Response characteristics of the phase Doppler particle analyzer for sizing spherical particles larger than the light wavelength

Abstract

A theoretical model, based on the geometrical optics approach, has been developed to simulate various aspects of the phase Doppler particle analyzer (PDPA). The model has taken into consideration the nonuniform (Gaussian) illumination of the particles as they pass through the measurement probe volume. Instrument response curves have been generated for various scattering angles by performing spatial and temporal integration of the scattered intensity distribution over the receiver surface. Experimental and theoretical investigations have established the applicability of this instrument to both forward scattered and backscattered angles.

The Use of Small Probe Volumes with Phase Doppler Interferometry

“…A previously developed phase Doppler response model was used to study the effect of droplet trajectory on phase response and scattering intensity [4]. The model is a geometric optics based scattering model that accounts for the Gaussian nature of the illuminating probe beams by integrating the appropriate scattering functions over the surface of the droplet.…”

“…The model is a geometric optics based scattering model that accounts for the Gaussian nature of the illuminating probe beams by integrating the appropriate scattering functions over the surface of the droplet. The model will not be discussed further here while the reader is referred to the published descriptions of the model [4]. The trajectory coordinate, T|, is defined as 2y/D w , where y is the trajectory normal to the scattering plane as defined from the center of the probe volume, and D w is the 1/e 2 beam waist diameter.…”

Statistical description of the bubble cloud resulting from the injection of air into a turbulent water jet

“…1) in the forward scatter direction. This gives a linear relationship between the phase diflerence and the diameter of the scattering bubble, as calculated from analytical modeling using the Lorenz-Mie theory (Bachalo and Houser, 1984;Breña de la Rosa et al, 1989, 1990Sankar and Bachalo, 1991). In all the cases presented here the measurements were taken at 20 nozzle diameters, 10 diameters downstream from the air injection point.…”

Development of a generalized theoretical model for the response of a phase/Doppler measurement system to arbitrarily oriented fibers illuminated by Gaussian beams

“…Many studies have been presented in the literature that have addressed design considerations as well as the applicability of the P͞D technique to spherical aerosol sizing under various measurement conditions. [1][2][3][4][5] The P͞D method has proved attractive for in situ measurements, as it offers several important advantages over alternative techniques, including nonintrusive operation, high spatial resolution, simultaneous particle size and velocity measurements, and measurements that are independent of absolute intensity. Despite the successes in spherical aerosol sizing, only recently has serious effort been made to generalize the P͞D measurement technique to sizing cylindrical fibers.…”