Abstract Summary (Max 250 words)
Traditional flow visualisation techniques such as Particle Image Velocimetry (PIV) and Positron Emission Particle Tracking (PEPT) are expensive and are essentially limited to specialist University Laboratories. Particle Tracking Velocimetry (PTV) is a 3D Lagrangian tracking technique for visualising fluid flow. Parallax setups limit the field of view in PTV systems. This study has addressed these issues by developing a low-cost optical PTV alternative based on a single-frequency light source and orthogonal mirrors to increase the field of view, which can be deployed in any open laboratory. The new PTV rig is presently optimised for a 300 mm stirred tank. Development was guided by finite element modelling of the system, including optical characteristics of the materials, enabling first-principles design and optimisation. This work discusses reconstruction-model development from first principles, approaches for handling large data throughput to obtain a more representative mixing study across a wide range of fluid mixing dynamics, and the use of optical mechanics to reduce signal-to-noise ratio. Conventional PTV methodology uses a narrow camera offset to minimise stereographic depth under obscuration constraints. As PTV does not have the same particle density as PIV, the camera offset need not be minimised; an orthogonal arrangement maximises spatial field while maintaining high spatial resolution. Finally, the benefits of combining the PTV digital twin with experimental PTV results in a stirred tank are discussed, with example results presented.
