Super Spatio-Temporal Resolution, Digital PIV System for Multi-Phase Flows With Phase Differentiation and Simultaneous Shape and Size Quantification

Abstract

A unique, super spatio-temporal resolution Digital Particle Image Velocimetry (DPIV) system for the analysis of time-dependent multiphase flows has been developed. The system delivers a sampling frequency between 1KHz and 10KHz, with continuous total acquisition time up to 4 secs and resolution 1Kx1K pixels down to 256×256 pixels. The hardware is integrated with sophisticated image processing algorithms that allow direct image segmentation in order to resolve the multiple phases present in the flow and provides quantitative information about the shape and size of droplets or bubbles present. Finally, the in-plane velocities are measured by a super-resolution, dynamically-adaptive cross-correlation algorithm which is coupled with a particle-tracking scheme. Each individual phase present in the flow is resolved with mean spatial resolution in the order of 3–4 pixels, and accuracy in the order of 0.01–0.1 pixels, while the spatial averaging effects of cross correlation are eliminated.