Optimization of optical parameters for particle sizing in multiphase flows

Optimization of laser light scatter detection technique based on the geometrical optics method for measuring the size, velocity and refractive index of spherical particles was performed. A new optical orientation for extended phase-Doppler anemometry (EPDA) had been developed to improve the accuracy of particle material recognition in multiphase flow. The effects of both the intensity and phase factor of the reflected and refracted light were examined. The inverse sign of the phase factors from the refracted light and reflected light resulted in a (2π–φ) effect on phase determination. This was used for minimizing and validating the errors in the refractive index measurements of large particles. Furthermore, optimization results were compared with the results of simulation based on the generalized Lorenz–Mie theory (GLMT). A newly developed signal validation scheme was also described in detail. The scheme was used to reject the inaccurate data in order to further improve the accuracy of the recognition.