for a gas turbine combustor. In the case of a conventional swirl atomizer, the droplet size increases and the spray cone angle decreases with decreasing fuel flow rate (or fuel pressure). Therefore, the swirl atomizer has a disadvantage at low flow rates. To overcome this disadvantage, a rapid air stream swirled by vanes was supplied around the swirl atomizer. This improvement has enabled the atomizer to produce finer spray (Sauter mean diameter or D32 ≤ 30 μm) and a constant wide spray cone angle (90 deg) over a wide flow rate (1:15). The spray characteristics were measured by a laser diffraction method (LDSA) and a phase Doppler method (PDPA). Results measured by the laser diffraction are sometimes different from those by the phase Doppler method. In this study, the results measured by LDSA are compared with the results measured by PDPA.
Sauter mean diameter measured by the LDSA and them converted into spatially averaged data from the PDPA is similar across the entire spray. However, Sauter mean diameter by the LDSA is a little smaller in the center region and a little larger in the outer edge region of the spray than that measured by the PDPA. For the measurement in the outer region, the difference seems to be caused mainly by the low signal-to-noise ratio of the LDSA. For the measurement in the center region, the measurement result is influenced by the supply voltage of a photon multiplier tube of the PDPA. %8 1997-06-01