Simultaneous High-Speed PIV-PTV Study Of Gas-Solid Suspension Flow in a Horizontal Channel

Pneumatic transport of solids is a vital industrial process involving the suspension of solid particles in a gas flow conveyed through conduits in a turbulent flow. Understanding the transition between two flow regimes - homogeneous suspension and settling flow - is crucial for efficient pneumatic transport. In particle-laden turbulent flows, an intricate interplay between particle dynamics, fluid turbulence, and inter-particle interactions determines the efficiency of pneumatic transport processes. Turbulence modulation plays a critical role, with large particles intensifying turbulent fluctuations and small particles attenuating turbulence. In order to examine the connection between turbulence modulation and particle dynamics, our research utilises high-speed PIV and PTV techniques to study turbulence modulation in dilute to moderately dilute gas-solid suspensions within a horizontal channel. The experimental setup features a glass channel for optical access, allowing clear visualisation of particle behaviour. Cross-validation with PIVLab and TSI Insight 4G ensures data reliability. Investigations extend to semi-dilute regimes, where the mean and root mean square velocities for the particle and gas phase are measured and compared with simulations. This is used to obtain criteria for homogeneous and settling flows and the transitions between the two. In conclusion, this comprehensive study offers valuable insights into particle-laden turbulent flows during pneumatic transport, contributing to advancing experimental fluid mechanics and practical applications in diverse industrial sectors.

This research was funded by the Department of Science & Technology, India (DST). We are grateful for their generous support of this project. The authors also acknowledge the IIT-Bombay's High-Speed PIV (HS-PIV) lab for providing a state-of-the-art facility for conducting high-speed PIV experiments.