Measurements of size and velocity of particle in two-phase flow by a three beam LDA system.

A three beam LDA optical system was developed to improve a particle sizing for measuring range up to approximately 400 MUm. The optical system makes a measuring volume with a larger beam and cross beams of smaller diameter, and they are linearly polarized in the orthogonal direction to each. Particle sizes are measured by light scattering intensity from the larger beam and particle velocities are given by Doppler signals from the cross region of two beams with a smaller volume. The experiment of calibration for particle sizing confirms that the measuring range for particle sizing is improved for a larger particle size. The measurement of particle size in free falling spherical glass particles by the three beam LDA system is in good agreement with that by microscopic measurements. (from authors' abstract)