High-resolution optical particle sizing in an optimized orientation

A novel optical technique has been developed to measure particle diameters in multiphase flows with high accuracy. This technique uses a photodiode ar ray to measure the spatial frequency of the laser light scattering from a s pherical particle located in the measurement volume. An optimized optical o rientation angle is introduced by taking two scattering mechanisms into con sideration, which provides high accuracy and avoids the measurement-volume effect in sizing large particles. The performance of the new method was sim ulated by using the generalized Lorenz-Mie theory (GLMT) and validated by e xperiments. The results show only 2% measurement uncertainty for particle s izes as large as 1200 mu m, which are commonly encountered in gas-solid and bubbly-water multiphase flows. The feasibility of this technique was demon strated experimentally. (C) 1999 Society of Photo-Optical Instrumentation E ngineers. [S0091-3286(99)02312-0].