Calculation of Calibration Curves for the Phase Doppler Technique: Comparison between Mie Theory and Geometrical Optics
The phase-Doppler technique (Durst & Zaré, 1975; Baohalo & Houser, 1984) measures the diameter and velocity of spherical particles simultaneously, with the spatial and temporal resolution of a laser-Doppler anemometer. The range of diameters and particle concentrations which can be measured range from a few to several hundred micrometers and up to about 1010 particles/m−3. Instruments based on this principle have a number of advantages over others based on the laser-Doppler anemometer. One is that the technique is not based on the intensity of the scattered light and the measurements are therefore insensitive to random beam attenuation by either particles which lie outside the measurement volume or by obscuration of windows in a test-section (Hardalupas et al., 1986). There is therefore also no need to account for any effect on the size information of the Gaussian intensity of the incident light beams, in contrast to systems which measure visibility, for example (e.g. Yeoman et al. 1982).
KeywordsInternal Reflection Geometrical Optic High Frequency Oscillation Incident Laser Beam Scatter Angle
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