Aerosol Deposition in Fully-Developed Turbulent Vertical Pipe Flows: Lagrangian Simulations and Experimental Validation
FATEMEH RAZAVI, Zack Milani, Nick Ogrodnik, Edgar Matida,
Carleton University Abstract Number: 782
Working Group: Aerosol Physics
AbstractAerosol deposition in turbulent pipe flows is a crucial phenomenon with significant implications for various industrial applications, including ventilation systems, pharmaceutical aerosol delivery, and particulate matter transport. This study presents a comprehensive investigation of droplet penetration in fully-developed turbulent vertical pipe flows using Lagrangian numerical simulations. Two Reynolds numbers (ReD = 37,700 and 11,700), representative of the pipe diameter, were considered in the simulations. The characterization of the single-phase flow, encompassing mean velocities, root mean square fluctuation velocities, and turbulence dissipation rate, was obtained by combining law-of-the-wall relationships and direct numerical simulation (DNS) statistical data from the literature. Lagrangian simulations were performed for monodispersed droplets ranging from 1.78 to 26.83 µm, introduced separately into the turbulent pipe-flow computational domain. The droplet phase was modeled using a one-way coupling Lagrangian random-walk eddy interaction model (EIM). A novel approach based on a modified eddy lifetime, derived from local turbulent Reynolds numbers (Reλ) and velocity fluctuations perpendicular to the walls, was proposed to assess droplet penetration. The simulation results were compared against experimental data from Liu and Agarwal, demonstrating overall good agreement and providing validation for the Lagrangian EIM modeling approach. However, some disparities were observed for droplets with dimensions below τ+ < 10 at ReD = 37,700, suggesting the need for further model refinement and calibration. The inherent semi-empirical nature of the current time scale model and the simplicity of the DRW EIM call for cautious consideration of deviations in certain scenarios. In conclusion, this research advances the understanding of aerosol deposition in turbulent pipe flows and provides valuable insights for both the scientific community and some industrial sectors. The Lagrangian simulations, validated against experimental data, serve as a valuable tool to comprehend droplet behavior in complex turbulent environments.
Keywords: Aerosol Deposition, Turbulent Pipe Flows, Lagrangian Particle Tracking, Eddy Interaction Model, Aerosol Behavior, Industrial Applications