The Phase Doppler Method: Analysis and Application

  • W. D. Bachalo


The measurement characteristics of the phase Doppler method are presented. Features of the light scattering were analyzed using the geometrical optics theory. In particular, the combined light scattering by reflection and refraction were considered along with the parameters affecting this problem. Bounds on the drop-to-beam diameter were suggested to mitigate the problem. Several experiments including direct comparisons to measurements by other instruments were described to demonstrate the relative measurement accuracies. Mass flux measurements which depend heavily upon the accurate determination of the diameters of the largest drops were compared to sampling probe results and nozzle flow rate. Number density measurements were compared to data obtained using extinction and the Lambert-Beer Law. These data were in agreement to within 5%. Detailed measurements in a complex turbulent two-phase flow with strong recirculation were summarized. Velocity measurements for discrete particle size classes were used to show the nature of the particle response. In such flows, it was found that particles as small as 10 um could behave quite differently from the gas phase. As an example, at some locations the gas phase mean velocity was opposite in direction to the dispersed phase. In general, the mean velocity and angle of trajectory response of the drops was consistent with their relative mass. Because of the need to obtain these data in difficult environments, off-axis backscatter light detection was considered. Comparative measurements between forward and backscatter were obtained using monodispersed drops and sprays.


Fringe Pattern Seed Particle Particle Number Density Laser Doppler Velocimeter Particle Response 
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Copyright information

© Springer Science+Business Media New York 1988

Authors and Affiliations

  • W. D. Bachalo
    • 1
  1. 1.Aerometrics, Inc.Mountain ViewUSA

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