Mono-Dispersed Droplet Delivery in a Refrigerated Wind Tunnel

An aircraft may experience inlight ice accretion and corresponding reductions in performance and control when the vehicle encounters clouds of super-cooled water droplets. In order to study anti-icing coatings, the EADS-IW Surface Engineering Group is building a refrigerated wind tunnel. Several variations of droplet delivery systems were explored to determine the most effective way to introduce mono-dispersed droplets into the wind tunnel. To investigate this flow, timeurate, unsteady viscous flow simulations were performed using the Loci/CHEM flow solver with a multi-scale hybrid RANS/LES turbulence model. A Lagrangian droplet model was employed to simulate the movement of water droplets in the wind tunnel. It was determined that the droplet delivery system required pressure relief to properly orient the flow inside the droplet delivery tube. Additionally, a streamlined drop tube cross-section was demonstrated to reduce turbulence in the wake and decrease the variability in droplet trajectories in the test section