A theoretical model based on the Lorenz-Mie theory was used to study the response characteristics of the Aerometrics phase Doppler particle analyzer (PDPA). The validity of the model was verified experimentally, and its suitability for calculating measurement uncertainties was established. The theoretical and experimental results suggest that size resolutions of the order of +/-0.3 microm are possible when the PDPA is used to measure small spherical particles (< 10 microm). We show that the optical configuration of the PDPA plays an important role in establishing the sizing uncertainty of the instrument.
The present work details the theoretical and experimental research undertaken to determine the size and morphology of bubbles, and their dynamic characteristics such as velocity, number density, and volume flux using light scattering interferometry. The approach is based on the measurement of the phase difference of the interference fringe pattern which is produced when a particle passing through the probe volume defined by the intersection of two laser beams scatters light and interferes in the surrounding medium. Detailed analytical/numerical modeling of the phase Doppler approach using Mie scattering theory and the geometrical optics approximation resulted in optimum light scattering collection angles and calibration curves for bubble diagnostics. Using several techniques to generate a steady stream of monosize bubbles in the range from 6 μ to 1800 μm in diameter, the measurements obtained using the phase Doppler method were compared with direct photography yielding an agreement of better than 95 percent. The morphology of spheroidal bubbles was also investigated by placing the transmitting and receiving optical units at specified locations with respect to the scatterers. It is believed that this theoretical and experimental work has given the phase Doppler method general validity as applied to bubble diagnostics and promises to become a powerful research tool in the study of two phase flows.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.