Positron Emission Particle Tracking (PEPT) validation for jet flow

Positron Emission Particle Tracking (PEPT) generates 4D Lagrangian particle trajectories and is increasingly used to evaluate flow in granular media and complex geometries where optical interrogation methods are not possible. A Multi-Particle PEPT (Multi-PEPT) approach was developed capable of finding and tracking many particles simultaneously to extend the utility of the PEPT method. This paper compares 4,014 trajectories generated using the Multi-PEPT method with 3,055 trajectories generated from High Speed Video (HSV) data. All trajectories are taken in an acrylic test section with water flow using resin beads. The flow geometry includes a flow restriction producing a jet of Reynolds number 23,500 ±800, with peak velocity near 2 m/s, and two recirculation zones. Variation between measurement outcomes is generally less than 0.1 m/s, and measured variations fall within measurement uncertainties. Data co-location uncertainty contributes to larger variations between Multi-PEPT and HSV velocities in regions of steep gradients.