Novel Cross-Correlation Technique for the Determination of Radial Velocity Profiles in Two-Phase Flows

摘要

A novel cross-correlation technique has been developed, which enables the determination of radial velocity profiles in two-phase flows with minimum disturbance of the flow. The method is based on cross-correlating the signals from a light beam source and a detector outside the flow, with the signals from a local light reflection probe which is located in the flow and can be moved to different radial positions in the tube. Subsequently, the local probe is 'switched' into a light detector, the light source diametrically opposite the probe is switched on, the two light beam signals modulated by the two-phase flow across the whole diameter of the tube are cross-correlated. Usually, during the latter measurements, there are two peaks in the cross-correlation function due to the existence of a radial velocity profile in the flow. The results of the latter measurements were reproduced by employing a computer simulation program, into which the radial velocity profile determined by this technique was input, and in the course of this simulation, the importance played by the radial void distribution in interpreting this kind of measurement was shown. The results presented in this investigation are to be considered of a preliminary nature; a much more detailed study of the advantages and limitations of the proposed technique is needed. (Atomindex citation 15:009996)