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Show Measurement and Interpretation - 8 - IFRF-~ of Flames Issued from a Generic Multi-Fuel Bumer The drop size and velocity measurements were performed by traversing the PDP A measurement volume along radii perpendicular to the spray axis and crossing the center of individual jets. The axial and tangential velocity components were measured by traversing along the x-axis. The radial component was measured after rotating the lance by 30° in the holder, so that one of the nozzle jet cones was centered on the y-axis. The accuracy of the PDP A probe volume position was approximately ±lmm. Measurements with superheated steam as atomizing medium were initially attempted. However, the nucleation of water vapor led to the simultaneous presence in the measurement volume of many particles smaller than the detection limit. This resulted in very noisy PDP A signals which prevented collection of meaningful measurements. Measurements using air for atomization did not exlubit these difficulties and were performed with high data and validation rates. 3.3. Correlation of Phase Doppler Anemometry (PDA) Data Characterization of sprays using the PDA technique provides extensive sets of data on the properties of the spray. Interpretation of these data sets with respect to their implementation in CFD codes is important and requires correlation procedures of droplet sizes, mass fluxesand velocities. 3.3.1. Droplet Probability Density Function (PDF). The droplet number fluxes were calculated by assuming that the radial variation in droplet number flux is proportional to the event rate as measured by the PDP A. An averaging procedure to account for the radial variations in droplet number fluxes is as follows. ntotm,L as the event rate at location L ni,L as the number of droplets of size i measured at location L k ntoflll,L as the total number of drop lets measured at location L, ntoflll,L = L ni,L ' i=1 where k is the total number of droplets size classes (SO for these data sets) n 0,L ni,L = ntoflll,L • _1- as the event rate of size class i at location L. n toflll ,L Method 1. - Geometric Averaging. This method is applied to account for radial variations in flux |