PERFORMANCE EVALUATION OF DIFFERENT PHASE-DOPPLER SYSTEMS

The results of comparative measurements of three different phase-Doppler systems applied to a steady-state water spray are discussed. The three receiving systems, i.e. DANTEC 57X receiving optics with covariance processor, an AEROMETRICS fibre-based receiver with DSA processor and a standard INVENT phase-Doppler extension, were used with a 2-D fibre-optics-based transmitting system. A constant scattering angle of 70-degrees was chosen, which is near the Brewster angle for water. Measurements were taken in the spray cone of a hollow-cone pressure atomizer at two different axial distances from the nozzle. Local size distributions, size/velocity correlations and the mean diameters D10 and D32 were compared. The results indicate very good agreement between the different systems, especially with respect to the mean diameters. Larger scatter of the results occurs for the measured volume flow rates, but the calculated mean volume flow rates coincide fairly well with the nominal flow rate of the atomizer.