Bulk Velocity and Mass Flowrate Estimation of Particle Plumes Through Particle Image Velocimetry Analysis of Thermogram Sequences

Particle Image Velocimetry (PIV) measurements are commonly used to determine velocity fields from a flow, given that sufficient tracers can be added and tracked to determine their motion. While these types of measurements are typically completed using high-speed cameras to capture the trajectories of the tracer particles, the experiments performed at the University of New Mexico generated extensive time-resolved infrared temperature image (i.e., thermogram) sets of a free-falling particle curtain captured at 300 Hz. The camera used for such measurements was high-speed infrared camera that provides a resolution of 640 x 512. The thermogram sets acquired have been extensively analyzed with two commonly used commercial PIV analysis packages, DaVis and PIVlab. The comparison between the two software packages showed consistent velocity fields and contours, along with corresponding average velocity as functions of discharge position. As expected, the vertical velocity component of these gravity-driven curtains follows a trend that resembles a free-falling sphere rather than a falling sphere experiencing drag. The study also found that the discharge velocity showed negligible effects due to the inlet particle temperature of the curtain. These results will be applied to the development of a methodology to estimate the mass flowrate of particle curtains and plumes using a novel non-intrusive image correlation methodology.