ON THE LDV SIGNAL PROCESSING SCHEME AND THE MEASUREMENT OF PARTICLE CONCENTRATION IN SOLID-LIQUID TWO-PHASE FLOW.

This paper presents a measurement technique for the analysis of soild-liquid two-phase flow with a laser-Doppler velocimeter. Setting up an optimum threshold value between amplitudes of Doppler signals from fluid and those from particle makes it possible to discriminate the particle from the fluid signals. The present two-photomultiplier system, which is composed of an optical arrangement with two reference beam modes, is effective for reducing the ambiguity noise in the spectrum of the fluctuating fluid velocities. It is also shown that the particle concentration can be calculated from the measured particle velocity, particle arrival rate, and the cross-section, where the amplitude of Doppler signal is greater than the threshold value, within the measurement volume.